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Immunotherapy in MSS Colorectal Cancer

ERASur trial: Local treatment options for limited stage IV CRC

DocTalk
2023
Ablation
Liver
Lung
MSS
Radiation
Stage IV
Surgery
Trials

Dr. Kathryn Hitchcock from the University of Florida, Dr. Eric Miller from Ohio State University and Dr. Paul Romesser from Memorial Sloan Kettering Cancer Center discuss new standards for ogliometastatic colorectal cancer treatment with Paltown Scientific Director Dr. Manju George. Recorded in March 2023.

Manju George 00:00
Hello, everyone. Welcome to Doc Talks. I’m Doctor Manju George, the scientific director at Paltown Development Foundation, the nonprofit that supports Colontown. Today, we have the privilege of having the principal investigators of the ERASur trial with us to tell us about their trial. So I will turn this over to the panel. Dr. Miller, do you want to introduce yourself?

Dr. Eric Miller 00:26
Thanks, Dr. George, I’m Eric Miller, I’m one of the radiation oncologists at Ohio State University.

Manju George 00:32
Dr. Hitchcock?

Dr. Kathryn Hitchcock 00:34
Thank you, Dr. George, thank you so much for having us here today. My name is Kate Hitchcock. I’m a radiation oncologist like Dr. Miller is, and I practice down here at the University of Florida, Go Gators.

Manju George 00:46
Thank you very much for joining us. So we can get started. I think Dr. Romesser is in clinic. So he’ll be joining anytime soon. So let’s get started so we don’t waste any time.

Dr. Kathryn Hitchcock 00:56
That sounds like a great plan. I’m hoping that we will get a lot of good questions at the end here. So we’ve intentionally written our talk to leave lots of time for good discussion in case folks are inclined toward that. So I’m going to start us off here, and the first thing I’m going to do, Eric, if you don’t mind flip into the next slide, is talk about what it is that we’re treating here. This study, the research study is designed to treat all oligo metastatic colorectal cancer. Oligo metastatic is a word that came about not too long ago, to describe a situation where a patient does have metastases from their cancer, but there’s only a few of them. And that’s what that word oligo means it’s from the Greek word meaning just a few or little. And the reason we needed a word for that, and the reason it was a new word is that up until you know not that long ago, 10 or 15 years ago, people really believed that if you had any metastasis anywhere in your body, that it was a signal that the cancer had spread to all of the parts of your body and that the cancer was there for incurable. We know now that in many, many cases, that is not true that there is a state in many cancers where yes, the cancer has metastasized to a new place. But if we are really careful and a little bit aggressive in treating that one place, or a few places that we can still cure the cancer, and colon and rectal cancers are definitely the prime example of this, I would say that this is the disease that people always think of first, when they think of curing folks with oligo metastatic disease.

And so some smart and brave people started really trying to cure the patient in that situation that started out with resecting metastases in the lungs that were because they were easy to see even when our imaging was not so good. And you can see we’ve given you some references there, we’re showing where people were resecting metastases from sarcomas and also from colorectal cancer. The liver then was the next one after MRI became common, and it was easy to find liver metastases, people started resecting those and the reason the liver and the lung were the places we started is that you can live without quite a bit of those two organs, you’ve got a lot more capacity for lung than you really need. So if somebody needs to take some out, you’re still going to do well afterwards and not have breathing problems.

You might know that your liver is one of the few parts of our body that grows back completely. That’s why we can donate part of our liver to someone else. And that part of the liver that’s taken out regrows. So if we do a surgical resection on part of the liver, it’s okay, you’re going to be fine with the liver that’s leftover if it’s done skillfully. And then that part of the liver will regrow. So that’s how things got started.

And ready for the next slide, Eric.

So we have some really, really good technologies now that give us lots of different tools to try to address these oligo metastases. As I explained, this started out with surgery, but there’s places where you can’t do surgery or maybe the patient just doesn’t want surgery to their body and all of the effects that that has. With the other options that we have our SBRT (stereotactic body radiation therapy), which means very intense, very focused radiation therapy to kill metastases. There’s also ablation that can be done in a lot of different ways. You see that in the middle panel on this slide that involves putting a probe into usually the liver in order to kill a metastasis or multiple metastases there. And of course, we still can do surgical resection. And it’s not uncommon for patients to need a combination of two or more of these techniques to address all of their sites of metastasis.

I’m so happy to be alive in a time in which we’ve started to really accumulate lots of data that shows that those techniques that I just described, you really do help. And we’ve shown you some panels from a couple of different studies here, showing that if you do go after liver disease here in the leftmost graph, or lung only disease over here on the right, this is patients who had metastases in their liver that was unresectable. And so they were being treated with a combination of surgery for the resectable ones, and that ablation technique for the ones that weren’t resectable.

And I think you can see here, if you look at these graphs, that there is a big difference in what happened to patients who got that intense local therapy, and those who didn’t, you don’t have to be a statistician to see that those two lines are not on top of each other. And what that means is, when they went after these oligo metastases, and really treated them aggressively, it helped patients a lot. Even though, let’s see, these studies were published in 2017. So you got to figure they started probably writing the studies in about 2007. And even, you know, five or six years before that, it would have been very difficult to convince anyone to go after these metastases with surgery or anything else. So this was a big revolution in the way that we treat cancer. This was a very, very big deal.

All right, I’m ready for the next slide, Eric, thank you. So the beautiful thing that’s happened even more recently is that we’ve been able to show that SBRT that intense radiotherapy also does an excellent job of treating oligo metastases. And it has been doing that for a long time, we’ve been using SBRT in this way for a long, long time. Now, unfortunately, there’s lots of radio phobia out there in the world, even among very educated people, like physicians. And so it’s been harder for people to accept using radiation treatment, like it often is. But it’s a great tool, because it’s the only one of those three techniques I showed you, that doesn’t involve poking any holes in your body. It doesn’t involve any blood loss or risk of infection. And my patients, when I treat them with this technique for oligo metastases do very, very well, it’s extremely uncommon for them to have really any side effect other than fatigue. So it’s exciting these graphs that you see here showing that when we use SBRT to treat oligo metastases, we get those same excellent results that you saw on the previous slide, for surgical resection and for ablation, and that’s what the study that we’re going to talk to you is all about. And then I hand it off to Eric, I think are you the middle slides here?

Dr. Eric Miller 08:08
Yep. Thanks, Dr. Hitchcock. So as Dr. Hitchcock really still skillfully described, we know the standard of care for patients who have a liver metastasis. If you remove that liver metastasis, either with surgery or with another ablative technique, we know that those patients do very well. And even a subset of those patients can be cured, so it can go a long period of time before any other type of cancer shows up anywhere else. So we know that there’s a benefit to local therapy in this patient with the liver metastasis. Our question is, what if a patient has a little bit more metastatic disease? What if they have two lung metastases in the liver metastasis and a lymph node metastasis? What is the role of local therapies such as radiation and ablation and surgery for that type of patient? And, really want to answer the question of why do we need a trial in this space? So right now, to date, there has not been a study looking at the use of multi modality and when I say multi modality, I mean, the use of radiation or ablation or surgery for metastatic directed therapy for colorectal cancer, and it really has not been done to date in a systematic manner. And the reason why it’s important is that, as Dr. Hitchcock described, imaging is improving, we have better techniques to find cancer and to detect cancer, we have better therapies to treat cancer. And so the use of that type of therapy outside of studies is rapidly expanding. And rather than it being really evidence based, there’s really no science behind treating that type of distribution of disease. It’s really provider bias rather than evidence-based and we all know that you really want evidence to prescribe a treatment. And so the benefit of extending the treatment paradigm that we have for patients with liver-only disease, where we know there’s a benefit, the existing paradigm for patients with more extensive disease is currently undefined. And you really have to balance it with any potential toxicity from the treatment. And so our trial ERASur is really hoping to fill this knowledge gap. And we’re designing what we think is a practical multimodality approach that mirrors the current clinical dilemma that we’re in.

And so this is our study. It’s a pragmatic randomized phase three trial, evaluating total ablative therapy for patients with limited metastatic colorectal cancer, evaluating radiation ablation and surgery. It’s called the ERASur trial. And it’s a joint trial between Alliance and NRG oncology, two different cooperative groups, national cooperative groups focused on on developing better cancer therapies. And we’ve really assembled a really great group of individuals with a lot of talent and expertise in different disciplines to help answer this question and conduct this trial.

So the primary objective of a ERASur is to evaluate and compare survival in patients with newly diagnosed all oligo metastatic colorectal cancer treated with total ablative therapy. And what we mean by total ablative therapy is treatment of all sites of disease using radiation, with or without surgery, and with or without ablative therapy with heat, adding that to chemotherapy versus just chemotherapy alone.
Number of secondary objectives for the trial as well, including looking at event free survival. So progression of the cancer, looking at safety of the treatment, as well as time to local recurrence meaning return of the cancer where it was where the individual local therapy was delivered, so a local recurrence of the cancer.

So this is the design of this study. So it’s including patients with newly diagnosed limited metastatic colorectal cancer and Dr. Romesser is going to talk about what we’re defining as a site of disease, but it’s for fewer sites of disease. On the initial baseline imaging that includes CT scans, the primary tumor, so the colon or rectal primary tumor must be either already removed or able to be removed, BRAF wild type or microsatellite stable disease. Patients can’t have liver only disease because we really, we know the paradigm for that already exists. But surgical resection or local therapy is beneficial in that patient population. So patients receive systemic therapy for four to six months. Those who progress on first-line chemotherapy are removed from the protocol because we know those patients should consider alternative therapy. And then patients who do have residual disease, meaning that there is still disease visible on subsequent CT scans. Following induction systemic therapies, that four to six month period of systemic therapy, patients have been randomized to continue standard care, systemic therapy, or the addition of total ablative therapy. And that, again, is ablative of radiation with or without surgery, and then with or without microwave ablation. And the primary endpoint of this study is overall survival. So I’m going to turn it over to Dr.Romesser to talk about the eligibility criteria.

Dr. Paul Romesser 12:54
Good afternoon, everyone. I hope everyone’s having a nice day. Thank you for joining us. So thank you, Dr. Hitchcock and Dr. Miller. So when we’re thinking about eligibility criteria for this study, we definitely want to limit it to metastatic colorectal cancer patients who are not known to have microsatellite unstable tumors, because those are patients who would likely benefit from a different type of therapy, largely immunotherapy.

We don’t want them to have known BRAF mutations where they might benefit from the BRAF inhibitors. No known peritoneal or omental metastases just because that’s not something that we can treat from a localized perspective. That takes a different type of treatment. And the primary tumor, the primary colon or rectal tumor needs to either have been surgically resected or amenable, to resection as part of this paradigm meaning that we have to address not only metastatic disease, but any localized or primary disease as well.

Patients can have up to four or fewer sites of metastatic disease, and we’ll talk about what a site is, but liver-only diseases not permitted largely because the studies that Dr. Hitchcock showed at the beginning have really reported on excellent outcomes where a subset of patients can have very prolonged progression-free and overall survival, are essentially cures as we see them. And so we don’t think we need to reestablish the you know, the wheelhouse there.

And then patients can have a maximum of four months of systemic therapy. So for registration, the patients can have any progression on induction chemotherapy, they can’t be eligible for hepatic arterial infusion pumps, which are gaining momentum and traction around the country. They must have measurable disease on imaging. And again, a minimum of four months of systemic but maximum of six months so really have to come in right in that sweet spot for eligibility.

And if they had prior definitive or curative intent treatment like such as stage two or stage three disease, they must be greater than 12 months out or greater than 12 months out from completing that, that treatment. No pregnant patients and everyone must be older than the age of 18 with a good performance status and labs as shown here.

Sorry, my eyes watering. So what’s a metastatic site? So it’s interesting, it’s, it needs to be radiographically evident, you know, biopsy or pathological confirmation is not required, but the patient does need to have a diagnosis of metastatic colorectal cancer, then lesions must be amenable to any combination of surgery, microwave ablation, which is the interventional radiology technique and or stereotactic body radiotherapy. Which is SBRT or stereotactic ablative radiotherapy, which is saber, they mean essentially the same thing.

So what’s a single site? Well, each side of the liver, we have a right and left side of our liver. So that’s the right side would be one site, the left side would be another site. Each lobe of the lungs is a site. So in the right lung, we have three lobes and the left lung, we have two lobes, and different organs like each adrenal gland with two adrenal glands on either side of her body, and those would be considered each of them a single site. Lymph nodes are a little bit harder to define, because lymph nodes obviously can be next to each other or spread out. But if the lymph nodes are amenable to single surgical resection, or can be treated in a single saber radiation field that would compromise a single site and bone metastases amenable to treatment in a single saber field by a single site, and we left it intentionally not overly restrictive, or, or, you know, confining, to allow us the flexibility of the sites of the of the centers, or the doctors to kind of have flexibility and kind of determining, you know, who is a good patient and to what level can we can we enroll them at.

So their study interventions, the control arm, you know, it is a randomized study. So patients will be randomized to either control or the experimental arm, the control arm is going to be continuing the standard of care chemotherapy. We allow maintenance chemotherapy, as well as local metastatic directed therapy for patients who have, you know, pain, discomfort or need palliation.

But for lesions that are not not causing any symptoms, we don’t allow local therapy. And that’s really kind of the standard. On the experimental arm, we give up to three months, to essentially complete what we call total ablative therapy, which is again, surgical resection, microwave ablation, or saber to all sites of disease. And thereafter, we ask the physicians to reconsider starting chemotherapy, as is. Again, chemotherapy breaks on both arms are permitted at the discretion of the primary team and this often do occur in the real world. And so it’s meant to be somewhat pragmatic in terms of mirroring what’s happening in the real world setting. But really looking at the addition of TAT or the total ablative therapy in this cohort.

For correlative study perspective, we’ll be asking patients to agree to allow us to bank their blood for future CT DNA studies. And I want to point out, you know, one thing that Dr. Hitchcock Dr. Miller and I were really, I guess, proud about and enthusiastic about, you know, we approached Dr. George, who you all know, early on and said, We’re designing this trial, but it’s important for us to hear from patients, it’s important for us to get the patient input. We wanted to know, a) was this something that they’re interested in was this enthusiasm. And also, we ask very pointed questions about what would they prefer? And in what order and to what degree they thought, you know, we should let patients enroll and what sorts of different types of treatments they would would agree to. And so the the patient perspective and the patient input for this trial was absolutely critical.

And it’s critical from an early early development time point. So I want to thank Dr. George, the entire COLONTOWN family and Paltown on behalf of all of us in terms of helping us with the trial design, and I think that’s really something that I know that we’re all very proud of. Separately, I just want to point out that your input helped us get this trial through and approved. 90% of you responded and said you would consider enrolling on this trial. 70% of you were enthusiastic for a potential treatment break. In terms of considering maybe omitting maintenance chemotherapy, in the setting of using maybe ctDNA analysis. Unfortunately, the National Cancer Institute and the GI steering committee felt like that was pushing the envelope a little bit too much, and they kind of dialed it back. But that’s something we’re going to look at in the correlative studies, and something we’re gonna consider for future studies down the road. And having something like this, where we’re showing 90%, enthusiasm, 70% enthusiasm, this is unparalleled. And I just want to really highlight that this made a really big deal. And it was incredibly impactful when we brought this to the National Cancer Institute, in terms of showing feasibility, enthusiasm, and overall, you know need for the trial. So thank you very much. So with that, I want to invite Dr. Hitchcock and Dr. Miller to kind of chime in here as well. And just really wanted to say we want to answer your questions. We want to bring up, highlight the trial. But we wanted to come here to thank you, most importantly, for your input with the trial design, and we hope they will continue to support us and guide us as we lead this trial for next couple years. Dr. Miller, Dr. Hitchcock,

Dr. Kathryn Hitchcock 21:44
I think we started to get some questions here in the chat. So if it’s alright with you, Dr. George, I’ll start working our way down the list here.

One question, when do you expect the sites to start recruiting? The study is officially open. And there are sites all over the country right now that are working on getting it open, you would be appalled if you saw how much paperwork it takes just to make it possible to treat somebody on a study like this. So I think everybody everywhere right now is in the process of getting this through the Institutional Review Board where they are, meaning the people who take a look at studies to make sure that they’re going to be done ethically and are going to respect the the rights of the patients who might be treated on this study. And the minute that’s approved, we’re ready for action, we’re so enthusiastic to start getting patients on the treatment on this trial.

Manju George 22:45
Dr. Hitchcock, I was kind of wondering that, since the video will be posted and this trial is now in the feature trial sections on COLONTOWN University, it would be kind of nice to know, you know, if you if someone can give us a list of what places they’re open, we will be happy to put it up on the website. So that I think this is a question that we often get from patients like they want to know where it’s open so they can talk about it. So that’d be nice to know, like as you get information on, you know, where all it is open?

Dr. Kathryn Hitchcock 23:16
That sounds like a great idea. And I think probably the smart thing would be I think there will be the Alliance cancer research group is the lead on this. Probably we can find a link to their page that it shows which sites are open, we’d be happy to pass that over so we can drop that into the site.

Manju George
Yes, that’d be great.

Dr. Paul Romesser 23:39
Yeah, is probably the day. So having a site I think would be critical. So Dr. Miller,

Dr. Eric Miller 23:45
Thank you. So also, I think on the colon cancer website where it’s a feature trial, there’s a link to the clinical trials.gov site. And that actually will contain, once sites are open, that will contain where all it is going to be open or where it’s open right now. It takes a little bit, a couple of months for it to actually get open. So we’re getting closer.

Manju George 24:08
Okay. I think there’s a question about the sites.

Dr. Eric Miller 24:12
There was a question about this four or fewer sites mean, you could have more than four spots, and that’s as long as they were confined to less than four sites.

That’s exactly right. That’s how you interpret it. So you can have, for example, in the right upper lobe of the lung, you can have two or three individual mets or lesions there. And that would be considered as one site. So that is under percent correct.

Manju George 24:35
For the patient that had a recurrence after curative intent liver resection be eligible?

Dr. Kathryn Hitchcock 24:40
Yes, they would. There’s a time limit a certain amount of time has to pass between that curative attempt and being treated here but it would definitely be worth looking into this study in that situation.

Manju George 24:55
I think the next question is about somebody from New Zealand. Would you consider patients located outside the US?

Dr. Kathryn Hitchcock 25:04
Absolutely, yes, in the United States, it always just comes down to how the hospital is going to get paid. So as long as that end of things could be worked out, I don’t see any reason that we couldn’t treat somebody from anywhere. We would love to take care of that patient.

Manju George 25:23
Yeah. So the next question is, would the patient have to have primary resected? I’m not clear on amenable to resection. What does that mean?

Dr. Kathryn Hitchcock 25:32
So great, great question. So it either has to be resected, before they get into the trial, or in the early period of the trial, it has to be resected. So amenable to resection, means it’s possible to be resected. And the patient agrees to have their primary tumor resected. Because the question that we’re testing is in people who don’t have their primary tumors still sitting there as a source of potential new metastases.

Manju George 26:05
I was kind of wondering, could you go back a couple of slides, where you had the control arm and the experimental arm?

Dr. Eric Miller 26:12
Yeah. Which one do you want to look at?

Manju George 26:15
I think there was one where you had on the left side, you had control? Yeah, that’s the study interventions. Yeah. So I was kind of wondering, can we think of a hypothetical patient, and then kind of go through each step? how that would be so that people are really clear about, you know, how this is happening. So let’s say I’m a stage four patient, and I have, you know, a primary tumor in my colon, and then one or two mets in my liver, couple of lymph nodes in the abdomen, and then one or two spots in the lung? So do I register now? Or, like, Could you walk me through that?

Dr. Eric Miller 26:53
Yeah, I can, I can try to tackle that one. So we actually designed it so that you can register, really any anytime during that initial six month period. So you can register before you start chemotherapy. Or you can register and that would be called pre-registration. Or you can register after that four month chemotherapy period and register at that point. So you can kind of register all throughout induction chemotherapy. But essentially, you would finish at least four months of chemotherapy, you’d register to the trial. At that point, you would then, you know, make sure that you’d meet all the eligibility criteria, you know, the lab values, make sure everything else is in order. You would have restaging imaging. And the one thing that we had talked about, kind of maybe glossed over a little bit is to make sure that there’s still something to treat. So if everything disappears on that restaging imaging, that’s great. But that would mean that you may not need local therapy, and we want to make sure that we know what we’re treating. And so there needs to be something that we can actually see on the imaging to treat. And so at that point, then you would be randomized for patients who still have something there’s a lot to treat, you’d be randomized to either continue chemotherapy, or local ablative therapy or TAT plus chemotherapy. There is some time built in there where you could get additional chemotherapy if necessary. We allow up to 90 days to get the total ablative therapy done. And so you work with your primary team, if you randomize to the TAT arm, with your primary team to figure out the best combination of therapy to treat all areas of disease. If you randomized to the chemotherapy alone arm then you would continue with chemotherapy. And then after you finish that treatment, you would then follow up with routine imaging scans and blood tests as you would off of this study. Did I miss anything? Dr. Hitchcock or Dr. Romesser? Sorry.

Dr. Kathryn Hitchcock 28:53
No, I thought that was a great explanation.

Manju George 28:55
Okay, so can I ask some questions about it? So when people are getting chemo, they can get anything they can get FOLFOX plus the biologic. If some patients wanted FOLFOXIRI, they would still be able to get that too.

Dr. Kathryn Hitchcock 29:12
Right or Yeah, okay. Yeah. And then we fought really hard for that. There were folks or advisers along the way that wanted us to specify, but we wanted people to have lots of lots of options, especially since everybody’s situation is different.

Manju George 29:25
Okay, okay. That sounds good. And then so, so you get like four months of chemo. So let’s think of my case. So I got four months of chemo. And then I had imaging and, you know, one month in my liver is gone. The lymph nodes have shrunk down, I can’t find anything on my lung. So I have now mets in the liver and, you know, the lymph nodes. So which means I can still continue with the local ablative therapy, right?

Dr. Kathryn Hitchcock
That’s okay.

And then I have 90 days during which time I can get radiation to the lymph nodes. Maybe have some thing down to the liver. And then I have that much time off chemo then is that what is meant, like in that 90 day period, I can get all the local treatments done.

Dr. Kathryn Hitchcock 30:09
Exactly. Because most of the time, if you’re doing these more concentrated therapies, you don’t keep chemo going, you want to make sure the body has a chance to recuperate from what it’s been through. So you get a chemo break during that time. Exactly. Right.

Manju George 30:24
Okay. And then after that, after the 90 days, you have one imaging, is it?. Okay, okay. And then you can continue with the, you know, either maintenance. So, let’s say after the imaging, there is nothing seen on scans, and you also have blood draw for ct DNA, and then you can, so I can talk to my care team. And, you know, if all the lesions are gone, I can go back to maintenance, just get Cape Bev and continue or if I wanted to take a treatment break, would it be possible to take a treatment break too?

Dr. Kathryn Hitchcock
Absolutely, yes.

Manju George
Okay. Okay. Okay. And then you’re going to watch me to see when those lesions come back, or if I have additional lesions? That’s, that’s what you’re trying to look at ?

Dr. Kathryn Hitchcock 31:05
Correct, exactly. Okay. Okay.

Manju George 31:07
Thank you very much. This was this. This was very clear. Let’s see if there are other questions. Okay. Paula has a question. If there is a large tumor considered to be one tumor, but in both the right and left lobe of the liver, Does this qualify as two sites?

Dr. Eric Miller 31:25
Good question. Actually, we didn’t think of that scenario, but I would probably kind of just two sites.

Dr. Kathryn Hitchcock 31:30
I think the way we have it written it would probably count as two,

Dr. Eric Miller 31:35
It’ll be a judgment call, but probably too, to go back. Just one thing to add to the I think that was a great explanation. Dr. George a great thought experiment of going through the trial, but so you would have 90 days to finish TAT. And then the first imaging time point is really one month after finishing TAT. So you finish TAT, let everything kind of calm down. And then 30 days after that is the first imaging time point. And then it’s it’s every three months that you would kind of do normally. But yeah, everything else was exactly correct.

Manju George 32:09
So Betsy has a question. Could I get the slides to post deliver Lovers Lane, Langston, and Legos land? So these are called on groups for different mets?

Dr. Kathryn Hitchcock 32:21
So yeah, yeah, absolutely. Yes. Yeah.

Manju George 32:22
Thank you so much. This was very helpful, especially, you know, walking us through a scenario that was, that was really helpful. Let’s see if people have other questions. They have plenty of time. Yeah, Brain mets? Are they eligible?

Dr. Kathryn Hitchcock 32:39
Unfortunately, no, we went back and forth about this early on, and they would not let us include folks with brain metastases.

Manju George 32:50
Okay. Okay. And then I had this question about CtDNA. So are you planning certain time points like how’s that being planned?

Dr. Paul Romesser 32:59
We built in specific time points we’re working, we’re asking all the sites to draw blood for ct DNA analyses. So they’ll draw the blood, spin it down and send it to a central repository, which then we can actually go through and do the analysis after the trial is complete. So they are standardized, there’s four or five of them throughout the trial, that are pretty well standardized. So that’s something we’re hopeful that patients and sites will enthusiastically participate in.

Manju George 33:35
Okay, so the only thing like I what you explained with the GISC not thinking not allowing ctDNA testing. So if it’s going to a central facility, that means that people won’t be able to, you know, you’re probably not analyzing it during the trial, is it?

Dr. Paul Romesser 33:52
Correct or not analyze it during the trial. Now, that’s not to say that, you know, there are some centers that are routinely using ctDNA, and they may still want to continue their standard practice, others aren’t doing that in the metastatic setting. So we’re not here to, you know, opine on that or to prevent anyone from using it. But from a scientific perspective, we won’t be able to use an external ct DNA test that that site is using, but if we have a little bit of that blood bank, we can go back and with, you know, one or two vendors, go back and do the analysis for the full whole cohort. And we’re certainly very enthusiastic that it may identify or help us identify patients who would maximally benefit from these types of interventions in the future.

Manju George 34:47
Okay. Okay. So just, not to put you on the spot. But just to ask, so what when you said that if there was a site that was already using ctDNA testing for these kinds of patients, then those patients would get the results? So but the blood would be banked and that banked blood is what you will do for your analysis for the trial endpoints. Is that what you meant?

Dr. Paul Romesser 35:09
Yeah, so the bank blood is just banked. It’s not analyzed in any patients upfront. But if a doctor at Site y, for example, routinely sends ctDNA on their patients, his or her patients, he or she can still on their own accord, draw an additional tube of blood and send it for real time ctDNA analysis. Okay, that’s just not part of the trial will be included in a trial, and that’s not data that we collect on the trial.

Manju George 35:41
Okay, okay. Okay. So, sorry to belabor this, but what it means is that if the patient is in a center where they routinely use ctDNA, then they will be able to get the results of the ctDNA testing too, but if it’s not, then they won’t have the data because that data is not analyzed till the end of this trial. Right. Okay. Okay. Yeah, it’s good to know, because we didn’t want patients to be confused, you know.

Dr. Paul Romesser 36:08
Put a maybe a little bit more clearly, there’s their no ctDNA, patients will not get any ctDNA information or testing done. In real time on this trial, any ctDNA testing that they want done on the trial is outside of the trial and their provider will have to do that separate.

Dr. Kathryn Hitchcock 36:33
Okay. But with that said, they can still make decisions based on that we’ve intentionally left it. So whatever information you have with your care team, whatever decisions you are going to make, normally, we’re not stopping you from making that decision on this trial. We tried to make it as unrestrictive as we could, so that we weren’t taking any options off the table for anybody.

Manju George 36:58
Okay, that’s absolutely, yeah, I think that’s a great point. Because I think that’s where I was trying to get to that, I mean, the design is in such a way that, you know, it allows the maximum flexibility. And for every patient, wherever they’re located based on what their care team is doing, they can actually use the, you know, the tools that are available in the child, but then they have the care that is almost tailored to how they are getting it anyways. Right? Yeah. Okay. Paula has a question, how does insurance handle this trial? Can the patient remain where they live? Or would they need to be at a specific center long term?

Dr. Kathryn Hitchcock 37:35
The beautiful thing about this is, you have to be treated at a site that has the study open. So you can’t enroll in this study at one hospital and then go get your ablative treatment at another. However, you can get your chemotherapy someplace else. So we were hoping that would for patients who don’t have an enrolling hospital near them, they could come and get enrolled and get their local therapy if they were assigned to that arm and then go back home and get their chemotherapy and not be stuck anywhere for months and months getting chemotherapy. But any center that has the trial open can do the local therapies. There’s not one or two sites, we’re hoping to have, in fact, quite a few sites. So hopefully, there’ll be one close to everybody who wants it.

Manju George 38:28
Okay. Okay. Thank you very much. That’s a great point. Great question, Paula. So basically, so I will just summarize what you said. So chemo, if I’m a patient enrolling in the trial, I can get the chemo at my local wherever I get my treatment, but I have to enroll at a place where I will get the local therapies, right, the local ablative therapies that has to be done at a center that’s close by and from what you’ve explained, that’s only for the short duration of time, whether I’ll have that local surgery or the ablation, or the radiation that I’ll go to that center, have it done, and then I can come back and continue all the rest of my treatments here. What about imaging? Where will I have to do the imaging?

Dr. Kathryn Hitchcock 39:11
Imaging can also be done close to home.

Manju George 39:15
Okay, great. This is this is really very, very patient friendly and patient centric design.

Dr. Kathryn Hitchcock 39:21
Exactly what we were going for. Thank you, you just made our day by saying it. And again, that’s because you all weighed in and made your opinions known. Without your input. We could never have made it that way. We’re so grateful for the time that people took to educate us on that.

Manju George 39:39
So what else can we do to spread the word about the trial, like, how can we help?

Dr. Paul Romesser 39:44
I think we just want patients to know about it. That it’s an option, that it’s maximally flexible, it’s pragmatic. We’re not here to put up barriers, we’re here to break them down. And we hope that you know, even if the trial is not open where your primary site is, you’ll talk to your doctor about it. And we can link you up with some, you know, locations where it’s open. And, we hope to see that, you know, it’s not only at big kind of cancer centers, but that it’s kind of spread out around the country, and patients kind of come in for, for this trial to seek out TAT, or at least to help assess the question.

Manju George 40:32
Okay. Okay. Thank you very much. As I was talking, so we have on COLONTOWN university, we have this diagnostic and surveillance test Learning Center. It’s a different topic. But where I was going with this is that, so we had like, for example, when we started when patients started using Signatura, not everyone was ordering the ctDNA test. But then what we did was that we asked patients to let us know where all they were getting the test. So then we actually put up a list of centers where they were getting the tests. So any new patient, when they wanted the tests, they could go and check to see whether there was a center close by. So I think that one of the things that we can do to facilitate, you know, people knowing about it is, as soon as you know that there is a site open or you know, certain techniques can be done in a particular place, if we can provide a list, you know, where all what is available, then that would be very helpful, because then people could go and click on it and find out, you know, how far it is for them. And I think that might facilitate, you know, more people knowing about it and enrolling. So that should be something that we could do on COLONTOWN University.

Dr. Kathryn Hitchcock 41:41
That sounds great.

Dr. Paul Romesser 41:43
And I’ll add one more thing some big centers have, like I know, in New York, and I’m not trying to plug my own Center, but I know in New York, we have the American Cancer Society has something called the Hope Lodge, which is a free lodging. So it’s not just unique to my center, it’s available to anyone with cancer, who comes to New York City for treatment. And so there are resources, if there’s not something close to home, where we could find other additional options for patients. And I think there’s many Hope Lodge equivalents around the country, and many great sites that we could try to put together to increase options for patients as well.

Manju George 42:25
I think that’s a great idea. Any other questions, comments? Yeah. So we’ve worked with, you know, Dr. Miller, and Dr. Romesser, and Dr. Hitchcock. So we have this trial design and more details about this trial up on feature trials on COLONTOWN University. So if you wanted to, you’ve heard whatever you heard them speak, and then you wanted to, you know, look at those, the details and, you know, when you have time, you can go over there, and it’s there. And Betsy will post, you know, I think one of you will send me the slides. Right, then I can send it to Betsy and Betsy will post the slides in Lungston. And yeah, in all the relevant metastatic groups, yeah, that would be great. So there are multiple ways that people can know about it. And then the other thing that we’ve been doing in COLONTOWN is that when we have newly diagnosed patient join, when we actually have an onboarding, so we asked them, you know, to tell us about where they are and what’s going on. So when we come to know that they might be eligible for certain trials, then we tell them, that there are these trials, because many times, you know, when patients join, they don’t know anything. And, you know, it’s sometimes they won’t come to know about it. And trials are not, you know, in general, people think that trials are something that, you know, when you have failed all lines of therapy, that’s when they should do it. So we try to tell people about firstline trials like this. So that’s another place that we would be talking about it. Yeah.

Dr. Kathryn Hitchcock 43:56
That is perfect. I’m so grateful that this whole system exists that you guys have put so much work into it. And the good that comes out of that just can’t even be measured.

Dr. Paul Romesser 44:08
Thank you, Dr. Miller, do you want to comment on the insurance and the insurance review that you all did with through Alliance as part of activating the trial?

Dr. Eric Miller 44:19
Yeah, so that’s a great question. So they do an insurance analysis to make sure that aspects of the trial will be covered. And we went through that analysis and everything checked out. Now, of course, you know, before any treatment, of course, they would do a prior authorization to make sure that all treatment would be covered. But there really isn’t anything on this trial that is really experimental, all the local therapies or established therapies that would be covered by insurance. Yeah, that’s a great question. Great question.

Manju George 44:55
One of the things I think we can also do is, as people start, you know, six months A year from now. And when we find like, we also have in COLONTOWN, Betsy is one of the Cabinet members. So we have a group of patients and caregivers who run the day-to-day activities in COLONTOWN. So we have something called the Alanna project, which is basically a place where we keep track of who all are in what all trials, and, you know, they will post updates. So if they have a clean scan, they’ll post if they have a progression, they will post so this way, you know, when a new person who wants to find out about trials, they can go and look in the Alanna project and find out if other people have been on the same trial and what their experiences are. So once we, you know, a couple of, you know, one year or something after the trial is open, we’re hoping that we will get to hear from patients, right, how this is going, if there are concerns? So I’m hoping that we can bring that back to you. And you know, if there is something that is in the way, maybe I don’t know, you can do an amendment or, you know, you can at least find out if there are ways to help, you know, for people to get over that block, whatever that is, right?

Dr. Kathryn Hitchcock 46:08
Yes, if there are barriers, we really want to know about them as soon as possible. Because you’re right trials, it’s not like you write a trial, and it goes through as written from the beginning. There’s always amendments, when we figure out that something didn’t work quite the way that we thought it was going to. So please, that would be wonderful. If folks would communicate with us in that way.

Manju George 46:30
We can, we can certainly think of collecting information, because I think, overall. So I would like the three of you to tell us, you know, how, you know, in your mind, like when we have the results? What are you hoping for the field from this trial? You know, like, how is this going to be practice changing? I mean, if you could comment.

Dr. Eric Miller 46:50
Yeah, I guess I can, I can start. I think for us, the big thing is just clarifying the role of local therapy in patients who we wouldn’t necessarily think about local therapy for. So if it’s shown to be beneficial, then we should be offering this therapy to more patients. So one of the impetuses for this trial was that, for the for the vast majority of metastatic colorectal cancer patients, you know, there aren’t really new drugs right now, you know, systemic therapy is sort of at an impasse. And so if we can come up with a different method, we can offer local therapy and improve survival, we need to figure out the patient population that’s going to benefit. And the kind of converse of that if we’re doing things that aren’t helpful, that are just adding toxicity and increasing the cost to patients. And we probably shouldn’t be doing those things. I’ll turn it over to Dr. Hitchcock & Dr. Paul Romesser.

Dr. Kathryn Hitchcock 47:43
Now, I’d say part of that we’ve kind of touched on today in that. I know a lot of patients in the process of dealing with this specific disease situation, don’t ever get a treatment break. And that was kind of where the idea came from originally, not just the chance for curative potential. But if that doesn’t happen, are we able to at least give patients a long, meaningful period of time where they’re not constantly in the hospital and dealing with doctors. So at the very least, we’re hoping we can achieve that.

Manju George 48:15
Dr. Romesser, do you have something to add?

Dr. Paul Romesser 48:19
I think they summed it up really well. I mean, it’s, I think whether it’s unique, and that whether it’s positive or negative, I think it’s going to impact how care is administered. Obviously, we spent a lot of time working on this, and we’re very passionate, we have every reason to believe this is going to be positive. But I think we can learn from both ways. And so we’re just really kind of humbled by the opportunity to run this trial and to offer this to patients.

Manju George 48:53
Thank you. I think that one question is, Is this only for first-line patients? Or is this also for patients who have had other treatments?

Dr. Paul Romesser 49:02
It’s predominantly first-line unless they had other treatment for stage one, two or three colorectal cancer?

Manju George 49:11
Okay, so I was thinking that like, I really liked what, you know, all three of you said, so, from a patient perspective, what you’re really saying is that right now, when somebody is stage four, you know, we hear this chemo for life, right? That’s what we hear for a lot of patients. So basically, what you’re trying to do is, you’re trying to break that big group of stage four patients into smaller subsets, to see if there is a group that you can treat many of their mets locally, so that they don’t have to be on chemo for life. They have these treatment breaks and hopefully, you know, the best-case scenario would be they’re cured by it. The worst case scenario is that they get a treatment break and the disease comes back after a long period of time. So then, you know, that is essentially a long chemo break for them, and that adds to their overall survival. Have I kind of summarized it?

Dr. Kathryn Hitchcock
That’s it. Exactly.

Manju George
Okay, thank you. Any any parting comments from the listeners?

Betsy Post 50:14
This is Betsy and I am the Community leader for the metastatic groups. And I’m really excited about this trial. And for all the reasons that you said, and I’m just, I don’t know, this is exciting. And I think patients are going to be very excited about the trial, and I’m happy to share the information. And you know, especially with the initial onboarding, we do get a good sense of some of these patients and the extent of disease and, you know, try to talk to them immediately. Because it’s such a good opportunity when they come to us new, and you’re able to talk to them about treatment options. And so I think, you know, this is great. I mean, it’s, I keep saying exciting, but I am excited, because I’ve been doing this a long time. And I think that there is a real need for this. It needs to happen, like you said, so I’m appreciative of all you’re doing.

Manju George 51:09
Thank you so much, Betsy

Dr. Kathryn Hitchcock 51:12
It’s good to hear you’re as excited as we are. We are on the edges of our seats, for sure.

Dr. Eric Miller 51:20
I think it’s a great point about it being first line and not necessarily thinking about trials when you’re first diagnosed. So I think if we can let patients know about it early to potentially give them an opportunity, I think that is that is exactly what we’re hoping as well. So thank you.

Manju George 51:37
Yeah. Okay. So I think then we can thank everyone, and thank you. Thank you. Thanks to everyone for joining and thank you, doctors, Hitchcock, Miller and Romesser. And I hope that, you know, with all of this, we will be able to tell patients about, you know, we hope to be able to take this information to the most number of patients and, you know, kind of help with enrollment too that, that’s, I hope that’s together, we can, you know, get the trial enrolled and, you know, get everything going quickly.

Dr. Eric Miller 52:18
Thank you. Yeah, thank you so much. We’ll send the slides. Okay.

Manju George 52:23
Okay. Thank you very much. Have a great day. Thank you. Bye bye.

DocTalk
2023
Dr. Hitchcock
Dr. Miller
Dr. Romesser
Ablation
Liver
Lung
MSS
Radiation
Stage IV
Surgery
Trials

Dr. Kathryn Hitchcock from the University of Florida, Dr. Eric Miller from Ohio State University and Dr. Paul Romesser from Memorial Sloan Kettering Cancer Center discuss new standards for ogliometastatic colorectal cancer treatment with Paltown Scientific Director Dr. Manju George. Recorded in March 2023.

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ERASur trial: Local treatment options for limited stage IV CRC

ERASur trial: Local treatment options for limited stage IV CRC

DocTalk
2023
Ablation
Liver
Lung
MSS
Radiation
Stage IV
Surgery
Trials

Dr. Kathryn Hitchcock from the University of Florida, Dr. Eric Miller from Ohio State University and Dr. Paul Romesser from Memorial Sloan Kettering Cancer Center discuss new standards for ogliometastatic colorectal cancer treatment with Paltown Scientific Director Dr. Manju George. Recorded in March 2023.

Manju George 00:00
Hello, everyone. Welcome to Doc Talks. I’m Doctor Manju George, the scientific director at Paltown Development Foundation, the nonprofit that supports Colontown. Today, we have the privilege of having the principal investigators of the ERASur trial with us to tell us about their trial. So I will turn this over to the panel. Dr. Miller, do you want to introduce yourself?

Dr. Eric Miller 00:26
Thanks, Dr. George, I’m Eric Miller, I’m one of the radiation oncologists at Ohio State University.

Manju George 00:32
Dr. Hitchcock?

Dr. Kathryn Hitchcock 00:34
Thank you, Dr. George, thank you so much for having us here today. My name is Kate Hitchcock. I’m a radiation oncologist like Dr. Miller is, and I practice down here at the University of Florida, Go Gators.

Manju George 00:46
Thank you very much for joining us. So we can get started. I think Dr. Romesser is in clinic. So he’ll be joining anytime soon. So let’s get started so we don’t waste any time.

Dr. Kathryn Hitchcock 00:56
That sounds like a great plan. I’m hoping that we will get a lot of good questions at the end here. So we’ve intentionally written our talk to leave lots of time for good discussion in case folks are inclined toward that. So I’m going to start us off here, and the first thing I’m going to do, Eric, if you don’t mind flip into the next slide, is talk about what it is that we’re treating here. This study, the research study is designed to treat all oligo metastatic colorectal cancer. Oligo metastatic is a word that came about not too long ago, to describe a situation where a patient does have metastases from their cancer, but there’s only a few of them. And that’s what that word oligo means it’s from the Greek word meaning just a few or little. And the reason we needed a word for that, and the reason it was a new word is that up until you know not that long ago, 10 or 15 years ago, people really believed that if you had any metastasis anywhere in your body, that it was a signal that the cancer had spread to all of the parts of your body and that the cancer was there for incurable. We know now that in many, many cases, that is not true that there is a state in many cancers where yes, the cancer has metastasized to a new place. But if we are really careful and a little bit aggressive in treating that one place, or a few places that we can still cure the cancer, and colon and rectal cancers are definitely the prime example of this, I would say that this is the disease that people always think of first, when they think of curing folks with oligo metastatic disease.

And so some smart and brave people started really trying to cure the patient in that situation that started out with resecting metastases in the lungs that were because they were easy to see even when our imaging was not so good. And you can see we’ve given you some references there, we’re showing where people were resecting metastases from sarcomas and also from colorectal cancer. The liver then was the next one after MRI became common, and it was easy to find liver metastases, people started resecting those and the reason the liver and the lung were the places we started is that you can live without quite a bit of those two organs, you’ve got a lot more capacity for lung than you really need. So if somebody needs to take some out, you’re still going to do well afterwards and not have breathing problems.

You might know that your liver is one of the few parts of our body that grows back completely. That’s why we can donate part of our liver to someone else. And that part of the liver that’s taken out regrows. So if we do a surgical resection on part of the liver, it’s okay, you’re going to be fine with the liver that’s leftover if it’s done skillfully. And then that part of the liver will regrow. So that’s how things got started.

And ready for the next slide, Eric.

So we have some really, really good technologies now that give us lots of different tools to try to address these oligo metastases. As I explained, this started out with surgery, but there’s places where you can’t do surgery or maybe the patient just doesn’t want surgery to their body and all of the effects that that has. With the other options that we have our SBRT (stereotactic body radiation therapy), which means very intense, very focused radiation therapy to kill metastases. There’s also ablation that can be done in a lot of different ways. You see that in the middle panel on this slide that involves putting a probe into usually the liver in order to kill a metastasis or multiple metastases there. And of course, we still can do surgical resection. And it’s not uncommon for patients to need a combination of two or more of these techniques to address all of their sites of metastasis.

I’m so happy to be alive in a time in which we’ve started to really accumulate lots of data that shows that those techniques that I just described, you really do help. And we’ve shown you some panels from a couple of different studies here, showing that if you do go after liver disease here in the leftmost graph, or lung only disease over here on the right, this is patients who had metastases in their liver that was unresectable. And so they were being treated with a combination of surgery for the resectable ones, and that ablation technique for the ones that weren’t resectable.

And I think you can see here, if you look at these graphs, that there is a big difference in what happened to patients who got that intense local therapy, and those who didn’t, you don’t have to be a statistician to see that those two lines are not on top of each other. And what that means is, when they went after these oligo metastases, and really treated them aggressively, it helped patients a lot. Even though, let’s see, these studies were published in 2017. So you got to figure they started probably writing the studies in about 2007. And even, you know, five or six years before that, it would have been very difficult to convince anyone to go after these metastases with surgery or anything else. So this was a big revolution in the way that we treat cancer. This was a very, very big deal.

All right, I’m ready for the next slide, Eric, thank you. So the beautiful thing that’s happened even more recently is that we’ve been able to show that SBRT that intense radiotherapy also does an excellent job of treating oligo metastases. And it has been doing that for a long time, we’ve been using SBRT in this way for a long, long time. Now, unfortunately, there’s lots of radio phobia out there in the world, even among very educated people, like physicians. And so it’s been harder for people to accept using radiation treatment, like it often is. But it’s a great tool, because it’s the only one of those three techniques I showed you, that doesn’t involve poking any holes in your body. It doesn’t involve any blood loss or risk of infection. And my patients, when I treat them with this technique for oligo metastases do very, very well, it’s extremely uncommon for them to have really any side effect other than fatigue. So it’s exciting these graphs that you see here showing that when we use SBRT to treat oligo metastases, we get those same excellent results that you saw on the previous slide, for surgical resection and for ablation, and that’s what the study that we’re going to talk to you is all about. And then I hand it off to Eric, I think are you the middle slides here?

Dr. Eric Miller 08:08
Yep. Thanks, Dr. Hitchcock. So as Dr. Hitchcock really still skillfully described, we know the standard of care for patients who have a liver metastasis. If you remove that liver metastasis, either with surgery or with another ablative technique, we know that those patients do very well. And even a subset of those patients can be cured, so it can go a long period of time before any other type of cancer shows up anywhere else. So we know that there’s a benefit to local therapy in this patient with the liver metastasis. Our question is, what if a patient has a little bit more metastatic disease? What if they have two lung metastases in the liver metastasis and a lymph node metastasis? What is the role of local therapies such as radiation and ablation and surgery for that type of patient? And, really want to answer the question of why do we need a trial in this space? So right now, to date, there has not been a study looking at the use of multi modality and when I say multi modality, I mean, the use of radiation or ablation or surgery for metastatic directed therapy for colorectal cancer, and it really has not been done to date in a systematic manner. And the reason why it’s important is that, as Dr. Hitchcock described, imaging is improving, we have better techniques to find cancer and to detect cancer, we have better therapies to treat cancer. And so the use of that type of therapy outside of studies is rapidly expanding. And rather than it being really evidence based, there’s really no science behind treating that type of distribution of disease. It’s really provider bias rather than evidence-based and we all know that you really want evidence to prescribe a treatment. And so the benefit of extending the treatment paradigm that we have for patients with liver-only disease, where we know there’s a benefit, the existing paradigm for patients with more extensive disease is currently undefined. And you really have to balance it with any potential toxicity from the treatment. And so our trial ERASur is really hoping to fill this knowledge gap. And we’re designing what we think is a practical multimodality approach that mirrors the current clinical dilemma that we’re in.

And so this is our study. It’s a pragmatic randomized phase three trial, evaluating total ablative therapy for patients with limited metastatic colorectal cancer, evaluating radiation ablation and surgery. It’s called the ERASur trial. And it’s a joint trial between Alliance and NRG oncology, two different cooperative groups, national cooperative groups focused on on developing better cancer therapies. And we’ve really assembled a really great group of individuals with a lot of talent and expertise in different disciplines to help answer this question and conduct this trial.

So the primary objective of a ERASur is to evaluate and compare survival in patients with newly diagnosed all oligo metastatic colorectal cancer treated with total ablative therapy. And what we mean by total ablative therapy is treatment of all sites of disease using radiation, with or without surgery, and with or without ablative therapy with heat, adding that to chemotherapy versus just chemotherapy alone.
Number of secondary objectives for the trial as well, including looking at event free survival. So progression of the cancer, looking at safety of the treatment, as well as time to local recurrence meaning return of the cancer where it was where the individual local therapy was delivered, so a local recurrence of the cancer.

So this is the design of this study. So it’s including patients with newly diagnosed limited metastatic colorectal cancer and Dr. Romesser is going to talk about what we’re defining as a site of disease, but it’s for fewer sites of disease. On the initial baseline imaging that includes CT scans, the primary tumor, so the colon or rectal primary tumor must be either already removed or able to be removed, BRAF wild type or microsatellite stable disease. Patients can’t have liver only disease because we really, we know the paradigm for that already exists. But surgical resection or local therapy is beneficial in that patient population. So patients receive systemic therapy for four to six months. Those who progress on first-line chemotherapy are removed from the protocol because we know those patients should consider alternative therapy. And then patients who do have residual disease, meaning that there is still disease visible on subsequent CT scans. Following induction systemic therapies, that four to six month period of systemic therapy, patients have been randomized to continue standard care, systemic therapy, or the addition of total ablative therapy. And that, again, is ablative of radiation with or without surgery, and then with or without microwave ablation. And the primary endpoint of this study is overall survival. So I’m going to turn it over to Dr.Romesser to talk about the eligibility criteria.

Dr. Paul Romesser 12:54
Good afternoon, everyone. I hope everyone’s having a nice day. Thank you for joining us. So thank you, Dr. Hitchcock and Dr. Miller. So when we’re thinking about eligibility criteria for this study, we definitely want to limit it to metastatic colorectal cancer patients who are not known to have microsatellite unstable tumors, because those are patients who would likely benefit from a different type of therapy, largely immunotherapy.

We don’t want them to have known BRAF mutations where they might benefit from the BRAF inhibitors. No known peritoneal or omental metastases just because that’s not something that we can treat from a localized perspective. That takes a different type of treatment. And the primary tumor, the primary colon or rectal tumor needs to either have been surgically resected or amenable, to resection as part of this paradigm meaning that we have to address not only metastatic disease, but any localized or primary disease as well.

Patients can have up to four or fewer sites of metastatic disease, and we’ll talk about what a site is, but liver-only diseases not permitted largely because the studies that Dr. Hitchcock showed at the beginning have really reported on excellent outcomes where a subset of patients can have very prolonged progression-free and overall survival, are essentially cures as we see them. And so we don’t think we need to reestablish the you know, the wheelhouse there.

And then patients can have a maximum of four months of systemic therapy. So for registration, the patients can have any progression on induction chemotherapy, they can’t be eligible for hepatic arterial infusion pumps, which are gaining momentum and traction around the country. They must have measurable disease on imaging. And again, a minimum of four months of systemic but maximum of six months so really have to come in right in that sweet spot for eligibility.

And if they had prior definitive or curative intent treatment like such as stage two or stage three disease, they must be greater than 12 months out or greater than 12 months out from completing that, that treatment. No pregnant patients and everyone must be older than the age of 18 with a good performance status and labs as shown here.

Sorry, my eyes watering. So what’s a metastatic site? So it’s interesting, it’s, it needs to be radiographically evident, you know, biopsy or pathological confirmation is not required, but the patient does need to have a diagnosis of metastatic colorectal cancer, then lesions must be amenable to any combination of surgery, microwave ablation, which is the interventional radiology technique and or stereotactic body radiotherapy. Which is SBRT or stereotactic ablative radiotherapy, which is saber, they mean essentially the same thing.

So what’s a single site? Well, each side of the liver, we have a right and left side of our liver. So that’s the right side would be one site, the left side would be another site. Each lobe of the lungs is a site. So in the right lung, we have three lobes and the left lung, we have two lobes, and different organs like each adrenal gland with two adrenal glands on either side of her body, and those would be considered each of them a single site. Lymph nodes are a little bit harder to define, because lymph nodes obviously can be next to each other or spread out. But if the lymph nodes are amenable to single surgical resection, or can be treated in a single saber radiation field that would compromise a single site and bone metastases amenable to treatment in a single saber field by a single site, and we left it intentionally not overly restrictive, or, or, you know, confining, to allow us the flexibility of the sites of the of the centers, or the doctors to kind of have flexibility and kind of determining, you know, who is a good patient and to what level can we can we enroll them at.

So their study interventions, the control arm, you know, it is a randomized study. So patients will be randomized to either control or the experimental arm, the control arm is going to be continuing the standard of care chemotherapy. We allow maintenance chemotherapy, as well as local metastatic directed therapy for patients who have, you know, pain, discomfort or need palliation.

But for lesions that are not not causing any symptoms, we don’t allow local therapy. And that’s really kind of the standard. On the experimental arm, we give up to three months, to essentially complete what we call total ablative therapy, which is again, surgical resection, microwave ablation, or saber to all sites of disease. And thereafter, we ask the physicians to reconsider starting chemotherapy, as is. Again, chemotherapy breaks on both arms are permitted at the discretion of the primary team and this often do occur in the real world. And so it’s meant to be somewhat pragmatic in terms of mirroring what’s happening in the real world setting. But really looking at the addition of TAT or the total ablative therapy in this cohort.

For correlative study perspective, we’ll be asking patients to agree to allow us to bank their blood for future CT DNA studies. And I want to point out, you know, one thing that Dr. Hitchcock Dr. Miller and I were really, I guess, proud about and enthusiastic about, you know, we approached Dr. George, who you all know, early on and said, We’re designing this trial, but it’s important for us to hear from patients, it’s important for us to get the patient input. We wanted to know, a) was this something that they’re interested in was this enthusiasm. And also, we ask very pointed questions about what would they prefer? And in what order and to what degree they thought, you know, we should let patients enroll and what sorts of different types of treatments they would would agree to. And so the the patient perspective and the patient input for this trial was absolutely critical.

And it’s critical from an early early development time point. So I want to thank Dr. George, the entire COLONTOWN family and Paltown on behalf of all of us in terms of helping us with the trial design, and I think that’s really something that I know that we’re all very proud of. Separately, I just want to point out that your input helped us get this trial through and approved. 90% of you responded and said you would consider enrolling on this trial. 70% of you were enthusiastic for a potential treatment break. In terms of considering maybe omitting maintenance chemotherapy, in the setting of using maybe ctDNA analysis. Unfortunately, the National Cancer Institute and the GI steering committee felt like that was pushing the envelope a little bit too much, and they kind of dialed it back. But that’s something we’re going to look at in the correlative studies, and something we’re gonna consider for future studies down the road. And having something like this, where we’re showing 90%, enthusiasm, 70% enthusiasm, this is unparalleled. And I just want to really highlight that this made a really big deal. And it was incredibly impactful when we brought this to the National Cancer Institute, in terms of showing feasibility, enthusiasm, and overall, you know need for the trial. So thank you very much. So with that, I want to invite Dr. Hitchcock and Dr. Miller to kind of chime in here as well. And just really wanted to say we want to answer your questions. We want to bring up, highlight the trial. But we wanted to come here to thank you, most importantly, for your input with the trial design, and we hope they will continue to support us and guide us as we lead this trial for next couple years. Dr. Miller, Dr. Hitchcock,

Dr. Kathryn Hitchcock 21:44
I think we started to get some questions here in the chat. So if it’s alright with you, Dr. George, I’ll start working our way down the list here.

One question, when do you expect the sites to start recruiting? The study is officially open. And there are sites all over the country right now that are working on getting it open, you would be appalled if you saw how much paperwork it takes just to make it possible to treat somebody on a study like this. So I think everybody everywhere right now is in the process of getting this through the Institutional Review Board where they are, meaning the people who take a look at studies to make sure that they’re going to be done ethically and are going to respect the the rights of the patients who might be treated on this study. And the minute that’s approved, we’re ready for action, we’re so enthusiastic to start getting patients on the treatment on this trial.

Manju George 22:45
Dr. Hitchcock, I was kind of wondering that, since the video will be posted and this trial is now in the feature trial sections on COLONTOWN University, it would be kind of nice to know, you know, if you if someone can give us a list of what places they’re open, we will be happy to put it up on the website. So that I think this is a question that we often get from patients like they want to know where it’s open so they can talk about it. So that’d be nice to know, like as you get information on, you know, where all it is open?

Dr. Kathryn Hitchcock 23:16
That sounds like a great idea. And I think probably the smart thing would be I think there will be the Alliance cancer research group is the lead on this. Probably we can find a link to their page that it shows which sites are open, we’d be happy to pass that over so we can drop that into the site.

Manju George
Yes, that’d be great.

Dr. Paul Romesser 23:39
Yeah, is probably the day. So having a site I think would be critical. So Dr. Miller,

Dr. Eric Miller 23:45
Thank you. So also, I think on the colon cancer website where it’s a feature trial, there’s a link to the clinical trials.gov site. And that actually will contain, once sites are open, that will contain where all it is going to be open or where it’s open right now. It takes a little bit, a couple of months for it to actually get open. So we’re getting closer.

Manju George 24:08
Okay. I think there’s a question about the sites.

Dr. Eric Miller 24:12
There was a question about this four or fewer sites mean, you could have more than four spots, and that’s as long as they were confined to less than four sites.

That’s exactly right. That’s how you interpret it. So you can have, for example, in the right upper lobe of the lung, you can have two or three individual mets or lesions there. And that would be considered as one site. So that is under percent correct.

Manju George 24:35
For the patient that had a recurrence after curative intent liver resection be eligible?

Dr. Kathryn Hitchcock 24:40
Yes, they would. There’s a time limit a certain amount of time has to pass between that curative attempt and being treated here but it would definitely be worth looking into this study in that situation.

Manju George 24:55
I think the next question is about somebody from New Zealand. Would you consider patients located outside the US?

Dr. Kathryn Hitchcock 25:04
Absolutely, yes, in the United States, it always just comes down to how the hospital is going to get paid. So as long as that end of things could be worked out, I don’t see any reason that we couldn’t treat somebody from anywhere. We would love to take care of that patient.

Manju George 25:23
Yeah. So the next question is, would the patient have to have primary resected? I’m not clear on amenable to resection. What does that mean?

Dr. Kathryn Hitchcock 25:32
So great, great question. So it either has to be resected, before they get into the trial, or in the early period of the trial, it has to be resected. So amenable to resection, means it’s possible to be resected. And the patient agrees to have their primary tumor resected. Because the question that we’re testing is in people who don’t have their primary tumors still sitting there as a source of potential new metastases.

Manju George 26:05
I was kind of wondering, could you go back a couple of slides, where you had the control arm and the experimental arm?

Dr. Eric Miller 26:12
Yeah. Which one do you want to look at?

Manju George 26:15
I think there was one where you had on the left side, you had control? Yeah, that’s the study interventions. Yeah. So I was kind of wondering, can we think of a hypothetical patient, and then kind of go through each step? how that would be so that people are really clear about, you know, how this is happening. So let’s say I’m a stage four patient, and I have, you know, a primary tumor in my colon, and then one or two mets in my liver, couple of lymph nodes in the abdomen, and then one or two spots in the lung? So do I register now? Or, like, Could you walk me through that?

Dr. Eric Miller 26:53
Yeah, I can, I can try to tackle that one. So we actually designed it so that you can register, really any anytime during that initial six month period. So you can register before you start chemotherapy. Or you can register and that would be called pre-registration. Or you can register after that four month chemotherapy period and register at that point. So you can kind of register all throughout induction chemotherapy. But essentially, you would finish at least four months of chemotherapy, you’d register to the trial. At that point, you would then, you know, make sure that you’d meet all the eligibility criteria, you know, the lab values, make sure everything else is in order. You would have restaging imaging. And the one thing that we had talked about, kind of maybe glossed over a little bit is to make sure that there’s still something to treat. So if everything disappears on that restaging imaging, that’s great. But that would mean that you may not need local therapy, and we want to make sure that we know what we’re treating. And so there needs to be something that we can actually see on the imaging to treat. And so at that point, then you would be randomized for patients who still have something there’s a lot to treat, you’d be randomized to either continue chemotherapy, or local ablative therapy or TAT plus chemotherapy. There is some time built in there where you could get additional chemotherapy if necessary. We allow up to 90 days to get the total ablative therapy done. And so you work with your primary team, if you randomize to the TAT arm, with your primary team to figure out the best combination of therapy to treat all areas of disease. If you randomized to the chemotherapy alone arm then you would continue with chemotherapy. And then after you finish that treatment, you would then follow up with routine imaging scans and blood tests as you would off of this study. Did I miss anything? Dr. Hitchcock or Dr. Romesser? Sorry.

Dr. Kathryn Hitchcock 28:53
No, I thought that was a great explanation.

Manju George 28:55
Okay, so can I ask some questions about it? So when people are getting chemo, they can get anything they can get FOLFOX plus the biologic. If some patients wanted FOLFOXIRI, they would still be able to get that too.

Dr. Kathryn Hitchcock 29:12
Right or Yeah, okay. Yeah. And then we fought really hard for that. There were folks or advisers along the way that wanted us to specify, but we wanted people to have lots of lots of options, especially since everybody’s situation is different.

Manju George 29:25
Okay, okay. That sounds good. And then so, so you get like four months of chemo. So let’s think of my case. So I got four months of chemo. And then I had imaging and, you know, one month in my liver is gone. The lymph nodes have shrunk down, I can’t find anything on my lung. So I have now mets in the liver and, you know, the lymph nodes. So which means I can still continue with the local ablative therapy, right?

Dr. Kathryn Hitchcock
That’s okay.

And then I have 90 days during which time I can get radiation to the lymph nodes. Maybe have some thing down to the liver. And then I have that much time off chemo then is that what is meant, like in that 90 day period, I can get all the local treatments done.

Dr. Kathryn Hitchcock 30:09
Exactly. Because most of the time, if you’re doing these more concentrated therapies, you don’t keep chemo going, you want to make sure the body has a chance to recuperate from what it’s been through. So you get a chemo break during that time. Exactly. Right.

Manju George 30:24
Okay. And then after that, after the 90 days, you have one imaging, is it?. Okay, okay. And then you can continue with the, you know, either maintenance. So, let’s say after the imaging, there is nothing seen on scans, and you also have blood draw for ct DNA, and then you can, so I can talk to my care team. And, you know, if all the lesions are gone, I can go back to maintenance, just get Cape Bev and continue or if I wanted to take a treatment break, would it be possible to take a treatment break too?

Dr. Kathryn Hitchcock
Absolutely, yes.

Manju George
Okay. Okay. Okay. And then you’re going to watch me to see when those lesions come back, or if I have additional lesions? That’s, that’s what you’re trying to look at ?

Dr. Kathryn Hitchcock 31:05
Correct, exactly. Okay. Okay.

Manju George 31:07
Thank you very much. This was this. This was very clear. Let’s see if there are other questions. Okay. Paula has a question. If there is a large tumor considered to be one tumor, but in both the right and left lobe of the liver, Does this qualify as two sites?

Dr. Eric Miller 31:25
Good question. Actually, we didn’t think of that scenario, but I would probably kind of just two sites.

Dr. Kathryn Hitchcock 31:30
I think the way we have it written it would probably count as two,

Dr. Eric Miller 31:35
It’ll be a judgment call, but probably too, to go back. Just one thing to add to the I think that was a great explanation. Dr. George a great thought experiment of going through the trial, but so you would have 90 days to finish TAT. And then the first imaging time point is really one month after finishing TAT. So you finish TAT, let everything kind of calm down. And then 30 days after that is the first imaging time point. And then it’s it’s every three months that you would kind of do normally. But yeah, everything else was exactly correct.

Manju George 32:09
So Betsy has a question. Could I get the slides to post deliver Lovers Lane, Langston, and Legos land? So these are called on groups for different mets?

Dr. Kathryn Hitchcock 32:21
So yeah, yeah, absolutely. Yes. Yeah.

Manju George 32:22
Thank you so much. This was very helpful, especially, you know, walking us through a scenario that was, that was really helpful. Let’s see if people have other questions. They have plenty of time. Yeah, Brain mets? Are they eligible?

Dr. Kathryn Hitchcock 32:39
Unfortunately, no, we went back and forth about this early on, and they would not let us include folks with brain metastases.

Manju George 32:50
Okay. Okay. And then I had this question about CtDNA. So are you planning certain time points like how’s that being planned?

Dr. Paul Romesser 32:59
We built in specific time points we’re working, we’re asking all the sites to draw blood for ct DNA analyses. So they’ll draw the blood, spin it down and send it to a central repository, which then we can actually go through and do the analysis after the trial is complete. So they are standardized, there’s four or five of them throughout the trial, that are pretty well standardized. So that’s something we’re hopeful that patients and sites will enthusiastically participate in.

Manju George 33:35
Okay, so the only thing like I what you explained with the GISC not thinking not allowing ctDNA testing. So if it’s going to a central facility, that means that people won’t be able to, you know, you’re probably not analyzing it during the trial, is it?

Dr. Paul Romesser 33:52
Correct or not analyze it during the trial. Now, that’s not to say that, you know, there are some centers that are routinely using ctDNA, and they may still want to continue their standard practice, others aren’t doing that in the metastatic setting. So we’re not here to, you know, opine on that or to prevent anyone from using it. But from a scientific perspective, we won’t be able to use an external ct DNA test that that site is using, but if we have a little bit of that blood bank, we can go back and with, you know, one or two vendors, go back and do the analysis for the full whole cohort. And we’re certainly very enthusiastic that it may identify or help us identify patients who would maximally benefit from these types of interventions in the future.

Manju George 34:47
Okay. Okay. So just, not to put you on the spot. But just to ask, so what when you said that if there was a site that was already using ctDNA testing for these kinds of patients, then those patients would get the results? So but the blood would be banked and that banked blood is what you will do for your analysis for the trial endpoints. Is that what you meant?

Dr. Paul Romesser 35:09
Yeah, so the bank blood is just banked. It’s not analyzed in any patients upfront. But if a doctor at Site y, for example, routinely sends ctDNA on their patients, his or her patients, he or she can still on their own accord, draw an additional tube of blood and send it for real time ctDNA analysis. Okay, that’s just not part of the trial will be included in a trial, and that’s not data that we collect on the trial.

Manju George 35:41
Okay, okay. Okay. So, sorry to belabor this, but what it means is that if the patient is in a center where they routinely use ctDNA, then they will be able to get the results of the ctDNA testing too, but if it’s not, then they won’t have the data because that data is not analyzed till the end of this trial. Right. Okay. Okay. Yeah, it’s good to know, because we didn’t want patients to be confused, you know.

Dr. Paul Romesser 36:08
Put a maybe a little bit more clearly, there’s their no ctDNA, patients will not get any ctDNA information or testing done. In real time on this trial, any ctDNA testing that they want done on the trial is outside of the trial and their provider will have to do that separate.

Dr. Kathryn Hitchcock 36:33
Okay. But with that said, they can still make decisions based on that we’ve intentionally left it. So whatever information you have with your care team, whatever decisions you are going to make, normally, we’re not stopping you from making that decision on this trial. We tried to make it as unrestrictive as we could, so that we weren’t taking any options off the table for anybody.

Manju George 36:58
Okay, that’s absolutely, yeah, I think that’s a great point. Because I think that’s where I was trying to get to that, I mean, the design is in such a way that, you know, it allows the maximum flexibility. And for every patient, wherever they’re located based on what their care team is doing, they can actually use the, you know, the tools that are available in the child, but then they have the care that is almost tailored to how they are getting it anyways. Right? Yeah. Okay. Paula has a question, how does insurance handle this trial? Can the patient remain where they live? Or would they need to be at a specific center long term?

Dr. Kathryn Hitchcock 37:35
The beautiful thing about this is, you have to be treated at a site that has the study open. So you can’t enroll in this study at one hospital and then go get your ablative treatment at another. However, you can get your chemotherapy someplace else. So we were hoping that would for patients who don’t have an enrolling hospital near them, they could come and get enrolled and get their local therapy if they were assigned to that arm and then go back home and get their chemotherapy and not be stuck anywhere for months and months getting chemotherapy. But any center that has the trial open can do the local therapies. There’s not one or two sites, we’re hoping to have, in fact, quite a few sites. So hopefully, there’ll be one close to everybody who wants it.

Manju George 38:28
Okay. Okay. Thank you very much. That’s a great point. Great question, Paula. So basically, so I will just summarize what you said. So chemo, if I’m a patient enrolling in the trial, I can get the chemo at my local wherever I get my treatment, but I have to enroll at a place where I will get the local therapies, right, the local ablative therapies that has to be done at a center that’s close by and from what you’ve explained, that’s only for the short duration of time, whether I’ll have that local surgery or the ablation, or the radiation that I’ll go to that center, have it done, and then I can come back and continue all the rest of my treatments here. What about imaging? Where will I have to do the imaging?

Dr. Kathryn Hitchcock 39:11
Imaging can also be done close to home.

Manju George 39:15
Okay, great. This is this is really very, very patient friendly and patient centric design.

Dr. Kathryn Hitchcock 39:21
Exactly what we were going for. Thank you, you just made our day by saying it. And again, that’s because you all weighed in and made your opinions known. Without your input. We could never have made it that way. We’re so grateful for the time that people took to educate us on that.

Manju George 39:39
So what else can we do to spread the word about the trial, like, how can we help?

Dr. Paul Romesser 39:44
I think we just want patients to know about it. That it’s an option, that it’s maximally flexible, it’s pragmatic. We’re not here to put up barriers, we’re here to break them down. And we hope that you know, even if the trial is not open where your primary site is, you’ll talk to your doctor about it. And we can link you up with some, you know, locations where it’s open. And, we hope to see that, you know, it’s not only at big kind of cancer centers, but that it’s kind of spread out around the country, and patients kind of come in for, for this trial to seek out TAT, or at least to help assess the question.

Manju George 40:32
Okay. Okay. Thank you very much. As I was talking, so we have on COLONTOWN university, we have this diagnostic and surveillance test Learning Center. It’s a different topic. But where I was going with this is that, so we had like, for example, when we started when patients started using Signatura, not everyone was ordering the ctDNA test. But then what we did was that we asked patients to let us know where all they were getting the test. So then we actually put up a list of centers where they were getting the tests. So any new patient, when they wanted the tests, they could go and check to see whether there was a center close by. So I think that one of the things that we can do to facilitate, you know, people knowing about it is, as soon as you know that there is a site open or you know, certain techniques can be done in a particular place, if we can provide a list, you know, where all what is available, then that would be very helpful, because then people could go and click on it and find out, you know, how far it is for them. And I think that might facilitate, you know, more people knowing about it and enrolling. So that should be something that we could do on COLONTOWN University.

Dr. Kathryn Hitchcock 41:41
That sounds great.

Dr. Paul Romesser 41:43
And I’ll add one more thing some big centers have, like I know, in New York, and I’m not trying to plug my own Center, but I know in New York, we have the American Cancer Society has something called the Hope Lodge, which is a free lodging. So it’s not just unique to my center, it’s available to anyone with cancer, who comes to New York City for treatment. And so there are resources, if there’s not something close to home, where we could find other additional options for patients. And I think there’s many Hope Lodge equivalents around the country, and many great sites that we could try to put together to increase options for patients as well.

Manju George 42:25
I think that’s a great idea. Any other questions, comments? Yeah. So we’ve worked with, you know, Dr. Miller, and Dr. Romesser, and Dr. Hitchcock. So we have this trial design and more details about this trial up on feature trials on COLONTOWN University. So if you wanted to, you’ve heard whatever you heard them speak, and then you wanted to, you know, look at those, the details and, you know, when you have time, you can go over there, and it’s there. And Betsy will post, you know, I think one of you will send me the slides. Right, then I can send it to Betsy and Betsy will post the slides in Lungston. And yeah, in all the relevant metastatic groups, yeah, that would be great. So there are multiple ways that people can know about it. And then the other thing that we’ve been doing in COLONTOWN is that when we have newly diagnosed patient join, when we actually have an onboarding, so we asked them, you know, to tell us about where they are and what’s going on. So when we come to know that they might be eligible for certain trials, then we tell them, that there are these trials, because many times, you know, when patients join, they don’t know anything. And, you know, it’s sometimes they won’t come to know about it. And trials are not, you know, in general, people think that trials are something that, you know, when you have failed all lines of therapy, that’s when they should do it. So we try to tell people about firstline trials like this. So that’s another place that we would be talking about it. Yeah.

Dr. Kathryn Hitchcock 43:56
That is perfect. I’m so grateful that this whole system exists that you guys have put so much work into it. And the good that comes out of that just can’t even be measured.

Dr. Paul Romesser 44:08
Thank you, Dr. Miller, do you want to comment on the insurance and the insurance review that you all did with through Alliance as part of activating the trial?

Dr. Eric Miller 44:19
Yeah, so that’s a great question. So they do an insurance analysis to make sure that aspects of the trial will be covered. And we went through that analysis and everything checked out. Now, of course, you know, before any treatment, of course, they would do a prior authorization to make sure that all treatment would be covered. But there really isn’t anything on this trial that is really experimental, all the local therapies or established therapies that would be covered by insurance. Yeah, that’s a great question. Great question.

Manju George 44:55
One of the things I think we can also do is, as people start, you know, six months A year from now. And when we find like, we also have in COLONTOWN, Betsy is one of the Cabinet members. So we have a group of patients and caregivers who run the day-to-day activities in COLONTOWN. So we have something called the Alanna project, which is basically a place where we keep track of who all are in what all trials, and, you know, they will post updates. So if they have a clean scan, they’ll post if they have a progression, they will post so this way, you know, when a new person who wants to find out about trials, they can go and look in the Alanna project and find out if other people have been on the same trial and what their experiences are. So once we, you know, a couple of, you know, one year or something after the trial is open, we’re hoping that we will get to hear from patients, right, how this is going, if there are concerns? So I’m hoping that we can bring that back to you. And you know, if there is something that is in the way, maybe I don’t know, you can do an amendment or, you know, you can at least find out if there are ways to help, you know, for people to get over that block, whatever that is, right?

Dr. Kathryn Hitchcock 46:08
Yes, if there are barriers, we really want to know about them as soon as possible. Because you’re right trials, it’s not like you write a trial, and it goes through as written from the beginning. There’s always amendments, when we figure out that something didn’t work quite the way that we thought it was going to. So please, that would be wonderful. If folks would communicate with us in that way.

Manju George 46:30
We can, we can certainly think of collecting information, because I think, overall. So I would like the three of you to tell us, you know, how, you know, in your mind, like when we have the results? What are you hoping for the field from this trial? You know, like, how is this going to be practice changing? I mean, if you could comment.

Dr. Eric Miller 46:50
Yeah, I guess I can, I can start. I think for us, the big thing is just clarifying the role of local therapy in patients who we wouldn’t necessarily think about local therapy for. So if it’s shown to be beneficial, then we should be offering this therapy to more patients. So one of the impetuses for this trial was that, for the for the vast majority of metastatic colorectal cancer patients, you know, there aren’t really new drugs right now, you know, systemic therapy is sort of at an impasse. And so if we can come up with a different method, we can offer local therapy and improve survival, we need to figure out the patient population that’s going to benefit. And the kind of converse of that if we’re doing things that aren’t helpful, that are just adding toxicity and increasing the cost to patients. And we probably shouldn’t be doing those things. I’ll turn it over to Dr. Hitchcock & Dr. Paul Romesser.

Dr. Kathryn Hitchcock 47:43
Now, I’d say part of that we’ve kind of touched on today in that. I know a lot of patients in the process of dealing with this specific disease situation, don’t ever get a treatment break. And that was kind of where the idea came from originally, not just the chance for curative potential. But if that doesn’t happen, are we able to at least give patients a long, meaningful period of time where they’re not constantly in the hospital and dealing with doctors. So at the very least, we’re hoping we can achieve that.

Manju George 48:15
Dr. Romesser, do you have something to add?

Dr. Paul Romesser 48:19
I think they summed it up really well. I mean, it’s, I think whether it’s unique, and that whether it’s positive or negative, I think it’s going to impact how care is administered. Obviously, we spent a lot of time working on this, and we’re very passionate, we have every reason to believe this is going to be positive. But I think we can learn from both ways. And so we’re just really kind of humbled by the opportunity to run this trial and to offer this to patients.

Manju George 48:53
Thank you. I think that one question is, Is this only for first-line patients? Or is this also for patients who have had other treatments?

Dr. Paul Romesser 49:02
It’s predominantly first-line unless they had other treatment for stage one, two or three colorectal cancer?

Manju George 49:11
Okay, so I was thinking that like, I really liked what, you know, all three of you said, so, from a patient perspective, what you’re really saying is that right now, when somebody is stage four, you know, we hear this chemo for life, right? That’s what we hear for a lot of patients. So basically, what you’re trying to do is, you’re trying to break that big group of stage four patients into smaller subsets, to see if there is a group that you can treat many of their mets locally, so that they don’t have to be on chemo for life. They have these treatment breaks and hopefully, you know, the best-case scenario would be they’re cured by it. The worst case scenario is that they get a treatment break and the disease comes back after a long period of time. So then, you know, that is essentially a long chemo break for them, and that adds to their overall survival. Have I kind of summarized it?

Dr. Kathryn Hitchcock
That’s it. Exactly.

Manju George
Okay, thank you. Any any parting comments from the listeners?

Betsy Post 50:14
This is Betsy and I am the Community leader for the metastatic groups. And I’m really excited about this trial. And for all the reasons that you said, and I’m just, I don’t know, this is exciting. And I think patients are going to be very excited about the trial, and I’m happy to share the information. And you know, especially with the initial onboarding, we do get a good sense of some of these patients and the extent of disease and, you know, try to talk to them immediately. Because it’s such a good opportunity when they come to us new, and you’re able to talk to them about treatment options. And so I think, you know, this is great. I mean, it’s, I keep saying exciting, but I am excited, because I’ve been doing this a long time. And I think that there is a real need for this. It needs to happen, like you said, so I’m appreciative of all you’re doing.

Manju George 51:09
Thank you so much, Betsy

Dr. Kathryn Hitchcock 51:12
It’s good to hear you’re as excited as we are. We are on the edges of our seats, for sure.

Dr. Eric Miller 51:20
I think it’s a great point about it being first line and not necessarily thinking about trials when you’re first diagnosed. So I think if we can let patients know about it early to potentially give them an opportunity, I think that is that is exactly what we’re hoping as well. So thank you.

Manju George 51:37
Yeah. Okay. So I think then we can thank everyone, and thank you. Thank you. Thanks to everyone for joining and thank you, doctors, Hitchcock, Miller and Romesser. And I hope that, you know, with all of this, we will be able to tell patients about, you know, we hope to be able to take this information to the most number of patients and, you know, kind of help with enrollment too that, that’s, I hope that’s together, we can, you know, get the trial enrolled and, you know, get everything going quickly.

Dr. Eric Miller 52:18
Thank you. Yeah, thank you so much. We’ll send the slides. Okay.

Manju George 52:23
Okay. Thank you very much. Have a great day. Thank you. Bye bye.

DocTalk
2023
Dr. Hitchcock
Dr. Miller
Dr. Romesser
Ablation
Liver
Lung
MSS
Radiation
Stage IV
Surgery
Trials

Dr. Kathryn Hitchcock from the University of Florida, Dr. Eric Miller from Ohio State University and Dr. Paul Romesser from Memorial Sloan Kettering Cancer Center discuss new standards for ogliometastatic colorectal cancer treatment with Paltown Scientific Director Dr. Manju George. Recorded in March 2023.

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BREAKWATER: 2026 Update

BREAKWATER: 2026 Update

DocTalk
2026
Dr. Kopetz
BRAF
MSS
Trials

In this DocTalk, Dr. Scott Kopetz, MD Anderson Cancer Center, discusses the much awaited results of the FOLFIRI + Encorafenib + Cetuximab arm of this 1L trial for patients with BRAF V600E–mutated metastatic colorectal cancer. Recorded in February, 2026.

Manju George 0:00
Hello everyone. Welcome to Doc talks. I’m Dr Manju George the Scientific Director at PALTOWN Development Foundation, the nonprofit that supports COLONTOWN.Welcome to my first Doc Talk of 2026 and for those of you who are joining live, welcome. And I am so excited to have Dr Kopetz with us. And as many of you know, he’s no stranger to us in COLONTOWN. He’s an amazing oncologist, a very well known researcher , who designs these amazing colorectal cancer trials, and is a speaker at all the international and national conferences, and has received so many awards. And in between all of that, he finds time to engage with us, and for that, I’m so grateful. And he has many titles and honors, and I think to us, he’s a beloved oncologist who’s focusing on BRAF and KRAS mutated colorectal cancer. And so once again, I’m so thrilled to have Dr kopets with us to talk to us about the 2026 BREAKWATER updates. Welcome Dr Kopetz.

Dr. Kopetz 1:14
Yeah, thanks so much for such a delightful and kind introduction, and thanks for all that you do, and you really do such an amazing job of educating and advocating. And so we’re so grateful for community, for you as well. So delighted to be able to share some of the updates in BRAF.And I thought during this, I would take opportunity to kind of take a step back with a little bit of history, but then really talk about where we are. How are we thinking about this in 2026 so with that, I had to start with just the complexities that we’re dealing with. Don’t worry about interpreting all this. This is for the gurus in the field. There’s a Frank McCormick, he’s kind of considered one of the fathers of RAS and he’s kind of put together this pathway about all the complexities of how normal cells and then cancer cells signal. We kind of think about, and you may have heard in biomarker testing, kind of the key ways that colorectal cancer can acquire mutations. These can be through KRAS, NRAS mutations commonly, but also BRAF. And BRAF is a distinct entity. It’s probably the one that we were able to target first, but a lot of the lessons that we’re learning, and we’ll come back to this point that in BRAF are now being applied to KRAS G12C, and think in the future, G12D will be following right along in this path. So hopefully these wedges of targetable oncogenes will continue to grow.

Dr. Kopetz 3:05
Okay? I said BRAF was targetable. This now goes back for more than a decade where the kind of first inhibitors which some brilliant medicinal chemists figured out that you could actually target this specific mutation that’s present in BRAF. Now I’ll take a moment to say what we’re talking about is a BRAFV600 E, so it’s the most common mutation, but there are others. Now the others are a little more complex. Everything that we’ll be talking about in terms of targeting is really this most common V600E mutation. Others we’re not fully sure what to do with, because they’re so heterogeneous and complex. But the BRAF V600E, also common in melanoma, and some of the initial studies that kind of a classic one.

Dr. Kopetz 3:54
This is one of the first studies that we ran where we said, okay, let’s treat melanoma. Let’s treat colorectal the same and we got very different outcomes, and that kind of set us off down this path to try to figure out what is it that’s unique about colorectal? How do we better target that? So there’s really two main crux, right? We have to improve the shrinkage of the tumor. And then, importantly, really, really target the durability. And we’ll talk about that, about how can we keep the cancer, shrink it down, and keep it down for as long as possible? So a lot of the work has been trying to do both, and you’ll see progress has been made there. All right, so let me take a step back. If you were a medical student, maybe first or second month of medical school, you would get introduced this concept of homeostatic regulation and how it’s used in the body. But I think it’s a useful concept for us to understand, and it’s this idea that our bodies like to be in a certain condition and that they have feedback mechanisms to keep us in that that condition. And there’s the more critical the pathway is, the more critical that regulation is, the tighter the feedback is present. And it turns out that this growth factor pathway, we call it the MAP kinase pathway, it incorporates K RAS, NRAS, BRAF. Those are incredibly important for cell growth and healthy cell division, and so that the cells, especially the colon cells, have a lot of these mechanisms to keep that level of signaling just right. so this is homeostatic. And Walter Cannon really was the–and you can see how, just by virtue of the picture, how old this concept is, but we still see it.

Dr. Kopetz 5:58
So what does it mean? Well, when we are in normal physiology, you can think about your glucose levels, if you’re not a diabetic, about how tightly regulated that is, but even something simple, like your body temperature, right? So you go out and sit in the sun, your body temperature rises, your brain recognizes that. It then dilates your blood vessels and also induces sweating. And then the response is, your body’s temperature is restored, right? Very simple concept, but it’s this kind of regulation to say your body wants to keep its temperature in this really tight range, and it’s going to do everything it can to maintain that. So the same thing happens after targeting BRAF, right? So in a BRAF mutation growth signaling this tumor cell is has a level of signaling that it wants, and we can give an inhibitor of BRAF, but there are feedback mechanisms that this tumor uses to say, nope, nope. That’s too low. I want higher signaling in this growth pathway. And one of the things that does is it activates EGFR, and it turns out that that then reactivates the growth, and the signaling is restored from the concept of the cancer cell, right? So this is homeostasis from the perspective of a cancer cell.

Dr. Kopetz 7:29
Now, I know there’s a lot of aficionados out there, so if I were to do this and try to do this simplistic Frank McCormick figure, it would look like this, right? Where there’s this signaling cascade, where one protein, activates the next one, which activates the next one, and down at the bottom of that is growth, right? This is the signal that says cancer’s growing. So if we have the BRAF mutation now, green is kind of signaling, an activation that’s just pumping out signal– we inhibit BRAF, what happens? It gets shut down, right? So transiently, it does a good job, but what happens then is you get these feedback mechanisms that get de repressed. EGFR now gets turned on. It now signals around that inhibition. We’re still blocking BRAF, but there’s pathways to get around it, and the signaling is restored, right? So that’s why BRAF alone doesn’t work, because the tumor is adapting so quickly. Now, when you then now come in and block BRAF and EGFR together, that’s when you can shut down the system, right? It can no longer compensate. You block two key nodes and and that was the premise. So fast forward through a lot of clinical trials and work, the BEACON study was the first to really show this, that when you combine BRAF and EGFR, compared to a control arm, you can improve overall survival response rates in this setting, and this was in a later line population, where there’s improvements here from 5.9 to 9.3 months. So improvements, there’s a bit of a tail. This idea that a proportion of patients can really have a longer duration of that as well. And the overall the side effects that you can see here as well. So this was several years back, and resulted in approvals for the second and third line. But we want to do better, right? And so really trying to understand, well, how could we do that? What’s the path forward there?

Dr. Kopetz 9:47
So gonna take a step back to the lab, because I’m a physician scientist. So we tend to do something the lab, bring into the clinic, learn from the patients, bring it back into the lab, and kind of keep iterating. And so throughout all of this, we’re doing a lot of preclinical modeling of cancer. And so, how do we do this? Well, we use mice for this. And why mice? It’s kind of weird, right? Like, why do we use mice? Why don’t we use other areas or other model systems? So it turns out that we actually have a fair bit of similarity with mice, like 95% similarity to mice in our genetic code. A lot of the ways that the our systems work are very similar. And then there’s some practical advantages that we can house them in controlled environments. Can handle them, and they have kind of been used for decades, continue to be used for a lot of this testing, right? And so we’re really really, I think, thankful for the opportunity to learn as much as we can in these systems before we bring to patients, so we’re bringing better things forward.

Dr. Kopetz 11:04
So, you know, just want to advocate. This is kind of what what the mice look like. So we actually use these mice that don’t have any hair, so they’re called nude mice. So, and then a lot of times the tumors are kind of grown on the flanks of the mice, so we can put little calipers around it and kind of measure how things are are going and advancing. Now we take extraordinary care to provide a really good environment for the mice. We actually have veterinarians whose sole job is every day to check on the well being and health of the mice, and they get all sorts of like things to socialize together through all of this. And so just know that we’re trying to be really good stewards of this, and we don’t take this research lightly, but we know that it’s really important for our patients. Okay with that a bit of aside, because we like to show as researchers how can we do things right? And so one of the questions that we were asking is, how can we improve the targeted therapy, and we did an earlier study where we actually combined with the earlier generations BRAF and inhibitors with with irinotecan and we had patients that their disease responded. So we gave chemo, EGFR and BRAF inhibition, and not just BRAF and EGFR alone. And so the question was, okay, we had responders, and it was working, and we had some patients that were really generous, and they said we will be willing to do a biopsy so that you can take tissue out from my tumor and you can study it. And so we’re so thankful for the patient’s contribution to not only enrolling in research, but to support things like this. But what that allowed us to do is say, Okay, I’m going to take that piece of tumor, I’m going to take it back to the mice, just like you saw, and I’m going to grow that patient’s tumor on the flank of the mouse, and I’m going to propagate that tumor, so I can treat many different mice, and then I can treat that tumor with the targeted therapy alone, the chemotherapy alone, or the combination. And then ask the question like, if that model works, what was that the patient was responding to? They got three drugs. But did they need all three? Maybe you only needed two in this or our other one. And we were really intrigued. And I just showed three examples here, where you want to see things kind of going below the lines, the lower, the better, smaller the tumors here. And what we found was that the targeted therapy slowed growth. Chemo slowed growth, in two of the models, but you only really got regressions and things shrinking down when you did the combination. And so that was a really important finding for us. Now it turned out because I wanted to show all the data that one on the far right here. What that said is, you know what? The targeted therapy didn’t do anything. It was all chemotherapy doing the heavy lifting here, we would predict in this patient. And so we kind of expanded that out and looked at some really resistant tumors and showed that indeed, that when you combine this, we were using a full theory regimen, so irinotecan and 5FU, that you could really get these synergies and really suggesting that there is opportunities to improve outcomes and the durability through this. So that kind concept, as well as the idea to say, well, let’s try to get this into more patients sooner, really led to the idea of the BREAKWATER study.

Dr. Kopetz 15:06
And so what did we do? Well, designed this study, randomized 637, patients to a standard of care without targeted therapy at BRAF. Patients could still get BRAF and EGFR in second or third line because it was approved. But the idea is to start with standard chemotherapy in the control arm. Or EC, encorafenib, cetuximab and FOLFOX or EC alone as a kind of a third arm. And so we were trying to gather some data, like, do you need the chemotherapy there? And then we’re looking at progression free survival, response rate. Here’s the characteristics of the patients enrolled, and this really reflects a bit of what we see in kind of general practice here. So what do we see? So remember, we said we want to improve response rate and durability. So first thing we said is, let’s look at response rate. And indeed, if you look at the blue bar with the EC and FOLFOX now we had two thirds of patients approximately responding to the therapy, meaning the tumor shrank down by 50% or more, versus 37% with the standard of care therapy, a little more than a third. And that this was durable, and that was encouraging. So when we get a response and there was some increased durability, now one of the terms that we use to measure durability is progression free survival, as you’re likely aware. And so we looked at that progression free survival curve, what we saw was an improvement in progression free survival of seven to 12 months.

Dr. Kopetz 16:42
So what does that mean? I’m sure many of you are well versed in these curves, but I thought it was always worth to do a little bit of a primer about what this means. These are a measure of any time point along the way, the number of patients that are still receiving therapy and have not progressed. So we can look at this, and for example, we can see about it at six months time frame here, that 60% of patients were still on therapy and were free of progression. And over time, more patients progress, and you can see the curve coming down. And so by the time you get to 12 months here in the control arm, about only 30% of patients were no longer progressing. So we’ll say, Okay, that’s good. How do we describe the curves here? And so you’ll hear this term median, right? Well, what does that mean? Well, it means, really at that 50%, meaning half the patients progress before, half the patients progress after that time point. So the median here we use as our estimate. And you can see, you know, the median is a little over six months 7.1 exactly here in the control arm, but that median is closer to 12.8 months here in the in the experimental arm. Now we can use these numbers and now start to compare across different settings, BRAF has always been a tough or has not always felt to respond well to standard chemotherapy. FOLFOX, FOLFIRI alone, even with Bevacizumab, usually get like 6-7 months. Now, while the non BRAF colorectal cancer is usually around 10 months or, maybe 11 months. So this is really striking, because we’ve taken a tumor that had well worse than your average outcomes, and now with this regimen, now we have a median progression free survival that looks better than all the other tumor types, subtypes of colorectal cancer out there. So it’s a really big kind of chip. And I think, as we mentioned before, we also see this, this tail, and this gets a little noisy because we don’t have as long a follow up yet, but this idea of, this flattening here, and about a third of patients, even at two years, are kind of still ongoing, and that’s a much higher tail, as we say. So, the idea that there’s a subset of patients that we don’t fully understand why, but they get a really durable, prolonged outcome from this. So we need to know more. We need to make more people like that. So that’s one of our goals.

Dr. Kopetz 19:48
All right. Now we talked about, there’s a third arm, if you recall, right where encorafenib, cetuximab was used alone, no chemotherapy. And here’s the orange line for the encorafenib Cetuximab alone. So didn’t do better than the standard chemotherapy, but didn’t do worse either. So it is, it kind of is in that middle ground. The kind of interpretation of this is, you know what this is, typically the the EC alone is better tolerated than FOLFOX. If there’s a patient that is maybe not the best candidate for FOLFOX, can’t really tolerate it well, for whatever reason, there’s an option to at least do the EC alone, and that may be better than than other options for that unique case. But for most patients, we think that that is EC and FOLFOX should be there. Now, progression free survival is important, but remember I mentioned that well, the control arm could go on and they could get BRAF and EGFR right, and so is this just shifting when things are and if that’s the case, for what we really care about is, can patients live longer with this regimen?

Dr. Kopetz 21:08
And so that’s the overall survival– very similar. We use this median to say half of patients now, in this case, are living longer and half are living shorter than that estimate. But what we saw was that the standard of care about 15 months– what we expect on average, but that we’re able to double that number. So really, a doubling of overall survival is a really, a compelling number to see. And so now getting medium survivals that are much, much higher. What about that third arm? Kind of fell right in between. So, it’s not an unreasonable consideration to kind of start with that, but still not as good as the EC and FOLFOX alone.

Dr. Kopetz 21:59
Okay, thanks doc for showing all those complex slides. What does it really mean? So, here’s kind of that graphic summary, thanks to nano banana. I’ll say a little AI generated one. But what you can see here is that really, progression free survival, you’re reducing that risk of progression. And then that survival time is, in essence doubled, going from 15 to 30 months. Those are the kind of the key takeaways. Now, what about side effects here? Most frequent side effects are shown here, in this figure. And what we can see is that nausea, diarrhea, those kind of things that we normally think about with the chemotherapy, is about the same between these and that the real difference here is kind of in some of the BRAF specific toxicities. In this case, it’s looking at arthralgia and rash. So you can see that the combination of with encorafenib+ cetuximab can generate some rash. We use grading systems to grade one two, which means a more mild rash and arthralgia, and still impact quality of life. And so it’s something that we manage and work through with patients.

Dr. Kopetz 23:35
Now, one of the questions that’s come up is like, well, is this better than if we did really intense chemotherapy at the beginning. And so there are regimens where we put FOLFOX and combined with irinotecan and what we call the triplet regimen. And so this was just a bit of an aside to say that we looked at what patients could have gotten some of these more intense regimens, and then looked at some of the survival here. And the bottom line is that it didn’t matter in the control arm, if you use really intense chemotherapy that that really you got the best survival with the with the EC FOLFOX. Now we’ve been talking a lot about FOLFOX, and this is data from last year. So, but what about alternates? So we like our acronyms as we know and so FOLFOX, of course, is a 5FU oxaliplatin. Oxaliplatin is the neuropathy one. There’s the FOLFIRI, it is irinotecan and 5FU. And there are situations where patients, just may not be best served with FOLFOX. They may have had prior oxaliplatin exposure, may have had an early stage tumors, resected, got adjuvant FOLFOX, for example, and then the disease recurred later. Or maybe patients that have kind of diabetic neuropathy, for example, where they have other reasons for nerve damage. And then sometimes it’s just a lot of providers are looking at the side effect profile and just saying, you know, I just think FOLFIRI is a better choice in general to start with. And so all these things now to the credit of the sponsoring company for BREAKWATER they heard us when we said, we really want to have more options for our patients. And we want to generate data as well with with FOLFIRI. Right now, most companies, I would say don’t really do two studies to look at the same thing, but they heard us and and agreed to run this smaller study. So remember, before we’re looking at over 600, here we have like, 140 something patients.

Dr. Kopetz 26:02
And now this is just after the BREAKWATER finished enrolling. We then opened and enrolled this one. Endpoints, response, rate, side effects, very similar here. There was, interestingly less arthralgia and rash in this one, not sure I fully understand it, but it was that’s kind of what we saw there, but really low rates of grade three toxicities in general. So didn’t add much in terms of toxicity. Here again, we saw very similar, about two thirds of patients responding versus about 39% of the control arm there. So encouraging that there’s that much higher response rate, even with a FOLFIRI backbone. And overall survival, really early, we will have some updated data we’ll be sharing in Jun. But that this kind of really nice early separation of the curves that were similar in magnitude to what we saw before. So that’s great. It tells us FOLFOX and EC can be a backbone. FOLFIRI and EC can be a backbone.

Dr. Kopetz 27:15
So wanted to spend maybe the last few minutes and just talk a little philosophically, and that little more of the science here, right? So one of the questions is, wow, we’re doubling overall survival, not by bringing a new drug in, but by taking a drug that we would normally give in second and third line, and now combining it with our first line regimen. What gives? Yes, maybe it’s better, but why a doubling in overall survival? And, I shared some of that kind of concepts pre clinically, and I didn’t get into a lot of the deep science that led us to think that this could really work. But one way to really think about this is that when we give chemotherapy alone, and these are completely arbitrary numbers. We give chemotherapy alone, there may be 10 different ways that the tumor cells can develop resistance. When we give BRAF EGFR inhibition, again, maybe 10 different ways that resistance can develop, including acquisition of KRAS and NRAS secondary mutations, for example, which are really well described and and I didn’t present that data, but this idea that other mutations can develop that can reactivate the pathway. Now the concept, though, is that a new KRAS mutation is not going to make them resistant to FOLFIRI, right? And likewise, some of the resistance mechanisms to the chemotherapy may be blocked by BRAF and EGFR. And so it’s not that the cancer can’t find a way to develop resistance. Gosh, it almost always does, but we’re just making it much, much harder. So the idea is that the shared pathways of resistance are constrained, so that’s this lower level of number of mutation or resistance pathways that can occur. So by putting them together, you really make the tumor work hard to find some mechanism that will result in resistance to the chemo and resistance to the targeted therapy together.

Dr. Kopetz 29:25
Now it’s a great theory. Did we actually see any data about that? Like is what we have there? So I mentioned that, and we did a lot of work and published papers around different mechanisms of resistance to BRAF and EGFR when it’s given alone. These secondary mutations are kind of the key ones that we see. So what we did is presented some of the data on the CT DNA, so you can use circulating tumor DNA to explore the mechanisms of resistance there. And what we showed was that by month seven in the targeted therapy arms of the of the BREAKWATER study that EC alone, about 38% of patients already had these resistance mutations that were developed and evident. They developed KRAS variants, NRAS, MAP2K1, which is downstream, amplifications like MET or BRAF exon deletions, all these things that have been shown. But when we combine it with chemotherapy, now there’s no selective pressure, really, to generate that the chemo can keep the cancer from growing, even with those. And only 6% of patients at month 7 in the combination arm had that mechanism of resistance. And you can see, even at the end of study, after prolonged treatment, that we were seeing much lower rates of these secondary alterations. So we’re trying to and this is really where we are at the frontier of trying to understand this, is kind of the idea to say, how can we constrain the mechanisms of resistance. What are those two remaining shared mechanisms that are allowing the cancers to evade? We don’t think they’re genomic. They’re not acquiring second mutations, necessarily, that’s driving this, but there’s some tumor plasticity, state changes that are occurring. These are kind of the terms you’re hearing in oncology field now about what’s the plasticity of the tumor, like, how is it adapting to these different states? So stay tuned. But this is really where we’re working on it. We’re trying to nip these remaining things in the bud.

Dr. Kopetz 31:42
Okay, so adaptive resistance, you got your primer on homeostasis, right? There’ll be a test later on the homeostatic regulations, but this combination of BRAF and EGFR blunts that. It is a standard of care, but that the chemotherapy combinations have compelling biologic rationale, as well as the really now strong clinical data, doubling overall survival. And so that we do think that EC and FOLFOX, and I would say EC and FOLFIRI as well, are a new standard of care in the US and and I think this is even when you compare to the really intense chemotherapy there. The key for all of this is that in order to actually act early and take advantage of all this great biology, you got to know what your molecular subtype is, and so this is why one of the key things about this is molecular testing early. Don’t wait till second or third line of treatment to really start to act on the molecular subtype of your tumor. It’s really important for patients to understand their molecular subtype at diagnosis and act on it, if there’s ways to act on it, and so that’s really a challenge for us to make sure we’re communicating that to oncologists throughout the US and throughout the world. And I think increasingly we’re seeing that most, most providers now, are getting that molecular testing done and and making treatment decisions early. And just want to end by thanking the patients first and foremost. We are always trying to do better, and this is always bittersweet. When we see advances, because we see progress, but we also recognize how far we still have to go. And I just wanted to thank the the patients in the past who really participated wholeheartedly and in these, this clinical trials and the patients in the future that are still upcoming, and where we hope we’ll have better therapies to offer. So with that, thanks and happy to take some questions.

Manju George 33:57
Okay, thank you, Dr. Kopetz, that was an amazing presentation. As always, you take us through hard concepts, explaining them very simply. So thank you very much. So with questions, in COLONTOWN, people have posted some questions, and I had emailed you them, so maybe we can start with those, f you’re okay,

Dr. Kopetz 34:20
Sure, absolutely.

Manju George 34:22
Yeah. So the first question is, of all the patients on the different E plus C combinations, what’s the longest time in your experience someone has been on it? And the second part of it is, what do you think is the reason? Like, what have we learned?

Dr. Kopetz 34:39
Yeah, great question. I don’t know the answer yet about why. So we’ve had some patients that are now four years or so, on some of these combinations. The front line, chemo, plus a lot of times, what we’ll do is just continue the 5FU and encorafenib, cetuximab, and we’ve had patients on that two and a half years going on three so that really there is a subset of patients who can do really well with it. We don’t understand, we don’t know, if the tumor has some biology that’s called adaptive mutability, which is how the tumors change, in essence, they kind of turn themselves in and increase the rates of their secondary mutations, so that this is one of the ways the tumors can adapt. They start making more mutations. Each time they divide, they have more mutations. And the hope is they, imputing a lot of of intent to them, but the idea is that they, as they develop a lot more mutations they can find, stumble across other mechanisms of resistance. So there is some hint, maybe, that some of these really patients with really long duration don’t engage this adaptive mutability pathway, so their tumors don’t use this as a mechanism. But that’s I think, work that we still have to sort out.

Manju George 36:24
Okay, thank you. The next question is, what advice do you have for someone who was on FOLFOX plus E plus C and is now on maintenance 5FU plus E plus C. Is adding irinotecan to this at progression a good idea. If not, what else can they get?

Dr. Kopetz 36:44
Yeah, great question. So one point, not the question, is that when there’s this inclination, no one likes the pump, I get it, right? There is this inclination and maintenance to say, well, EC is working, what if we just stopped the pump as well as the oxaliplatin, right? And I really, I think that biology suggests that you need that 5FU, so I would say, try to maintain the 5FU now, the great question was, should we add more on to that? We just don’t know, to be frank, on this, I think, there is this sense that trying to put something into it before progression may not be the best approach, but we honestly just don’t have a good sense of this yet. I think we have tried it in some patients where you’ll start to see things kind of creep up. It’s not that full resistance is developed to 5FU and encorafenib Cetuximab, we either add the oxaliplatin in, or, if there’s neuropathy, add in the irinotecan, alternatively, so and that can work. The question is, is that better than than using irinitecan later, we just don’t know.

Manju George 38:07
For someone with a sustained response to E plus C and E plus C plus FOLFOX who is now progressing, what’s the best option next? Yeah, similar question.

Dr. Kopetz 38:19
Yeah. Great question. So there’s a few approaches there. There are studies to say, remember we talked about that these tumors are really dependent on this MAP kinase pathway. So there one approach is to say, well, let’s double down on this inhibition. And there is another protein downstream called ERK and so there’s a next generation ERK inhibitor. We tried ERK once, but that was really intermittent ERK inhibition, and that didn’t work. For the officianados, that had been tried once, but we think there maybe a better inhibitor. So there’s a study ongoing to double down on that pathway inhibition. The other is, we talked a little bit about the plasticity and the state changes. And so we have a study through the ETCTN or the NCI, federal government sponsored study, where we’re trying to use an epigenetic modifier. It’s called a BET inhibitor, but the idea is that it really inhibit some of these state changes. And so that’s a study that’s enrolling right now. And then there are studies to kind of ask questions about, well, what if you go and you do something else altogether, right? Like, if you haven’t gotten FOLFIRI, maybe you go and get FOLFIRI, you give it a break from EC. And what we see is that a lot of times, the tumors will rewire in order to evade the FOLFIRI. Sometimes they’ll shift back into a state that becomes EC sensitive. And so this idea to say, can you do what we call a re challenge, which is do something separate from MAP kinase targeting, and then come back and hit again with the MAP kinase. We see benefits with that with the EGFR inhibitors. This is a RAS RAF, wild type tumors that you can inhibit EGFR and then take a break and then come back and do EGFR alone. So that’s another strategy, but I think there still is a lot more that we can do.

Manju George 40:26
Okay, okay, thank you. So I think that brings us to the next question where people have asked, Can the BEACON and BREAKWATER regimens be reused? And then, if yes, like with EGFR inhibitor, we say, like, four to six months. Do you have any idea what’s the break that people would need?

Dr. Kopetz 40:48
Yeah, we don’t, to be frank, I think, we would typically check Ct DNA to make sure there’s no secondary mutations. All those are uncommon after BREAKWATER. But can be seen. So just make sure those have gone away. Because if you can still see a KRAS mutation present on CT DNA, then maybe it’s not long enough. You give it a little more time. But you’re right, we kind of think about, four month or so time away. It may be enough to have the tumor resensitize,

Manju George 41:25
okay, okay. And then the next question is, for people who miss the first line option of breakwater, what’s your advice on using this in second line or third line?

Dr. Kopetz 41:36
Yeah, great question. I think it does give us confidence that, bringing EC in combination with chemotherapy may be better than EC alone. So the the SWOG study that I showed the one with then looked at and second or third line looked at, in essence, BRAF, EGFR, with irinotecan, and that showed activity. And so I think if, for example, you got FOLFOX alone, I think there’s a rationale to say that you could do an EC, irinotecan, or EC FOLFIRI, in a second line setting. In that sense, all we have are these kind of cross trial comparisons to suggest, so in it, and we don’t have that, what we say level one, randomized data, but that tends to be my practice in those situations.

Manju George 42:35
Okay, thank you so much. The next question is, what’s the status of the E plus C Nivo trial. Do you have some updates?

Dr. Kopetz 42:44
Yes, so we’re going to be so that is a small kind of phase II study that is trying to build on the EC nivo single arm data there. The hope is there’s a subset of patients that may be deriving benefits from the nivo. So that one we should be able to present at ASCO this year. So we’ll have some of that that it was small the control arm was I think less than 30 patients there, but we’ll have that data.

Manju George 43:22
Okay, okay, thank you. So the next is, what is in line next, in terms of new regimens, now that breakwater is done, where’s the field heading? What’s cooking in your lab?

Dr. Kopetz 43:36
Yeah. So we’re really interested in the these epigenetic state, inhibition, I think the the idea to say that, that there’s a subset of cells that are kind of are adapting in some way to evade the those therapies. And if we can understand what those dynamic changes are, then we can potentially, kind of come in with inhibition and and look at different ways, the different vulnerabilities that may come up now. These can take the form of, potentially, thinking about ways to combine it initially, like, how do you extend duration when combination? Or can you understand these paths of resistance and then, kind of treat upon progression? So we’re trying to explore both ways.

Manju George 44:39
Okay, okay, thank you. So I’m done with those questions, and then here we have some Q and A questions. So those who are listening, if you have more questions, please add them in there. So the first question is, if there is a chemo for life patient, is there an argument to be made to do standard of care followed by E plus C or vice versa to prolong longevity rather than use the efficacy of both treatments together?

Dr. Kopetz 45:06
Yeah, no, that’s a, I mean, that is, that’s the angst, and I think that’s what surprises us about BREAKWATER. So the control arm, even if we limit to those patients who and the majority of patients, had access to BRAF, EGFR and second line in the control. So this was that study, in essence, the say standard of care chemo, followed by EC. How do patients live longer than when you put it all together? And the short answer is, it really matters, when you put them all together, that there’s a true synergy. It’s not kind of a one plus one equals two, but you’re getting much more. We think it’s because of and I know this looks like this question was like part way through my lecture, so hopefully I answered it with the kind of explanation of the how we’re trying to constrain the mechanisms of resistance. But I really think the data suggests that in this case, at least, it’s not about stringing it out, but really about bringing the best regimen together at the beginning.

Manju George 46:09
Okay, thank you. The next question is for can this drug regimen be used for patients without a BRAF mutation?

Dr. Kopetz 46:19
Yeah, great question that the short answer is, not, at the moment, there are, there been kind of different areas to explore in this space to kind of think through how you know what BRAF can do. One little bit of an aside is that there has been a recognition that the skin toxicity of the BRAF and EGFR combination is much less than you’d expect with EGFR alone. So the Cetuximab rash kind of acneform, kind of face trunk, but when we give the BRAF inhibitor, it’s actually less. They actually have much less, patients still have some skin rash, but it is substantially less so one of the areas has been like, Okay, well, could you use BRAF inhibitor to try to modulate some of that toxicity? But now, instead of taking it as encorafenib, as a pill trying to reduce that toxicity, there’s a company that’s actually made an essence of BRAF inhibitor skin cream. And so the idea is, could you just put a BRAF inhibitor skin cream on and treat the EGFR rash there? So that’s one kind of creative way where the BRAF inhibitors are being utilized there and I think in some extent, these drugs were engineered to be more potent against the mutated form of the protein. So that mutation is not there, it makes it a little harder to kind of utilize it, although I still think there’s some creative opportunities there, we just have not fully explored.

Manju George 48:07
okay, but in general, like to as a line of treatment for somebody without a BRAF mutation. You don’t generally recommend it?

Dr. Kopetz 48:16
yes, I should just be clear with that. No, we shouldn’t use it. There’s really no data about using encorafenib for anything but that BRAF V 600 E. Now the corollaries we also, I talked a little bit at the beginning about what about other BRAF mutations? And I think the data really has not.. we’ve tried for some of them. There’s different classes as we talk about them and characterize them, we tried these in different ones, and they have not provided benefits. So I know it’s tempting, because sometimes you say, Well, my report says a BRAF mutation, but they behave very differently than the V600E.

Manju George 48:51
Okay, thank you, for those who can only tolerate E plus C alone. Can it be continued once progression occurs, will it slow growth? Does it have to be stopped once progression occurs?

Dr. Kopetz 49:06
Yeah, so good question. We don’t fully understand all the dynamics of it. What we can say is that when we’re doing EC alone, that the mechanisms of resistance tend to be genomic, and kind of a get acquired pretty robustly. So we do think in those settings that kind of stopping the EC is beneficial, and that doesn’t necessarily result in any kind of progression or that continuing, it doesn’t result in more inhibition of the growth.

Manju George 49:46
Okay, so the next couple of questions, like in the BREAKWATER trial, do you have some data on whether people were able to get to surgery to resectability?

Dr. Kopetz 49:57
Right, yeah. So we do. There is some data suggesting, perhaps, that more patients may be able to get to surgery. We just, we need to kind of get that data little cleaner. It’s been a complex area, because there were several years because of the biology of BRAF and the outcomes, surgeons had just said, I’m not going to take a patient with a BRAF mutation to surgery. I just don’t think that it’s kind of beneficial in that regard. I think now the field has shifted a little bit, and people are more willing to do that, and we are seeing that, we are seeing anecdotally even, that some patients that go to the or for resection of their metastatic disease can have complete pathologic responses, which is just really extreme, great response to the treatment.

Manju George 50:53
Okay, okay. And then the next thing is do you have some breakdown of the people on BREAKWATER like, what kind of mets? I think you had the table, right? How many people had peritoneal Mets, and how did they respond?

Dr. Kopetz 51:09
Yeah, we don’t have breakdown by sites. It’s a great question. And so that we don’t have that data to say, you know that this group of patients perform better than the others. We do have in some of our waterfall plots, we can try to tease that out by eye, and then there are kind of we call forest plots, that have looked at that. The numbers are just small, but it looks like, in general, they’re performing better, but we don’t have, like, a breakout of response rate, for example, by peritoneal mets in particular.

Manju George 51:50
Okay, so next question is, what trial options are available for BRAF patients after BREAKWATER, you mentioned the BET inhibitor, right? Like, what else?

Dr. Kopetz 52:02
ERK and the rechallenge are the main ones that are out there right now being explored.

Manju George 52:08
Okay, the next question is, can you speak to any BRAF targeted therapies that are in the pipeline that are expected soon?

Dr. Kopetz 52:15
Yeah, so there’s work on on degraders. So degraders are one space. The idea is, instead of inhibiting it, can you grab the BRAF and just pull it and destroy it? So just kind of chew it up. Now, the cell remakes it, so you have to keep grabbing the BRAF and destroying it. So that’s kind of one of them. There’s been other areas to try to improve upon them. Kind of these next generation BRAF inhibitors that has some characteristics about how the different BRAF and CRAF and ARAF all kind of linked together. So these other family members, it’s B, because there’s an A, B and C, by the way, in case you want to know where the B came from. So there’s these other family members in the RAF family, how they interact. So there are some smart chemists out there trying to sort that out. We don’t necessarily know that they’re going to be better than what we have right now.

Manju George 53:19
Okay, okay. And then what about immunotherapy combinations? Is anything new being tested?

Dr. Kopetz 53:26
Yes, we have the PD-1. And that was done when we are looking back in the preclinical models. And again, always trying to learn everything we can and thinking about other strategies. The intriguing thing is that it really looks like that more than PD-1 is CTLA-4 that is the one that’s driving a lot of benefit, which is a kind of a common theme we’re seeing in in colorectal in general. That PD-1 is okay, but CTLA-4, really, is kind of what induces a bit of greater responses. So there is some intriguing data to say if we had the SWOG study that the encorafenib, cetux nivo study, would a CTLA-4 be better than that. So, these are things that we just have to try to prioritize the questions that we ask and try to understand if that’s going to be better. The other is vaccines. So there are some. There’s been a lot of push. Elicio, for example, the company that’s been generating K RAS vaccines for pancreatic cancer and then for colon and many others have been whispering in their ear to say, think about BRAF. Think about BRAF. So that’s on their radar. And so the hope is that maybe there could be some vaccine strategies to to kind of follow since we are talking about a single point mutation. So it’s kind of well aligned for that.

Manju George 55:06
OK. Next question is, are we close to a CAR-T, options for BRAF V600E?

Dr. Kopetz 55:15
Great question. We don’t see anything. I don’t know I say close, I mean, I think CAR- T’s have just been tough to try to find the cells that can get into the tumor there. So, so I would say we still have a little bit of way to go to even get CAR- T’s, in general, in solid tumors working. But we’re starting to see some, some progress. The difficulty is that you know when you have a single point mutation, that it’s getting expressed by a TCR, and these are really more like TCR TIL therapies where you’re trying to target the BRAF itself is that you’re looking for just a single mutation, and sometimes it’s hard for the immune system to tease out, like, really small differences in there. A lot of the CAR- T options are targeting completely separate proteins that are on the surface of the tumors. So the CAR-T’s are coming in and binding something on the surface that may not be related to V600E, so maybe that some of the CAR- T therapies being developed can be applied to BRAF population, but may not be BRAF specific.

Manju George 56:33
Okay, okay. And then in the BREAKWATER results, do you see a difference in patients who are younger with the BRAF mutation versus the older, right sided tumors. Is there a difference in outcomes?

Dr. Kopetz 56:47
Yeah, so that we have some data on early onset BRAF that says that they are deriving benefit from the therapy just as well as patients that are average age of onset. So I think the you know some subtle differences, but that there are some distinctions. Now, BRAF, in general, tends to be associated with MSI high in later onset BRAF, so I guess the caveat is that early onset less likely to have a BRAF associated with MSI high more likely to be MSS, but within the MSS BRAF, they tend to do the same as average age.

Manju George 57:36
Okay, okay. And then this is my other favorite question. So, with the pharmacogenomics testing, because we are combining E plus C with FOLFOX or FOLFIRI. Do you think that there can be more tailoring of the chemo part of the regimen so that people can stay on it longer? Are there any efforts to do that?

Dr. Kopetz 58:01
So, you know, we’re still, I would say, nascent in our understanding of pharmacogenomics. We know for irinotecan, UGT1A1, there’s some older data about the utility of that to kind of tailor things that really is more relevant for higher dose. irinotecan, kind of saturates a lot of the metabolism transporters, for the doses that we’re giving every two weeks, it’s kind of less relevant. So there has been some discussion like, Well, gosh, could you increase the dose of irinotecan in a patient that may have just the right pharmacogenomic subtype there, and I think that there hasn’t been a lot of work being done on kind of dose escalating the chemotherapy based on pharmacogenomics. But certainly a possibility. The problem is we don’t yet have pharmacogenomics for why the patients are responding to BRAF, for example, so we don’t have good answers there.

Manju George 59:03
Okay, okay, I think we are at time. And thank you so much. This was an incredibly informative talk, and I hope we can have you back when you have new trials and give a talk.

Dr. Kopetz 59:18
Yeah, always a delight.

Manju George 59:20
Okay, thank you. Thanks to everyone who was able to join. And as I said before, a recording of the video will be posted in COLONTOWN University in about two weeks. Thanks. Thank you, everyone. Thanks. Bye. Dr. Kopetz, bye.

DocTalk
2026
Dr. Kopetz
MSS
Trials
Doc Talks

In this DocTalk, Dr. Scott Kopetz, MD Anderson Cancer Center, discusses the much awaited results of the FOLFIRI + Encorafenib + Cetuximab arm of this 1L trial for patients with BRAF V600E–mutated metastatic colorectal cancer. Recorded in February, 2026.

Recommended Resources

Research article
Encorafenib, cetuximab and chemotherapy in BRAF-mutant colorectal cancer: a randomized phase 3 trial
Scott Kopetz | Nature Medicine
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BOT+BAL trial for MSS CRC

BOT+BAL trial for MSS CRC

DocTalk
2025
Dr. DeVito
MSS
Immunotherapy
Trials

In this DocTalk, Dr. Nicholas DeVito broke down the promising 1L BOT + BAL trial and explained the current state of immunotherapy for MSS colorectal cancer. Recorded in June, 2025.

Manju George 0:00
Hello everyone. Welcome to COLONTOWN DocTalks. I’m Dr Manju George the Scientific Director at PALTOWN Development Foundation, the nonprofit that supports COLONTOWN. So today for our DocTalk, we have Dr Nicholas DeVito with us from Duke University, Duke Cancer Institute. So before we start, I would like to ask Dr DeVito how he got involved in this kind of research, and especially into GI oncology. Welcome, Dr DeVito.

Dr. Nicholas DeVito 0:27
Thank you for the introduction. And my foray into immunology goes way back. I actually became interested in immunology while volunteering with an HIV and pregnancy prevention program in high school, and I wanted to understand immunology a lot better, so I kind of started from the immunology perspective, then joined a cancer vaccine laboratory, and then it kind of developed from there. And there was such a need and such a high ceiling, and so much work to be done in gastrointestinal cancers. I had an opportunity here at Duke to stay on board and continue my laboratory research, as well as kind of go into some of the trials that we’ll talk a little bit about later on, but it allows me to really bring things from the bench to the bedside and back again in these emerging immunotherapeutics and colon cancer. So I think that’s that’s worked out well.

Manju George 1:19
Okay. Thank you very much for that introduction. And I think everyone is really excited to hear about Bot Bal, because it has been a topic of interest in COLONTOWN. So thank you so much for making the time to be here with us today and to tell us about immunotherapy in MSS colorectal cancer.

Dr. Nicholas DeVito 1:39
Great. All right, so I’ll go ahead and get started. Anyone feel free to interrupt me at any point in time. If you have a question, you can just raise your hand through the chat or come off mute. So here are some of my disclosures. The most relevant one here is that I’m a PI and that stands for Principal Investigator on studies from Xilio, and then I received drug only support from Agenus as well. They do not fund our trial directly, however. So let’s start with an outline of kind of how we’re going to approach this, which will be a layered talk where we talk a lot about immunology. As I mentioned before I came into oncology with an immunology background, which is a bit inverse of what most people are doing now, which is they came in as oncologist and then starting to learn immunology later. So I do think it’s important that we we ask the basic question of, like, why immunotherapy? Why do we like the idea of immunotherapy and and how do we think of the immune system and cancer in the age of immunotherapy? And why hasn’t it worked in micro satellite stable colorectal cancer to date? Why have there been so many disappointments? What are sort of the molecular reasons for that? What are the the situational reasons for that, all of these other kinds of things.

Dr. Nicholas DeVito 3:00
In this time, I’d like to explain immune checkpoint blockade, and one thing I’ve done before with some of our fellows is drawn this out on a board, which I have behind me here. So we’ll kind of talk about that, and I’ll scribble it out on the board, and you guys can try to read my handwriting. But I think it’s nice to see immunology visualized, because that’s it’s such a multicellular, interactive process. We’ll also talk specifically about second generation FC modified CTLA 4s which are like botansilimab or Vilastobart and how they’re different from standard first generation CTLA-4 drugs which simply block the receptor as their primary mechanism of action. This would be like Yervoy or Ipilumumab or tremelimumab. We’ll then go into some of the completed and active trials with Bot Bal and then management of adverse events.

Dr. Nicholas DeVito 3:50
So I’ll start with why immunotherapy. And every immunotherapist probably thinks of like renal cell carcinoma or melanoma as the first step with immunotherapy, rather than colon cancer, because these are tumors that had some response to a drug called IL-2, which was very toxic. And I say some response, I mean, like 5 to 10%, they were very, very low. It was hard to get patients through therapy. But the promise was there that if you could get the immune system to reject a cancer and and learn what the cancer looked like, you could reverse the process, essentially. And you would see that in some patients with metastatic melanoma. So it was like this thing that everybody kind of kept grasping for, and still at the time, if patients couldn’t tolerate IL-2, which many could not, they would get to the decarbicine chemotherapy’s overall survival was only nine months. It’s pitiful. It’s unacceptable in metastatic melanoma. But when we look at what ipilumab and nivolumab have done, anti CTLA-4 and anti PD1 drugs, respectively, in metastatic melanoma, the median overall survival is six years and over. Half of patients are living melanoma free at 10 years. So I bring this up because this is one of the next bars that we need to get to. And when I talk about the ceiling in GI cancer, it’s like, it’s important to know where others have been and realize that with the right drugs and the right trials, we can get there too. So this is sort of an inspiration for me, and I hope it is one for you as we go through this talk.

Dr. Nicholas DeVito 5:24
But one of the problems is how we used to think of the immune system. Now, I’m sure many, many people still do is as this binary, there’s up and there’s down, and so we’re just going to boost the immune system and it’s going to fight off all the cancer, and there’s not going to be cancer anymore, and it’s just that simple. And I bring up this picture because it’s just like a drastic oversimplification, when really it’s like the Department of Defense, which is that map in the top left, you can see how many immune cells have come out of these advanced technologies, like single cell RNA Seq. And so I bring this up to point out that in the past 20 to 30 years, immunology, and in particular, tumor immunology has advanced very, very, very rapidly, and our understanding has deepened very quickly. And for us to catch up to this, we need to have a basic understanding of immunology to start with, and we need to kind of rethink what we consider cancer itself as, in some ways. So I really would say that cancer is a complex “neo organ” that arises due to a failure of immunity. It fails genetic checkpoints, like it doesn’t die off when it gets a RAS mutation or a P 53 mutation together. And that’s bad inside the cell, but then outside the cell, the immune system is supposed to fight it off and recognize it as non-self. So the two checkpoints have failed, the genetic checkpoint and the immune checkpoint. Ergo, you get a tumor. And it’s not simple. It’s not like just T cells are going into the tumor and they take care of everything you have. Like in this graph alone, I think 11 different types of macrophages when they used to think there were two. So this is just to show you the complexity and how daunting it is and how we need to really learn and understand things on a niche level. And when I say we, I don’t just mean physicians and researchers. I mean patients as well, because these things have other implications, like side effects down the road, and separating side effects from effectiveness, and keeping drugs that are effective but tolerable. So our understanding of immunity will continue to advance, but there’s a lot that’s already been done, and I think that is really something that we have to recognize up front.

Dr. Nicholas DeVito 7:33
My favorite framework of this, and I think this is very accessible, especially if you just take some time with it and kind of look at it on the visual perspective, like I was talking about, are the 3Es of immuno editing by Robert Schreiber. So you have normal tissue, and then cells are transformed, and they’re supposed to get recognized, and then they’re supposed to be eliminated by these NK cells, CD8 and CD4 Tcells, and then antigen presenting cells, like macrophages and dendritic cells. But unfortunately, if we don’t get that extrinsic tumor suppression, if immune control fails, then we reach a state of equilibrium where tumors can sit in dormancy for months and years at a time, or they can escape, later on. And those escape mechanismsare defined by suppressive cells coming in. These are like T regulatory cells, or there you’ll see the abbreviation MDSC, which is Myeloid Derived Suppressor cells, or bad neutrophils, would be another way to think of them. And the goal of immunotherapy is to push these tumors to the left of this chart, to go closer towards elimination. And I think that this is a really nice framework, because it also fits the framework of response– stable disease and progressive disease. So this is a basic scientific idea and concept, but it is one that helps us think of the clinical concept of tumor and immune interactions over time as this kind of evolutionary struggle, and maybe help us determine where we need to go with an immunotherapeutic and how we can define populations that will benefit, and then how we can also define where we should use novel agents.

Dr. Nicholas DeVito 9:12
And one of the best examples of this is if you have micro satellite instable colorectal cancer. So this is a subset of colorectal cancer that we know has a screaming high tumor mutational burden, but more importantly than the number of mutations, because there’s been studies in the lab that MSI alone is not sufficient to induce anti tumor immunity, the number of mutations are very high, but they’re also these mutations called frame shift mutations. And this would be like if you were reading a book instead of there’s some spelling errors, the entire type shift is off, and you’re like, This is all wrong. You wouldn’t recognize a single word in it, and then you just throw the book out, or whatever. And instead of being like most tumors, where they have maybe like a misspelled letter here and there throughout the page, and you could skip over it without recognizing something’s wrong potentially. And what you can see is that there are just astounding results in these 5 to 10% or so of MSI high colorectal cancer patients, because they have an antigen that’s being recognized by the immune system, and the immune system is trying to attack it, and the only thing that’s keeping it from killing the tumor are these immunosuppressive mechanisms, like immune checkpoints. And one other important point that I would bring up too, is that in these studies, they allowed crossover. So starting on chemotherapy first and then doing immunotherapy was not ideal for these patients, and I think that’s something that often gets lost in this data, but many of these patients crossed over after progression on chemotherapy, and then they benefited less than immunotherapy, given the continued decline that you see of those curves and progression free survival in both these data points.

Dr. Nicholas DeVito 10:53
So that’ll come up a little bit more later, but to kind of parse these differences more of why we’re not getting responses in MSI high colorectal cancer, aside from being a much less common, and therefore there’s a much higher need in MSS, CRC, right now, they’re very different tumor types. And I bring this up here, not to go through every specific point necessarily, but I really, really, really would think of these as two different diseases when I’m teaching fellows or residents, or we were just talking about this in a lab meeting earlier today. It’s like when you’re looking at human data, there is MSI high colon, and there’s MSS colon, and it is as different as like melanoma and lung cancer, like they are not the same cancer type. Missing doing microsatellite instability on any colon cancer in the in 2025 is completely unacceptable. It’s part of the diagnosis. So that’s really what I want to convey with this slide, because we’re treating these cancers very differently. We’re giving one pure immunotherapy regimens all the way forward. And then there’s some interesting trials for MSI- high too and MSS, we’re treating with a lot of chemotherapy and targeted based therapies as standard of care. So very, very different diseases, and therefore they have very different immune micro environments, which this is kind of harkening back to what we were talking about before.

Dr. Nicholas DeVito 12:17
So rather than just thinking about tumor, tumor, tumor– the tumor is this ecosystem, and it has these immune cells that are associated with it. And in MSS colorectal cancer, with a low mutational burden and known limited responses to traditional checkpoint blockade, you see fewer CD8 T cells overall. There’s a small subset that may have some some higher amounts of CD8 T cells. You see dominance in T regulatory cells, which I mentioned before, whereas these are more variable in MSI high, and you see these suppressive myeloid cells that are enriched in the tumor and usually the most dominant immune cell overall. So once again, on almost every facet that we look at, these two tumor types, they’revery different, and it’s important to think of them that way, immunologically, because it helps us understand why immune checkpoint blockade doesn’t work in microsatellite stable colorectal cancer, and it does work in microsatellite in stable colorectal cancer.

Dr. Nicholas DeVito 13:15
So one thing I’m going to attempt to do right now is a board drawing. So bear with me, because we’ll see how it goes. But I think it’ll be worth it. If we can get itgoing. All right, so, okay, can everybody see the board as the primary screen? Okay, wonderful. All right. So what I’m going to do is, I’m going to start with a tumor here, and tumors have antigens that are recognized by these traveling cells throughout the body called dendritic cells, or DCs. Dendritic cells can do something very special that other cells can’t do, which is antigen cross presentation, where they digest this antigen up and they can present it on MHC -I, or major histocompatibility complex one, and MHC-II. But they don’t do that in the tumor. They actually travel up here to a different site called the lymph node, which I’m sure most you are very, very familiar with, for a number of reasons, and there’s an importance to the fact that it is often co opted by cancer in one of the first places that they spread to. So the dendritic cell then travels to the lymph node. And inside the lymph node, what that dendritic cell is doing is interacting with CD8 T cells and CD4 T cells, and they’re getting TCR recognition, or T cell receptor recognition. And this is supposed to be similar. So they’re recognizing the same antigen. They’re agreeing, hey, this isn’t supposed to be here. And the T helper cell with CD4 is stimulating. Then after they get this first signal, stimulating via another molecule called CD 40 ligand, and CD 40. And then you get a second signal on CD 80 and CD 86 then and only then do you get a CD 8 that travels to the tumor after all of that and then produces things like interferon gamma and perforin and granzymes, which kill tumor cells.

Dr. Nicholas DeVito 15:18
So why are the tumor cells not all dying, and why are they not going away, if we have this complex mechanism of recognizing self versus non self? Well, tumors do something to naturally defend themselves, which is to up regulate PD-L1. I think this is an important concept in all of anti tumor immunity, is that this requires all of this. That means that there’s antigen recognition and that there is [I see Annie Delores has a question about the sword in the window, which I’m going to take a break to recognize that I was a knight for a Halloween costume a while ago. So I think that picture is somewhere on my LinkedIn, but I wore a suit of armor to clinic. It was, it was a lot of fun.] So again, the PD-L1 up regulation occurs in response to interferon gamma. And the interferon gamma isaround because you have a tumor that is recognized by an antigen specific CD8 T cell. So all of this process comes down to PD-L1, and it ends up being the last step, and it ends up being why it’s such a good backbone for a lot of our immunotherapies, and why it’s so rational that we’re using it now.

Dr. Nicholas DeVito 16:28
What else occurs here that keeps our immunotherapies from working is the up regulation of CTLA4, and this was really focused on primarily in CD8 T cells, because it would compete for the second signal and block it. But CTLA 4 is actually expressed on another cell that’s really important in suppressing CD8 T cells, and those are those T regulatory cells that I brought up before. So they actually express the highest levels of CTLA 4. And when you give drugs like ipilumumab, they don’t necessarily get rid of these cells, whereas other drugs like botensilimab will. So it is working primarily here, and then all of your other drugs, like your anti PD1 drugs are working here, and this is why they work together synergistically, and this is why we use some of these biomarkers and all of these therapies together. So I’ll pause for a second if anybody has quick questions on like the board, and then I’ll kind of launch into into next steps here.

Manju George 17:31
Yeah, I wanted to say that I loved your introduction about the different cell types and how all of that kind of correspond to stable disease or progression. I mean, that’s a very nice way of presenting it.

Dr. Nicholas DeVito 17:44
Good, good. I’m glad to hear it. Okay, so I will go back to my screen here. All right, great. Um, so I think that’s a useful framework, and we will actually have an immunology lecture up on a website called VuMedi hopefully in the next month or two that can help to answer some of these questions, too, for anybody who’s interested in a real deep dive in immunology. So I’m going to focus on botensilimab now, because it’s a much different mechanism of action than just freeing up that second signal of costimulation on CD8 T cells, and it’s what makes it really effective when you remember the micro environment that you see in MSS CRC, as opposed to MSI.

Dr. Nicholas DeVito 18:32
So the first generation CTLA4 antibodies, again, as you all know, are designed to block that interaction with CD 80 and 86 and allows for the second signal to occur. But if you modify the back end of the antibody that is not sticking to its target, this is called the FC gamma receptor, you can get depletion of the cells that it is in contact with. And the way this works is that NK cells, or Natural Killer cells can can attach to this FC enhanced region and other cells– in that case, they put APC or just Antigen Presenting Cell–but often these are macrophages, and they will eat or destroy the T regulatory cell that’s there. And in doing so, it actually activates those myeloid cells and shows reprogramming. And this has been demonstrated in multiple mouse models now, as well as some pretty interesting data from the early botensilimab trials, that this mechanism of action is quite believable. And I will say, from my own experience, that the another mechanism of action that was recently published, like two weeks ago is that it increases the flux of high endothelial vessels to the tumor, meaning it’s essentially generating a lymph node in the tumor and potentially generating tertiary lymphoid structures. And you can even see that on scan sometimes where there’s like lymphatic engorgement around the tumor site. So it’s really a fascinating immune activating drug that ultimately just results in decreased T regulatory cells, activated myeloid cells instead of suppressive ones, and potentially increase lymphatics, so acting very differently than first generation CTLA4 drugs, and addressing a lot of the mechanisms of immune suppression that we see in MSS, CRC.

Dr. Nicholas DeVito 20:24
So I will start with some of the resulted trials in the metastatic setting with Bal and I think you all probably know this already, but balstilimab is an anti PD1 antibody. So I won’t go into tons of detail about that, since we kind of talked about it a little bit, and you all may be familiar from other talks. And then I’ll talk about in the neoadjuvant setting, which I think is really, really fascinating, tells you a lot about its mechanism, too. So this was the Nature Medicine paper that came out last year, about a year ago now. And what they found was that if they treated patients who are late line, microsatellite stable colorectal cancer with botensilimab, they saw a significant benefit if patients didn’t have active liver metastasis, but if they did have active liver metastasis, they were very, very unlikely to benefit, as seen in the red there. That’s something called a waterfall plot, and shows the percent change in a lesion over time, or the best percent change. So you can see that all of the ones that are more than 20% growth for the most part, are active liver metastasis, and all of the ones that are above 30% tumor reduction, have no history of liver metastasis. And then a couple patients that have treated liver metastasis. So this is a really, really important finding, because we essentially have an anatomic biomarker, is how I would think of this. So PD-L1 is useless here, and as I’ll show you in a second, so were things like tumor mutational burden, an interferon gamma signature and a neutrophil signature, which have been shown in other studies to predict immunotherapy response. All of these things washed out in importance to active liver metastasis, which tells me that since all of your blood volume circulates through your liver, there must be a systemic immunosuppressive effect that is induced by liver metastasis. This is something that we and others are studying in the lab using colorectal cancer models that are implanted in mice endoscopically into the wall of the colon and then metastasized to the liver, to better understand how they’re systemically suppressing anti tumor immunity, and we can then convert those to responding lesions. So really important early findings telling us there’s an anatomic biomarker here, and again, this is just to show their overall survival and progression free survival. They have a number of patients who did not have active liver metastasis, or had treated liver metastasis, who actually did quite well on bot bal and have durable responses. So this is very encouraging activity, especially in a late, heavily pre treated population. So what if you give it before other therapies? You know, this is like neoadjuvant bot bal, or given before the surgical resection of the primary so a lot of this work was done by Pashtoon Kasi who was at Cornell and is now at City of Hope. And then Myriam Chalabi, who is in Europe, she has done in other tumor types and shown some very interesting data as well. So a lot of encouraging responses here. And what Dr Kasi really focused in on is the fact that when you use a spatial analysis, and you you look at pre treatment and post treatment. So the tissue is intact on a slide, and you’re seeing where the T cells are in the tumor. And you can just see the increase in blue, CD 4 T cells and pink, the CD 8 T cells. And it’s almost impossible to tell from this slide, but you also see a decrease in the red FOXP3 which are T regulatory cells. So again, botensilimab working how we expected to, checking boxes on our scientific hypotheses.

Dr. Nicholas DeVito 24:19
Here showing us what we’re seeing from the mice. And then there’s again, and this was sort of prophetic, if you think about it. And in those terms, is that he observed responses from the outside of the tumor in, which would support the development of HEVs and lymphatics outside the tumor into the tumor, not that they’re developing like an immune organ inside the tumor, necessarily. So that’s how the early response to these drugs looks. So this was really fascinating. Therewas a 50% pathological, or greater than 50% pathological response rate in MSS CRC, and I think that owes to the fact that these locally advanced colorectal cancers have fewer immunosuppressive mechanisms that develop concordant with metastasis. So very interesting.

Dr. Nicholas DeVito 25:10
Here’s the waterfall plot, I mean, and that’s all MSS on the left side. So these patients are, in some cases, potentially avoiding surgery, though all of them were assessed for surgery. They also had no delays in surgery, which is really remarkable to me, which shows you the safety and manageability of side effects with with bot bal, which we’ll talk about and in the end, and it’s really, really important to as you all are reviewing immunotherapy studies, and you’re kind of like trying to catch up with this incredibly fast moving world is that it’s important to ask where the trial was done, and what the populations they were treating etc, and how the study was executed, because it tells you if this is just kind of a one hit wonder, or if this is actually like something that is really has a lot of meaning. So the GONO group in Italy did exactly this with all MSS CRC, so this isonly micro satellite stable CRC, and they saw a pretty decent response rate. I mean a partial response rate in their bowel cohort of71% is not bad, even though these are small numbers, it gives encouraging data towards, again, the mechanism of action and the fact that this could be a real therapy for a lot of patients.

Dr. Nicholas DeVito 26:21
And importantly, really, the only side effects that they’re seeing that are of any concern are things that are extremely manageable, so no one is experiencing severe side effects, at least on either of these trials, and they treated 56 patients in this one, they’ve treated over 100 in the metastatic setting in the previous paper, and many more since then. So all really, really encouraging data, and that’s why there are so many trials ongoing right now with bot bal in so many different settings. So this is kind of the the potpourri part of the talk before I before I get to a specific first line bot bal trial. So I’m going to go through some of these briefly to the best of my ability, and I’ll present results when they become available. But otherwise I’m just going to tell you where they’re, they’re enrolling at and knowing how fast this is moving, and in this space they’re they’re probably outdated already. So this platform study is very interesting. This is being done by Dr Shah at Cornell. It involves patients with MSS CRC, with resectable liver metastasis, and they undergo a random assignment, either receiving bot bal or bot bal plus a novel agent. And this agent basically tries to block two immunosuppressive pathways, TGF, beta and adenosine, which is the CD73 receptor, and then another one, which is bot bal and radiation together. So this is called a platform trial, because there’s lots of different arms that one could be placed on. They don’t have any data yet that I know of, and it’s interesting because they give all of their agents before and after surgery, so they will get data on what’s going on the liver micro environment. So I think we’ll learn a lot from this trial. I think it’s a really, really interesting study. I think if you’re interested in enrolling in these kinds of studies, I would definitely like reach out and make sure that you know all the your eligibility is correct before you make a trip to New York, if it’s a if it’s a trek for you. There are combinations with other novel agents Other than that, one from the Agenus that I mentioned before, including one that enrolls patients with MSS CRC after one line of therapy. So taking patients even as early as second line, which I’m always a proponent of, is allowing some flexibility there, given that there are lots of folks that really struggle with chemotherapy. And this one involves an ENPP1 inhibitor,which also decreases adenosine, but is known to activate a pathway called stimulator of interferon genes. And the idea would be that it makes tumors more immunogenic essentially, and maybe makes them more likely to respond to MSS, CRC. This is at multiple sites, so I think this is a really good option for people, especially if there are no liver metastases, to get access to bot bal and a novel agent.

Dr. Nicholas DeVito 26:32
There is also a KRAS targeted peptide vaccine that’s enrolling at Johns Hopkins. They have a lot of experience in this area. The idea, again, kind of like you saw on the board, would be to increase that antigen load and then induce interferon gamma responses and CD8 T cells into the tumor, and know that they’re going to get suppressed by immune checkpoints, which is why a lot of tumor vaccines failed, and then chasing them and depleting Tregs as well. So I think this is a good study as well and now they’re enrolling patients with with at least one line of therapy, so it’s a really safe population that they’re taking on. There are a few studies that are active but not recruiting, like this one from Marwan Fakih over at City of Hope. This is bot bal and regorafenib. I am not sure when that is going to start recruiting, but it combines an approved third or fourth line agent, regorafenib, with bot bal. And the idea would be that it decreases angiogenesis, which can be another suppressive mechanism, and has an approval in a lot of other cancers like hepatocellular carcinoma, where we give this kind of combination, in general.

Dr. Nicholas DeVito 26:59
And then this one, I thought was really fascinating. It’s bot bal with a fasting mimicking diet plus vitamin C, and it’s in KRAS mutant colorectal cancer patients. And I think the most interesting is that they do permit patients with liver metastasis. However, the patient has to have progressed on oxaliplatin and irinotecan already. So this is one that I think is probably a pretty intense study, but it could be an option for a lot of people and and one of the reasons it’s good to talk through all of these different studies as people could be in very different places in their cancer care, and we need to be addressing all of those places, not just one line of therapy. So it goes to show you that these trials are available in a lot of different settings, and that’s important for access.

Dr. Nicholas DeVito 31:11
Marwan Fakih at City of Hope has also started this trial, which they reported some initial results that I’ll share of FOLFOX and Avastin plus bot bal, and most of these patients are being retreated with FOLFOX from my preliminary review of the data. But you see, everything is kind of given all at once together. So this is somewhat resembling some of the other studies that have been done with like durvalumab and tremelimumab in combination. This has also been done in the first line with drugs like atezolizumab, with FOLFOXIRI which is called the Atezo TRIBE study, which showed some marginal benefit. But this was interesting to me, because this is a pretty decently pre treated population. There are some patients who had not received treatment before, and they get chemo plus bot bal as almost like a first line, but it’s nice that you’re involving like a mix of patients. You’re giving access to patients with liver metastasis, and you’re getting responses. Some of that could be just due to FOLFOX re reintroduction, but the classical reintroduction FOLFOX response rates are somewhere in like the 10 to 20% range. So I think this is still encouraging. And again, gives gives people options. I put the swimmer plot in there, though, as sort of the the salt or the rub, if you will, because most of these patients have progressed, and there is only two patients who are ongoing on therapy. So this does concern me that the responses that they’re seeing are transient and more typical of like a chemotherapy response. So I think that’s something we have to explore a little bit more of these combinations with chemotherapy. Is it rational, or is it known to combine these drugs together?

Dr. Nicholas DeVito 33:26
And then, before I talk about an investigator initiated first line trial, I do want to bring up another important question that I would think of whenever you’re looking at trials, is I’m looking at this class of drug, and there’s no way it’s the only drug in that class. Some other company makes a drug that’s similar to that, right? So KRAS inhibitors are a great example. There’s Quanta therapeutics and Rev Med, and all of these different companies making KRAS inhibitors. So if you saw one of them that showed a bunch of activity and looks like, it reduced tumors and did really well, and all of the others didn’t. That would be something to raise alarm and suspicion and to say, like, is that real? Whereas the opposite can happen, I think, with drugs like botensilimab, where a similar drug called Velocibart by a company called Xilio has demonstrated very similar activity in patients without liver metastasis. And this tells me this is a class effect of second generation FC modified CTLA4s. The patient on the far right there is my patient. She had a transverse colon mass and had a really, really impressive reduction in the size of that mass, and it’s unresectable. And she’s in her 30s, so this was areally good trial for her to be on, and she got on at second line. So you can see that the responses in a lot of these patients appear to be durable, and that circulating tumor DNA is correlating with response. So this is very reassuring, that this is a class effect.

Dr. Nicholas DeVito 34:59
So taking this data collectively, it makes us ask the question, why should we not give this first line without chemotherapy at all? Because most trials of immunotherapy have occurred in later lines, and we know from gastric cancer and from melanoma and from MSI high CRC, like I showed you before, that if you give chemotherapy first and then you switch to immunotherapy, you might reduce their effectiveness. And there’s mouse studies and some human studies pointing to the idea that chemotherapy can restrain the durability of immunotherapy efficacy by disallowing the formation of memory T cells. A lot of that has to be worked out. Unsurprisingly, we don’t know a lot of the effects of chemotherapy on the immune system or the tumor immune microenvironment, so we have to ask ourselves, with these impressive responses, is there a population of patients that could potentially benefit just from bot bal and not necessarily need chemotherapy? And I kind of mentioned that a little bit already,and we have a biomarker already. The biomarker is liver metastasis. If you have liver metastasis, you’re not going to respond. It seems like a simple biomarker. You don’t have to send it to a pathologist or or anything like that, to get PD-L1 ostaining, but it’s a biomarker, nonetheless, it tells you who is going to benefit from your therapy. So this is very important, because, again, these therapies are durable, they’re tolerable, and they don’t have a lot of the long, lasting side effects that chemotherapy does. So there could be a decent amount of people that could benefit from getting bot bal first line.

Dr. Nicholas DeVito 36:34
So we designed an investigator initiated trial called BBOPCO, or botansilimab and balstilimab optimization in colorectal cancer, wherein we take untreated patients with stage four MSS CRC, without liver, brain or bone metastasis. We get baseline circulating tumor DNA in either an optional biopsy or archival tissue we treat with botensilimab and balsilamab, and then at six weeks, we get circulating tumor DNA, and we get a CT of the chest, abdomen, pelvis. And if a patient experiences progression, we would biopsy that progressing lesion. And I think this is important too, because coming from a laboratory perspective, you always try to reduce variables as much as possible. So this is a tumor that has only been exposed to immunotherapy, and if the immunotherapy fails, then this is our way to get a potential answer to why, without having confounding mechanisms like other drugs involved or pre treatment, or anything like that. So these are very, very valuable samples, I think. And then if the patient has an ongoing response or disease control, we continue doing scans every six weeks and monitoring them and not starting chemotherapy unless we need to. In patients that do progress, we add FOLFOX and a biologic, and that is, I think, supported from a safety standpoint, by Dr Fkih’s study, where this has been done already, so we’re not worried about safety signals there. And we may be able to rescue some patients with FOLFOX in that manner.

Dr. Nicholas DeVito 38:07
So this study is funded by the Gateway Cancer Research Foundation, Crush colorectal cancer, which is the Duke Colorectal Cancer Fund. And we do a yearly 5k in March. So I encourage everyone that’s in the Durham area, if you can make it, that would be great. But this is something that came together on really a shoestring budget, and was something that is a really promising, I hope forfuture treatments. It is not a very involved study. Either, most patients are not spending a lot of time other than this q6 weeks CT scans. So we collect the normal baseline demographics, and we do ask for an optional fresh tissue biopsy, but this is not feasible in a lot of our patients that have lung metastasis and it’s impossible to access tissue. Then in the treatment period we are administering bot bowel, and folks are coming in every three weeks. And then if there’s progression of disease, as I mentioned before, then we’re adding FOLFOXand a biologic.

Dr. Nicholas DeVito 39:13
Our frequently asked questions that we’ve gotten about this study is are patientswith peritoneal metastasis eligible? Yes, they are as long as they don’t have clinically relevant ascites. We have had at least three patients enroll so far with peritoneal metastasis and in peritoneal carcinomatosis. And so I think it is safe to enroll these patients. And there’s a major need, for peritoneal carcinomatosis treatments that are more effective than chemotherapy. Patients may need to get another CT scan within 28 days of starting. And we have some of our oncology referral lines there, and we have a 48 hour rule, so we’re getting folks in 48 hours. Our GI oncology department at Duke is the largest in medical oncology. We all enroll to each other’s trials. So this is something we assess every new colorectal cancer patient for who does not have liver metastasis. Everything is provided by the study or standard of care billed to insurance.

Dr. Nicholas DeVito 40:16
And I kind of mentioned this already, but we either have your original biopsy, or we obtain another one, optionally, if that’s feasible and safe and we definitely try to gain a lot of knowledge from patients disease that progresses and obtain a biopsy at that time. So we expect to report results of this 15 patient pilot study in early 2026 we’ve already recruited half our cohort, and have no safety concerns at this time. So you can expect to see our results kind of on that timeline. But I hope that this is something that will expand first line immunotherapy options for patients with MSS CRC, going forward, I will stop there for a minute, and then if we have time, I will go into the management of immune related adverse events. And if not, that’s something I can share slides with you all.

Manju George 41:17
Yeah. Thank you so much, Dr DeVito, I was thinking that if you have just a couple of slides, maybe that’s a value to patients too, the side effects.

Dr. Nicholas DeVito 41:25
Yeah, let’s go through it. So the main three side effects that we see, and it’s almost always the botensilimab. Now keep in mind with any immunotherapy that can cause any itis, pneumonitis, colitis, thyroiditis, hypophysitis , any of these things are theoretically possible– myositis, where the muscles get inflamed, myocarditis, which is an inflammation around the heart. So they’re all very rare. They happen like less than 10% of the time, and some of them are less than 1% of the time. But it’s important to report any symptoms or any way that you are feeling different than you normally would, even if it seems very mild to your physician if you’re receiving botensilimab, because I think any immunotherapy can cause any of these side effects, and pretty much anytime you’re getting them, it’s just that most people don’t have them. So it requires a different vigilance than chemotherapy. It’s a completely different way of thinking, in my opinion, but the three that we see most frequently, that we have to manage on I would say probably about half of our patients that we’ve had on trial so far are infusion related reactions, early onset syndrome and immune mediated diarrhea and colitis.

Dr. Nicholas DeVito 42:33
Infusion reactions are fairly typical of other infusion reactions where this is a hypersensitivity reaction. It’s rapid, and we know that we need to give pre medications going forward. This is something that your treatment rooms and most oncology centers are extremely familiar with, with monoclonal antibodies, and I am not worried about people managing that at all. This early onset syndrome is a little bit different. It can be very self limiting. Can seem just like someone has, like, the flu. A lot of people have gotten tested for COVID because they’re like, I’ve got the same symptoms when I had COVID, fatigue. I’m tired, I and I have these chills, I have, like, a mild fever. You may have some other kind of associated symptoms with it, and it can be quite vague, and that’s something I think that it my suggestion here is one of my frequent suggestions with any side effect is like, write it down. Just write it down, keep a journal. Keep a log. Write down the symptoms you’re having. Write down the temperatures that you measure. Because, they mentioned Tylenol here, but Tylenol has been known to suppress immunotherapy responses, and it’s been known to suppress the immune system in general through the generation of iIL-0 and T regulatory cells.It’s been known for years that it decreases the efficacy of vaccines. So I’m not a big fan of using Tylenol, and everyone in our study so far has benefited from either using naproxen or ibuprofen, non steroidal anti inflammatories for a few days. And then we’ll start them on Imodium if they have mild diarrhea that doesn’t rise to the point of IMDC.

Dr. Nicholas DeVito 44:09
So I actually had one patient who during her first cycle of bot bal, she had the early onset syndrome, and then during the second cycle she had IMDC. So it was a very clear comparison between the two and how they’re different. This is very systemic, and the diarrhea is kind of like not your biggest problem. It’s really more that you feel achy and tired. But I think the thing that also has to be considered is this could also be infection. This could be something else completely. So alternative etiologies, alternative causes, need to at least be considered and brought up. IMDC is the one that everybody watches out for and is familiar with, because in very, very rare settings, and I think this happens very infrequently, now that we’re more familiar with it– you could have a perforation where the wall of the colon is so inflamed, particularly in this case, potentially around the tumor, where the wall of the colon is already damaged that it could perforate into the abdomen, which can be a fatal event. We actually send all of our patients out with prednisone at home, so they have it on hand, so they don’t have to call their ER or anything like that. They actually just have a prednisone script for just a short taper, and they say, Hey, I started having five stools a day. I’m starting the prednisone right now. There’s no time to go to the pharmacy, it takes all of that out in the middle. So time to treatment is really, really important, and patient education is really, really important. Some of these symptoms can be very vague and just seem like you kind of have, oh, maybe it’s a GI bug, and then it goes on for more than two or three days, it’s like, no, we need to get on that and treat it. And the best treatment for this, and I kind of alluded to this earlier, is to be able to separate those side effects and the benefit, right? So you want to get rid of the side effects when you keep the benefit. And if you just load people up on steroids, you do reduce the effectiveness of immunotherapy. So we tend to use within about seven to 14 days of symptom onset a drug called infliximab or another drug called vetalizumab. These are drugs for conditions like ulcerative colitis. Makes sense, right? The colon is inflamed. Use an ulcerative colitis treatment, and this can turn people around like that and get them off steroids. So it’s steroid sparing, it’s effective. You only have to give a few doses of it. You can continue the bot bal while you give it. So there’s a lot of reason that patients and providers need to know that these treatments exist.

Dr. Nicholas DeVito 46:31
So I am going to wrap up on the last slide, and I wanted to put on this slide the history of CTLA 4, because CTLA 4 was discovered in 1987 and everybody thought it was a costimulatory molecule like CD. 28 they’re like, oh, it’s the same.And Jim Allison, who won a Nobel Prize in 2018– so quite a long time after that, is the one who challenged that idea. And you can see what kind of an incredible benefit it has had for patients that he did that, but it also reminds you how long it takes for some of these things to develop. So this was not possible without NIH and NCI funding. And I think that it just underscores the fact that CTLA4 research, is just a great example of how federally funding laboratory science today can bring cures to patients tomorrow. So that’s, that’s where I’ll end on for questions. And I thank everybody for their time.

Manju George 47:25
Okay, thank you so much, that your talk was excellent at so many levels. So I would like to if you could go back one slide. I was thinking that from the patient perspective for IMDC, so can you give us a time course, like, for example, you give the infusion, when does the more than five stool happen, and how long people take prednisone, and then when do they get infliximab? Like, an example, patient,

Dr. Nicholas DeVito 47:55
Yeah. So a typical course, like one that I’m thinking of off the top of my head, it was, like, about three or four days after she got the botensilimab, she was fine after she got the balstilimab–, and then diarrhea started up to five times a day, she started the prednisone, and it’s always on a Friday, that’s when these problems always happen for folks, which is just cruel. And we went through this debate of like, Oh, do you come in and get inpatient infliximab and you spend time away from home and everything else. And she was like, no, let me see how I do taking 40,30, 20 of prednisone. And then we got to Monday, and we’re like, this is not happening. And we gave her infliximab that day. So to me, it is a little bit loose, like it can happen at any point, really, but it is usually within two weeks of giving the bot, and it is usually better to do a very short, like burst dose of steroids, or like, 40 milligrams, start it until we get you to infliximab. Because in that patient’s case, she was already down to 10 milligrams of prednisone and then stopped the next day, her taper, just like, continued going off. She’s like, I’m fine. Mad with the kids, having fun. No big deal. Infliximab did the trick. So I’m a big fan of using these biologics early. And if you’re on these drugs and you don’t feel like you’re getting assessed for them, I think it’s something to bring up.

Manju George 49:15
Okay, okay. Thank you so much for that. I think then let’s look at the questions, because we…

Dr. Nicholas DeVito 49:20
I scrolled up, I’m going up to one from Michael Nagel before, who asked what distinguishes treated liver Mets from active? So a treated liver met would be one that’s removed with surgery, or that it is treated with an ablation, and that it has demonstrated stability for a predetermined point of time. I think in that Agenus study, they needed to have three months of disease stability in the liver or something like that. Is there any evident difference between patients with treated liver Mets who respond to bot bal? That’s a great question, and those with treated liver Mets, yeah, yeah. We don’t know. We don’t know. I think there are more questions than answers around liver metastases and bot bal responses. I’ve also heard the question or argument that, if you gave it before doing some of these other therapies, would it be effective, or do the liver Mets become systemically immunosuppressive after exposure to chemotherapy? So this is a brave new world, and we’ve got to ask the kind of questions like this, and I think that’s a really good one.

Dr. Nicholas DeVito 49:20
UNICORN [trial], I believe, was colorectal. I think it included both colon and rectal. I’d have to double check myself on that, but that is a published study.

Dr. Nicholas DeVito 50:37
Do you ever see the NCCN approving immunotherapy for those without liver mets or FDA? Yeah, I do. I don’t know if they will need phase three trials. I think that these drugs are really effective, and they offer something that’s better than a lot of third line therapies for patients. So I think that the way to change that narrative, I hope, is with trials like ours for our first line, where hopefully we get to say, hey, chemotherapy has never touched this person’s vein. Since when they were diagnosed with stage IV cancer? And then it will be hard to kind of ignore that data.

Dr. Nicholas DeVito 51:18
Let’s see, “did not qualify for bot bal, are you familiar with compassionate use?’. I am familiar with the compassionate care program. There is information on their website about that with Agenus, and if you have problems, then go ahead and shoot me an email, we’ll get connected. But I have treated at least two patients on compassionate use. It is possible.

Dr. Nicholas DeVito 51:42
Are the doses less than other trials for MSS patients? They are the same Biomarkers that can distinguish patients at higher risk of immune mediated colitis? I love it! Gut microbiome profiles! So one of the coolest experiments I ever saw in the lab was that if you treat a mouse that has a melanoma in place with anti PD1, they get colitis. If you treat a mouse that doesn’t have a tumor in place, they don’t get colitis. What does that tell you? You need the tumor in place to get that kind of noeoantigen exposure to get colitis? So how we predict that? I don’t know. It’s an amazingly good question. I think that there’s a lot of people who are chasing down like Th 17 cells as a marker and others, because you’re right, if you can predict that, then you can just straight off the bat, give people, okay, you’re going to get Bot bal, and then day two, you’re going to get vedolizumab or something. And again, split that side effect and efficacy profile up.

Manju George 52:42
Okay, now that we have covered those questions. So is there a way for you to expand this trial using, you know, the NCI, CTAP and the trial system?

Dr. Nicholas DeVito 52:52
We have a grant into the DOD to do that right now. And I think there’s that, and other mechanisms are all on the table. We have several people that are very interested in moving that forward, but I agree with you,

Manju George 53:08
Okay. And the next question is, I’ve heard that the primary tumor being in place plays a big role with immune response. Do you have any insights on why that is other than the myeloid derived suppressive cells and all of that.

Dr. Nicholas DeVito 53:24
So you’re saying, if there’s a primary tumor versus metastatic, basically,

Manju George 53:29
yes, like the Neoadjuvant versus after you have surgery to remove the primary tumor, and then treating,

Dr. Nicholas DeVito 53:37
I think it speaks to kind of how tumors must suppress the immune system to metastasize to a different organ, they have to occupy a different micro environment and adapt. And part of that adaptation is immune evasion. So there have been organ specific metastatic like niches that have been described, like PMN MDSCs or polymorphonuclear myeloid derived suppressor cells leading to emergence in the lung, osteopontin macrophages, and these things called fibroblast activating protein positive fibroblasts in the liver and similar macrophages have been seen in the bone. So I think it is kind of like a chicken and the egg phenomenon. It’s like to get there, they had to suppress the immune system, and it’s like, Well, okay, so now, do we work backwards, or is it all different now? Where did it start and where did it end? And is there a difference when you have a primary tumor in place and a metastasis, or just a primary tumor or just a metastasis, it seems like, right now, the best situation is, always, always, always in cancer, earlier treatment, better, like it just is an across the board phenomenon and, and sometimes we can get away with, like oligometastatectomy and things like that in colorectal cancer. But I think to get to real, novel therapeutics, we’re going to have to understand that cascade of immune evasion.

Manju George 55:06
Okay, do you have to leave, it’s one o’clock, or do you have a couple more minutes?

Dr. Nicholas DeVito 55:12
I have a few more minutes. I also see one in the chat, which I think is a question that’s really important. There is a survival difference when you add ipilumimab to nivolumab in MSI colon cancer. And I think the reason for that is kind of the synergy that we talked about on the board. But there’s also one important facet of that synergy, and why you see longer survival, I think specifically is that when you block CTLA 4 you facilitate that CD 40 interaction, and you get professional antigen presenting cells. And those professional antigen presenting cells facilitate something called epitope spreading, which means that they recognize different antigens. So it’s like, yeah, you got this really strong response with PD 1 to the one antigen that was already recognized. But tumors are evolving, and they need to be kind of gotten ahead of so the immune system needs to adapt quickly, and CTLA4 helps them to have a more diverse PCR repertoire, meaning that they recognize many, many more antigens with CTLA4 blockade in place. So they really are like non redundant beneficial therapies, and they are rational in their combination.

Manju George 56:22
Okay, thank you so much. I think I will just ask this question, and then I would like, if you have some references. So there was this one study, like two years ago maybe, looking at pancreatic cancer survivors and looking at immuno editing, and the difference in the immuno editing. I mean, could you explain some of the ideas around immune editing and surviving, like, simply

Dr. Nicholas DeVito 56:44
Yeah, I think the best way to think about it is especially in pancreatic cancer, you have a subset of patients that have lung metastasis only, and they do really, really well. And there could be a number of reasons for that. I’ll take a step back. Tumors are random, right? They’re just random. They do anything they want, at any time they want. They have the whole genetic playbook at their disposal. They’re dividing. They’re making mistakes. They’re fixing mistakes. And so if you have a tumor that de novo, like right from its inception, is recognized by the immune system. The immune system is holding it in place. If you were to–what has been done in a lot of mouse studies– deplete CD8 T cells, just get rid of the T cells that are holding it in place, that tumor goes crazy. It explodes. It’s completely taken off. So even when you’re treating patients with chemotherapy, if you have an antigen that’s being recognized and a T cell that’s trying to kill the tumor you have, kind of like a tonic control of the tumor that translates into a patient living longer. And that’s kind of like the impetus for a lot of the KRAS adjuvant vaccine studies, which I really, really like. You’re just inducing like another bolt of immunity, essentially, and hopefully getting those long term effector memory cells that are constantly keeping it under wraps.

Manju George 58:08
Okay, okay, thank you so much. I think that’s a question about peritoneal meds.

Dr. Nicholas DeVito 58:13
Yeah, not resectable.. yes, this is critical. We initially had the trial capped at three, but the trial has been going well enough that we lifted that cap. So I feel what you’re saying in the clinic. I explained peritoneal carcinomatosis as like weeds going through a garden and how it strangulates the intestines. So it says, I know it’s a broad question, how do you see cancer vaccines working together with bot bal or similar approaches? Cancer vaccines have a history of failure, and I think most of those failures are due to the existence of PD 1 and not recognizing that early as such an important mechanism. So I could see that. I could see that being something that gets incorporated in a lot of different ways, but I would most typically expect it to come out first in like an adjuvant setting, like you give bot bal, then you take the tumor out. You design the vaccine, and you keep the tumor gone by just vaccinating the person, and that way you avoid adjuvant chemotherapy. You have a long T cell memory there, and you have long term disease control. Whether it’s going to be effective in the metastatic setting, where there’s all those kind of immune suppressive mechanisms that we talked about before, I’m less certain of that, I wouldn’t rule them out.

Dr. Nicholas DeVito 59:43
And then question about liver Mets that are not respectable, yeah, this is, this, is it, man, this is like the whole focus of the laboratory research. This is a big question. We’ve got to figure out a way to undo that systemic immune suppression from liver metastasis without needing to just go in and spot weld or or slice up a liver or something like that. We need that kind of sophisticated understanding. And we have some some interesting findings already, and that they overlap with others, but it’s a matter of finding like a drug and when to use it. And I think one thing that I’ll say about that too, and this has been my goal from the very beginning with BB OPCO, is that by treating patients that do not have liver metastasis and finding those who do not respond and why they don’t respond, maybe that gives us some insight into patients with liver metastasis who do not respond, maybe we start to gain some knowledge there. And I hope that our correlative studies that we do on tissue that are so much more advanced than they they could have possibly been 10 years ago, illuminate some of those interactions so we can apply existing drugs, maybe even and not have to go through the creation of a whole new drug. And that would be the most ideal,

Manju George 59:44
okay, okay. And so HCC is probably the only liver cancer where the immune system really works, like immunotherapy,

Dr. Nicholas DeVito 59:44
Yeah, yeah, it’s true. I mean, patients with melanoma have a lower response rate. with liver metastasis, they still respond though. I mean, I do think that there’s, like, tumors that are, just.. there’s an antigenicity threshold where they’re just so different to the immune system that it’s like, Ah, you get the PD1 inhibitor, and they really just can’t compete with it. But colon cancer is different. I mean, it’s very, very different. I think this is very interesting biology that needs to be studied aggressively.

Manju George 1:01:40
Okay, okay, I think we can stop now. Thank you so much for doing this with us and for the great talk.

Dr. Nicholas DeVito 1:01:48
Yeah, and thanks Absolutely. All right, thanks a lot. Have a good one. Talk to you all soon. Bye, bye.

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NEST-1 trial

NEST-1 trial

DocTalk
2024
Dr. Kasi
MSS
Trials

In this DocTalk, Dr. Pashtoon Kasi from Weil Cornell talks about his NEST-1 Trial with PALTOWN Scientific Director Dr. Manju George. Recorded in January, 2024.

Manju George 0:00
Hello everyone. Welcome to DocTalks. Today, we have Dr Pashtoon Kasi with us, and he will be talking aboutneoadjuvant, Bot/Bal in resectable mismatch proficient colorectal cancer. But before that, I want to ask Dr Kasi how he got involved in doing work on colorectal cancer. I’m not going to introduce Dr Kasi more, because for people from COLONTOWN, he’s a familiar figure. And the only thing I want to say is that if you’re interested in learning about what’s happening in the CRC world, I would recommend that you follow Dr Kasi on Twitter. So welcome, Dr Kasi.

Dr. Pashtoon Kasi 0:38
Oh, thank you again for the kind words, Manju. So in terms of how I started in oncology and GI, specifically in colorectal cancer, I think for me, the journey has been punctuated by the experiences during residency and fellowship and the mentors and the colleagues you encounter that inspire you to seek a particular pathway. Mayo Clinic is home to a lot of innovation when it comes to the role of GI oncology and colorectal cancer. Some of the regimens that we talk about, some of the figures who have shaped the whole field are folks that you get to walk the same hallway with, especially during the fellowship at Mayo Clinic that allowed me to focus on GI cancers and then colorectal cancer specifically moving forward.

Manju George 1:34
Okay, thank you very much. I also want to say that your poster was one of the most trafficked ones at GI ASCO, so we are really excited to hear about your work

Dr. Pashtoon Kasi 1:43
Yeah, when I went to put up the poster at 6:15am before I could even put up the poster, there were people asking me about the poster. So and then, from six to nine, and then there was a brief break for the Bespoke CtDNA oral presentation, and there were people still walking upstairs with me. And then when I came back at 10:30 we were still talking till like 2:30 till they forced us to get out of the area. So again, it’s a good problem. I lost my voice later that evening.

Manju George 2:19
I can imagine. Okay. Thank you so much for doing this for us.

Dr. Pashtoon Kasi 2:25
No, thanks for having me. Yeah. So do you want me to discuss some of the high level updates and the about the trial in the background next?

Manju George 2:35
Yes, yes, please.

Dr. Pashtoon Kasi 2:37
So you know some of you might have seen some of the discussion, but I kind of wanted to high level describe, all the relevant findings to date. I have some slides, and I also then have the poster that we can dive into. But in terms of background there’s a lot of things going on the world of colorectal cancer in the last few years. Two things that are in particular, of note, that allowed us to develop this particular concept was, number 1), there’s been a neoadjuvant paradigm shift. So the term neoadjuvant means that treatment that you would do before somebody’s surgery happens. People are familiar with the term adjuvant chemo, which is kind of like the adjuvant or mop up chemo that you do to eliminate somebody’s cancer. The idea of doing that treatment beforehand is something that is already considered the standard for patients with rectal cancer, where you want to do your chemotherapy and or radiation if necessary, and the final plan for surgery is the last step. In fact, people have gone from neoadjuvant to something called TNT, which stands for Total Neodjuvant Therapy for rectal cancer. So that’s how quickly that has changed for patients with rectal cancer. In fact, all the trials moving forward are focusing on TNT as a strategy, not just neoadjuvant, but in general, for not just for colorectal cancer, but for all cancers, neoadjuvant studies, there are many things that why would one would want to do the systemic therapy part?

Dr. Pashtoon Kasi 4:11
First, a lot of our surgeons who like to operate, they’ve actually been in the proponent to help us understand that maybe them operating right away is not always the best strategy. There is suggestion that they might be perturbing the micro environment of the cancer by doing surgery first. There could be reasons to affecting your immune system in an adverse way, where they’re taking a lot of lymph nodes and things out at the time of surgery, you might be affecting drug delivery or the immune response that your body itself may be mounting. There’s also suggestion that maybe keeping the primary or the mothership where everything started would be helpful, that be part of the treatment plan, as you introduce, especially something like immunotherapy, and also just the whole stress of surgery itself. Even though patients are getting minimally invasive surgery or robotic surgery, especially for colon cancer, and literally going home the next day. Those are all things that are happening every day in our hospitals and other hospitals that are Centers for Excellence for colorectal cancer. But also you have to realize the body is still surviving that insult or injury, so to speak. So immune changes in a negative way could also be in the post operative phase. So for all these reasons, there’s suggestion or idea that maybe doing some treatment beforehand might help increase the chances of success, and some of the parallels have been happening in other tumor types. Melanoma or skin cancer, is one of the tumor types where a lot of research has been focusing on the vaccine, immunotherapy, before and after surgery, and they’ve been striking differences of the exact same treatment done in a clinical trial, randomized fashion, where outcomes were significantly better if the same treatment was done before surgery, as opposed to doing surgery first and thereafter.

Dr. Pashtoon Kasi 6:17
In the world of colorectal cancer, one trial that a lot of colleagues and patient advocate as well as caregivers, are familiar about is the story of the MSI high, or mismatch repair deficient colon and rectal cancer. And we’ve noted that in the metastatic setting, while a third of patients with MSI high cancers, even with drugs like pembrolizumab, and at the actual GI oncology conferences a couple of days ago, at ASCO, they also presented data with Ipi-Nivo, with updates. So there are striking differences, but there’s still a proportion of patients who don’t respond, and it’s anywhere from a third to at least, 20% if not more. We’re still trying to figure out why that case is, but when Dr. Chalabi and their group moved the treatment with their NICHE-! study to neoadjuvant setting. Nearly everybody responded. So I guess there is definitely some pretext to why neoadjuvant would be a good strategy. From a clinical trial standpoint and from a scientific standpoint, neo adjuvant — they call like them as the window of opportunity, meaning that you could still do whatever you’re trying to do, but get a quick readout as opposed to doing calls with hundreds of patients, I think, with novel clinical trial designs and how things are evolving, this is something that is being challenged, that we need trials that take years to mature, that take hundreds of patients & effort to realize that something is not working. With novel precision medicine based focused design, and in this case, the Precision Medicine being the setting itself, you can probably get away with smaller numbers, especially if the difference is significant.

Dr. Pashtoon Kasi 7:58
You don’t need huge trials to tease out those minor differences depending on the therapy you’re dealing with. So that was one reason why we thought that neoadjuvant would be a great fit. But the other parallel update that has happened in the last couple of years while patients with the so called cold tumors, or mismatch repair proficient tumors or microsatellite stable tumors, all meaning the same, which is the fair majority, 95% in the metastatic setting, and anywhere from 80 to 90% in the non metastatic setting are the MSS cancers that unfortunately don’t respond to immunotherapy. In the last few years, we’ve seen this regimen called the Bot Bal, or Botensilimab, combined with Balstilimab showing the first hint of a promise of novel immunotherapy that works in patients with cold tumors. One interesting finding that shaped the change in the trial moving forward is they noticed that folks who had active liver metastases, and the definition of active liver metastases was that, it’s not like you could never have had liver metastases. It’s just that at the time when you enroll in the study, they had to be resected, ablated, removed, or radiated at least six months ago, because the first 17 are patients that they treated, the ones who were benefiting the most were the ones who didn’t have liver metastases at the time.

Dr. Pashtoon Kasi 9:28
So moving forward the phase II study, and then the randomized phase II that has been completed third quarter of last year, just eagerly awaiting readout, there was a huge proportion of patients who did not have liver metastases at the time have benefited. So that’s how this regimen came to note in terms of patients with colorectal cancer. So keeping these two big advances in mind with the neoadjuvant paradigm shift, and then this regimen Bot/Bal, we had proposed as an investigator initiated trial to Agenus, the company who makes this drug–how about if we could consider the same combination, but in the neoadjuvant setting. We also looked at designing this in terms of as a parallel to the NICHE study that was published in Nature Medicine. Also there’s been an update to that presentation at ASCO, with over 29 patients treated with the immunotherapy that is approved for MSI high in melanoma, the ipilimumab or nivolumab, or ipi- nivo for short. So the idea was to compare and contrast how would this combination Bot/Bal fare in the setting of mismatch repair proficient and deficient tumors in the neoadjuvant setting, we designed it to kind of keep safety in mind.

Dr. Pashtoon Kasi 10:56
Its the last thing you want to do is in a person who can get colon cancer surgery tomorrow, next week, curative intent, is to jeopardize the surgery. Because we cannot cure patients with colon cancer for the most part, without surgery and or chemotherapy for the ones who need it, who are high risk. So the main objective of our trial was safety. So one of the things that we wanted to make sure was any surgery that got delayed would be considered a negative and the study would have to be shut down if two or more patients in the 12 patients that we wanted to treat would lead to a delay or cancelation of their surgery. So even a delay beyond 12 weeks was considered as what we call in our scientific world, like a dose limiting toxicity or something that would want us to stop the trial prematurely. So that was the main goal. And of course, we wanted to make sure that surgery happens safely as well, so any kind of serious adverse events or toxicity happening in the perioperative period even up to 90 days or 100 days after surgery, because immutherapy is a like a vaccine, it stays in your system.

Dr. Pashtoon Kasi 12:00
So could it even impact somebody’s clinical care beyond the first few months was the main end point, and so we really find combed any kind of side effects that were attributed to treatment and or any side effects period, that happened during the build up to the surgery as well as in the post operative period. But at the same time, we, of course, wanted to see the efficacy question as well. And we on purpose, had MSI high cancer patients as well, because if immunotherapy is already known to work there in the subset that have mismatched efficient tumors, we should have proof that it’s working in those patients as well. But more so, the interest and focus was on the cold tumors, which is mismatch proficient tumors. And at the time when we were designing the study, I would say anything more than a couple of patients responding would have been still promising for further investigation, because pretty much the bar has been close to zero in the metastatic setting and some hint of signal in the early stage setting. So any kind of responses for us would have been considered promising.

Dr. Pashtoon Kasi 13:13
Just to give you an idea of the dose, you know, the actual doses that have been studied have been the up to 150 milligrams of bot, which is a multi immune activator. Some folks, while can argue that this is the next generation, or the second generation, CTLA-4 antibody, with the mechanisms that we were able to find in our trial, as well as some of the correlative work. It’s not simplistically, just another ipilimumab. It is different, which is why even the toxicity that we are seeing is different, and also the efficacy that we’re seeing is different in also in parallels in other cold tumors like sarcoma and other tumor types. The fact that this is working is is very promising. So we only chose half of the recommended dose, or the lowest possible dose that we thought would be effective, and also just one dose of it, as opposed to ongoing immunotherapy, which is every six weeks, up to four times in some of the studies. So just to kind of give you an idea, this was the lowest possible dose that one could have thought of or conceived to be given in this study. As shown here in this cartoon as well these are kind of like don’t eat any signals or signals that prompt the immune cells to stay away from the cancer that some of these immune checkpoint blockade as the name checkpoint suggests is to kind of break those interactions so that the immune cells are able to recognize, expand and activate, and also try to kill the cancer. But there are other mechanisms that are it seems like there are some immune cells that are the good immune cells that are killing the cancer. But then there are some immune cells that can dampen the response, these are Tregs or bad immune cells. So it seems like it’s not as simple as just activating your immune system, but kind of the diversity that’s expanded is of value to note. And then which of the cells are expanded more than the other, the ratio of it in terms of circuitry, is important to recognize.

Dr. Pashtoon Kasi 15:22
So jumping onto the results, and the waterfall plot, where things hanging down is a good sign, and every single line is a patient and their response, which was actually the surgical response, meaning how much of the cancer was alive or dead when the pathologist looked under the microscope. Just to kind of give you an idea, I mean, this was also a learning experience for me as well. The pathologist do look under the microscope, and they have a surgical sample, but they don’t necessarily look at every single looking corner of the specimen. They, of course, examine the lymph nodes, and they examine how much tumor is left. But in general, not every single section of a huge specimen is looked at. But in this particular trial, our surgical pathologist, Dr Erica song is kind of worked hand in hand as a co- PI on the study, and also one of the senior author on our paper. Is also important, because without the pathologist, and of course, it goes without saying, without the colorectal surgeons who see these patients, this trial would not have seen the light of day. And so these are in some ways conservative numbers, because even in some cases where there were just a couple of cells floating around in a dead mucin pool, like this person and MSI high on the farthest right, who had a 98% responsepretty much the whole entire ginormous tumor was all dead, but just a small cluster of cells were present. So we made sure that we reported all of this so that we, in any way, the last thing you want to do is overestimate something and lead to a wrong signal. So these are, in fact, conservative numbers. But it’s hard to fake no cancer being present at all, or the cancer disappearing. And what was very fascinating as an experience, and very rewarding as an experience for us was, the it was a subjectivity, and the adjectives that our pathology colleagues started describing at some of these tumor board meetings, where every week here at Cornell, on every Thursday night, we review every single patient’s case, every new patient gets discussed, and that’s true for all academic and community centers as well. It’s good practice to be making decisions as a team, but then that’s also a meeting where we look into the microscope together as to what did the pathologist find? How aggressive was the tumor? What did it look like? What was the mutation testing? And also in patients who got any chemotherapy or immunotherapy, what was the pattern response? Did you see immune cells around the cancer? How much of the cancer was alive or dead? But the way they were describing from the very first patient that got this as a treatment was what did the patient get? What did you give the patient? And we’ve never seen immune response like this much, or the exuberant nature of the response, or the striking area of immune cells, or tons of inflammation and necrosis, meaning dying of the cancer cells. There were things that even the first two patients that were the cold tumors that had over 90% and 85% kill, the patients here that are on the third and fourth that prompted us to write a whole publication that was in the Oncogene journal. And we can share the links afterwards, and it’s available online, free to read because it has some striking images that we had pre and post, even just the first two patients. We wanted to get the word out, because for things to work and also to work as quickly, remember, these patients could have gotten surgery as early as three weeks from starting the treatment. That’s very important to recognize that if you can have just three weeks of a treatment causing this much kill of the cancer, that is unprecedented in many ways. In fact, a lot of patients as early as 21 days had surgery.

Dr. Pashtoon Kasi 19:32
We wanted to keep this trial pragmatic and practical meaning that right now in the United States, a patient like I said, with colon cancer is often seen by the surgeon first, and with the surgery team as well as the patient and caregiver alike, the immediate plan is to get the tumor out of your body as soon as possible. Now again, I would do the same if this was me or my family member, but at the same time. It’s good to realize that this didn’t start this week or last week, this month or this year. Some of the polyp to adenoma to carcinoma sequence can take three to five years to develop. That’s why, if somebody has a colonoscopy that’s clean, the next one is not due to, like, five years or so. So that’s because we know that this is how things develop. But we still have to remember there’s the psychosocial piece. So the surgery happening ASAP on the calendar whenever the surgeon can get an operating date, which could be tomorrow, it could be next week. So most patients, if not all of them, actually already came with a surgery date in hand, and we’re told that I’m getting my surgery on February 4. The surgeon asked me to do the pre op testing and the COVID testing, and I’m also here to talk to you, because I hear you have a trial. So keep that in mind we wanted to keep it as pragmatic as possible, so that all we were asking patients is you’re getting a surgery on February 4, a couple of weeks away from now. We have this immunotherapy that is not yet proven or tested in the neoadjuvant setting, but may have value, especially for those with advanced cancers, with chemo and surgery, may or may not even cure all of them, is to consider this trial. So we were only pushing out surgery by a week or so at the most, so that was something that was acceptable to all the patients that the trial was offered. So it also shows the interest in the patient and caregivers as well who participated in the study, and the trust that they showed to consider something which is not necessarily the norm.

Dr. Pashtoon Kasi 19:48
And like I said, as the trial progressed, was also very fascinating was patients and their caregivers, also the surgeons were themselves asking, can we postpone the surgery by another couple of weeks? Because maybe we can get more more shrinkage and kill all the cancer? So that’s how you might see, I’ll show you in the poster as well, that there were patients who had surgery a little later. Wasn’t because of any side effects or anything. In a positive way it was because the signal was getting more profound as we waited even a few days longer, that prompted the surgeons and the teams taking care of the patient on a week by week basis to maybe purposely allow for things to be delayed some.

Dr. Pashtoon Kasi 22:24
As shown here in dark green, are the MSS, or cold tumors. You can see from cancers entirely disappearing. The one of the first patients who is a 100% is somebody who had so much bulky tumor that even one of my colleagues who saw me the next day, who where the patient was starting the trial, was a little apprehensive about a person who was having some symptoms and bulky tumor to consider a trial that you know potentially may or may not work. So that patient’s symptoms and pain and things improving, and then the cancer being down to nothing it was very rewarding. The second patient was a 100% is somebody who actually had rectal cancer. So it’s important that while this trial and NICHE-1 looked at colon cancer, and a lot of the mismatch deficient studies from Dr. Cercek from Sloan and other teams have looked at Dostarlimab in rectal cancer where, of course, living with a permanent ostomy and can be a life altering experience from a quality of life perspective. So we did allow rectal cancers to enroll as well, as long as there was a plan for surgery as next and no chemotherapy or radiation. Because, of course, the ones who are candidates for chemotherapy and radiation, maybe in the future, in different trials, but for the context of this trial high rectal cancers or rectal cancer, where there’s a plan for surgery and no chemotherapy or radiation, are pretty much like colon cancer. So they were allowed to enroll.

Dr. Pashtoon Kasi 23:47
So we had one, mismatch deficient MSI high rectal cancer that had a 100% response. The second, mismatch repair proficient MSS rectal cancer had a very low rectal cancer, it would have been something called an ultra low LAR, something that could have risked an ostomy as well, that the type of surgery that was done had changed and ended up in a complete response, as well. We had an 85% and also we had a 10% response. And also, as we understood some of the micro metastatic disease in the pattern response, just trying to give you an idea, as shown here in the cartoon on the right hand side, we also noticed that what was striking was even if the cancer was present, it was kind of at the luminal or the tip of the colon. So if you can imagine this cancer reaching through the walls of the colon and the lymph node that’s involving, typically when we’re killing the cancer with chemotherapy or radiation, even if it’s eradicating let’s say approximately 90% of the cancer here is dead when it’s dead and scattered in different parts, and there could be cells floating around that are not bigger than we’ve seen, because we never really fail locally. For the most part, things are getting so much better with surgery and radiation, with sophisticated software and stuff. It’s more so the question of systemic recurrence or the cells kind of being present in the soil, just like grass with pollen or grass with weed, or in terms of things spreading elsewhere. But with immunotherapy, the responses that we see, we call it like inside out, versus like root up or kind of like serosa to mucosa, meaning, even if there was cancer, the immune cells, like a wave, were destroying them in a way where, kind of like the trash was just at the door for pickup. So even if there was leftover cancer, 75% alive, 90% alive, as long as it was in the specimen that is already out of the patient’s body in the trashcan honestly, from my standpoint, it’s great to have more kill, but at the same time, as long as we didn’t leave any cancer cells behind, that’s more important, because for MSS cold tumors, they’ll get their surgery anyways. It’s not like we’re planning to avoid surgery here, but the fact that you can eradicate micrometastatic disease, that was something very fascinating and novel, which was part of the like I said, this paper is available online on Oncogene, and also some cool immunofluorescent analyzes looking at immune cells that we did with this company called Rarecyte Inc, which required very minimal tissue to be sent to them. But you can see pre and post shown here in this golden is the cancer itself and around the golden cancer is the immune cells, different kinds. CD4, CD8, good cells, bad cells. Foxp3 it’s like a swarm of bees that you can see between pre and post, just a few weeks apart. The swarm of bees around the cancer is such exuberant increase, and even within the same patient, parts of the body that had some cancer left behind, versus part of the body that had more cancer, you could see the activity of immune cells like a busy office versus an office after 5pm as you could see, the differences between the type of immune cells, how active they were pre and post. So it was something that was very striking.

Dr. Pashtoon Kasi 27:24
While arbitrarily, you can argue that for major response, anything less than 50% is considered maybe not a success, and anything that 10% or less is considered “a failure”. I would argue, if even for the 0% and 10% since we saw some inflammation, and if we eradicated the micrometastatic disease, and the person still had surgery and everything is removed with the goal being cure, then even these might be not necessarily failures, in my opinion. So I would say that every single case has been a valuable insight since even the patients were at 50% 25%, when we checked their cancer cells or DNA after surgery with a blood draw to see if there was any leftover cancer, in any of these patients at more than 30 time points over six months, none of them had a recurrence. So the fact that we have such a strong black and white signal kind of speaks to the mechanism of action here, and also our understanding, a lot of these crude measures of response were invented back in the day with the esophagus cancer getting chemotherapy/radiation. So these numbers may need to be revised. In fact, a new study published in lung cancer, for example, question some of these arbitrary cut offs. Who said 90% is the cut off or 50% is good? We kind of use the real world where we come up with these arbitrary numbers of six months or three months or 50% is good, or the glass half full or half empty. But they actually showed that it’s a continuous measure that every 10% increase, or as a continuous variable, the more shrinkage you were getting that was equating to the being cancer free odds years down the line. So this is kind of changing the understanding, so to speak, of what we understand with with what’s happening in these patients.

Dr. Pashtoon Kasi 29:18
And so the study, by the way, is expanded based on these results. Iwanted to kind of highlight some of the key conclusions first, and then I’ll show some details regarding the poster as well. So we found it to be a safe and active regimen. Again, going back to the safety that we didn’t discuss yet, there was only one person, and again, that’s the same person who had the 100% response who had diarrhea, that’s from inflammation of the colon called colitis, that can be managed proactively with what we call steroid sparing drugs, or as the name suggests, you don’t need to use steroids to hamper the immune system or dampen the immune system. And ifrecognized early can allow the side effects to be nipped in the bud. That patient had the diarrhea on a Friday. It’s always the Friday afternoon when you hear about these events, and he still was able to get surgery the following Thursday, so the surgery was not delayed. And in fact, that’s the same person who also had the 100% response. So if you talk to some of these immunologists and oncologists who’ve been treating and have had a lot of experience with immunotherapy of the years, of course, we don’t want you to have severe side effects, but even in the days of melanoma, back in the day, having some rash or having some diarrhea or having some thyroid inflammation, it was one of those things that patients, caregivers and oncologists were looking for, and there would be more worried if there was none of it, because how do you know? There’s no direct of knowing if somebody’s immune system is activated, not activated, some of these side effects, symptoms, what they were going by and not just this particular regimen. Across the board, having any immune adverse events is very different than coming off of the trial let’s say if you had a serious adverse event for chemotherapy or target therapy, where as soon as you stop the treatment, pretty much the cancer is going to do what it was doing before. With immunotherapy, it is very different. I’ve had patients with vaccines or different kinds of immunotherapy that didn’t even get more than one dose and had to be taken off because of whatever adverse events. It’s the tale of patients who are alive and alive years out where the word cure is being used, that is happening even in the patients who there’s no specific number of doses, in my opinion, and no specific duration that you need to get immunotherapy as long as it’s working, it’s a it’s a gift that keeps giving.

Dr. Pashtoon Kasi 31:43
And because of the down staging we saw and the responses we saw in MSI high, the goal that we’re going to ask in the next set of patients is, and that was also something that we actually changed last minute again, because we also heard from our surgeons that in a good way that they were not inclined to operate on the next patient who was MSI high who got immunotherapy, because they never find cancer, and often everything responds so briskly, just like a marshmallow melting, that sometimes it’s actually it’s harder for them to operate because there’s a lot of scar tissue and so much robust infiltration from an immune standpoint. In fact, even at the discussion section at the ASCO, somebody asked about strictures developing. And we’ve had some similar experiences as well with just even pembrolizumab used in advanced setting, where the surgery was only done, because in a good way, there was so much response that actually there was a narrowing that had developed as an outcome of that. So maybe in those cases, we have less reliance on surgery and no surgery at all, or give that decision to the patient and caregivers and the surgeon. If they wanted to go for surgery and everything was dead, that will still be a success. If they didn’t want to go for surgery and just had no cancer worsening, that should still be considered a success. So we’ll allow for that as a composite or as an option, to give and empower the patient, so to speak, and the caregiver to make that decision. And then for the ones who are going for surgery, we’ll look at how much of it is dead as the key outcome variable. But going back to the MSS or cold tumor story, if we were able to get this much shrinkage with just three to four weeks of therapy, the idea is what would happen if we let the immunotherapy brew longer?

Dr. Pashtoon Kasi 33:25
We have some idea from the NICHE-3 study that was recently presented from Dr. Chalabi and colleagues, where there were deeper responses with the immunotherapy, nivo, with LAG-3. And while some folks were discussing if LAG-3 is the one that’s causing this, I think the big difference between that and NICHE-1 is also the fact that they use the monthly four week dosing of NIVO, so the average time of surgery was longer. So that just the fact that immunotherapy was allowed to simplistically bloom for longer, in my opinion, that’s what led to more responses. So we’re going to formally investigate without changing the doses of the Bot, just one dose still and keeping safety in mind, we’re going to allow for patients to have double the duration of the same regimen in MSS moving forward, and compare and contrast the results with the results what we have here.

Dr. Pashtoon Kasi 34:18
So with that let me just quickly, just show a little bit of the the poster as well, which had some additional data that is available online. But one of the things that we found, as shown here in the poster is shown here in the red are the patients who had CT DNA positivity, who through different platforms, again, this was commercially available tests, robust, deep analysis in-house that we’re doing with some of the scientists here, which had more insights, but none of the patients in the post op setting that have been tested, some tested as much as four times on both plasma only assays, as well as tumor informed assays, have remained negative to date. And if you look at the mutations, for the next 12 patients that might be seen in any cancer center, this is a mix of anybody and everybody. We had a patient who was HER2 positive, KRAS mutant, KRAS wild type, P53 mutant, Wnt mutations, MSI high. We had young folks were germline Lynch syndrome. We had older folks who had the somatic MSI high, from as young as 26 years of age to as old as 78. We only had four Caucasians in our trial, which is quite the opposite of the story of all the trials that are conducted in the United States, where sometimes, even in hundreds of patients, you barely find one African American enrolled in the trial. That’s important for immune therapy. That’s not just about equity and diversity, but also there isdifferent types of HLA and immune features that distinguish us apart. Again, not just race, even males, females, we had six of each. Same thing, for example, we saw was, there were five people, four out of five, all young females who had this thing called early immune activation, where they had fevers as high as like, 102 103, 101 but no signs of infection. And the symptoms of the flu, like symptoms that go along with it, that again, with just some proactive Tylenol or Alleve or naproxen. If necessary, in some patients, just the low dose, 20 milligrams of prednisone, just for a couple of days to kind of nip it in the bud, was something that overcame that. Again, goes to show that there are biological differences in your immune system as well, that have to be kept in mind from, male female biology, as well as different races. So we had Southeast Asians, we had African Americans, we had Hispanic Mexicans, we had Middle Eastern we also had Caucasian. So we hadpeople mix of older, younger. So in a good way, there’s no signal to differentiate who is the one who had more response and where the one who is this fast. Because we had folks older, whichever race, who also had the response, and younger, whatever age. Because, of course, we are noting there’s also the difference in biology between young onset, colon versus older onset. And you know the plenary at ASCO-GI, for those of you who attended or heard was in fact, on the rise of cancers in young adults from Dr Kimmie Ng. That was the plenary. So it’s important to note that biology differences might be there between young and older onset. So the fact that we saw no differences so far on all the crude analysis that we’ve done to date, nothing from a CPS or PDL-1. In fact, just a few hours ago, I got results from all the patients before and after PDL-1. And in every single patient, the PDL one went through the roof so and a lot of these patients had the so called cold tumors with not much immune inflammation. So there’s not much to tell or tease apart. We’ll have more additional results from Rarecyte to go over. And as you can see in this line plot, you can see all kinds of immune cells, CD20, B cell, T cells, that went up. But then if you look at the cells that are, what we call immune proliferation, versus the ones that are that dampen the immune cells, the ratio of that was going down, we should explain some of the responses that we are seeing. So I know there are a lot of questions, so I think I’ll probably just stop there and we can maybe look at the questions, and then based on the questions, we can revisit things on the poster, or the talk.

Manju George 38:58
Okay, sounds good. Thank you very much, Dr Kasi, so shall we start from the top of the questions?

Dr. Pashtoon Kasi 39:05
Yeah, yeah.

Manju George 49:42
So the first question is, how do Bot/Bal findings apply to unresectable cases? And then I’ve heard on COLONTOWN that liver Mets disqualify one from receiving Bot/ Bal. Is this accurate?

Dr. Pashtoon Kasi 52:04
Yeah, it’s a great question. We saw a lot of CD20 cells going up as well. And I think in the comments it’s also mentioned that it was a tumor up stage as well. I think the issue, as I said, is as opposed to rectal cancer, where you can pretty much, it’s not 100%, but it’s really good, in terms of MRI pre op staging versus post op staging. Of course, there is discrepancy, but colon cancer is a mess. Colon cancer does not get MRIs. Colon cancer is diagnosed on CT scan, and if the lumen is collapsed, you may not even be able to assess how big the tumor is. And lymph nodes are always tricky to evaluate on a CT scan. So overall, the work from European colleagues show that colon cancers are under staged when it comes to the MSS variety, and overstaged for the MSI, because in the MSI, the lymph node may just be swollen because of your immune system activation. So they could be misinterpreted as stage III, and then post op, they may be stage II. So overall, we saw pretty much clearance for them. For the most part, I think the anybody who waited at least a month to get their surgery, we saw like that inside out where the lymph nodes were negative. There was no lymphovascular invasion, no perineural invasion. And now the tumors were beyond T1, T2 so I think that the N1, N2 patients, if they had waited a few weeks longer, which we will test in the upcoming cohort, we would have seen the activity go down.

DocTalk
2024
Dr. Kasi
MSS
Trials

In this DocTalk, Dr. Pashtoon Kasi from Weil Cornell talks about his NEST-1 Trial with PALTOWN Scientific Director Dr. Manju George. Recorded in January, 2024.

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Early-stage BRAF V600E MSS colon cancer — What’s next after adjuvant treatment

Early-stage BRAF V600E MSS colon cancer: What’s next after adjuvant treatment

DocTalk
2024
Dr. Yaeger
BRAF
MSS
Early-stage

In this DocTalk, Dr. Rona Yaeger from Memorial Sloan Kettering discusses how to approach early-stage BRAFV600E MSS colon cancer following adjuvant treatment with PALTOWN Scientific Director Dr. Manju George. Recorded in June, 2024.

Manju George  0:00 
Hello, everyone. Welcome to DocTalks. I’m Dr. Manju George, the Scientific Director at PALTOWN Development Foundation, the nonprofit that supports COLONTOWN. Today we have Dr. Rona Yaeger from Memorial Sloan Kettering Cancer Center to talk to us about what’s next after adjuvant treatment for early stage BRAF mutated MSS colon cancer. But before we start, I want to ask Dr. Yaeger how she got interested in GI oncology,  and in doing the kind of work that she does. Welcome.

Dr. Rona Yaeger  0:33 
Manju, thank you for having me, it’s a pleasure to be here. Like you mentioned, I’m very lucky that I get to focus on an area that interests me a lot. I work on colorectal cancer and targeted therapies. I find genetics very interesting. And when I was younger, and I saw the way you could see how colorectal cancer develops from polyps, I thought this is really an interesting area to work. And I like the relationships we have with patients, where I have many patients I’ve treated for many years, and have a very close relationship. So I felt like this was the right area for me. I see patients one day a week. And then I run clinical trials and also have a wet lab. So I have a nice combination of kind of all the components. But the actual work we do is very focused on colorectal cancer and targeted therapies. So thank you for having me and give me the chance to give an update on what’s next, potentially after adjuvant therapy for colon cancer with a BRAF V600E mutation that’s microsatellite stable.

Dr. Rona Yaeger  1:40 
So I wanted to just start off by talking about how we treat early stage colon cancer, and what we think of when we see these tumors. So this is a slide kind of showing the current paradigm of treatment. So initially, patients are diagnosed either they will have a screening colonoscopy, and something might be found in the colon, or they may have symptoms that lead to an evaluation with a colonoscopy that can show mass within the colon that is biopsied and comes back as cancer. The next step is to be sure there’s no evidence of spread. So patients have scans to look at the body, usually a CT scan to make sure there’s no evidence of spread. And if there isn’t, and the colon tumor is limited, the next stage is what we call a resection where we remove the cancer. So here you can see within the bowel, there is an abnormality that is removed, and then the bowel is reconnected. Following that, the tumor that is removed is studied under the microscope by pathologists who generate a report describing what they see. And that’s what’s used for risk assessment. So patients who have a tumor that’s limited to the colon has no evidence of distance spread are early stage. And if the tumor has higher risk features, such as having lymph nodes involved, involving the full thickness of the bowel wall, we often suggest additional treatment with chemotherapy with a goal to reduce the risk of recurrence. And if patients don’t have this features, they are then observed. And we watched patients for a total of five years, after which the chance of recurrence is so low that we say that’s it, you’re cured and you don’t need to be followed so closely. So this is our current paradigm. And we know that most patients are cured following this current paradigm, but there are some patients who still recur, even despite chemotherapy. So this brings up the question, is there anything more to do for those patients?

Dr. Rona Yaeger  3:40 
So my next slide is looking at colorectal cancer both in advanced disease and early stage disease, where we now see that it’s particularly when we think of advanced disease, the colorectal cancer isn’t a single cancer. We can define different subsets of patients and tailor treatment based on how the cancer is developed. So the first group that I want to point out is this MSI high. Patients who have tumors or MSI high either have a genetic predisposition, or they have a colon tumor that has evolved in such a way that it feeds into a similar pathway. And MSI, what does that mean? Basically, when cells divide, they need to make another copy of their DNA. And there are stretches within the DNA where you have the same letter are the same two letters of DNA that repeat. And in those structures when you make another copy, it’s easy for the enzyme that is filling in those nucleotides to slip because you see the same two letters repeating over and over. And so when that happens, there is afterwards a proofreading, where the copy that’s made is checked to be sure that it matches what was there in the kind of parent strand. And so people who have inherited problems with this proofreading function- there’s this cancer syndrome called Lynch, or people who have silenced the proofreading function in the development of the colon tumor or have what’s called microsatellite, unstable, MSI high colon cancer. And that name comes from the fact that these stretches are what’s called microsatellites and they’re unstable because they can be shorter or longer if you don’t have correct proofreading. So that’s a small group of patients with advanced disease. But it’s very important because first of all, those patients may have a genetic risk, and they need to be followed more closely and their family should be alerted. And also, there is now Immunotherapy. So they respond differently to treatment than other patients. But beyond that group, in patients with advanced disease, we have many subsets depending on how the cancer has developed. And one group is what you see in our title is this BRAF V 600E, where there’s a mutation in a gene called BRAF that can turn on signal to the cancer to grow. And that has target therapy associated with that. So we treat those patients differently. It’s also important because patients with advanced disease who have a BRAF mutation in their cancer have a more aggressive disease. And we know that the presence of BRAF V 600E mutation marks a group of patients who have a kind of a more aggressive, a tougher prognosis. And so those are patients we want to think about and figure out how we can give them matched therapy and what more we could do for them. There are other groups in advanced disease, we have other groups with matched treatment, patients who have amplification of a gene called HER2, or a specific mutation in KRAS you may see, I’m sure there’s a lot in Colontown about Biomarkers. So these are markers that we think about in patients with advanced disease. And we actually split the pie into what is driving the patient’s cancer, and how can we target that.

Dr. Rona Yaeger  7:01
When we look at early stage colon cancer, so again, this is colon cancer that’s limited to the bowel, has not spread beyond local lymph nodes, and is removed surgically. We really only think about this one biomarker, the MSI, and we know those patients do a lot better. And there’s a lot of studies now looking at giving Immunotherapy, potentially, after surgery, some trials even in lieu of surgery. So that’s an area of a lot of research. But the rest of the patients who have microsatellite stable colon cancer, are treated the same. And this is the large majority. And in the rising incidence of colon cancer in young people, most of those tumors developing microsatellite stable. So we know that in early stage colon cancer, there’s also a subset that had BRAF B 600E mutation. And there’s a subset that have this BRAF mutation that are not MSI high. It’s about 6% of patients. And we’re going to focus on them today for two reasons. The first is, like I said that in advanced disease, they have a worse prognosis. And we know that in early stage disease, they have a higher risk of recurrence. And the second is we have a matched treatment for them. We have a targeted therapy that goes after the BRAF, the altered BRAF. And so there’s a potential to do more.

Dr. Rona Yaeger  8:18
So what does it mean to say, oh, there’s this mutation and BRAF. What does that do for the cancer. So I have here a cartoon of a cell, and I’ll walk you through it. So basically, normally, a cell will only divide and grow if there is a stimulus to the cell, saying it’s a good time to grow. And so there are growth factors that lie outside the cell. This is the outside of the cell. Here, you can see below the membrane inside of the cell that bind to receptors on the surface, these receptors are meant to sense what’s going on outside. And when the growth factors bind, they basically are telling the cell this is a good time to grow, there’s a reason to grow. And when that happens, that signal is carried to the nucleus through a bunch of proteins that include the RAS protein, which is often mutated in colorectal cancer, and also RAF, which includes BRAF as one of the RAF proteins, and they signal down this group of proteins to get to the nucleus to say to the cells, it’s time to grow, we should divide we should survive. But at the same time, these signals are turned on normally there’s a counter signal, that puts a stop. So cells divide a little bit and then they stop. What happens in cancer is cells divide and they divide irrespective of having any growth factors, they just divide on their own, and they don’t have the normal brakes. So for example, this BRAF V600E is a mutation in BRAF, it turns on this RAF member and makes the RAF member turn on irrespective of what’s happening outside the cell. In fact, the BRAF V600E doesn’t need any activation from RAS, it’s on all the time. And if there is a feedback to turn off the signal, the BRAF is on on all the time, it’s insensitive to that. So that allows the cancer to keep growing. And all cancers have to figure out a way to keep growing. This is one way the BRAF mutation. Another way is the KRAS mutations that we often see. But today we’re focusing on BRAF, because as I’ve said, there’s matched treatment for it. So this matched treatment, there is an FDA  approved treatment for patients who have advanced disease where the tumor has spread beyond the bowel. So distant sites like liver or lung who have received prior treatment with chemotherapy. There’s an FDA approved a treatment based on an improvement in the time to progression for patients compared to standard therapy, patients live longer who get targeted therapy, and the quality of life is preserved. The targeted therapy consists of two components. It consists of a pill, BRAFTOVI is the trade name, encorafenib is the generic name. Patients take four tablets once a day. And it’s combined with an infusion called cetuximab that’s given intravenously, it can be given weekly or every other week, together with the pills taken daily. And what these drugs do the encorafenib+Braftovi binds to the activated BRAF and turns it off. And that’s the cetuximab binds to the receptor and turns off any other input into this growth pathway to hopefully turn off all the growth signal and to stop the cancer from growing. It doesn’t necessarily work for every patient. But most patients with advanced disease have some regression. And we think that this combination can stop the growth signal and most cancers that have a BRAF V600E. Most colorectal cancers, they have a BRAF V600E mutation.

Dr. Rona Yaeger  11:46
So how about early stage disease. So, like we said, most patients are cured. So these are curves that look at recurrence and survival after recurrence. So I’ll walk you through it. But basically, in black, you see the curve for patients who don’t have a mutation in the BRAF gene, or in the KRAS gene who have microsatellite stable and not the MSI high colon cancer. And you can see that all our curves are above 50%. Most patients are cured. But there is a big gap between the black and the blue or the blue is BRAF V600E mutated.  In the middle is a KRAS mutated so you see that the BRAF causes a higher risk of recurrence, but it’s a small effect. However, when patients recur, this is the survival after recurrence, we see having the BRAF leads to worse outcomes. So if we could prevent patients from getting to the point of recurring, it would make a big difference. So that’s what we are looking at with a new clinical trial that I am excited to talk about today. This is a trial that’s being done through the NCI so it’s open across the country. And it is open for patients who have early stage so stage three so that’s colon cancer that involves local lymph nodes, or stage two, T4, T4 means the tumor involves a full thickness of the bowel wall. So like if our bowel were like a hose, the tumor would reach the other side of the hose. You can see it through but it does not spread to distant site and might touch an adjacent organ but it is a contiguous involvement. So stage III, so nodal involvement from colon cancer or T4 full bowel wall thickness, patients who have received standard treatments, so these patients are considered higher risk, they would receive chemotherapy. In the study, if their tumor has a BRAF V600E mutation, they are randomized, half the patients will get usual care, which is observation after they finished chemo and half the patients are getting the targeted treatment of encorafanib and cetuximab for six months.

Dr. Rona Yaeger 13:46 
BRAF V600E testing is not currently standard, because like we said, we don’t really do anything with it. So patients who whose doctor has tested them for BRAF V600E, and know that their  tumor has a BRAF mutation, they can go on study based on that. But if their doctor did not test for it, if their site participates in this clinical trial, we set up retesting through the NCI where a few slides can be sent to a central lab. That’s a single lab working with the clinical trial, the single lab is in Dartmouth, a few sites can be sent and then your doctor will get a result BRAF V600 E mutation present or BRAF V600E mutation not detected. The patients start the study after they complete treatment. So there’s a lot of time after surgery, to think about the trial and patients only enroll after they complete treatment. So we account for the different treatments and also for the different extent of disease that patients had when they go on study. So this stratification is to make sure we have in both arms and equal group of patients who got FOLFOX or CAPOX–these are the two standard chemotherapies given for colon cancer. We stratified by the the length of time they got treatment, if they got three months or longer than three months, and also by the extent of the tumor that was removed, how far the tumor penetrate the bowel wall and were lymph nodes involved. And then we also stratify for something called circulating tumor DNA. What that is, is there are small fragments of DNA that are released by cells, they can be released by our normal cells, and they can be released by cancer cells. And they are available in the blood, in the circulation. So if the patient still has cancer cells present in their body, those cancer cells can release small fragments. And they can be detected. For example, they might have the BRAF V600E mutation. So there’s blood tests that are available to test for this, its not a standard test, but it’s being increasingly done with patients who have early stage disease. And if patients had this detectable DNA fragments from the tumor, we we want to have them on equal groups, because we know that that is associated with higher risk of recurrence. And the patients are then treated for the six months versus observation, you know what arm you get, there is no blinding, and then they’re watched, they’re followed as you would anyway, with scans and with blood tests to see what happens.

Dr. Rona Yaeger  16:13
So I just want to go over a little bit about the endpoints of the study and who is eligible. And then I’m happy to discuss and take any questions. So this trial is called a phase 2/phase 3 study, a phase 2 study is looking at the efficacy of an intervention saying how effective is this? And the phase 3 is saying how does this compare to what we do as a standard? So the phase 3 is saying do we affect the disease free survival? Do we have fewer patients recur when they get this treatment? But that’s a long endpoint, we have to follow patients for years. So we put in the study a phase 2, where we could look sooner and enroll fewer patients and be sure that there is something happening with this combination, before opening to the full phase 3. And so we’re looking at the circulating tumor DNA. In the patients who have circulating tumor DNA present, do they clear it more when they get this treatment compared to just observing them. And in the ones that don’t have detectable circulating tumor DNA, do they remain without detectable circulating tumor DNA, where they are in treatment, and if either group looks better for the treatment, we are good to continue and to proceed to the phase 3. The secondary endpoints, the other things we’re watching is we’re evaluating people for overall survival, we’re checking their toxicities from this treatment. And we’re looking at this alternative disease free survival from the time in which they had surgery to match with the published data on disease free survival. We’re looking at patients in the subset who have positive circulating tumor DNA, because we know they have a higher risk of recurrence. So maybe this is only helpful for those patients. And then we’re asking patients to fill out information-key symptoms associated with these drugs, which include rash, diarrhea, fatigue.

Dr. Rona Yaeger  17:58 
And so who is eligible? We went through a lot of this, but I want to reiterate –patients with colon cancer, that is stage III, that means colon cancer involving lymph nodes, or stage II, that is T4 involving the full thickness of the bowel wall, the patient’s tumor has a V600E mutation. If you don’t know if you have it, your doctor can send it to a central test, it requires only three slides and you get the result within a few days. Or if your doctor has already tested for that and they found that you have a BRAF mutation in your tumor, that is sufficient to get on study. The tumor has to be microsatellite stable, or mismatch repair proficient, so not that group that is MSI high that does better. All patients going on the study have to receive chemotherapy first. We require at least five cycles of FOLFOX or three cycles of CAPOX, they have to go on within eight weeks of completing treatment, no other cancer therapy besides the surgery and the chemotherapy, this is how well they have to be , you have to be more or less okay up in about for at least half the day. We know people just got chemo so we’re trying to be flexible, but we want them to be well enough to be on study. Similarly, we have some lab parameters, which we tried to make very flexible, because we know people just got chemo so their blood counts might be low.

Dr. Rona Yaeger 19:15 
So this is a national study. It is open in sites across the country. This is a map that  shows the number of sites currently, this is from clinical trials.gov. And you can see that in the northeast, we’re open in New York and Boston. We’re open in the Chicago area. It is open in Minnesota and Ohio. There are sites in Texas, and there are more sites coming online. I’m happy to connect people and to try to help figure out what site is closest. And also to turn to local hospitals and see if maybe they can open the study if there are patients who are interested. So this is my final slide I wanted to put up here. This is the clinical trials.gov ID for this trial. And this is the formal name of the study. It is a randomized study of the additional treatment with encorafenib and cetuximab versus observation for patients with Stage III or stage IIII BRAF V 600E in colon cancer. And I want to give a shout out to Qing Shi, she’s a statistician who helped me design the study. And the study’s open through the NCI, we have it open through multiple NCI groups to hopefully have national coverage. Thank you.

Manju George  20:31 
Okay, thank you so much, Dr. Yaeger. There are a couple of questions in chat. So one question is,  the patient, he’s concerned about once somebody enrolls in this trial, and then there is a recurrence and he’s on, encorafenib + cetux. What happens, he is using that one line of therapy already, right? So what are you thoughts on that?

Dr. Rona Yaeger  21:02
That’s a good question. So when the patients go on study, we do a CT scan, first, make sure they go on without any visible disease. But say a patient, like you’re saying in the scenario gets the six months of encorafenib+ cetuximab, and during that time, recurs. So that means that that tumor recurred through this treatment. So it is true, you wouldn’t give that treatment later, but it’s also true that for that tumor that treatment wasn’t doing enough, right? Because if the tumor was able to recur through it, even in the advanced setting, where are you starting treatment, when you see it, it was not giving you enough. There are trials for patients with advanced disease, but this is the only FDA approved treatment right now, that is matched for a BRAF V600E mutation. I think, while it is possible, this could happen and you wouldn’t want to give that treatment again, I think that it’s not highly likely, it’s quite unlikely to recur. First of all, the patient just had a scan, and they’re being followed within the first six months. And also we know that if you look at advanced disease, most people have some response, some shrinkage with this combination. But it’s true. It could happen. And if it does, this is just not the right treatment for your cancer.

Manju George  22:21 
Okay, continuation to that question is that they are wondering that prior exposure to E+C would make them ineligible for a trial like the SWOG 2107? Yeah, that would be the case.

Dr. Rona Yaeger  22:36 
Yeah, that would be the case. Because this trial, you mentioned is this combination of encorafenib and cetuximab  versus this combination plus Immunotherapy. And if this tumor was able to grow through it’s not a good treatment for that cancer. And so that trial, one half of it is giving you a treatment where the tumor would have already grown through that. So that is correct. Yeah. So we’re saying if you give it earlier, do you do better? And we don’t know. That’s, that’s what we’re asking.

Manju George  23:07 
Yeah. Okay. And then the question I have is that like, so the assumption is that, because these are people without any visible disease, getting them on encorafenib plus cetux early on, you’re trying even if there is microscopic disease growing that is not yet visible, because the tumor volume is so low this treatment is like, it’s almost like prophylactic treatment to prevent or delay the recurrence. Is that what the idea is?

Dr. Rona Yaeger  23:39
Exactly? That’s an idea. We don’t see anything. We know some people will recur,  so some people must have microscopic disease. And we’re trying to hopefully prevent the recurrence, or at least, to delay the recurrence and there is precedent in melanoma. The treatment with these BRAF drugs actually improves the cure rate, not these, but with BRAF drugs, improves the cure rate and we know in lung cancer, targeted therapy can also after surgery, improve the cure rate. So there’s precedent, but there’s no experience for this in colorectal cancer. So, so we don’t know we’re looking at patients with colon cancer here. Yeah.

Manju George  24:14 
Okay. And I think so this patient is saying that it’s a tough choice. Okay. So they’re asking why is the therapy not six months? Oh, I think they’re asking why the patient’s only need– I’m hoping that what this person is asking– is that you say that the patient should have at least three months of adjuvant chemo and then they’re eligible, right?

Dr. Rona Yaeger 24:14 
Yes, exactly. So they should get standard treatment at least three months, then they can go on to study and then we limited the time of the target therapy as six months. Because when we look at the effects of target therapy in the advanced setting, we see the greatest benefit within the six first six months.

Manju George  24:59
Okay. That makes sense. I hope your question is answered. And then I think that like from from our BRAF group, what we have generally seen is that, people after they have the treatment, they finish urgent treatment, they are very nervous about what to do next. So in that setting, I think having a trial like this, it’s something to do, because otherwise patients are just waiting. Many of them are really anxious that they might have a disease recurrence. So with this trial they have the feeling that they’re doing something more proactively to catch it, and then to do something about it. Right?

Dr. Rona Yaeger  25:37
Yeah, exactly. And so we’re thinking, this is a subgroup, but we have something we can do, and there is enough of a risk that we think it’s worth testing. Yeah.

Manju George  25:48 
Okay. And so the next question is, would stage IV have any chance of using this maybe after chemo can staging ever go down from 4 to 3.

Dr. Rona Yaeger  26:02 
So there are patients who have stage IV colon cancer, who can have all the tumor removed. And there are patients who have stage IV disease where the tumor is too extensive to remove. In the patients where it’s not all removed, these are FDA approved, they can get the BRAF therapy. In the ones where they might have a single or a few liver or lung lesions that can be removed, we don’t have data at that point for giving the additional BRAF treatment. And this study, we limited to patients who have stage II or III because we’re trying to select a group that is very similar. So it’s unknown. So at this point, if someone has stage IV, and they enter what we call NED, there’s no evidence of disease, they shift from visible disease where all disease is removed, they would be watched. Your doctor will guide you in terms of how long to do chemotherapy, but afterwards, just like the early stage patients, they’re watched and many of them can be cured. If this study, were positive, we may end up thinking about that stage IV setting but this study is limited to the stage II, stage III.

Manju George  27:14 
Okay, Thank you. And I think I asked this question before we started the call. But we also have patients who are MSI. High. Could you please explain why they are not included in this trial?

Dr. Rona Yaeger  27:27
Yeah, so the patients who are MSI high have a much lower rate of recurrence. So the stage II patients who are MSI high colon cancer, the rate of recurrence is actually very low. And most of those patients we just watch. And then the stage III setting there is some recurrence but the risk is a lot less than for the MSS, BRAF, V600E. And there are also studies in that group for Immunotherapy. So we think that there’s a very good tool available, and that rather than develop this treatment, in patients who are MSI high or the BRAF mutation, we’re giving a chance for the Immunotherapy data to develop where we think if more treatment is needed, there is a good tool there that could have a long, long effect. Patients here who are MSS can’t get Immunotherapy, the tumors don’t respond. And so we have to find another way to go after it. And that’s why we’re doing the targeted therapy here.

Manju George  27:51 
Okay, that that makes sense. So the this question is, so someone coming off adjuvant chemo with a ctDNA negative, do those people have a lower risk of recurrence?

Dr. Rona Yaeger  28:47 
Yes, they do. So we know that having detectable ctDNA after treatment raise raises the risk of recurrence, probably there’s some cells that are making this circulating tumor DNA. If ctDNA is negative, the risk is lower, but it’s not zero. So our study is enrolling irrespective of circulating tumor DNA. So there are studies out there that are for circulating tumor DNA positive only, this study enrolls either way, but we take the circulating tumor DNA into account to make sure that there’s an equal number of patients in both groups with that with that feature. But you’re right, that is a very important prognostic marker.

Manju George  29:31 
Okay, thank you. And the next question is, I think I’m probably missed it. What is the number of people or number of slots that are available for this trial?

Dr. Rona Yaeger  29:41 
The trial has about 200 slots for the phase II component and about another 200 for the phase III. So in total, it’s up to 400. So lots of slots because it’s a small subset of patients, so it’s no issue in terms of slots for the study.

Manju George  29:57 
Okay, so, for a patient who was stage III or you know, T4 stage II. So your recommendation would be that, if they know that they are BRAF V 600E, mutated, they contact, the trial sites to find out if they can get on the trial almost when they come to know of their BRAF status?. Yeah. And then for for the other people who don’t know their BRAF status, how would they go about getting the tests? What do you suggest.

Dr. Rona Yaeger  30:33 
So if you’re interested in the study, anytime after surgery, even during chemotherapy, I would discuss it with your doctor who can set up the BRAF testing. They can do it, if they are set up to do it with their own labs, they can just do it that way. If not, they can send it to that NCI central site, and then they’ll tell you whether the BRAF mutation is detected. And if it is, then you can talk about whether to consider the study. And then after you finish treatment, you’re already set up you know what to do, you know, oh, I’m planning to consider the study I want to register, or I’m not interested in the study. If the testing is done through the NCI, there is a consent form. That’s a pre screening. So you’re already set up to easily enroll on the study. But we know that most patients who have the the testing will not have the BRAF mutation, it’s about 6% of patients overall, who are microsatellite stable and have a BRAF V600E mutation.

Manju George  31:30 
Okay, so my next question is, is there like a specific group of colon cancer patients that you know, with a higher chances of being BRAF that you would recommend to ask their oncologist for this test? Like, what would that group be?

Dr. Rona Yaeger  31:48
That’s a great question. BRAF is, like we said, it has a slightly higher recurrence. So it’s associated with T4, and N2. So that means tumors that penetrate deeper and involve more lymph nodes, we tend to see that go along with BRAF. You can see BRAF in patients who are older, but sometimes those are MSI high and not the MSS. But you can definitely see as people get older, there is a higher incidence of the BRAF mutation. But often it’s a less aggressive MSI high subset. Otherwise, there’s no easy marker.

Manju George  32:27 
What about like ceacal tumors or proximal colon?

Dr. Rona Yaeger  32:33 
Yeah, it’s more on the right side. Yeah, that’s a great point. So we talk about the colon is like an upside down U. So the first part of the colon you have that arm that you that goes up, and so that’s called the right side. So the Cecum, the first part of the colon or the ascending colon, the BRAF V600E mutation is more common there. But it can be anywhere along the colon. Yeah, that is correct.

Manju George  32:59 
Yeah. Okay. So for us to talk about it in in Colontown, we could say that people with T4 tumors, and especially they have T for N2, then we would strongly recommend that they talk to their care team about this trial. And if they have not got a BRAF V600E testing, then this would be a way to get it tested. And then they can decide if they want to be part of the trial or not. Right, this will be an opportunity to find out if they have high risk disease that may have a high slightly higher chance of recurrence. So this other question, is they are asking if you must enroll within eight weeks of conclusion of adjuvant chemo?

Dr. Rona Yaeger  33:46 
Yeah, because we don’t want to have some people who go on and have had such a long gap. So we try to keep it similar. Yeah, so that’s where we are.

Manju George  33:57 
Okay, so maybe then another point to keep in mind is that it might be as as soon as they know their TNM status, maybe at that time is the best time for them to reach out and find out if they are BRAF positive, right?

Dr. Rona Yaeger  34:11 
I agree.

Manju George  34:11 
Okay, So let me see if there are other questions.I’m not seeing any so let me think if I have anything else.

Dr. Rona Yaeger  34:31 
I’m happy to talk to anyone. The trial’s up in clinical trials.gov My email is on clinical trials.gov. You can send me a quick email if you want and say, Oh, I have this scenario. And I can say it looks like this is appropriate or it looks like this is not the right study. I’m happy to quickly screen for anyone. I’m happy to speak about BRAF V600E. You know, you can connect with me if needed. But yeah, it’s as you said, so the T4 Stage III patients, patients who are at higher risk, it’s worth considering if you’re T4N2, if there’s something more you can do, it’s probably worth considering. So that’s a good group to look for that BRAF mutation to see.

Manju George  35:10 
Okay, okay, I think Julie is making a list of firstl ine trials that we were wanting to give more information to patients.  So we could talk about this trial in stage II, as well as stage III groups, and then say that, you know, if you don’t know your BRAF status, and you have a T4 N2 tumor, then this will be a great opportunity to find out if you have in the unlikely chance that you have the BRAF mutation, here’s something else that you can do.

Manju George  35:44
There is another question.

Manju George  35:54 
Oh, I think this person is asking, which is just a little more explaining of what we think is happening while the patient is on treatment? Is it removing any microscopic cancer or suppressing it?

Dr. Rona Yaeger  36:09 
So what we think is that the patients on the study had all the cancer that we can see removed, but we know that many of them, that’s all the cancer there is, and they’re here. But for some of them, there are cells that we didn’t see that are still there. And so the goal of chemotherapy is to kill those cells. But not not everyone gets chemotherapy  is cured. So that means that some of those cells, some people who have those cells, it’s only a portion of patients, but some people will have those cells, the cells are able to survive the chemotherapy. So the goal here with the BRAF treatment, is to try to kill any cells that have a BRAF mutation. And that’s what we need the tumor to have a BRAF mutation to go on the study. But if those cells have a BRAF mutation, these drugs will go in your body and all your circulation will hopefully get to those cells and hopefully destroy them. And so if that’s possible, that would improve the cure rate. But we don’t know. So that’s why the study is randomized, because any treatment has some risks. So we’re saying, you know, is it is it worth it? Do do we affect the chance that the cancer will come back to affect patient survival with this treatment? And also we ask patients, like what were your side effects, was it worth being on the study?. But that’s our goal. But if there are some cells out there that have the BRAF mutation, this treatment can get there and hopefully kill those cells.

Manju George  37:32 
Okay. And then maybe, I don’t want you to explain a little bit about the the idea of emergence of resistance. And you know, the selection of those things depend on what’s the initial volume of the cells, right, like, if there is very micro metastatic disease, and the number of cells is so small, then the chances of resistance emerging is much lower when compared to when there is established disease.

Dr. Rona Yaeger  37:58
Exactly. So that’s our hope here. So when patients have metastatic disease that we can see, there’s actually millions and billions of cells. And so when you give the target therapy, you don’t usually cure patients. The tumor shrinks, you can get a nice response, but you don’t usually get rid of all of it. So our hope here is that there’s very little right, we don’t even see it. And so that treatment here might be sufficient to kill all of that, just like Manju said that when there’s less there, you have fewer cells available to find a way to outsmart the drug. And so maybe if you’re killing off a portion here, you can kill off all of them, especially because they’re simpler. They haven’t figured out a way to spread yet. They’re just few cells probably that haven’t yet implanted and extended to be a visible metastasis. So that’s the idea. And that’s why we take hope that in melanoma and lung cancer, they actually seem to be curing more patients. So we see a paradigm where it is possible.

Manju George  39:01 
Okay, Thank you so much. This is about the Stand Up To Cancer, the Dr. Parikh’s trial. Has the arm with the targeted treatment shown any promising data?

Dr. Rona Yaeger 39:16 
So the Stand Up To Cancer trial has a BRAF V600E arm for patients who are ctDNA positive, and they have a BRAF V 600E mutation. They get the same encorafenib and cetuximab, but they also get a MEK inhibitor, Binimetinib. So they’re getting a triplet therapy. The FDA approved double a therapy but the triplet therapy is meant to have a similar effect to shut down this pathway. At this point, there are too few patients treated on that arm for us to know. But it’s really a similar idea, but that arm is exploratory in the patients who have ctDNA positive. So on some level the study is asking the question in a bigger way but it’s a similar idea. If given BRAF therapy after chemo improves the chances the patients will be cured.

Manju George  40:09 
Okay, I think that’s all the questions. Thank you so much. And I think that we will probably also share your email address with everyone. So you know if they have any questions then they can reach out to you. Okay. A recording of the talk will be available on Colopntown University.

Dr. Rona Yaeger  40:30 
Thank you. Thank you for the opportunity.

Manju George  40:34
Okay, take care. Bye. Thanks, everyone for attending.

DocTalk
2024
Dr. Yaeger
BRAF
MSS
Early-stage

In this DocTalk, Dr. Rona Yaeger from Memorial Sloan Kettering discusses how to approach early-stage BRAFV600E MSS colon cancer following adjuvant treatment with PALTOWN Scientific Director Dr. Manju George. Recorded in June, 2024.

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BREAKWATER trial

BREAKWATER trial

DocTalk
2023
Dr. Kopetz
BRAF
MSS
Trials

Dr. Scott Kopetz from MD Anderson Cancer Center discusses the BREAKWATER trial with PALTOWN Scientific Director Dr. Manju George. Recorded in May 2023.

Manju George 0:00
Hello everyone. Welcome to DocTalks. I’m Dr Manju George, the Scientific Director at PALTOWN Development Foundation, the nonprofit that supports COLONTOWN. And today we have the pleasure of having Dr. Scott Kopetz with us, who’s going to tell us about the BREAKWATER trial. But before we start, Dr. Kopetz can you tell us how you got interested in doing clinical trials and working in GI oncology?

Dr. Scott Kopetz 0:25
Most certainly. So I think, like many, I had personal reasons to get into oncology. I lost my mother to cancer at a young age, and so I was motivated to tackle this, and ended up in GI oncology, because I just fell in with a wonderful mentor, Paul, who was here at MD Anderson at the time, and was working in colorectal cancer and just kind of fell in love with the clinical problems and the wonderful patients of course, and really have been inspired ever since by all of our patients.

Manju George 1:08
Thank you for sharing. So then, do you want to share your screen?

Dr. Scott Kopetz 1:11
Yep, absolutely. Yeah. So just delighted. This is always so much fun. And I just start by saying, really a delight to be able to discuss and to share some of the updates here, and want to touch on some of the efforts that are ongoing. I know it’s been a little while since we’ve had an update, and so I’ll start with a little bit of background, and then dive into where the field is now and where we’re going. So some conflicts: very involved in a lot of these companies that are involved in developing novel therapies for BRAF. So kind of a key point I always like to start off with, and so apologies for those of you that have seen this slide a dozen times before. But the idea is that this is a cancer that when we have a BRAF mutation, it results in activation of growth factors, or a growth signaling pathway, right? This is a normal, healthy pathway in your body. When you cut your skin, your epithelium- your skin cells, turn it on to grow and repair, and then it gets turned off. The problem when there’s a mutation in the pathway like BRAF is that it’s constantly on and these cells are then growing. And what we found, though, is that these cancer cells like to be in this state, and that when you inhibit BRAF, with a medicine like encorafinib, that you indeed can shut down that pathway. The growth turns off, but the tumor adapts. The cancer likes this state. And then in cancer terms, we talk about this as homeostatic regulation. It’s like the thermostat: If it’s hot or cold, things get turned on or off with your heat or AC to adjust, and it’s the same thing with with cancer cells. And so there’s a transient inhibition, but the tumor adapts, has all these feedback mechanisms. The wiring that turns on other things upstream through the EGFR receptor is one of the prominent ones, and then what happens is that same signaling pathway gets turned back on.

Dr. Scott Kopetz 1:11
So the fundamental concept, and why we are using combination therapy and BRAF is because when you inhibit that second node, the EGFR, then you can shut down that adaptive mechanism, and so the combination provides benefit where either one alone doesn’t. So of course, this is the rationale behind the BEACON study, which looked at the encorafinib, the cetuximab, the BRAF and EGFR, compared it to chemotherapy control, then and looked at both triplet with a MEK, which didn’t provide any benefit, or the doublet with the BRAF and EGFR, which showed very nice results and improved overall survival, increased response rate, was a nice building block then for us to now become a standard of care, but also recognizing ways that we want to improve.

Dr. Scott Kopetz 2:42
So one way to look at this is to say it’s clearly active providing benefit from patients. There’s a subset of patients who can be on this regimen for a really long time. There’s also a number of patients that get some benefit for several months, and then the tumor adapts and progresses. So one of the questions is, well, why is that? And one of the areas that we’ve been able to characterize is really understanding these mechanisms of resistance. This is a complex slide, but what I want to do is just to have you visually look at the control and looking for any red mark, and a red mark means there’s some acquired event in the tumor. You can see very little evidence of red but when you look at the treatments with the BRAF and EGFR, you see all of these red marks. These red marks are predominantly around RAS mutations. There’s some other ones. But really, this idea that KRAS and NRAS can get mutated, the tumor mutates those in order to maintain that addiction to that growth signaling. And so, there’s an example here of a case study. And this is something I reported last year at ESMO. And this is a patient that was on the trial and at the time of progression, after about eight months on treatment that we looked in the tumor by circulating tumor DNA. So all of these KRAS mutations. These are all present in different subclones. And this is a real challenge, right?

Dr. Scott Kopetz 2:42
How do we prevent these subclones from growing out and developing resistance to the therapies? So put a pencil on that -we’ll come back to that, and some interesting hypotheses coming on that, but just acknowledging that, that’s one of the limitations that we’re dealing with. So where’s the field going? This is a good foundation, as I mentioned, and I’ll talk about some of the studies here briefly, and not really focusing a bit on BREAKWATER study, which is our first-line trial, really trying to understand how we best utilize this.

Dr. Scott Kopetz 2:42
So first, let me share some of the preclinical data that’s ongoing, and asking, “Can we do better? Is the idea of targeted therapy and more traditional chemotherapy, can we combine those and get more benefit out of that?”. Well, one of the findings that we had when we looked at this in our mice work is–in the mouse, we can generate the tumors, we can treat them with one therapy, and then move into second-line in the mouse, and then, compare this to when we do it altogether. And what we can see is that this interesting phenomenon. We think about chemotherapy and targeted therapy is two different things, but the reality is that there is some degree of cross-resistance between them, meaning that when a tumor develops resistance to chemotherapy, itcan sometimes develop resistance to the BRAF inhibitor, even though it’s never seen the BRAF inhibitor, and then vice versa. So these are kind of complex figures, but I think the way to look at it is to say, here is the benefit of encoafinib in this model, when you give encorafinib and cetuximab in first-line, the tumor has never seen a chemotherapy. However, if you give chemotherapy first, wait for the tumor to progress, and then give the BRAF and EGFR, you don’t get as much benefit. So these models aren’t under control for as long. And interesting– the same with the chemotherapy, so the prior targeted therapy may impact that. So the question is that sequential may not always be optimal in that situation. And so when we look at this and say, ‘Well, what if we put them together? What if we put the chemotherapy together with this?’.

Dr. Scott Kopetz 2:42
If you’re not used to looking at these mouse model graphs, what you’re looking for are tumors that are shrinking, going below the lines. And here you can see in the blue, these are the lowest, the best, and the combination of the targeted therapy and chemotherapy may actually induce more activity. So some of the conceptual rationale behind the BREAKWATER study: This is a large international phase III study that’s ongoing, and I’ll show you some of the data from the safety lead-in which was just ensuring, as we thought, that this would be safe to combine chemo, either FOLFOX or FOLFIRI, with the encorafinib and cetuximab. The ongoing study from phase III has three arms currently as you can see here. We don’t have any results from that, so nothing I can share yet on the randomized portion. Well, I’ll share some of the really promising data on this safety lead-in. First we should reflect and remember that chemotherapy alone in first-line gives us about a 40% response rate, the targeted therapy about a 20% in the later lines. And so we’re looking at some of these response rates, now the combination and seeing in first-line now 68/75% of the patients are having their tumors shrink down by more than half in volume. And even in second-line, where we expect maybe a 10% activity of the chemotherapy, you can see really promising, 40 or so percent shrinkage. and that duration of response is really fairly long. So remembering that with encorafenib-cetuximab we’re seeing duration of responses in under six months or so, we seem going much higher. The other way we can look at it is these progression-free survival curves where we’re seeing PFS’s that are really promising here, even in second-line, where medium PFS is somewhere in that four to six months with our current standard of care now, these small cohorts see really promising data. So, just acknowledging encouraging numbers, these are small cohorts, but I think giving us in the field a lot of enthusiasm that we’re going to see benefit with these combinations.

Dr. Scott Kopetz 2:42
Alright, so let’s go back to this–what about the mechanisms of resistance? So, a little complex– throwing a lot of scientific terms out here, but you we can actually look and see what’s changing in the tumor. And the bottom line is that when tumors progress on chemotherapy or targeted therapy or the combination, they actually have a very different pattern. And you see a number of different changes that suggest that we’re constraining the potential mechanisms of resistance, and that when you give the cancer fewer opportunities to progress there are fewer solutions to the problem of how to grow it in this regimen, what we see is that means that the tumors have a longer period of disease control. So I think the biology is really suggesting that.

Dr. Scott Kopetz 2:42
Now, interestingly, if we look at not BRAF colorectal cancer tumors, but if we look at patients that don’t have a BRAF mutation or a RAS mutation, these are ones that would benefit from the EGFR inhibition alone. There’s some data that we presented just recently in 2 JCO papers that reflect on the fact that RAS mutations occur in 40 and 20% KRAS and NRAS of patients treated with an EGFR inhibitor alone, but when you combine that in first-line with chemotherapy, it turns out that less than 10% of patients develop one of these secondary alterations. So we’re going for more than 50% like we see in BEACON, acquiring these secondary alterations. Now, when we combine it with chemotherapy earlier on, you don’t see the tumors picking that mechanism of resistance of acquiring RAS mutations. So we don’t know, I think it’s going to be really interesting to find out, but the same could occur, right? Can the combined chemotherapy prevent some of these acquired RAS mutations? Now this kind of makes sense, if we recognize that RAS mutations actually don’t result in resistance to chemotherapy, right? So RAS mutations may be the easy way out for developing resistance to the BRAF, but when you’re giving a combination, the tumor has got to find a way to grow through the BRAF inhibitor and the EGFR inhibitor, and through the chemotherapy. And if the acquired RAS mutations doesn’t result in resistance to the cytotoxic chemotherapy. Well, that’s not a solution to the tumor to grow. It’s got to find a harder way an alternate way. So this conceptually makes sense, that we’re cutting off pathways of resistance that may occur. Now the other question that we’ve asked is, well, this combination chemotherapy, we know that at some point with oxaliplatin, we need to stop the oxaliplatin. We use these maintenance regimens. So how do we do that optimally?

Dr. Scott Kopetz 14:26
And and the mouse modeling at least, suggests, probably what we would think makes sense, which is, you can’t just do maintenance with encorafenib. You need both encorafenib and cetuximab, and then also that you may get some benefit by continuing some of that 5-FU alone with it, as we had been alluding to, resulting in some of the alternate mechanisms. So we really think that the maintenance regimens, and this is how it’s written in the study, should be like a 5FU, encorafinib, and cetuximab, once a patient has received a maximal amount of oxaliplatin.

Dr. Scott Kopetz 10:19
All right, so where else is the field going? I’ll share a little bit about some of the updates in the IO space here. And this is building on some nice data that MAPK pathway inhibition, can enhance some of the immune responses in BRAF patients. And so this is that actually, from Ryan Corcoran’s group, looking at – these are old studies that we have done in years past, looking at, in responding patients, it turns out that you see an evidence of immune infiltration. And when you look at paired biopsies from patients who were gracious enough to consent to those, you see this increase in these these T cells. So we know that even though there’s no immunotherapy given in these figures, that just the targeted therapy alone may drive an immune response. And so there was nice data for those interested, looking at a BRAF, MEK, PD-L1 that is in that prior publication, thinking about how do we build on encorafinib and cetuximab, a nice trial led by Van Morris in our group looking at this, saying, “Can you add a PD-1 on top of this, even in microsatellite stable?”, so a small study but encouraging 50% response rate, which favorably compares the 20% we’d expect with the encorafinib-cetuximab alone. And then increasing the durability of this, and I think really seeing some patients that are having amazing durability to their disease.

Dr. Scott Kopetz 16:43
So that is an ongoing randomized study that’s currently enrolling nationwide for patients in second or third-line to be randomized, encorafinib-cetuximab, with or without nivolumab. So two to one randomization, so every three people enrolled, two get the nivolumab and one with the encorafinib-cetuximab. I will mention as an aside that there’s some data suggest maybe the PD-1 can rescue resistance in some settings. So there is a study, or now a cohort, that’s open– encorafenib-cetuximab-nivolumab at our institution, even if patients that had prior encorafenib and cetuximab, there are openings there. So it’s an option to consider.

Dr. Scott Kopetz 1:11
The final study I’ll mention is the rare subset of patients that have MSI high, which is more immune-sensitive and a BRAF mutation. And this is a trial ongoing that’s randomizing an initial first line setting; Pembro or PD-1 with or without the encorafenib, cetuximab to try to again, show that synergy between immunotherapy and targeted therapy. All right, so with that, just to conclude, I think this group knows: BRAF mutations, poor prognosis. We should be testing for it. We should make sure that this is a known status and that combination strategies are certainly successful, the encorafenib-cetuximab’s, the current standard of care. But hopefully I convince you that there’s some good rationale, pre-clinically and preliminary data from our first 60 patients, of potential benefit when we combine chemotherapy with encorafenib-cetuximab, and that study is ongoing, the BREAKWATER study, but there’s really interesting biology suggesting that you may be influencing and constraining the mechanisms of resistance. So if we can really shut off some of those RAS mutations, for example, that would be a substantial benefit. A lot of other areas, I don’t have time to go through all of them, but just updating where we are with the PD-1 combination: There’s work going on in neoadjuvant in the UK and adjuvant settings here in the US, a number of novel combinations are ongoing, including – I’d highlight this really interesting data that came out of an unbiased screening study with BET inhibition which is a epigenetic modifier in BRAF-mutated colorectal cancer models that was presented at AACR this year, and there’s actually a trial through the NCI network that will be opening up here the next few months to test that in patients who’ve previously been treated with encorafenib and cetuximab. So with that, thanks, as always, for your time and interest.

Manju George 19:37
Thank you very much. So, I think I will ask the first question. For a newly diagnosed patient who is BRAF mutated, with all these trials available, what do you think – if they have access to all the trials, what would be the good sequence for them to enroll?

Dr. Scott Kopetz 20:01
I think if they have MSI-H tumor, about 20% of BRAF patients will, the SEAMARK study, the last one that I showed is a great one, thinking about, how do we combine immunotherapy and targeted therapy. In patients who have microsatellite stable, 80% of BRAF patients, those are ones that we really think the BREAKWATER study is a great one to participate in. I think it is really an exciting study. We really hope it will be beneficial there. After that, if after patients have been exposed to encorafenib and cetuximab in some way, again, thinking about, can immunotherapy rescue that, as Dr. Morris’ study here is exploring, but then thinking also about how these other novel therapies, deeper inhibition of MAP kinase pathway and others may play a role.

Manju George 21:01
So basically, you’re saying that – it’s really nice that, Dr. Morris’ study is now accepting patients with encorafenib and cetuximab, right? Because that was something that people were concerned about. And then the other thing is that, so you really believe that the combination plus chemo is better instead of waiting and then, having that separately and then getting on, say, for example, the Van Morris trial?

Dr. Scott Kopetz 21:27
Yeah, so the SWOG study. Right – and I think, and for patients that are maybe on the control arm, for example, of BREAKWATER, I think the SWOG study is a great one. I think your point’s a good one. Just participating in clinical trials is important, and not all trials will be available to all sites, but we really do think that these are some of the more compelling directions that the field could go.

Manju George 22:00
Annie has a question, “Have you seen responses in BRAF patients with peritoneal mets?”

Dr. Scott Kopetz 22:05
Hi Annie, great, great question, as always. So yes, we have. You know, peritoneal disease is sometimes hard to measure and so response rates kind of get a little murky. Without getting too detailed, peritoneal is a, kind of a strip more, kind of across a surface of a tumor. The way that the guidance is to measure tumors, is that you measure the longest dimension of the tumor. So if you think of a strip of cancer, you’ve got to kind of measure that the long dimension. So even if the tumor kind of shrinks down this way, it doesn’t really get reflected. So you will see lower response rates. But part of that’s a bit of a function, a little artificial, just how we quantify the responses, and so you don’t always appreciate the extent of that, but yes, we can see responses in that setting.

Manju George 23:07
OK. I have a question about the schema of BREAKWATER. It seems that they have many cohorts, some of them, I think the main studies, like FOLFIRI plus encorafenib, plus cetuximab, and then they have an additional cohort, like a side one cohort D or something, where they are combining with FOLFOX. And then I also heard that there is some kind of prioritization that patients would be first enrolled into the encorafenib plus cetuximab arm. So, these are some of the questions that patients have, if I’m a newly diagnosed patient and I’m considering BREAKWATER, what are my chances of getting into each of these arms? Because, for example, if I’m just going to get into encorafenib plus cetuximab and I won’t get into a combination arm, then patients are thinking whether that’s a good strategy for them first, to get exposed to it, because then you can’t get on, it shouldn’t narrow down the options that are available to them later.

Dr. Scott Kopetz 24:01
Yeah, right. Yeah, it is. And I think it is important things to understand; So a little clarification: There are some amendments coming to BREAKWATER, really to focus that down a little bit more. And what we’re seeing is that the FOLFIRI component will be evaluated in a bit of a later point, and won’t be part of the initial randomization. So it’s still going to be a FOLFOX based chemotherapy backbone. Just to say, there are some changes coming that will make it a little more condensed and I think a little more patient friendly. Because I think the arms that we really are interested in is, how much does the combination of chemotherapy and targeted therapy compare to what right now is considered the standard of care, which is the chemotherapy alone. So that’s the main question. And I think the goal of really trying to get to that question as soon as possible.

Manju George 25:08
Okay, okay… okay – we will see if there are other questions. I think Annie had maybe one more.

Dr. Scott Kopetz 25:15
Oh yeah, how full SWOG 2107 is right? So, yeah, it’s enrolling. There’s still openings. And I suspect at least over the next six months or so, we’ll have openings there as well.

Manju George 25:33
Then she’s asking about class two and class three mutations.

Dr. Scott Kopetz 25:37
Yeah, great. Yeah, the class two and class three. So class one, is the BRAF V600E. The other mutations in BRAFget separated out into two different classes of therapies. There were some low levels of activity that were presented with a number of different trials. It was a little heterogeneous across many different kinds of settings. Not a great home run evidence of activity in colorectal cancer there. So I’m not sure we have a great solution to those yet, but the rationale is still there. I think part of the problem is that these are very heterogeneous, like not all class twos behave the same, not all class threes behave the same. So it is a little hard to sort out, and they are a bit rare, but we’re learning. We’re making progress. There’s hints of activity, but not any amazing responses yet.

Manju George 26:45
There’s a question from Katie, are you able to get into the BREAKWATER trial, as a second line of treatment?

Dr. Scott Kopetz 26:52
So not into the BREAKWATER. Even though I showed some data from the safety lead-in that included second-line patients, that was just in the safety lead-in. Right now, in the randomized phase III portion it’s patients that are previously untreated that are entering. So the second-line would be more the SWOG 2107 study, enco-cetux with or without PD-1.

Manju George 27:18
Yeah, I think Annie has a question. We had a few patients on the BREAKWATER trial, what is the best next treatment? I think you had mentioned some in your talk, right?

Dr. Scott Kopetz 27:26
Yeah, good question. If they were on the chemotherapy arm, they could then go over to the SWOG study, for example. If they were on the encorafenib-cetuximab, or the combination arm with chemotherapy and encorafenib-cetuximab, then, at that point, you’re right thinking about, if they were just on encorafenib-cetuximab, you could certainly think about chemotherapy at that point. Or, like mentioned, there are clinical trials ongoing in that setting to try to explore.

Manju George 27:27
With the safety lead-in, there were some differences in results with FOLFOX and FOLFIRI, right? So, I’ve heard some people ask, with FOLFIRI, there were some interactions, and the drug availability was less… or something. And then the main randomized portion of the trial is now with FOLFOX, but then the long term data show that FOLFIRI as acombination has been better, right?

Dr. Scott Kopetz 28:35
Yeah, so, we don’t really know for sure, I think it’s fair to say. I hate to make too much out of these cohorts of 10 or 15 patients and try to combine in one or the other way. So I think I would be a little more cautious there. There’s a little bit of a PK interaction as I was mentioning, so you don’t get the same exposure to the drugs as you would normally. But not sure that’s playing a big deal based on the results that we’re seeing. Like you said, it was certainly encouraging. So I think that the data really suggests that there’s substantial benefit with the FOLFOX out of the safety lead-in so I’ve been very comfortable in recommending that to the patients. I don’t think we’re missing an opportunity necessarily, on the right partner.

Manju George 29:31
Okay, okay. And then once they finish the chemo plus the Encorafenib+Cetuximab potion, then are you thinking that, say for example, if they don’t have access, we have many – because BREAKWATER is open worldwide, we are fortunate to have the SWOG 2107 right? But many other countries, they don’t. The the idea of combining encorafenib plus cetuximab with nivolumab isn’t that common. So do you think that in that case, they can get LONSURF+bev, or once they progress on the trial, what options could they consider?

Dr. Scott Kopetz 30:08
Right, yeah, so, there’s always the alternate side of toxic regimens that may make a difference. LONSURF+bev I think certainly is reasonable as well. So we do, you’re right, just kind of lean back on what kind of works in general, in colorectal cancer.

Manju George 30:23
Okay, and then, when you look at the resistance mutations, there are so many met amplifications and things like that. Do you think STIVARGA (regorafenib) has worked for people? I’ve seen that some people prefer to use STIVARGA when they get progression on encorafenib plus cetuximab. So what is your personal —

Dr. Scott Kopetz 30:44
–Yeah – we don’t – It’s not great data on that, necessarily. I think it’s a reasonable option, but I don’t know that it’s not something we’ve seen pan out in our preclinical studies, that we’re driving towards a more sensitive phenotype to regorafenib, but certainly a reasonable option.

Dr. Scott Kopetz 31:05
Okay. Were there any learnings from ANCHOR CRC trial regarding PFS or OS to those without peritoneal mets?

Dr. Scott Kopetz 31:14
Yeah, so ANCHOR was a study looking at the encorafenib plus cetuximab plus a MEK inhibitor, and that was running in parallel with BEACON, and we learned from BEACON that the MEK was adding more toxicity, not adding as much benefit. So it’s a little harder to extrapolate some of the ANCHOR data otherwise, but I think what we recognized is that the PFS was kind of in the same range as what we’d expect with the chemotherapy alone and the OS, likewise, looked encouraging, but it was non-randomized for the OS, which makes it hard to interpret. So, the breakdown by with/without, peritoneal metastasis is not really well laid out.

Manju George 32:00
Okay. And then could you say something more about that BET inhibitor trial?

Dr. Scott Kopetz 32:11
Sure. So, this is through an unbiased screen where we asked, ‘if you have a patient or a tumor on encorafenib-cetuximanb, and we screen 1000s of different nodes for ways to modify and we find a node that really tends to be a vulnerability of the cancer, and that turns out to be a bromodomain, which is a regulator ofgene expression. And so there is actually an inhibitor of bromodomain, so we were able to then show the benefits there and bring that together into a clinical trial. So there’s a bromodomain inhibitor plus encorafenib and cetuximab. What it’s doing is, really for those aficionados, is deeper inhibition of the MAP kinase, as well as shutting down MYC signaling, which is a key survival mechanism. So it’s a really way to inhibit MYC, which is one of the key oncogenes.

Manju George 33:09
Okay, I think it’s sort of hard to get the word out to BRAF folks about this trial. Has enrollment been fairly brisk at NCI centers and academic centers worldwide?

Dr. Scott Kopetz 33:22
Uh, let’s see. So I’m not sure which trial?

Manju George 33:27
I think BREAKWATER.

Dr. Scott Kopetz 33:28
Oh, BREAKWATER, yes, it is. It’s going, you know, first-line studies are a little harder, because a lot of times we don’t always know the BRAF status by the time that patients start treatment. So it’s not quite as fast as BEACON but it’s going reasonably well. We’ll get it done. Not always as fast as we like, but we’ll get it done. And I think we’re kind of on track on projections at the moment.

Manju George 33:57
Yeah, yeah. I think that we are working with Pfizer to get, in COLONTOWN University, we are going to be having a featured trial, we’re doing that for BREAKWATER. So my other question would be, since you have those mouse lines that seemed very interesting, where you’re doing sequential treatment and testing, what kind of resistance develops. Are you also doing experiments where you’re doing the encorafenib plus cetuximab plus FOLFOX and seeing what else you can give those mice?

Dr. Scott Kopetz 34:25
Right, so, we haven’t pursued that. I think it’s an interesting area to say, ‘how do you even improve upon where the BREAKWATER is going to be’, right? But no, we haven’t started that type of work yet. But I like the way you’re thinking, let’s take a step ahead.

Manju George 34:44
Yeah, because I’m sure that in a year or two, then you’ll have lots of enrollment, and then people are going to be asking, ‘what next?’.

Dr. Scott Kopetz 34:53
So that’s right, – have something ready – because that’s right… we’re looking for good post docs to do that. If anyone knows of some good post docs out there, let us know.

Manju George 35:02
Okay, okay, yeah. So Annie says it was great to see that there was an epithelial to mesenchymal transition in preclinical research. Is that showing up in BREAKWATER patients too?

Dr. Scott Kopetz 35:15
Good question. We don’t know. You know, we don’t have progression biopsies on patients on BREAKWATER, orany biopsies, for that matter. So as phase III, they tend to not have that same degree of translational research. So we’ll have blood, but we can’t always assess some of these transition states, like you mentioned Annie, in some of the samples that we’re collecting. So we’re going to rely on other ancillary, smaller phase II studies or preclinical models.

Manju George 35:48
Okay, I think we have gone through this really fast.

Dr. Scott Kopetz 35:53
Wonderful. Yeah, no, that’s great. Well, thanks so much to everyone for the time and interest and happy to answer any other questions that come up offline.

Manju George 36:03
Thank you so much.

Dr. Scott Kopetz 36:06
Thanks.

Manju George 36:07
Bye

Dr. Scott Kopetz 36:08
Bye bye.

DocTalk
2023
Dr. Kopetz
BRAF
MSS
Trials

Dr. Scott Kopetz from MD Anderson Cancer Center discusses the BREAKWATER trial with PALTOWN Scientific Director Dr. Manju George. Recorded in May 2023.

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CAMILLA trial — Cabo + Durva for metastatic refractory MSS CRC

CAMILLA trial — Cabo + Durva for metastatic refractory MSS CRC

DocTalk
2022
Dr. Saeed
MSS
Immunotheapy
Trials

In this DocTalk organized by PALTOWN Scientific Director Dr. Manju George, Dr. Anwaar Saeed from Kansas University Cancer Center talks about the CAMILLA trial for treatment-refractory Microsatellite Stable (MSS) stage IV colorectal cancer. Recorded in May, 2022. 

Table of contents

00:00: Introduction
01:35: Dr. Saeed outlines her research activities at KU Cancer center
06:26: Background/rationale for CAMILLA trial, Cabo & Pembro each as single agents in CRC
10:47: Mechanism of action of Cabozantinib
14:10: Cabo as a “dirty Tyrosine Kinase Inhibitor (TKI)”
15:14: Cabo + Immunotherapy for CRC
17:28: CAMILLA trial introduction — Dose-limiting toxicity evaluation
21:05: Results of the Phase 1b study
25:30: PD-L1 CPS & its role in treatment response
26:30: Phase II multi-cohort schema
28:31: Phase II Cabo + Durva in MSS mCRC results
28:50: Background
30:45: Methods
33:14: Baseline characteristics of the patient population
35:32: Safety data from the study
38:48: Efficacy data
51:14: Conclusions
51:49: Other VEGF TKI + IO combinations
53:00: Coming soon! STELLAR 303 600 patient global Phase 3 trial using offspring of Cabo + Atezo vs Rego in MSS stage IV CRC with RAS WT tumors

Dr. Manju George 0:00
Hello everyone. Welcome to DocTalks. I’m Dr. Manju George, the Scientific Director at PALTOWN. I organize these DocTalks, where we invite leading clinicians to talk to us about topics that are relevant to colorectal cancer patients and caregivers. And today, we have the pleasure having Dr. Anwaar Saeed with us. She’s an Associate Professor of Medical Oncology at the Kansas University Cancer Center and the Associate Director of the Early Phase Program. She’s going to tell us about the CAMILLA trial, but before that, let’s chat a little bit with her and ask her about her work. So Dr. Saeed, welcome.

Dr. Anwaar Saeed 0:43
Thank you Manju. Thanks a lot for the invitation. It’s really an honor and it’s my pleasure to be here today and talk about my research work and present the data on the CAMILLA trial, and also chat on future perspectives where we’re heading and any promising combinations or regimens in this field.

Dr. Manju George 1:03
I see on the website that you are an active member and lead investigator in the GI Oncology program and Early Phase Developmental Therapeutics Program, and I also see that you have a bunch of trials running. So could you tell us a little bit? – And so you had your medical degree at the Arabian Gulf University in Bahrain and then a clinical fellowship at the University of Kansas Medical Center. So do you want to tell us a little bit about your research activities and other trials that are going on at the Kansas University Medical Center?

Dr. Anwaar Saeed 1:34
Sure. So we are so invested in immune modulatory approaches. As we know, over the last few years, we have seen how checkpoint inhibitors, particularly the agents that target the PD1 and PD-L1 , have revolutionized the way we treat solid malignancies, as we’ve seen multiple approvals of those agents, either a single agent, or in combination with chemotherapy or other biologic therapies and multiple solid malignancies. And particularly I would say, over the last two to three years, we’ve seen those agents invading the GI or gastrointestinal cancer space, and particularly in hepatocellular carcinoma, upper GI cancer, like gastric and esophagus, as well as in colon cancer space as we are trying to identify a way of modulating those cold tumors to turn them into a hot tumor and make them respond to those immunotherapy agents. We’ve seen how those PD1 or PD-L1 inhibitors have already had approvals in the frontline setting and later line settings in patients with microsatellite instability high or mismatch repair deficient tumors. But when we look at the advanced stage colorectal cancer space, we’re looking at really not more than 5% – 10% of the whole population. So my interest and my investment in terms of research effort and activity really lies in finding a space for those agents in the majority of colorectal cancer, which represent the microsatellite stable space. So within this space I’m looking at combining those checkpoint inhibitors with novel agents. So the CAMILLA trials combining durvalumab with a multi VEGF tyrosine kinase inhibitor in this case, cabozantinib. And I also have other studies I’ll go into, looking at combining the checkpoint inhibitor or a PD1 inhibitor with cell cycle inhibitors. The one that I have interest in is called 9-ING-41. It’s an agent that is very interesting that combines very well with chemotherapy through chemosensitization effects, but has shown recently immune modulatory impact by modulating or upregulating, PD-L1 and LAG-3. As we know, LAG-3 is another checkpoint inhibitor just like PD-L1 and we know blocking it can unlock the immune system like how we block PD-L1. And so I’m really excited about that area of research, because I feel like combining agents like this with a PD1 inhibitor as well as chemo in the frontline space could really change the horizon for our patients. So I have that study, I got recently opened. It’s actually looking at the combination of chemo with PD1 and that agent in the pancreatic space but I have a vision of looking at a similar approach in patients with colorectal cancer in the frontline space. And then there are several other stuff, I’m also interested in the GI chemo prevention. And so me and my partner, his name is Dr. A.J. Mansell, are working on several chemo prevention ideas we have. I have an ongoing trial looking at omega-3 fatty acids as a chemo prevention option in patients with Lynch syndrome. We feel like we need a chemo prevention method, in those patients with Lynch syndrome who have 80% lifetime risk of developing colorectal cancer yet we don’t have any chemo prevention agents in this space beyond aspirin. I mean, there are some vaccine trials ongoing, but we don’t have any data yet from those. But we need something: diet modifications or a chemo prevention agent, so we’re looking at omega-3 fatty acids as a prescription drug using moderate doses. That trial is ongoing, and we’re hoping to present it at one of the upcoming conferences.

Dr. Manju George 6:00
Okay, thank you very much. That all sounds exciting and if you have a link of the trials, especially for CRC, that’d be kind of nice to see. And then I also saw the two posters, the one from GI ASCO earlier this year and the SITC. So if you can send me a PDF of those, that would also be something that would be very helpful. Okay, so we can get started on the CAMILLA trial then.

Dr. Anwaar Saeed 6:25
Sure. Thank you. I’m going to present our talk about highlights of immune modulatory approaches in patients with advanced microsatellite stable colorectal cancer with a spotlight on the CAMILLA trial and particularly cohort 2, as this trial is ongoing, has a multi-cohort focusing on testing this regimen of cabozantinib plus durvalumab in multiple disease cohorts, but we will focus today’s talk on the colorectal cancer cohort. As a background or rationale, looking at what we have tested so far in patients with colorectal cancer, before delving into the data from the CAMILLA trial, we know that cabozantinib in colorectal cancer as single agent leads to some, I would say, modest impact on disease control rate. There was a small phase 2 study that tested cabozantinib as monotherapy in patients with chemo refractory: patients who already tried and progressed on standard of care chemotherapy options– so we’re talking about the third-line and fourth-line setting. Usingcabozantinib as a single agent in this population led to a response rate of 3% so kind of modest responses here. And I would say reasonable disease control rate of 72.7% and they have a 12 week progression-free time of 34%. In comparison, when we look at how PD1 inhibitors perform in this population, in patients with microsatellite stable colorectal cancer. So looking at the trial that led to the approval of pembrolizumab in patients with MSI-High disease, in that trial they will count all patients, regardless of MSS. So we had a cohort in that trial that looked at pembrolizumab as a single agent in patients with microsatellite stable disease, as well as another cohort looking at it in the patients with microsatellite instability, or MSI-High. And as you see in the right hand side of the slide the trial has shown that pembrolizumab as a single agent, in patients with chemorefractory colorectal cancer, do not lead to any responses. So overall response rate of 0%, in patients with microsatellite stable disease, as opposed to really good responses, as you see here in the blue bars and the black bars, the MSI-High status. So clearly, immune checkpoint inhibitors as single agents do not really do anything, just do not work. As you see, progression-free survival here is two months. Similarly in cabozantinib. And then if we use this days tab, which is in contrast with historic results of standard of care agents that we currently have in the third-line setting, namely regorafenib and LONSURF. And I put them here just for us to compare– when we look at regorafenib as a single agent based on the CORRECT trial that led to the approval of this drug, overall response rate was 1%, the median progression-free survival was 1.9 months. Really similar to what we’ve seen with PD1 inhibitor in microsatellite stable disease. So a really minimal benefit to a placebo effect and a median overall survival of around six months. Similarly here, using LONSURF, as a single agent overall response rate is 1.6% so really not more than 2% here, median progression-free survival of two months, and then a median survival of seven months. So this is what we have, as a standard of care. And those single agent activity here with either cabozantinib or any checkpoint inhibitor, do not go beyond what we’ve seen as standard of care. So this is a background of what we have so far.

Dr. Manju George 10:37
Dr. Saeed, could you please go into a little bit more detail about how cabozantinib works?

Dr. Anwaar Saeed 10:44
Yes, cabozantinib, and I’m going to go on to the next slide, it will show you why we’re looking at cabozantinib, and why this drug. So what is the rationale of combining cabozantinib with checkpoint inhibitors, and before looking at the immunomodulatory effect of this drug, cabozantinib is a tyrosine kinase inhibitor, so it blocks the tyrosine kinases that are very important in phosphorylating very vital proteins that the cancer depends on for survival and proliferation or multiplication. There is a huge number of tyrosine kinase inhibitors out there, but those “dirty” tyrosine kinase inhibitors are the ones that block multiple tyrosine kinases, not just one. And the famous ones that led to multiple approvals, for example, cabozantinib, regorafenib, lenvatinib those all block the VEGF receptor-2 tyrosine kinase in addition to multiple other tyrosine kinases. Cabozantinib is one of them, it blocks the tyrosine kinase protein for VEGF receptor-2 and we know VEGF receptor-2 is a vital protein in our vascular endothelial system, and it helps with vascular proliferation and within the cancer tumor microenvironment we know that this vascular system is very vital for tumor replication and tumor growth, and any dysregulation in the vascular pathway is one way that the cancer uses to progress, metastasize and proliferate. Blocking the vascular system has shown, in for example, gastrointestinal malignancy, particularly in colorectal cancer, that it helps the chemotherapy work better. It improves the control rate and the median progression-free time, and it has shown to be a very good maintenance strategy, combining it with our standard of care chemo in this disease. And I’m referring by saying that, to Avastin, which is the standard of care drug that we utilize. The difference between Avastin and cabozantinib is Avastin is a monoclonal antibody that blocks the protein VEGF receptor-2, but just blocks the protein, not the tyrosine kinase, the enzyme that is linked to the protein. And so we call it a monoclonal antibody that blocks the protein receptor on the cell membrane, whereas cabozantinib is a VEGF receptor-2, blocks the same pathway, but it blocks the tyrosine kinase protein that is linked to that receptor. And it is not just blocking that VEGF receptor-2, it is a multikinase inhibitor. It blocks that protein, but also with it, blocks multiple other tyrosine kinases. So in this case, the profile of cabozantinib targets include “M-E-T” or “MET”, as well as “R-E-T” and multiple other tyrosine kinases like FLT and RET and KIT. We call it “dirty” tyrosine kinase because it blocks multiple kinases. It can lead to some certain side effects that I will highlight as we go through the slides. And as compared to the other multi-VEGF tyrosine kinase inhibitors, it has its unique targets because it is one of the only, I would say, approved multi-VEGF tyrosine kinase inhibitors that block both VEGF and MET at the same time. And we know that in gastrointestinal cancer malignancies, particularly colorectal cancer, the MET pathway plays a vital role, especially in patients who have RAS wild-type disease after progression on EGFR inhibitors like cetuximab or panitumumab. So that is what cabozantinib does as a drug.

Dr. Anwaar Saeed 15:04
But nowadays, because of all the immunotherapy approvals, there is a lot of research and trials that were done exploring, “how about looking at those biologic agents that block the tyrosine kinases and the vascular pathway and see if they could work well with immunotherapy? Do they have any immune modulatory impacts in a way that provide rationale to combining them with immune checkpoint inhibitors?”. And the reason for that is because when we modulate the vascular system in the tumor microenvironment, we know that the vascular system crosstalks with those checkpoint inhibitors, because this is what the cancer does to evade the immune system, modulating the vascular pathway, through the hypoxia pathway and such, it can upregulate certain checkpoints, like PD-L1. So for example, with this drug cabozantinib, it was tested a few years ago, back in 2014 in a colorectal cancer model, and testing it has shown that cabozantinib can reduce the immune suppressor cells in the circulation by suppressing T Regs and MDSCs, and those are suppressive T cells and it can boost the effector T cells like CD4 T cells and CD8 T cells. So, it has shown some immunomodulatory impact in colorectal cancer. And in a different model, in a prostate cancer in vivo model published in Nature back in 2017, combining cabozantinib with checkpoint blockade has led to significant suppression of MDSCs and significant boosting of the CD8 T Reg ratio. That was very significant in comparison to using either checkpoint blockade alone or using cabozantinib alone. This study clearly validates pre- clinically, that combining cabozantinib with immune checkpoint blockade leads to synergistic impact, and that provided the rationale to develop this trial. And not just this trial, because cabozantinib is being combined with immune checkpoint blockade and being tested in multiple other solid tumor types. But this is the first study that combined cabozantinib with immune checkpoint blockade in GI cancer malignancies, colon cancer and gastric and esophageal adenocarcinoma.

Dr. Anwaar Saeed 18:32
So this is the highlight of the schema for the CAMILLA trial, which is a phase 1/2 trial, combining cabozantinib with durvalumab in patients with advanced gastroesophageal cancer and other gastrointestinal malignancies. So, the highlight of what we’ve done for the Phase Ib part of the study: Part One of the study was a DLT evaluation or what we call dose limiting toxicity evaluation. We use the classic three plus three dose escalation, where we use the fixed dose of durvalumab, which is the standard dose for durvalumab, the PDL1 inhibitor. And this is a standard dose that we give once a month. So on the first day of every cycle–each cycle is four weeks. The first day of every cycle, the patient receives 1500 milligrams of durvalumab intravenously, in combination with cabozantinib, which is an oral agent. And in this phase, we escalated. We started with the lowest dose of cabozantinib, 20 milligrams daily, and then we went up to 40 milligrams daily in the next dose cohort. And then we went up to the maximum dose, which is 60 milligrams, so just three dose levels that we tested.

Dr. Anwaar Saeed 18:54
And then we opened the phase 2, or the expansion phase. So from phase 1, we’ve learned that going up from 20 to 60, we did not see any dose limiting toxicities per the protocol, per our protocol definitions of those limiting toxicities. However, most of the patients who went into the 60 milligram dose through the expansion phase needed dose reduction to 40 milligrams after cycle two, and most of this was related to accumulated fatigue and anorexia, or loss of taste and weight loss. Because of that, we regrouped and discussed in detail all the side effects that we’ve seen and the safety profile, and we agreed that the 40 milligram dose would be the happy medium, and we should use that as the recommended phase 2 dose. We did not see any fatal drug toxicities or adverse events throughout the study. For the phase 1 part, which included, as you see here, colorectal cancer as well as gastric and esophageal adenocarcinoma, I presented the first 20 patients’ data back in ASCO, 2020, just to show the preliminary results from the phase 1 at that time. We’ve seen really good, impressive results. Overall response rate was 25% among those first 20 patients, and a disease control rate of 85% and most of those patients, not most of them, I would say all of them have chemorefractory disease and they are micro satellite stable. So they progressed on the standard of care chemotherapy regimens in the front line, second line, and then they went on the trial. Those are the mature Phase 1b results that I presented at the SITC meeting. And as you see, those are the first 30 patients that went on the study. Part of them went on the dose escalation cohort, and then the second part was the dose expansion cohort. We have 17 patients among those with colorectal cancer, 10 patients with gastric and esophageal and 3 patients with hepatocellular carcinoma. As you see, we’ve seen a really good overall response rate 26.6% so around 27% disease control rate of 83% and a median progression free survival of 4.5 months, median survival of nine months, and the six month progression-free survival was 36.6%. And we looked at, as I highlighted earlier, because of the immune modulatory impact of cabozantinib, we expect some immune modulation and rationale for combining with durvalumab. We know from the upper GI literature and some other solid tumor literature as well, that PD-L1 expression, using the combined positivity score or CPS methodology, can predict or identify a subgroup of patients that might respond better to regimens that contain PD1 or PD-L1 inhibitors. So we ran a subgroup analysis, we obtained baseline biopsies, so before all of those patients went on the trial, we obtained a fresh tumor biopsy from all of them, and we tested those tumors for PD-L1 using the CPS method. And then we’ve seen that among the 30 patients were evaluable for response 12 of them have relatively high PD-L1 expression defined as CPS 5 and above. So among those 12 patients, we’ve seen better responses, which is in line with what what we’ve seen with using this methodology in patients with upper GI malignancies, when nivolumab and pembrolizumab was combined with chemotherapy in the frontline space and in that disease population. But so far, there’s no other studies that looked at PD-L1 CPS in patients with colorectal cancer who have advanced stage disease, or even early stage disease. This is the very first study that explored using this biomarker to identify a group of patients who might benefit the most from this combination, and we’ve seen that the overall response rate was better: 33%. Disease control rate is better: 91%,and the median progression-free survival was really better 6.1 months, and then the median survival was way better, not reached here, but I have up to date data that showed the median overall survival: 14 months. The six month PFS was 50% so those patients are able to stay on the study longer, and they are able to derive deeper responses than the rest of the patients.

Dr. Manju George 24:13
Dr Saeed, in the study, how many are colorectal cancer patients?

Dr. Anwaar Saeed 24:19
17.

Dr. Manju George 24:20
Okay.

Dr. Anwaar Saeed 24:21
So, among the 30 patients, we had 17 colorectal cancer, 10 gastric and esophageal and 3 HCC. And the colors here, if you look at the graphs, the green is the colorectal cancer patient, so most of those are colorectal. The red is the gastric and esophageal and the blue is the hepatocellular carcinoma or liver.

Dr. Manju George 24:44
Thank you.

Dr. Anwaar Saeed 24:44
Thank you. So this is just showing the couple more curves, highlighting the subgroups. As you see here, looking at progression- free survival, there’s a clear separation of the curve. Those patients really do better. Patients with PD-L1 CPS score 5 and above, there’s clear separation throughout from the get go and then, similarly, with the overall survival, clear separation of the curve. And this is why one way of identifying a clear biomarker, we know that PD-L1 CPS has its own pros and cons, and own challenges when it comes to testing it in the tumor micro environment, because of intratumoral and intertumoral heterogeneity, because if you obtain different biopsies from the same patients, you might get different results. But most of those patients have numbers ranging, if you find a CPS PD-L1, – CPS of 10 – from the primary tumor in the colon, is likely that you’re going to find eight or seven in the liver, or maybe higher in the liver. So despite the heterogeneity, it is one of the best markers out there that could identify the population that will benefit the most. And again, I have to say that this is a small sample size, and so we should not use this as a conclusion that this is a good marker, but this definitely sets the stage for us to test the marker in a larger patient population, in our larger study, and also in the ongoing study. So this just highlights what we have in the study so far before I review the results for the colorectal cancer cohort.

Dr. Anwaar Saeed 26:27
As you see, there’s four cohorts in the study, all of them are ongoing, except the colorectal, because we completed that enrollment of the colorectal cancer cohort. And I presented that data at the GI ASCO meeting. So 29 patients are expected to enroll in each one of those cohorts. We are almost done with enrolling to the gastric and esophageal cohort, and as I said, completed enrollment to the colorectal cohort and those two liver cancer cohorts are currently ongoing. We actually, on the cohort four of the liver cancer cohort here, we are testing the triplet. So in addition to cabozantinib and durvalumab, there is some data recently that have shown that combining durvalumab with another checkpoint inhibitor called tremelimumab, also from AstraZeneca, have shown really good responses in a small Phase 2 study in the 2nd line space. And then recently, this was validated based on the HIMALAYA trial, which is a large Phase 3 trial – FDA registration trial, in the front line space, and patients with advanced liver cancer. This combination, or doublet, showed positive results in this large frontline study. And based on that, we decided, well, if those two checkpoint inhibitors work very well, then we could probably just add this checkpoint to our doublet here in the CAMILLA study and test the triplet to see if we will be able to capitalize on what they’ve seen in the HIMALAYA study. So this is currently ongoing as part of cohort 4, and obviously, if we’ve seen good results with that triplet, my vision as far as next step is to possibly test the triplet in the other disease types, including colorectal cancer.

Dr. Anwaar Saeed 28:24
So with that, we can delve into the results of the colorectal cancer cohort, which tested again, the same regimen, in the MSS colorectal cancer population, mostly in the third-, fourth- and fifth- line setting. So, I already went through the background and discussed how combining checkpoint inhibitors with anti- angiogenic agents have antitumor activity in multiple cancer types. As an example, we could highlight renal cell carcinoma within the kidney cancer space, liver cancer and lung cancer in those spaces, combining agents that target the vascular pathway, or what we call antiangiogenic agents with immune checkpoint blockade led to benefit and led to approval of those drugs in those settings. Cabozantinib, as I highlighted earlier, is an anti-VEGF Receptor-2, MET and AXL multi-tyrosine kinase inhibitor. It has multiple studies in the pre clinical and the clinical space and various solid tumors that demonstrated favorable immune modulatory activity of this drug and clinical synergy when this drug combined with PD1 and PD-L1 inhibitors, like durvalumab, in this case. So this study is just following what was shown in other disease types, but testing it in the gastrointestinal cancer space, particularly colon cancer and gastric and esophageal cancer. Upon completion of this Phase 1b basket study that I just highlighted, evaluating cabozantinib and durva in those 30 patients and demonstrating favorable safety and efficacy, the trial was then expanded to a Phase 2, multi-cohort, multi-center study of 117 patients. It’s currently ongoing. We almost completed two cohorts, and two of our cohorts are still ongoing.

Dr. Anwaar Saeed 33:51
As far as the methods for this Phase 2, the patients who were enrolled in this Phase 2 received the recommended Phase 2 dose of cabozantinib, which is 40 milligrams daily, as I highlighted earlier, and they received a fixed dose of durvalumab, which is a standard dose for this drug, 1500 milligrams through IV infusion, once every four weeks. The enrolled patients should have a microsatellite stable disease or proficient mismatch repair phenotype. And this is the majority, around 90% of the advanced colorectal cancer population belong to this, or have this phenotype. They must have progressed on two or more lines of therapy. So we’re only testing this in the third, fourth and fifth-line setting. We have run a subgroup analysis on the RAS wild type tumors, and I will highlight them. We’ve been doing scans, or per the protocol, the scans were done every eight weeks, so every couple months the patients will have a scan to evaluate disease response. We allow disease beyond progression just one time, so if the patient shows any evidence for disease progression that meets our, what we call it: the RECIST criteria, the trial followed a modified RECIST criteria, meaning if thepatients have disease progression, we allow the patient to continue to study beyond progression one time and then repeat another scan in at least four weeks from the first scan that showed progression. If the follow-up scan shows disease progression, that means the progression is confirmed, and at that time, we can move the patient off the study and discuss other options. If the second scan shows response or improvement or stable findings from the first scan then we consider that this could possibly reflect something called pseudo progression in the setting of immunotherapy, and that patient would be allowed to continue the therapy.

Dr. Anwaar Saeed 34:13
So those are the baseline characteristics for the patients who went on the trial. So we had balanced, I would say female/male ratio around 50%, as far as the median age who went on the study? 57 years was the median age. But we have quite a good number of patients above the age of 60 who went on the study, 45%. As far as performance status, most of the patients have performance status of one. As far as sidedness, most of the patients had left-sided colorectal cancer, including rectum. So: 16 have rectal cancer; 25 patients have left-sided; and only 4 patients have right-sided colorectal cancer. The results, I would say, represent the left-sided, mostly, colorectal cancer space. As far as the RAS status, 41% or 12 patients who went on the study had wild type, and 17 patients had RAS mutant phenotype. As far as the HER2 amplifications, we had two patients on the study who had HER2 amplification and they went on the study after failing a HER2 targeted approach. Similarly with the RAS wild type, the study mandates that the patient fail the standard of care, EGFR blocker, whether cetuximab or panitumumab, before enrolling on the trial.

Dr. Anwaar Saeed 34:13
And as far as prior lines of therapy, as you see 100% of the patients who went on the study had at least two prior lines of therapy. 14 of them had two lines of therapy, meaning they received the regimen in the third-line. And then 15 of them, which is half of the patients who went on the trial, received the regimen in the fourth or fifth-line. As far as the prior therapies, we have four patients who went on the trial after failing LONSURF, and we did not have any patients who went on the trial with prior exposure to Regorafanib. Most of the patients who went on the trial had prior VEGF targeted agent, Bevacizumab, and around half of them had prior EGFR antibodies like cetuximab or panitumumab. And most of the patients have pretty good volume load of the disease. As you see, all of them, 100% of the patients went on the study had at least three sites of metastasis. Patients who have liver metastasis constitute 79% of the study population. So most of them have liver metastasis as well.

Dr. Anwaar Saeed 35:32
As far as the safety, as you see here, when looking at the significant grade three and above treatment-related adverse events, 31% of the patients, so 11 out of the 36 had grade three and above treatment-related adverse events. And as I alluded to earlier, we did not have any grade five, which are the fatal toxicities. So we do not have any patients who died because of toxicities related to the trial regimen, and those are either grade three or four, but mostly grade three. As far as the immune related adverse events, as this is an immunotherapy combination regimen, six patients had grade three and above immune related adverse events, and among those, three of them required at least four weeks of steroid therapy to calm down the immune therapy related toxicity. And as far as the dose modifications required, half of the patients who went off, around half of the patients who went on the study required a dose delay or hold in either durvalumab or cabozantinib. And as far as the number of patients who required permanent discontinuation of one of those drugs, it is, I would say, amazing that none of the patients had required permanent discontinuation of cabozantinib, but we have one patient who needed to have permanent discontinuation of durvalumab, and that is related to a recurrent immunotherapy related inflammation in the colon or colitis, after rechallenging. So, a patient developed immunotherapy related colitis, we treat it with steroid, then we rechallenge the patient with durvalumab again. And we’ve seen that that patient developed immunotherapy related adverse event again, so the colitis reoccurred. So in situations like this, we typically permanently discontinue the immunotherapy. We had one patient who have… those are the most common side effects that we’ve seen with the combination. Most commonly, as you see, and this is in line with with the side effects that for this type of combination, that what’s shown or what’s seen in other tumor types. The most common side effects, as you see here, are fatigue, nausea, diarrhea, anorexia, hand foot syndrome, liver enzyme changes – or we call it transaminitis, high blood pressure, hypertension, headache, thyroid issues, either hypothyroidism or hyperthyroidism. Skin Changes: mostly dry skin, inflammation and the mucosa membranes or oral mucositis, muscle cramp, commonly happens with cabozantininb and low cell counts, particularly thrombocytopenia, is common with cabozantinib as well, but not severe enough. So as you see, all of the patients that we’ve seen with thrombocytopenia had, I would say, grade one or two, proteinuria, weight loss. We’ve seen some patients with hair color changes and some other toxicities, as you see here.

Dr. Anwaar Saeed 38:47
So those are the efficacy results you see.

Dr. Anwaar Saeed 38:51
We have 29 patients who are evaluable for efficacy. Overall response rate was around 27.6% or 28% confirmed partial response. Those are the patients who had another scan after the first partial response that confirmed the same deep response that we’ve seen on the first scan, is 20.7%. The disease control rate is 86.2%, median progression-free survival is 3.8 months, and the median overall survival is 9.1 months, the six month progression- free survival is 34.5%. And as you may all know that we ran a subgroup analysis on patients who have RAS wild type, and because around half of the patients who went on a study had RAS wild type status we ran a subgroup analysis on this group, and as you see, in patients who have RAS wild type disease, the overall response is way better, 50%. The disease control rate is 83%, median progression-free survival is 6.3 months, their median overall survival is 21.8 months. So clearly, those patients, I would say, significantly benefit. There’s significantly improved progression-free survival and overall survival when compared to the overall population. If you look at the graphs, the green bars and the green arrows here, including the green lines in the spider plot, are all patients who have partial response. And when I run my analysis, I noticed that all of those green bars, green lines and arrows, belong to the RAS wild type. So those are the population that really benefit the most from the regimen. And so far, we don’t know why – we’re running an ongoing analysis – we obtained fresh tumor tissue before all of those patients went on the trial. So we’re running tumor environment assays to see if there are any new markers that correlate with better response beyond just the RAS wild type status, to identify why, maybe the RAS wild type has a different tumor microenvironment than the RAS mutant population, or maybe there is a pathway that’s upregulated after they fail the EGFR blocker, because all of those patients who have RAS wild type failed prior cetuximab or panitumumab before going on the study. So are we dealing with a situation where those patients progressed on cetuximab or panitumumab because they upregulated a different pathway than EGFR and we know from prior published literature that a common scenario in this situation is upregulation of MET, and we know cabozantinib is targeting the MET pathway. So it could be a scenario where cabozantinib came in the right space, MET was upregulated, and those patients benefited the most. Or, their tumor microenvironment is immune permissive, meaning the tumor suppressor cells are not that populated in the tumor microenvironment and throwing in durvalumab there led to way better survival advantage than the other group. So those are ongoing studies that I’m running and I’m hoping to definitely present at a later conference this year or early next year.

Dr. Manju George 38:51
Dr. Saeed, I had a question about the spider plot. The blue one which goes above, is that some kind of hyper- progression or something that you saw?

Dr. Anwaar Saeed 42:42
I would say the red ones, yes. So the red ones are primary refractory disease. They did not benefit. They did not have any stable scans. Most of the blue ones are the ones who have stable scan up to four to six months, so they have stable disease for four to six months. Some of them progress kind of slowly, but then they maintain overall…, if you look at this one, it’s an interesting line. There’s no flare, there’s slow progression, but then it stabilizes. And this is something we see with immunotherapy, even in other disease types that, if you allow patients to continue to be on progression, you might meet progression criteria at some point, but it’s only one. Like here, he had a rise, but then he maintained it.

Dr. Manju George 43:29
And I was wondering whether, in your wild-type RAS patients, do you think that EGFR inhibitors changed their sensitivity to PD-L1 inhibition and made them more sensitive? Is that something that you think might be going on?

Dr. Anwaar Saeed 43:44
Possibly. As we know, targeting the EGFR – so if we can extrapolate even from the HER2 literature, if you’re targeting HER2, especially nowadays with all of those HER2 agents trying to target HER2 and an immunotherapy agent, and we’re seeing tons of positive studies coming out showing that if you target HER2 with an immunotherapy agent, you get better responses. Even in the upper GI space, like in gastric and esophageal, for the first time in decades we’ve trumped the results of the TOGA trial. So trastuzumab and chemotherapy. We’ve been using this regimen as a standard of care for years up until now, when pembrolizumab was combined with Herceptin, we’ve seen that we can show better results than, Herceptin and chemo. So this talks to the EGFR pathway, because HER2 is part of the EGFR pathway. I think it’s already validated that if you target HER2 or EGFR pathway with an IO agent, you get better results. And it’s probably the case. Those patients received an EGFR blocker, their tumor microenvironment may be modulated, and then we threw the durvalumab there, and cabozantinib, so you targeted a different kinase on that same pathway. And you threw the durvalumab, so I think that’s probably what’s going on. But we cannot for sure tell what happened without the testing, but all of those are valid theories.

Dr. Manju George 45:13
Okay. The other question I had is that in our patient groups, people were interested in the LEAP trial, where they did lenva plus pembro, but that result is different from what you’re seeing, right? And why do you think there is a, I mean, it’s just a curious question, what is the difference? Is it the TKI targeting different things?

Dr. Anwaar Saeed 45:33
I think there’s multiple things that we could think of, because it’s hard to compare those, because we’re not doing head to head comparison here, right? And so the population of patients who went on that study might be different than this one. I do not know if they ran a RAS wild-type analysis. Maybe the patients who went on that study are mostly not RAS wild-type and mostly RAS mutant. That would definitely, if I repeat the study and block the RAS wild-type, you would imagine that my overall response rate would not be right. So I’m not sure what’s happening in that space and whether they, at least looked at their RAS wild-type population. Because we also know that if you do not mandate a fresh biopsy before the patient goes on the trial, you cannot just use the historic results to label that patient as RAS wild-type, because we know from newer studies that even in the RAS wild type could change. It’s an ongoing target, so the patients who develop resistance might be RAS mutant by the time they went on on the study so they cannot take their historic results to say lenvatinib doesn’t work. So just looking deeply into into those things, it may be that, even if they run a RAS wild-type analysis, it might be that those RAS wild-type patients turn into RAS mutant before they went on the study. And the reverse is true. Some of the RAS mutants could also lose their as the KRAS mutation, and have a RAS wild-type phenotype. So the fresh biopsies are also very important. And I know how challenging it is to obtain fresh biopsies, especially if it’s an industry study or very large phase 3 studies. So I think this is the benefit of this CAMILLA study, because it’s an investigator-initiated trial. I can control it. It’s being run at my institution. So mandating those fresh biopsies, though challenging, is feasible in those kind of proof of concept early phase trials, and I can definitely tell that those patients are RAS wild-type, because we did a fresh biopsy before they went on the study, and that’s what we’ve seen. So it may be that. And then also, I believe, cabozantinib has different tyrosine kinase profile. And if you look at comparing how cabozantinib performed, even in other disease types, really better than lenvatinib and regorafenib. So it is not just in colorectal cancer space. We’ve seen better results with cabozantinib across tumor types when looking at those agents in historic comparison. So it has something to do with that drug as well.

Dr. Manju George 48:13
Thank you so much. And then you were saying that in your study, you had a lot of patients who had liver mets, and that did not seem to affect it right? There’s this idea that liver mets are supposed to be globally immunosuppressive, but that is not the case for you, right?

Dr. Anwaar Saeed 48:28
Yes, I think, yes, definitely. I agree with the studies that showed how liver metastases can lead to immune resistant environment in the liver. And I totally agree with that. It doesn’t seem to impact a lot the results we’ve seen here, maybe because we’re talking about some molecular phenomena here, because when it comes to molecular phenomena, for example, with HER2 targeted therapy, we didn’t see that process, like those patients’ responded, regardless, right? So if you use the targeted agents in the right population, you see the results regardless of those studies. And I think that’s what’s probably happening. There might be, I mean, if you look at the RAS mutant in my population, they’re clearly not responding very well, right? So, yeah, something to do with the RAS wild-type.

Dr. Manju George 49:24
Yeah, it’s, it seems like, here is you’ve shown proof of real personalization of therapy, right? You’re looking at CPS, you’re looking at RAS status, and then you’re seeing that effect. So you can actually narrow down what is the specific population that is responsive to something like this.

Dr. Anwaar Saeed 49:42
Exactly. Yeah.

Dr. Manju George 49:44
This is very exciting.

Dr. Anwaar Saeed 49:45
Yes. The good part about being a clinician, researcher, and investigator, is that I’ve seen this hands-on in clinic. Because, as I was enrolling patients, I was like, “Oh, this patient has been one year, and this patient on the study, and then you see another patient who’s been beyond nine months. I was, “Okay, what’s common between them? There must be something”. And then you go look at their profile. Oh, they are RAS wild-type. And then you go back, and then you look at all of those who really responded and stayed on the study. All of them share one thing, RAS wild-type. So it’s exciting to test those agents in clinic. And see that. This is just the Kaplan Meier curves. And again, I’m really excited about this, and though it’s a small study size, but we can clearly show how those lines are separating. So the RAS wild-type really benefiting the RAS mutant is in the lower and the blue line is like when you lump everyone. So if you separate the RAS mutant by themselves and the RAS wild-type by themselves, there’s clear separation without any noise, even from the get go. So just to conclude, we have demonstrated that combining cabozantinib and durvalumab show promising efficacy and was fairly tolerated without any new safety signals in heavily treated microsatellite stable colorectal cancer patients. Wild-type RAS status was associated with improved overall response rate, progression-free survival and overall survival. So these encouraging results were a further evaluation of this regimen in a phase 3 randomized trial as salvage therapy in this population. And this is just a time to ill…, — we discussed the other VEGF tyrosine kinase inhibitors. So I created this table to contrast our data with or our results with what was published with the other VEGF tyrosine kinase inhibitors. And as you see, we can control the disease way better than all of the things tested. And most of those are, I included, mostly the US studies, as you see. So we’re talking about US population here with lenvatinib, regoranfinib and cabozantinib, we have the best disease control rate, we have way better overall response rate than the others, and then better progression-free survival. And obviously, if we just look at the RAS wild-type population, we have way better median survival than the other regimens. So I would like to, since we’re talking to our colorectal cancer population, and I had lots of questions from many patients, I would say, across the US, emailing me and through Twitter and other social media, asking about what’s next, we have RAS wild-type, where could we go? And all of those things. So I figured I should highlight the trial that will open soon. It’s a global study.

Dr. Anwaar Saeed 52:46
So Exelixis is taking this to a phase 3 trial. It’s called STELLAR-303, it’s a pivotal study, FDA registration trial that will combine the offspring of cabo, so XL092 is pretty much cabozantinib. This is the offspring of cabozantinib. So cabozantinib patent has come into to an end, so they have to go to a phase 3 trial. They have to use the offspring or their new drug. The difference between this drug and cabozantinib is that this was engineered to have a lower half life, and so the company is feeling like this will have a better side effect profile than cabozantinib without an impact on efficacy. So that engineering part to create this offspring did not touch the targets for cabozantinib. So it’s pretty much similar drug with maybe a better side effect profile. It will be combined with atezolizumab, which is similar to durvalumab, it is a PD-L1 inhibitor, a well known PD1 inhibitor as well. So the study will look at this combination regimen, XL092, plus atezolizumab in the microsatellite stable advanced colorectal cancer who have progressed on the standard of care therapy. So it will be a third-line study. So patients in the third-line and they have to have a RAS wild- type disease. So this is a phase 3 study that is tailored to the RAS wild-type space, or the RAS wild-type population. And I mean clearly, just based on the CAMILLA study results, it will have 600 patients enrolled across the globe. They will be randomized to either the combination regimen versus the control arm, which is regorafinib here. They chose regorafinib because in order to see that we are showing a benefit, we have to compare it with a VEGF tyrosine kinase inhibitor. That’s why LONSURF was not included. So this is pretty much the study, and it will be activated around the summer of this year, so we anticipate the first site to open. It is not in clinical trials.gov yet, but it should go within the next month with the first site opening.

Dr. Manju George 55:22
And is this going to be open at your place?

Dr. Anwaar Saeed 55:23
Yes.

Dr. Manju George 55:24
Okay, okay. And then, so people shouldn’t get on if they’re interested in this, they shouldn’t get prior regorafinib?

Dr. Anwaar Saeed 55:29
I would say yes, because it’s a third-line study. So they should fail the first- and the second-line chemo regimens. They should have a RAS wild-type status failing, and if they are RAS wild-type, they should fail prior EGFR targeted therapy like panitumumab or cetuximab, and then they get this regimen.

Dr. Manju George 55:49
Okay,

Dr. Anwaar Saeed 55:54
That’s hopefully, yeah, addresses all the questions.

Dr. Manju George 55:57
One other question I had was that with the LEAP trial, there was a lot of intestinal perforation with lenvatinib, and you didn’t have any, any of that with the cabo?

Dr. Anwaar Saeed 56:08
No, we did not have any colon perforations or intestinal perforations. In our gastric patients, though, and patients who have esophageal and gastric cancer, we had one case, one patient who had esophageal perforation, but that was a case – in that case, I presented that data at SITC, there was an immunotherapy-related inflammation in the wall of the esophagus, which might have triggered the perforation, but it’s really hard to say totally not related when he was also taking cabozantinib, but that was the only case that we’ve seen in our study patients.

Dr. Manju George 56:46
Okay and with this particular trial, are you expecting more sites to open in the US?

Dr. Anwaar Saeed 56:52
Oh, yeah, they will have, I’m not sure exactly how many sites, but it will be open through the US. There will be multiple sites in the US, multiple sites in Europe and Eastern Asia.

Dr. Manju George 57:06
Okay. Okay, there is a question that has come in: Regarding the rationale behind choosing an anti PD-L1 rather than an anti PD1 in CRC, MSS patients do you think there is room for radiotherapy in this subset of patients as a means of immune priming?

Dr. Anwaar Saeed 57:30
Well, that’s a nice question. We don’t really know if radiation therapy provides immune priming. There are ongoing studies and similar in several solid tumor types that use the radiation therapy as a way to do immune priming. It would be hard to test it in a stage IV setting though, in a large study like this, especially if we don’t have validation for that concept, because the concept is being studied in order to validate it. So without validation, it would be hard to incorporate it in a study like this. But one thing also to think of when we think about radiation therapy as modulator of immune response, especially in a stage IV setting, I think it’s really hard to adopt this, or especially nowadays with all of those immune modulators there. Why use a classic kind of anti-tumor burning with radiation when we have novel agents that could be taken as an oral pill or something to combine, especially if we are seeking systemic immune modulatory impact rather than regional immune modulatory impact. So that’s my opinion.

Dr. Manju George 58:49
I think that people were very interested in the abscopal effect, like you radiate one site and you see something happening in other places. But so far, I don’t think there are any studies which show that is true, right?

Dr. Anwaar Saeed 59:00
Totally agree. This is exactly my answer. When they raised this question about the abscopal effect, show me one clinical study. We’ve seen case reports and case series – do we have a clinical study showing that there is a true absopal effect, or we’re just talking about it, you know? So, so far, we don’t have any studies that validated, that’s carbon effects, okay,

Dr. Manju George 59:26
Okay. Any other questions? Yeah, and thank you for spending all this time with us and answering all the questions. This was a great presentation. Good luck with all your coming studies, I’m sure that we will be looking forward to what is coming out from your lab and your work.

Dr. Anwaar Saeed 59:46
Thanks a lot. Thanks a lot, Manju, and this is my pleasure anytime, I’m happy to address any questions down the road that will come up, or come back and present stuff. I’m so happy and thanks again for the invitation.

Dr. Manju George 1:00:00
Yeah, thank you very much. And thank you all for participating. If you have any questions, feel free to email me, and I’m sure that I can email them to Dr. Saeed, or she’s on Twitter, and she’s very active. So thank you very much.

Dr. Anwaar Saeed 1:00:13
My pleasure, bye bye.

DocTalk
2022
Dr. Saeed
MSS
Immunotherapy
Trials

In this DocTalk organized by PALTOWN Scientific Director Dr. Manju George, Dr. Anwaar Saeed from Kansas University Cancer Center talks about the CAMILLA trial for treatment-refractory Microsatellite Stable (MSS) stage IV colorectal cancer. Recorded in May, 2022. 

Table of contents

00:00: Introduction
01:35: Dr. Saeed outlines her research activities at KU Cancer center
06:26: Background/rationale for CAMILLA trial, Cabo & Pembro each as single agents in CRC
10:47: Mechanism of action of Cabozantinib
14:10: Cabo as a “dirty Tyrosine Kinase Inhibitor (TKI)”
15:14: Cabo + Immunotherapy for CRC
17:28: CAMILLA trial introduction — Dose-limiting toxicity evaluation
21:05: Results of the Phase 1b study
25:30: PD-L1 CPS & its role in treatment response
26:30: Phase II multi-cohort schema
28:31: Phase II Cabo + Durva in MSS mCRC results
28:50: Background
30:45: Methods
33:14: Baseline characteristics of the patient population
35:32: Safety data from the study
38:48: Efficacy data
51:14: Conclusions
51:49: Other VEGF TKI + IO combinations
53:00: Coming soon! STELLAR 303 600 patient global Phase 3 trial using offspring of Cabo + Atezo vs Rego in MSS stage IV CRC with RAS WT tumors

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Immunotherapy in MSS Colorectal Cancer

Immunotherapy in MSS Colorectal Cancer

DocTalk
2022
Dr. Fakih
Immunotherapy
Liver
MSS
Stage IV
Trials

Dr. Marwan Fakih of the City of Hope Cancer Center takes a deep look at immunotherapy for MSS CRC in this Doc Talk, recorded in January 2022 with PALTOWN Scientific Director Dr. Manju George. Dr. Fakih discusses a number of recent clinical trials in this video conversation.

Table of contents:

1:38: Immunotherapy (IO) in MSS CRC—Broad overview: where are we currently with this?
3:02: What is MSI-H?
4:02: What is MMR?
6:35: dMMR Vs pMMR PD-L1 expression, how IO works
7:46: Why does IO not work in MSS CRC
9:25: KEYNOTE 177 results
10:31: Keytruda/Pembro or single agent IO in MSS CRC
12:17: IMblaze 370 trial Atezo+Cobi vs Atezo vs Stivarga in MSS CRC
13:35: CO.26 Double IO (CTLA4i+PD1i) vs best supportive care in MSS CRC
14:55: Liver mets & effect on IO-mice studies, what might be happening?
17:23: IO in mCRC patients: liver mets, a biomarker for lack of efficacy?
19:39: Immune modulatory effects of Stivarga
20:55: REGONIVO CRC-Japanese trial & similar combinations, results from GI22
28:10: CAMILLA CRC (Cabo+Durva) trial results
32:00: LEAP-005 trial (Lenva-pembro)
33:00: REGONIVO US study: why liver mets don’t seem to respond
38:10: New approaches for IO in CRC with liver mets
39:35: Summary
40:23: Other directions
42:50: Q & A Association of liver resection in the response to IO
45:00: Role of TMB in response to IO
48:22: Radiation therapy+IO in MSS CRC
50:46: Biomarkers for IO efficacy: TMB? CPS scoring? Others?
53:04: Role of gut microbiome?
57:21: IO in lymph node only metastases?
54:46: Treatment sequencing with IO?

Manju George 0:00
Hello everyone. I’m Dr Manju George. I’m the Scientific Director at PALTOWN Development Foundation, the nonprofit that supports COLONTOWN. Today we have with us Dr. Marwan Fakih. I’m sure that a lot of you already know him. He’s a professor of medical oncology and therapeutics research, a Judy and Bernard Briskin Distinguished Director of Clinical Research, Associate Director for Clinical Sciences, Medical Director of the Briskin Center for Clinical Research, Section Head of GI Medical Oncology, the City of Hope Comprehensive Cancer Center. We’re really excited to have you with us to talk to us about immunotherapy for MSS colorectal cancer.

Dr. Marwan Fakih 0:41
Thank you, Dr. George, and thank you for the invitation. Like many other physicians, we’ve all heard of COLONTOWN, and I have many patients actually, who participate in this forum, so it’s a pleasure to be here.

Dr. Marwan Fakih 1:01
I’m a medical oncologist, I treat colorectal cancer, and been doing so for the last 21 years. I’m very excited to see the field move forward. I know that we have a lot more work to do. Whatever progress we’ve made is good, but definitely not sufficient. So for those patients who are on the call, we feel you, we hear you, and I’m very hopeful that we will make more progress. So I’ve been asked today to talk about immunotherapy in microsatellite stable colorectal cancer. And this is an area that I certainly have a lot of interest in and I’ve seen some definite progress but I think it’s important that when we look at an area of research, to recognize where it’s working and also recognize where it’s not working. Defining a treatment is good, but it has to be the right treatment for the right patient. These treatments are not without side effects, and I think we have a lot more to learn, but I’m personally an advocate, and I think there are definitely patients who respond very well to immunotherapy with microsatellite stable colon cancer. I am personally treating many of those, and many of those have been on treatment for more than two years, but I’m also cognizant to the fact that not everybody responds. So when we start looking at immunotherapy, we have to ask ourselves, “what immunotherapy, and for whom”, and then try to understand how we can make it better. We all know that immunotherapy in colorectal cancer is approved for patients with microsatellite instability.

Dr. Marwan Fakih 3:09
What is micro satellite instability? I know that many of you have done a lot of your own research, are following the field of colorectal cancer very well, but, in a simplistic way, microsatellite instability – it means that there are errors in DNA within the tumor, and that the tumor cannot repair DNA damage, and that lack of ability to repair DNA damage is actually related to an error or a problem in the repair engine. And the repair engine here is what we call mismatch repair proteins, which simply are proteins that correct mismatches in the DNA. There’s two main reasons for mismatch repair protein loss. One is what we call Lynch syndrome, where one inherits a defective gene that is responsible for translation into one of those proteins: MLH1, MSH2, MSH6 and PMS2 are the four genes that we look for. And the other reason for mismatch repair deficiency or MSI-High, is silencing of those genes, which is more common in the elderly population, especially females, right sided colon cancer. And that’s really not a hereditary condition, but rather sporadic colon cancer, meaning colon cancer that we get without a hereditary predisposition. But both categories of patients who have this condition have the same issue, which is that they can’t repair the DNA damage, and therefore there is stacking of abnormal mutations in the genome of the tumor, which leads to a lot of abnormal proteins in the tumor per se, and now you suddenly have a tumor that has proteins that the body hasn’t seen before, and the body is able to recognize that tumor as, “Hey, you don’t belong here. You have proteins that are not part of my own normal makeup of protein and therefore I am going to unleash my immune system to attack this tumor”. And that’s why patients with mismatch repair abnormalities do a lot better when they have resected colon cancer than patients without mismatch repair abnormality.

Dr. Marwan Fakih 5:43
So if you look at patients with early stage disease, stage II and stage III who have MSI-High, they rarely relapse, and they have a better overall survival than patients who do not have MSI-High. And the main reason for that is that you have the immune system in the patients with MSI-High tumors, preventing metastases from happening, attacking the tumor before it develops micro metastatic disease, and therefore it gets a better overall survival. Indeed, if we look at the tumors from patients with mismatch repair deficient colon cancer, or otherwise known as microsatellite unstable or MSI-High – all is the same. You can see that these tumors have a lot of lymphocytes. These are CD8 positive cells. These brown dots are the lymphocytes at the tumor margin so it’s kind of preventing the tumor from expanding or attacking it where it is expanding. And so there are lots of what we call tumor infiltrating lymphocytes in the tumor, and the tumor is reacting back by trying to suppress these lymphocytes from killing it, and produces PD-L1. You can see the PD-L1 localizing at the sites of the CD8, and this PD-L1 is suppressing these lymphocytes. That’s simply why immunotherapy works so well, because when you give KEYTRUDA, you’re basically blocking PD-L1 from suppressing CD8s. Now these CD8s are happy, and they’re attacking the tumor and killing the cancer. And so either by using PD-L1 inhibitors, such as Atezolizumab or Nivolumab, or by using PD1 inhibitors where PD-L1 binds to, you can basically invigorate the immune response and stimulate these CD8 cells to attack the cancer.

Dr. Marwan Fakih 7:45
So why does immunotherapy work for MSI-High and why doesn’t it work for MSS very well? It is because you don’t have lymphocytes infiltrating the tumor in patients with mismatch repair proficient colorectal cancer, MSS patients. There’s not enough CD8s, and there’s not enough CD8s because the tumor is not hypermutated. The tumor doesn’t have a lot of antigens. Why it doesn’t have a lot of neoantigens or a lot of abnormal proteins, is because you don’t have that mismatch repair problem. So we’re looking at two different populations, and you have to think about these checkpoint inhibitors as unleashing an existing immune response, and that’s why they work in MSI-High, and why they don’t work in MSS is that there’s no immune response to unleash of significance in these tumors. But that’s the simple explanation as to the difference between MSI-High and MSS as far as to why we’re seeing differences in responses. Now, this is another way to look at the checkpoint inhibitors and differences between MSS and MSI-High. MSS is the blue and MSI-High is red, and you can see that CTLA-4 is higher in MSI-High tumors, PD-L1 is higher, LAG-3 is higher. All of these are checkpoint inhibitors. And you can see that in all compartments, especially in the invasive front of the tumor, the margin of the tumor. So there are inherent differences between these two tumors, MSI-High and MSS and that’s why in MSI- High tumors, we use pembrolizumab up front in the first line setting because it works even better than chemo, as we have seen from a very large study that compared patients with stage IV colon cancer who have MSI-High. Half of them received chemotherapy, and half of them received KEYTRUDA (pembrolizumab). And you can see that with KEYTRUDA, these patients who are without progression at three years, pretty much these are the cured patients. These patients rarely ever relapse afterwards. And I would say a lot of these patients may have something on their CT, but it could be just that tumor fibrosed, and you can’t tell that it’s gone, because it leaves a mark. We have many patients now who are MSI-High who are absolutely cured with immunotherapy for three years and never relapse. And so definitely a big difference in outcome, and we don’t want to miss those patients because they respond beautifully to immunotherapy.

Dr. Marwan Fakih 10:22
It’s not that KEYTRUDA has not been tested in MSS patients, patients without microsatellite instability. This is a study that said, “I’m going to look at MSS patients, I’m going to look at colorectal cancer patients. I’m going to only enroll patients who have a high PD-L1”. And PD-L1 is a biomarker of response to KEYTRUDA. In lung cancer it indicates that you have an immunosuppressive effect of the tumor against the lymphocytes, and the higher the PD-L1 is, the more likely the response in certain tumor types, such as non-small cell lung cancer. So in this colorectal cancer study, they screened 138 patients, and out of those, 138 patients, only 33 patients were PD-L1 positive. 10 had other exclusion criteria. They ended up treating 23 patients and only one patient had a response. The definition of response is shrinkage by more than half, by the way. When we use these terms, stable disease means either slight increase or slight decrease, but a partial response means major decrease, more than 50% of the tumor disappearing. As you can see, only one patient did very well on this study, and everybody else progressed, although for some it took almost about eight months before progression. But the only patient who had a good shrinkage or partial response actually was MSI-High, and all the MSS patients here did not have an objective response. So even when you’re enriching for PD-L1 positivity in MSS colorectal cancer patients it is not likely that a drug like KEYTRUDA or a drug like OPDIVO on its own is going to make a difference. We’ve been involved in this study as well.

Dr. Marwan Fakih 12:20
This study was published a while ago, looking at atezolizumab, which is a PD-L1 inhibitor, and patients who have gone through a couple of lines of therapy, first line and second line. In this study the comparison arm was Regorafenib, or STIVARGA, and 1/3 of the patients got Atezolizumab alone, so a PD-L1 inhibitor alone. 1/3 got cobimetinib plus atezolizumab. Cobimetinib is a MEK inhibitor, and at that point it was thought that that makes the immunotherapy work better based on a small phase 2 trial. But the bottom line is, in these patients who received atezolizumab alone, or atezolizumab plus a MEK inhibitor, there wasn’t really much of a difference compared to STIVARGA alone. So again, this large trial of almost 250+ patients failed to show that we gain much by using immunotherapy in patients with colorectal cancer, especially in microsatellite stable colon cancer. The majority of these patients in the study – I think, were 97% or so – were microsatellite stable. On the other hand, there was a glimmer of hope from a trial done in Canada called the CO.26 trial. And in this study, they used a CTLA-4 inhibitor, so another checkpoint inhibitor, another immunotherapy that takes off the brakes from the lymphocytes against the cancer, along with the PD-L1 inhibitor. So a KEYTRUDA-like drug called durvalumab, and that combination was compared to no treatment at all and even though there were no major shrinkages and there was no difference in the time for progression, there was an effect on the overall survival. The red line is the patients who got the double immunotherapy. The blue line is patients treated with best supportive care, and it prolonged survival by 30% in these patients, but it wasn’t really a big difference in terms of duration of how many months of addition, but it did add some, suggesting that even in this population of microsatellite stable colon cancer, there may be something to immunotherapy, but the signal is not very, very strong, and maybe adding CTLA-4 does make a difference as well as most of the studies so far have not looked at the combination of PD1, CTLA-4.

Dr. Marwan Fakih 14:56
Our group/myself had started looking at liver metastases and impact on response to immunotherapy, because we had many patients who would go on clinical trials receiving PD1 or PD-L1 targeting, who had MSS. What we would note is that some patients with lung metastases were having some shrinkage or prolonged stabilization, but everybody who has liver metastases, they tend to not do well at all on these studies. And I’ll show you some of the data that we generated, but some of the data that we published about four years ago after the REGONIVO data came from Japan also was substantiated by laboratory models. In this particular model, they treated mice by injecting colon cancer cell lines in their flank, and then they gave them immunotherapy with a PD-L1 inhibitor. And sure enough, the tumor in the flank shrunk. Now they got the same mice, the same tumor, and now they injected the tumor in the flank and the tumor in the liver, and let the tumor grow in the liver. And not only did the tumor in the liver not respond to PD-L1 therapy, but also the tumor in the flank of the mice did not respond to immunotherapy anymore, suggesting that when the colon cancer metastasizes to the liver, that that not only affects the response in the liver, but it may have a negative abscopal effect, a negative effect outside the liver on the response to immunotherapy. And there are many theories as to why that may be the case. Frankly, those theories come from mice models. They may not necessarily apply to humans fully. But one of the theories is that the tumors in the liver chew up the immune cells that are involved in attacking the cancer cells and therefore has a systemic impact on the overall response to immunotherapy.

Dr. Marwan Fakih 17:10
We looked at 95 patients who had microsatellite stable colon cancer, and those patients were treated with PD1 or PD-L1 therapy, and reported that data and in JAMA Network. What we did differently is we categorized patients according to their performance statuses. Are they: very weak/strong?; Do they have limitations in their physical activity? Is there any evidence of spread to the peritoneum? Any evidence of spread to the liver?; Any evidence of spread to the lung, lymph nodes, bone, brain? And then we also looked at tumor mutation burden in these tumors. And we looked at RAS mutation, BRAF mutation, APC and TP53. The thing that stood out the strongest here is that the liver was the biggest biomarker of resistance to immunotherapy. In this study, about 50-some patients with liver metastases were treated, and none of them had any major shrinkage. On the other hand, in the patients who did not have liver metastases, about 20% of those patients had major shrinkage, and you can see that the likelihood the impact on progression if patients had liver metastases – presence of liver mets, has a seven-fold increased risk of progression compared to non-liver metastases. We did see some other signs that are not very clear. The sidedness has a small impact on on on progression. The left did a little bit better than the right, so a higher chance of progression if they have right-sided tumor versus left-sided tumor. RAS mutation, there was slightly higher progression, like the progression of RAS mutation versus non-RAS mutation. I have to say, in other data sets that we have looked at we’re not as convinced on RAS, and that’s a story that needs to be unfolded some more. But APC mutation did not have a substantial impact. A lot of people report APC as a marker of resistance. – No. – You can have APC mutation with colon cancer, MSS, and still respond to therapy. So liver did come out as the biggest problem here, as far as response. And meanwhile, there had been some data suggesting that drugs that target what we call the vascular endothelial growth factor pathway, which is a pathway important in blood vessel formation that those inhibitors may substantiate or improve the response to immunotherapy. Particularly the drug STIVARGA, which is approved for refractory colon cancer, had been associated with decrease in macrophages or tumor-associated macrophages, especially the M2 phenotype, which associates with a poor outcome and switching it to the M1 phenotype, which are anti-cancer, that that may occur with STIVARGA, and that STIVARGA may also normalize the blood vessels, decrease the T-regs, the regulatory T-cells as well, which may also be important in reducing the immune resistance within the tumor microenvironment within the liver.

Dr. Marwan Fakih 20:43
I’m sure a lot of the folks on this forum had as much enthusiasm as I had about three years ago or more maybe, when this data from a Japanese group was reported at ASCO, I think it was three years plus now, looking at a small number of colon cancer patients, 24 patients, who had microsatellite stable colon cancer, I think, except one patient if I recollect right, and those patients were treated with STIVARGA (Regorafenib) plus Nivolumab (OPDIVO) and therefore the acronym “Rego” for Regorafenib; “Nivo” for Nivolumab. And the excitement was that these patients had progressed on standard of care, and when they were treated with this combination, almost half of those patients had not progressed at 7.9 months, or 8 months if we want to round it, and that approximately 1/3 of those patients had major response, – objective response, we call it. A majority had good disease control between stable disease and major shrinkage. And this data prompted many of us to consider offering this treatment on a compassionate basis, or rather than compassionate, the right term is “off-label”, even though this was not approved to offer this to patients with colorectal cancer. And to my surprise, when we were treating patients with this and we looked at our data in about 18 patients or so, initially we saw that 13 patients with liver mets, none of them responded, and that in the five patients without liver mets, maybe four of them had some minor shrinkages, not a major shrinkage, but were able to continue on treatment for a while and we reported that data.

Dr. Marwan Fakih 22:43
Before, we looked at the 95 patients. But this particular study from Japan has really triggered a plethora of trials looking at the same classes of drugs together, so a PD1 or PD-L1, plus what we call a “tyrosine kinase inhibitor”: pills that inhibit different enzymes and different proteins, including proteins that are important in the blood vessel activation process, what we call “vascular endothelial growth factor receptor inhibitors”. One such study is a study done in China. This is a tyrosine kinase inhibitor that is very similar to regorafenib, and this is a PD1 inhibitor, and 28 patients with microsatellite stability. Response rate was only 7%, but a lot of patients had stabilization and a good disease control so that’s not meaningless when you control the cancer in your patients more than six months. And so there are some signals, but not as strong as what’s been shown in the Japanese trial. This is a study that looked at STIVARGA plus pembrolizumab that was reported this meeting by a colleague of mine. Very discouraging is the fact that none of 73 patients had major shrinkages here. But when looking at the 16 patients who didn’t have any liver metastases, at least half of those patients were having ongoing benefit beyond the four months mark, while most of the patients had progressed at two months with liver metastases. That shows what we call the “progression-free survival curve”, the time to patients progressing. So those are the 16 patients in blue. And you can see that there are some patients who have more prolonged benefit, even at the one year, but that’s a small number of patients. Only two of the 16 probably were still deriving a benefit. So who are these two, and why and how can we identify them, is the big question. Who are those getting benefit beyond six months, right? Because, yes, liver metastases is a marker of resistance, but it doesn’t mean that everybody without liver metastases is going to benefit. Some will benefit more than others, and it does appear that those without liver metastases have a better survival. There are other studies we can go over and over, again. That’s another study of STIVARGA, plus another PD1 inhibitor and metastatic cancer. Again, microsatellite stable, and you can see, again, a big difference in response rates: patients without liver metastases – major shrinkage, more than 50% shrinkage, and 30% of patients stable disease, 20% here, major shrinkage with liver mets is only in 8% of patients. So again, showing a difference in time to progression in non-liver is better than liver. And this is a study presented… this meeting looking at bevacizumab, which is again a vascular endothelial growth factor inhibitor, plus KEYTRUDA (pembrolizumab), and they added what we call a MEK inhibitor, binimetinib to it. And here you see that about 1/3 of the patients had some form of shrinkage. And the patients who had major, major shrinkage – more than 50% shrinkage, are about 13% of patients. But a fair number of patients between mild increase and mild decrease. This is what we call stable disease. (That’s the yellow.) Again suggesting that there’s a signal here, but not too strong. And how can we identify those folks who benefit the most from this?

Dr. Marwan Fakih 26:38
That’s another study presented at this meeting, a couple of days ago, with a PD1 inhibitor, plus, again, an angiogenesis inhibitor that is novel because it blocks two angiogenesis pathways, angiotensin 2 and VEGF. There’s more shrinkages than growth here and I think the exciting thing is, definitely there are patients who continue to benefit beyond the eight months mark. But the bottom line is, all these studies are not telling us: who are the patients with liver mets and who are the patients without liver mets? They’re not really reporting yet the characteristics of those patients. I do believe that it’s less likely that patients who are having great response here are liver mets patients, and it’s important for you to know that you’re going to have a lot of variations and responses and benefits dependent on what type of patients are going on the study. If it’s a patient who has only lung mets, that’s a patient who probably is going to be more likely to respond. But a study that uses the same regimen and enrolls 90% of the patients with liver metastases, the results of that study are going to be dismal. And so it is very hard to extrapolate from these 20, 30 patient trials into: “What is a better regimen for a patient?”. You may hear a little bit more in your forum about this study. So cabozantinib is a compound by a drug company called Exelixis Inc., and which is a drug that is approved for kidney cancer and liver cancer. They have a couple of reports this meeting on cabozantinib, plus a PD-L1 inhibitor. This is durvalumab, which is the PD-L1 inhibitor and plus cabozantinib. This is called the CAMILLA trial, and they looked at colorectal cancer here, 29 patients is reported as efficacy. And then they say, well, eight patients out of 29 had major shrinkage, 27.6% but in six out of the eight that response was sustainable, meaning on the next CT, the were still benefiting versus two out of the eight, the next CT that were progressing and you can see the median progression-free survival is 3.8, they don’t report on the characteristic by liver or non liver, but they do show that there is slightly better outcome for the RAS wild-type versus the RAS mutant. Again, something that we have seen on our multivariate analysis from a year ago. So the question is, should this be evaluated further in RAS wild-type? The problem is, they didn’t do the analysis here based on where the tumor spread. Could it be that the patients without RAS mutation were more more enriched in patients without liver mets here, and that’s why you’re seeing that signal? We don’t know. The other thing about this study is that they actually enrolled 36 patients, and seven patients actually didn’t reach the first CT scan, so they did not include them in the analysis. So the reality is that this study shows similar outcome as all the other studies in that the final confirmed responses, if we include the full sample of 36 patients, is 16.6%. So again, there are patients who benefit. This is very exciting. If you follow the 25 months mark, there are some patients at two years who are still benefiting. So who are they? And how do we identify them and offer them these strategies, and how do we make sure they don’t get diluted, and in the patient population sample who are not benefiting? And more importantly, how can we exclude patients who don’t benefit so that they can find other strategies to look into. Interestingly, this meeting from two days ago, looked at cabozantinib plus atezolizumab. Atezolizumab is not much different than durvalumab that it’s a PD-L1 inhibitor. And here again, they looked at 31 patients. The difference here is that the objective response rate is actually quite a bit lower than the previously presented study here. Only 3 out of 31 patients had major shrinkage. But then they report that most of these 3 were in the patients without RAS mutation. So again, something that needs to be explored further. Does RAS wild-type tumor, no RAS mutation, enrich for better likelihood of response? Could it be that patients without liver metastases and without RAS mutation could be the best patient population to look into – I think the challenge is, all of these are small studies, and you can’t do this kind of deep analysis on a small sample size, and I wish we could pull all these efforts from different investigators to answer that question, and it would require that all the sponsors agree to do so, which may not happen.

Dr. Marwan Fakih 32:03
Many of you have heard about the LEAP trial. This is KEYTRUDA plus lenvatinib, again, same concept, the tyrosine kinase inhibitor that at least partly targets VEGFR plus KEYTRUDA. And this study reported a 22% major shrinkage, and at six months, almost 1/3 of the patients had not progressed. This regimen actually moved on to a randomized phase 3 trial that is ongoing, so we will know soon. The good thing about that study is that they are stratifying by presence or absence of liver metastases so we’ll have a better idea as to the outcome in patients without liver mets. On the phase 2 study, which I am showing you here, the company did not report the outcome by liver and non-liver metastases. So finally, this is a study we reported last year on regorafenib, Nivolumab in microsatellite stable colorectal cancer, we enrolled 70 patients, 23 without liver metastases. You can see the response rate here. The major shrinkage is about one in five patients, but the stable disease is another 1/3 of the patients. Half of those patients still progressed by three and a half months. The liver metastases did not respond. What we reported at this meeting is that we know partly why liver meds don’t respond. If we look at biopsies from liver metastases versus no liver metastases, the liver metastases have less CD8 cells. These are lymphocytes that attack the tumor, and when we enrich further for granzyme B positivity, which is the substance that lymphocytes release when activated against the cancer. Again, we don’t see much of that in the liver. We see more of it in patients without liver mets and tumor biopsies that are not liver. The immune system is more robust in these non-liver metastases, which results in a higher regulatory T-cells in those tumors. You don’t see as much in the liver, and you see also more macrophages outside the liver. So basically, there’s more of an immune activation in tumors that spread outside the liver than in the liver. I don’t think it’s the same between lung, and peritoneum, and bone, and abdominal wall, and lymph node. I think there probably are differences. I think at the end of the day, the question is, which sites of disease may benefit the most: is there a biomarker of site of metastases, number of metastases, size of metastases, molecular biomarker? What type of mutations the tumor has, is there a special formula that we need to know about, that we need to come up with? I’m sure we’re not going to come up with the perfect one, but there are a lot of efforts being made to try to identify at least some form of biomarker that helps us further. So this is the same study we conducted. Now, you can see that patients without liver metastases: this is a good thing. You can see you have 1-2-3-4 patients out of 23 who had not progressed at the 40 week mark. And frankly, we’ve got two patients who’ve hit the two year mark without progression in our institute on this study. And so that’s not something you will achieve with STIVARGA alone. How much of this is from OPDIVO versus OPDIVO plus STIVARGA remains to be seen, but there’s probably some synergy between these two, but I don’t think it’s sufficient for the majority of patients versus liver- the majority had progressed by the 24 week mark. Very few patients continue beyond, and most of those eventually did progress. And you see the tumors. None of these tumors had sustained shrinkage below the 30% decline in tumor in the target lesions versus the non-liver mets, you have quite a few blue squares that go in the “PR” partial response category. So this is work we’ve done in our institute. When we stain the tumors of liver and we look at what we call the core of the tumor, you can see that the core of the tumor has very few lymphocytes that get into it versus lung, a lot of lymphocytes get into it. (That’s the blue here, is the lymphocytes) and so part of the problem with liver metastases is that the immune cells don’t get into it to attack and that’s been a challenge, frankly. I don’t think anybody has the definitive answer today, although a lot of efforts are being made to answer that or to overcome it, whether it’s viruses or other type of drugs. Finally, I want to say that the CTLA-4 question is not really done yet. This is a study that looked at a novel CTLA-4 inhibitor, plus a PD1 inhibitor in patients with colorectal cancer. Here at the upper right corner they enroll 20 patients. This is without regorafinib, this is just the CTLA-4, PD1, no TKI, no tyrosine kinase inhibitor, just the checkpoint inhibitors. And four out of the 20 patients here had major responses. And you can see a lot of these, some of these are quite durable. And again, they did not report in the poster if these were non-liver mets or not but I think that means something to me. Probably we do need a CTLA-4 inhibitor. And the question is, do we need the three drugs together or not? And so this is actually what we had proposed to SWOG. First of all, we’re pretty certain liver mets don’t respond to regoraphenib-nivolumab, so we think those patients should not be treated with this combination. And also, we have some data that peritoneal metastases are little bit more resistant and may not benefit that much from that combination. And so we’ve proposed a study looking at STIVARGA plus OPDIVO, REGONIVO compared with regorafenib, ipilimumab and nivolumab so, CTLA-4, PD1 plus regorafenib, we have already completed a study with REGONIVO IPI in our center. That data has not been reported yet, so I can’t go over it today but we think there’s enough to compare these two to see if there is a winner, and perhaps that can move forward to be compared to a standard of care in the future. I’m hoping that this will move forward. It’s too early yet, but that’s one way of approaching colorectal cancer with a microsatellite stability to recognize the patients who are more likely to benefit from a strategy and then explore it further, and then narrow down more the biomarkers so that you can identify even better who the potential super responders are. So what I summarize today is that microsatellite stable colorectal cancer is not all one disease, and especially with immunotherapy, it’s different than chemo. The site of metastases matters. And liver metastases are different than lung. They have biological differences in lymphocytic infiltration, antigen presenting cells, B cells, etc, that we are reporting on, and that the lung metastases have more active immune microenvironment that may contribute to the response to immunotherapy.

Dr. Marwan Fakih 40:17
So where do we go from here? I think there are a lot of studies across the nation and across the globe trying to look beyond checkpoint inhibitors, beyond STIVARGA and tyrosine kinase inhibitors. There’s a lot of studies looking at what we call bispecific antibodies, which typically target tumor-specific antigen and CD3. There are cellular therapeutics going on, including tumor infiltrating lymphocyte infusions, but you have to harvest the tumor here, grow the lymphocytes infiltrating the tumor. It’s a long process, and then grow these lymphocytes into the billions and then re-inject them in the patient and hope that they infiltrate the tumor and attack it. There’s some data that that is effective in non-small cell lung cancer and melanoma, and there are some efforts in colorectal cancer. There’s no data yet if that is effective or not, but that’s what those studies are doing. There are studies called neoTCR, where you basically take a biopsy, identify cancer specific antigens, and then clone receptors to those antigens, and then engineer the lymphocytes of that patient to express those receptors and then re-infuse those lymphocytes. There are CAR T in early development. CAR T in solids have been much harder than CAR T in liquid tumors, and because these engineered T-cells have more difficulty infiltrating within the solid tumor. But certainly it is an area of interest and should be evaluated. But where CAR T is going to be, we still don’t know. There are some studies looking at combinations of neoantigens and vaccines plus checkpoint inhibitors. Certainly there are other studies that have integrated immuno-checkpoint inhibitors, like nivo plus FOLFOX early on, and those studies should be maturing soon. Whether one should also engage with CTLA-4, PD1 plus chemo early on, is another question. But those are other directions. So I hope this is a little helpful, and I think we can open it up for discussion.

Manju George 42:48
Okay, thank you, Dr Fakih, that was awesome. I have one question, and then we will look at the chat and look through all the questions. So in the mouse model that you mentioned when they had the tumor also implanted in the liver, in addition to the flank tumor, the animal did not respond to immunotherapy. Did they do an experiment where they then remove the liver tumor and then try to see if the animal was again sensitive to –

Dr. Marwan Fakih 43:10
–They did not. But we have clinical data that shows that with regonivo and others, that hepatectomy patients will respond. So there are data that our group/myself have generated that show that if you have a hepatectomy, and now the patient, six months later, has lung-only metastases, that those patients could respond, and some of them for a very long period of time. Whether it is as robust as patients with never liver metastases our data shows a little bit less robust, maybe, but some surprisingly, very protracted benefits. Once you don’t have active disease it’s a little bit different story. It’s important to note that all of these are associations that we are describing. So the question becomes, is an association, a cause-effect? Is it or not? Is it the biology of the cancer that leads to liver metastases that makes it more immune resistant? If that is the case, you wouldn’t expect that the surgery would fix that problem, right? Or is it also possible that the biology that is favorable enough that a patient can undergo liver surgery means that they are also a little bit more immune sensitive. It’s possible, but association is important enough in your patient selection, right? Even if you cannot prove a cause effect, if you have an association of lack of response, at least it helps you on how you define your patient population is to benefit from a specific strategy.

Manju George 44:43
Okay, thank you. So we will go through the questions. Annie has a question, “Can you comment on the KISIMA-01, combo approach with the vaccine, where Dr. Kopetz has indicated there has been response in liver mets?”.

Dr. Marwan Fakih 45:02
No, I can’t comment on that. I don’t have additional information.

Manju George 45:06
Okay, then other than liver mets and RAS status is tumor burden a factor determining efficacy of IO and MSS?

Dr. Marwan Fakih 45:17
Yes and no. If, for example, and I didn’t present that data, I think we reported the first case of Pol E mutation responding to immunotherapy. So about 0.5% of patients will have Pol E mutations, which is polymerase E, which is important. Those patients are MSS, but they have what we call an ultra mutated colorectal cancer. Their tumor mutation burden is more than 200. They respond as well as MSI-High, if not better. Those are one in 200 patients. You don’t want to miss them. You identify them by the super high TMB, and they definitely should get immunotherapy, even though there’s no indication for immunotherapy for those patients, yet (-official indication). Then you have what we call intermediate TMB. They’re not MSI high, but their tumor mutation burden is 14, 12, 16. I think some of these patients, may respond somewhat to immunotherapy. I don’t think they respond as well as the MSI high. They usually are more stable disease or less durable responses. There’s been case reports of such cases responding to pembrolizumab. It’s important to note that the keynote 158, that we reported that led to the approval of pembrolizumab in the TMB of more than 10. Actually, that study did not include colorectal cancer patients, so it’s hard to extrapolate as to the benefit, but even in that particular study, there was a correlation between the level of TMB and response, and even though it’s not in the paper. Merck, the sponsor of that trial, had reported that if you look at those patients who had a TMB of 10 to 15, the objective response rate, the major shrinkage rate, was less than 15%. The overall population was 29% but if you look at the 10 to 15, they didn’t do that well. And therefore immunotherapy in patients who have a TMB of more than 10, but less than 20 should not be first line and should not be second line, in my opinion, because the benefit is not clear, but they should not be excluded from from getting KEYTRUDA. In the MSS patients that we looked at in our center, we didn’t see a correlation between TMB in response to regonivo or other PD1 inhibitors. And we have many patients who had an objective response or durable, stable disease with a TMB of one and two. So those patients that you see that have the tail of the curve with ongoing benefits were not intermediate TMB, you know. So, the bottom line, yes, there are patients with very low TMB that respond to immunotherapy, but not liver mets.

Manju George 48:06
The second part of the question is, is there any evidence that in low burden or low tumor burden settings radiation treatment previous or concomitant to IO could increase IO efficacy? Can it make the tumors more immunogenic?

Dr. Marwan Fakih 48:22
I personally, I doubt. I think the data has been extremely thin. We had done a study of Y90 followed by a PD1 and CTLA-4 inhibitor. Unfortunately, we had to close the study because we had nine patients, and none of them responded, whether in the liver or outside the liver, to the immunotherapy. I think there’s been some reports about SBRT plus immunotherapy. Those data have been extremely mixed, and the benefit was slim, and it’s not really clear if it’s attributed to the SBRT or not, so I don’t think so. I am aware that the recent study, and I think everybody should take that with a grain of salt, that the REGONIVO that was reported at this GI ASCO has said the patients with prior radiation did better, but there’s two reasons to give prior radiation. One is rectal cancer, which tends to have more lung mets. So when you say prior radiation is… they had chemo radiation for their primary rectal cancer before surgery, and then they develop probably lung mets. So it’s enriching lung mets. The second is SBRT, right? And who gets SBRT? -The patients who don’t have diffuse disease, the patients who have only few metastases. And who are the patients who have only few metastases? -Those who have a robust immune response against their cancer. So here, the prior radiation therapy is likely enriching a patient population that would have responded to immunotherapy whether they got radiation or not, by selecting patients who have a better immunoscore. So a lot more to be learned. But I think the radiation concept had been tested for a very long time now, and the data should be still evaluated in a research setting, but I don’t think clinically there’s any reason to believe that we should be radiating to induce a response at this point. I think we need to evaluate it further.

Manju George 50:29
Okay, so the next part of the question, I think it’s very important to address that, how should, when patients are considering immunotherapy – you just mentioned TMB. What are the other ways to find the PD1, PD-L1, CPS scoring or TPS scoring? What do you comment about that?

Dr. Marwan Fakih 50:45
I think it’s important to note that not all tumors are the same, and I think we have to really look at the data within colon cancer. So far, the PD1 story has not panned out that much in colorectal cancer and we’ve had patients with a CPS score of 20, 30 with liver mets that we got excited about with them on immunotherapy, and we don’t see a response. And so I don’t think that we have a biomarker today of a response to immunotherapy in somebody with a low TMB, with the exception of saying that liver is a biomarker of high level of resistance, and frankly, everything else is still under investigation. I wish I would say otherwise, but there’s no definitive answer yet, and there’s a lot of conflicting data from different sets of studies.

Manju George 50:45
Okay, thank you. So maybe some kind of composite score where they look at the location of the mets, maybe CPS, maybe TMB, or all of that together?

Dr. Marwan Fakih 51:50
Yeah. I mean, eventually that would be the hope, right? It’s coming up with a formula that takes into consideration the host, the tumor, and the clinical presentation. So a molecular score, right? Patient score, it could be ECOG as well. We’ve seen ECOG 2’s don’t do as well with immunotherapy than ECOG zero likely, and site of metastatic disease. And also from my personal experience, somebody who has 1000 lung mets what we call “miliary disease” in the lungs, we don’t see them respond to immunotherapy, and partly because probably the tumor has escaped/there’s no immune system to prevent it from exploding in a diffuse process. Versus somebody with well defined 15 spots in the liver may respond to immunotherapy. So you cannot come up with such a score unless you have prospectively collected data sets that are very large, treated in a homogeneous manner, and the data is collected prospectively on all these variables. To my knowledge, that data set is not there.

Manju George 53:01
Okay, thank you. So another question is about the microbiome. Do you have any thoughts on whether the diet, gut microbiome – Does it have any effect in MSS CRC?

Speaker 1 53:13
I don’t have any data myself. I think the microbiome story is still evolving on some of the data with fecal transplantation had been intriguing in couple cases with melanoma. I think the disheartening thing is that that data came out three, four years ago and you would expect that somebody could have validated it already. There’s been so many trials that have included capsules that have different bacteria, etc, to try to answer that question. And I hope it’s true. I think it needs to be validated in probably non-small cell lung cancer and melanoma first. But today I don’t have any special diet that I prescribe to my patients. I’m not against them trying. I’m very open about that, but the evidence is not there.

Manju George 54:12
Okay, there’s one question about efficacy of IO and MSS patients with isolated lymph node mets, the rationale being that lymph nodes have a high concentration of the immune cells.

Dr. Marwan Fakih 54:21
They do very well. In our experience, lymph-only metastasis, not all of them respond. But I think if you ask me today, based on my observation and what we have seen, the two sites that benefit the most are lung and lymph node.

Speaker 1 54:39
Okay. And then there was this other question about sequencing. Dr. Barzi had reported that subsequent treatment with TAS-102, the responses were higher after people were on radiation. What do you think about it?

Dr. Marwan Fakih 54:54
I think one has to be very careful and anecdotal evidence from subgroup analysis, from studies. It seems to me that if you give immunotherapy, you change the course of the disease after immunotherapy. It’s not necessarily making TAS-102 work better. You’ve seen the data with the Canadian trial. There was no difference in progression, but the curve separated for overall survival. So even when patients do progress, we do see that not all the tumors necessarily progress after IO and so you’re dealing with a little bit different biology after immunotherapy. It doesn’t mean that because you gave immunotherapy, it’s going to make the chemotherapy… – It could be that those patients, even without TAS-102, may have had a more indolent course. So those are only hypothesis-generating questions and need to be validated. Of course, I would rather use a regimen of IO that has a 30% chance of keeping 1/3 of patients without progression at eight months than using Lonsurf. And hey, if Lonsurf works better afterwards, that’s great, but we need more work on biomarkers.

Manju George 56:07
Okay, so basically, what you’re saying is that – there is this talk in COLONTOWN too – that if you get immunotherapy, and then people who have gone back on chemo, they are responding better. And what you’re saying is that that might be because the immunotherapy affected the progression without actually responding to chemo, right?

Dr. Marwan Fakih 56:25
The disease may become a little bit more indolent in some patients. There are a lot of patients who, prior to IO, when they go and study you have 20, 30, tumors progressing. They have stable disease, and then only five tumors are growing, and the other 15 are still regressed, but they meet the guidelines of progressive disease, and they come off study and and now their immune system has been conditioned to attack those 15 tumors, but the other five have escape mechanisms. And even when they have escape mechanisms, they may not be growing at the same pace that they did before going on IO. It doesn’t mean that every patient that gets IO will have that benefit. That’s very important to note. You know, there’s even some thoughts of hyperprogressors with IO, where the disease is progressing more quickly. I haven’t seen liver metastases change course that much after IO for example.

Manju George 57:28
Looks like there are no more questions. Thank you, Dr Fakih for that very interesting and informative talk. Thank you all for attending. The video of the talk will be available soon at the Lecture Hall in COLONTOWN University.

DocTalk
2022
Dr. Fakih
Immunotherapy
Liver
MSS
Stage IV
Trials

Dr. Marwan Fakih of the City of Hope Cancer Center takes a deep look at immunotherapy for MSS CRC in this Doc Talk, recorded in January 2022 with PALTOWN Scientific Director Dr. Manju George. Dr. Fakih discusses a number of recent clinical trials in this video conversation.

Table of contents:

1:38: Immunotherapy (IO) in MSS CRC—Broad overview: where are we currently with this?
3:02: What is MSI-H?
4:02: What is MMR?
6:35: dMMR Vs pMMR PD-L1 expression, how IO works
7:46: Why does IO not work in MSS CRC
9:25: KEYNOTE 177 results
10:31: Keytruda/Pembro or single agent IO in MSS CRC
12:17: IMblaze 370 trial Atezo+Cobi vs Atezo vs Stivarga in MSS CRC
13:35: CO.26 Double IO (CTLA4i+PD1i) vs best supportive care in MSS CRC
14:55: Liver mets & effect on IO-mice studies, what might be happening?
17:23: IO in mCRC patients: liver mets, a biomarker for lack of efficacy?
19:39: Immune modulatory effects of Stivarga
20:55: REGONIVO CRC-Japanese trial & similar combinations, results from GI22
28:10: CAMILLA CRC (Cabo+Durva) trial results
32:00: LEAP-005 trial (Lenva-pembro)
33:00: REGONIVO US study: why liver mets don’t seem to respond
38:10: New approaches for IO in CRC with liver mets
39:35: Summary
40:23: Other directions
42:50: Q & A Association of liver resection in the response to IO
45:00: Role of TMB in response to IO
48:22: Radiation therapy+IO in MSS CRC
50:46: Biomarkers for IO efficacy: TMB? CPS scoring? Others?
53:04: Role of gut microbiome?
57:21: IO in lymph node only metastases?
54:46: Treatment sequencing with IO?

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HERKULES-3 trial for BRAF and RAS

HERKULES-3 trial for BRAF and RAS

DocTalk
2022
Dr. Lee
BRAF
KRAS
MSS
Stage IV
Trials

Dr. Michael Lee of MD Anderson discusses the HERKULES-3 clinical trial for BRAF and RAS-mutated GI cancers. Recorded in December, 2021.

Manju George  0:00 
Hi, everyone. I’m Dr. Manju George, the Scientific Director of Paltown. Today we have with us Dr. Michael Lee. He’s an assistant professor at MD Anderson. And he finished his MD from Duke University. And he’s board certified in internal medicine, hematology and oncology. Dr. Lee, I’m really excited and happy to have you here with us. Please take it away.

Dr. Michael Lee  0:24 
Thank you very much. Can I just confirm you’re seeing my slides and slide screen view?

Manju George  0:30 
Yes, I think yeah, yes.

Dr. Michael Lee  0:32 
There we go. All right. So I’m very pleased to be here. Thank you so much for inviting me to talk about this exciting new study, that we and many other centers are getting underway, looking at novel targeted therapy combinations, particularly focused on this new class of drugs called ERK inhibitors, in certain molecularly defined subclasses of colorectal cancer. This is the HERKULES 3 study. So just as a way of background, cancer cells in general, or cells in general, are very finely tuned regarding when they proliferate and multiply. Typically, when a cell multiplies, it only does so in response to when the environment is right. And usually in that situation, there will be molecules called growth factors released around the cells and these bind to receptors on the surface of the cell. In particular, in colorectal cancer, something called the epidermal growth factor receptor, or EGFR is a very important growth factor. Now typically, when this binding occurs, this triggers kind of the cascade of proteins being activated into an active state, and kind of propagating the signal through one protein through another through another, until it eventually leads to a number of cellular changes that actually cause the cell to multiply, you can think of these intermediate steps as a series of molecular switches. In particular, this MAP kinase pathway, so to speak, which is downstream of this EGFR receptor is a very important kind of modulator of cell multiplication. Normally, this process is very tightly regulated, as I said, in a normal cell. However, in the process of colorectal cancers going from a normal colon cell to a cancer cell, typically, these cells acquire abnormal activating mutations in one of these molecular switches. And we know that a significant proportions of patients with colorectal cancer actually have activating mutations, in one of these key genes, that eventually leads to this kind of pro growth switch being turned on all the time, inappropriately.

Dr. Michael Lee  2:41 
So we know about 45 to 50% of patients have a mutation in a gene called KRAS or NRAS, which causes constant activation of these growth pathways. Another 5 to 10% of patients have activating mutation in a gene called BRAF, with the particular mutation in BRAF called the V600E mutation most common among the BRAF mutations. These are very clearly driver mutations driving the biology of these cancers. And while we’re starting to develop new therapies, kind of targeting these very clear potential vulnerabilities of these cells, we need more novel, more effective therapies for these ranges of mutations.Clearly, the cells are being driven by abnormal signaling through these kinds of constantly turned on genes. And if we can find more effective ways to switch off these genes, or kind of block the downstream signaling that is a consequence.and this is a potentially very powerful strategy. ERK is one of the key downstream kind of effectors –downstream of activated RAS or BRAF. ERK is one of the last kind of switches that then goes on to directly activate a number of these kind of transcription factors that cause the cell to go on to multiply, and so on and so forth. So it’s one of the last common nodes in this pathway that we could target. And kind of because it’s further downstream, there’s a lot of preclinical and laboratory data showing that targeting ERK maybe a particularly potent strategy, even more so than targeting some of these upstream components. And in fact while they’re not currently ERK inhibitors that are FDA approved, there are several novel ERK inhibitors that are being developed, and one that’s particularly exciting is being studied in the HERKULES 3 study. This is the ERAS-007 compound. This is an oral pill based treatment, that’s a selective inhibiting ERK and it’s been active in the laboratory. So without going into too many nitty gritties actually, shown here are on the left hand panel are a number of mouse models of KRAS or BRAF, mutated colorectal, or pancreatic, or other cancers. And you can see here the red line on the bottom actually shows the activity of the ERK inhibitor, which was previously called a different name. And you can see that kind of when you looked at it compared to other kinds of earlier ERK inhibitors, or other classes of drugs targeting upstream like at MEK or BRAF, that the ERK inhibitor, at least as a single agent for a limited period of time in these mouse models seem to have the most promising level of activity. On the right here, you can see specifically in a range of colorectal cancers, that the ERK inhibitor was active in the majority of the mouse models that were studied. And in particular, here, the shaded kind of  maroon or blue bar show KRAS or BRAF mutated mouse models where you can particularly see benefit.

Dr. Michael Lee  6:00 
Now, with all that being said as much as  we’ve studied single agent or inhibitors and the early phase studies looking at single agent drugs, we know that from long experience with kind of inhibitors of this pathway, that you have better activity for a longer duration of time, if you target in combinations of therapies. Without going into too much detail, generally in the past when we tried targeting this path of the single agent, for example, MEK inhibitors or BRAF inhibitors, there’s been a lot of kind of adaptation within the cancer cell, that kind of reactivates upstream signaling, and it can kind of bypass the level of drug inhibition. As a consequence, we’ve learned that we -and studies in the lab have also shown- that we have better outcomes, if you treat with combinations of therapies, we really think the best chance of having more activity that’s clinically significant for our patients, is using combinations of ERK inhibitors with other rationally targeted drugs. So one combination that’s being studied in the HERKULES-3  study in KRAS and NRAS mutated patients, which again, about 45 to 50%, of colorectal cancers, is combining this ERK inhibitor with a compound of drugs called the cyclin dependent kinase 4/6 inhibitor CDK4/6 . The reason this is rational is that one of the other key pathways that is activated when you have activation of the signaling pathway, it leads to activation of CDK 4/6 –which is very important for helping the cell multiply its DNA and ultimately divide. The cell cannot multiply and divide without actually going through the cell cycle process to replicate its DNA. So if you can block that process, the thought is that if you’re blocking it at 2 different levels, both kind of at the ERK inhibitor level plus at the cell cycle pathway level, that this would be more effective. Andactually, our laboratory has shown that impairing that kinase pathway in combination CDK 4/6 inhibitors was synergistic -was particularly effective- in a range of KRAS mutated models, both in cells in the laboratory and also in mouse models. And consequently that’s combining ERK inhibitors -which again, as we think would be a more potent strategy with the CDK 4/6 inhibitors- we’re hopeful will be even more likely to be effective. Palbociclib  is the drug that’s being studied in combination with the ERAS-007 compound. And this is a CDK 4/6 inhibitor that is actually currently standardly used in some other cancer types, like breast cancer,  is being studied in clinical trials in a number of other cancer types as well, typically in combination with other kind of targeted drugs. And so that’s one rational combination that we’re looking to study. In the BRAF mutated patients, this study will be looking to combine ERK inhibitors with other targeted therapies, targeting BRAF. In particular, as we’ve kind of learned in the last couple of years, the current standard of care for patients with BRAF mutated Colorectal cancer is to treat with a combination of drugs called encorafenib and it is a BRAF inhibitor directly impairing BRAF. And again, kind of talking about this multi level inhibition strategy, combining it with a drug targeting upstream at the EGFR level, called cetuximab. So the combination of encorafenib and cetuximab is currently FDA approved for BRAFV600E mutated colorectal cancer.

Dr. Michael Lee  9:40 
And this is based on the positive results of a large phase III study the Beacon CRC study, which did kind of represent an important advance in our management of these patients with BRAF mutated cancer. While this was absolutely an important step, we also know that there’s more improvement to go. We know from the Beacon CRC study that the response rate among patients was about 20%, which means only about one in five patients were having a significant shrinkage of their tumors, the remainder of the patients are having stable disease or even growth, despite this being our kind of active, a combination, targeted therapy approach. We know that the median duration of time that patients did not progress through the study was about 4 months, 4.3 months, and the median survival for the patients receiving this combination was 9.3 months. Now, this was actually a significant improvement compared to the prior standard treatment. But I think we all acknowledge that we want to improve on these numbers, there’s more we need to do for these patients. And that’s motivated kind of new strategies to look at how can we build on this ground to further improve outcomes here. There has been a range of laboratory studies that actually shows that another level of inhibition, hopefully more potent inhibition, would better allay the resistance that can develop when you’re treating with just the BRAF inhibitor plus the EGFR antibody. For example, we’ve seen that you can see emergence of small sub clones of mutated cells with other kinds of resistance mutations elsewhere in this pathway, which renders resistance to just the encorafenib and cetuximab . And as a consequence, there’s additional preclinical data showing that adding an ERK inhibitor, like ERAS-007, to the BRAF inhibitor and the EGFR antibody, may well be more effective in treating or preventing the onset of resistance. And that has motivated another arm of the study looking at encorafenib and cetuximab plus ERAS-007.

Dr. Michael Lee  11:44 
Now you may be asking, what do we know about the tolerability and side effects ERAS-007. So this is a drug that was previously studied in a single agent, prior clinical trial. So they looked at just the tolerability of ERAS-007 alone. I will note that in that single arm study, while this was a single drug given –not even a combination, there were some patients with a range of BRAF or other RAS mutated cancers that actually did have significant shrinkage of their tumors. Now granted, none of the tumors that shrink was meant to be colorectal cancer. But I think this does provide an important proof of concept that this ERK inhibitor approach can be quite potent in the right patient with the right kind of mutational profile, further motivating this, the HERKULES 3 study. The side effects from this study were as expected, and generally included side effects we would have expected with this class of drugs we have learned to manage pretty well. And they include things like nausea, diarrhea, rash, and eye side effects, which do require kind of being vigilant for any new changes in vision or other concerning eye side effects. And the study does require ongoing eye exams just for safety through the course of the study. With that being said, these are side effects that are pretty common to this class of MAP kinase inhibitors. And so these are not unexpected per se, and certainly things that we would aim to be able to manage with supportive care.

Dr. Michael Lee  13:18 
So that’s motivated the HERKULES 3 study. So this is a study that has two different arms based on the mutational profile of the patients. This study at present is currently up, enrolling patients only who have either a KRAS or NRAS activating mutation –again, about 45 to 50% of patients, or patients who have a BRAF V600E mutation, about 5 to 10% of patients. Unfortunately, if your cancer does not harbor one of those mutations at this point, you would not be a candidate for this study, just based on the principle that we’re trying to kind of find the best personalized approaches based on the underlying mutational profile. There are other trial options. Aside from HERKULES 3 for patients who don’t have a mutation in any of these genes. Patients who have a mutation in KRAS or NRAS as I mentioned, they will be studying the combination of the ERK inhibitor ERAS-007 with the CDK4/6 inhibitor, palbociclib. For patients who have a BRAF V600E mutation study will look at the combination of the ERK inhibitor ERAS-007 with an otherwise standard approach of encorafenib and cetuximab.

Dr. Michael Lee  14:36 
It is important to make sure that patients who are interested in this study know what the key eligibility criteria are when at the point in their disease, it is really important for you to be evaluated for this study. All clinical trials have particular time points –or are kind of they’re designed around particular points in a patient’s journey with typically stage four colorectal cancer, at which they should be considered for the study. And if you’re not quite at the right point in your journey, the trial would not be the right fit for you. So in particular, the HERKULES 3 study is looking at patients who have had some prior standard chemotherapy regimen. So for the most part, this specific study is not for patients who have had no prior therapy. But usually they will have gotten a standard prior chemotherapy based regimen. It also requires that they haven’t been given drugs that are usually given in patients who are more refractory to standard chemo therapies, drugs like regorafenib or tipiracil/trifluridine — these are oral drugs that are FDA approved, are usually given after kind of prior lines of IV based chemotherapeutic regimens. And so, if you’ve gotten one of those treatments before, this wouldn’t be a good fit. So you really should come evaluated for this study, before your oncologist is talking about putting you on regorafenib or tipiracil/trifluridine, because if we start that you won’t be eligible for this study anymore. It also requires the patients who have not had prior RAS, MEK, ERK inhibitors, these are not currently standardfor patients. So I wouldn’t expect you to have gotten this unless you were on a prior clinical trial. And while the criteria are evolving, it’s preferred that patients with the BRAF V600E mutation have not previously received encorafenib and cetuximab. So ideally, if your oncologist is talking about putting you on that combination, you would kind of quickly get into a center which has the study open to try to get onto this study, if you’re interested.

Dr. Michael Lee  16:45 
I think a lot of the patients are probably familiar with clinical trials.gov. But you can get more information for this study, look up the sites that are currently enrolling on the study, because it’s several sites, not just MD Anderson. So you can go to clinical trials.gov and type in a keyword like HERKULES 3 or this specific identifier number. This was just kind of the header. But if you scroll down, you’ll see more extensive inclusion and exclusion criteria, the sites that are currently enrolling, contact information for the study. So I would encourage anyone who’s interested to go to this site for more information. Again, this is a very exciting study, it only recently got underway. So we do think that there will be a lot of slots in the upcoming months for patients to go on the study. There are a number of sites that are active and continuing to be activated across the country. So looking to kind of where your closest site is, we’re always happy to see folks here at MD Anderson. But I’m very excited about the study. I think it’s very promising and I  I’m happy to answer any questions from anyone.

Manju George  17:57 
Yeah Dr. Lee, thank you very much. This was very informative. There are a couple of questions in the chat. So maybe we can go through that first. So this question is about prior BRAF and MAPK pathway treatments, are you okay, if people wait for a little bit? Or you said ideally, you don’t want any prior BRAF or —

Dr. Michael Lee  18:19 
Yeah, so it’s a great question. I think in general, patients try to determine what’s the best timing for coming into being evaluated for a clinical trial. It can be hard, because the reality is that logistically, there’s always a little bit of lead time that’s required to get in a new study, especially if you have to travel and figure out kind of life issues with that. And the reality is, if you’re kind of actively progressing, sometimes patients may have more significant symptoms that are building. What we don’t want is for a patient to wait, not get any active therapy before they know that they’ve been off of therapy for a couple of months and then start having worsening symptoms or other issues. I’d encourage patients in general, if you’re interested in the study, you know that you have a potential activating mutation in one of these key genes, to get an opinion at one of the sites that has the study. While you’re in the middle of your first line therapy, you may be able to get a kind of with a planned restaging scan. That way you can get plugged in well in advance, you talked about the study, you have an updated sense of the actual slot availability. Particularly in earlier phase, the earliest portion of the study, I will tell you we do have to be a little bit slow and methodical in how we enroll patients, just because we were looking very cautiously for safety of these new combinations. And so we don’t want to enroll a ton of patients all at once and find out there was a significant toxicity and we have to adjust the dose. So there are kind of slots that come and go particularly in the early phase of the study. So it is helpful to get plugged in and really get an updated sense of what are the study options — really other study options other than HERKULES 3. While this is a very promising study, there may be other study options that may be right for you. So rather than waiting until you’re progressing, and then risking a long wait time to try to get into the center, I think it’s good to try to get in kind of earlier, when you have a little bit more breathing room to figure out what the options are, so that when the time comes, you can get in quickly.

Manju George  20:21 
Yeah. Okay. So what you’re saying is that, so is it true that when a person starts, say, for example, FOLFOXIRI, and do they have to wait through like eight cycles or till progression to start thinking about this trial? Or should they initially  start thinking about it and get talking about it?

Dr. Michael Lee  20:42 
Well, I encourage patients in general to think about trial options, even from the beginning. So if  know you’re very motivated to go for trials, you understand. I mean, I always advise all my patients, there’s always kinds of downsides, particularly having to travel  farther than normal to get on a study –it is important to be aware of logistically what’s involved. With all that being said, if you know you’re interested in a trial, I think it always behooves you to get plugged in to a center with a large number of trials earlier in your course. When you’re getting standard FOLFOXIRI based therapy,  or even a chemotherapy doublet, if that’s whatever standard therapy you’re getting. If you’re having a really amazing response to therapy, I don’t think anyone would tell you to stop what’s working. And we would hope that that response would last for a long time. But of course, we also understand that at some point, that response may run its course, and we want to be prepared and have this plan ready to go at that time. Usually, that requires restaging every two to three months, we typically will do it every two months at our center to keep an eye on things. And so if you already know you’re interested in the study, many patients will actually get their restaging scans done with us, for example, so that we are immediately aware of when we need to switch gears.

Manju George  22:02 
Yeah. I had a question about the side effects of ERAS-007. You talked about the ocular side effects, what particularly are you seeing or what is known?

Speaker 1  22:13 
Well, these classes of side effects in general can be associated with a retinopathy, which is a retinal inflammation, or, specifically, if you recognize it, and you hold the drug, it does get better. And it may manifests in things like blurred vision or flashers or floaters. The study is building in regular eye exams, but you should also be aware, and kind of letting us know if you’re having any of those side effects. This is a class of side effects that generally we’ve seen with other kinds of MAP kinase inhibitors, even other nodes of that pathway. So for example, this is a common side effect we see with MEK inhibitors as well. So it’s not unexpected, but it is something we need to be aware of. And of course, when you’re giving drugs in new combinations, we have to be aware of that maybe a different side effect profile, again, kind of part of the reason in the early phases study, we proceed with due diligence and caution to make sure we’re maximizing patient safety.

Manju George  23:13 
Okay. So the other question was you mentioned a couple of doses, right for thyroid cancer and for the other cancers, 180 milligrams and 250. So what is the dosing? Are you also dose escalating during this initial part of the study?

Speaker 1  23:27 
The initial part of the study does have a dose escalation. Now the initial that’s kind of part of the slot, the slow and steady kind of slot determination, there is an ultimate dose expansion that’s planned. But we are planning a priori for the potential for needing to modulate the doses based on the toxicities we’re seeing –the unique novel combinations. So there will be ongoing tweaking of those doses.

Manju George  23:49 
Okay. And then about this ERK inhibitor, this is ERK1 and 2 inhibitor combined, right, blocking both? –And how does it compare to say the other ones available? Like ulixertinib or the BVD drug? –What is the difference?

Dr. Michael Lee  24:06 
So, I mean, every drug pharmacologically has different kinds of affinity for binding for the receptor and different kind of selectivity. Generally, the more selective the drug is for its intended target, and the less it hits off target, we would hope for better toxicity profiles, we do also see differences in the pharmacokinetics, which is kind of how long the drug persists. And that not only affects dosing, but the idea is that it can affect the optimal effectiveness level of the drug. This is a little bit subjective. But there are folks who will even say that this is more promising, I think you had seen in those preclinical studies that responses did tend to look better than then some of the predecessor ERK inhibitor –the prior ERK inhibitors. So we’re very hopeful that this will be even more effective than kind of prior drugs in the class.

Manju George  25:07 
Okay, I think there’s a question about what information do you have on palbociclib? In other cancers, what is the toxicity or efficacy, what have you seen?

Speaker 1  25:16 
Sure. So we have a pretty good handle on the expected side effects of palbociclib — at least kind of as a single drug. As I mentioned, it is approved with kind of estrogen directed hormonal therapies in combination in a range of estrogen receptor positive breast cancers. In that context we typically will see the biggest potential side effects with palbociclib typically is your blood counts. So it can cause low red blood cells or white blood cells or platelets. So that’s a known side effect we would have to follow, it actually doesn’t usually cause too bad of like febrile neutropenia, which is what we usually worry about with, say, chemotherapy and low blood counts. But that being said, we obviously do have to monitor and be very wary of potential infection and keep an eye on your counts. It can be other side effects like fatigue, like, rarely lung toxicity, or pneumonitis. Rarely, things like mouth sores. These are things we would obviously pay attention to. And obviously, their risk in combination will be more potentially there. Palbociclibn isn’t really given as a single agent, really, in any disease type, it hasn’t shown much activity, it tends to probably work best in combination, when there’s another targeted drug that’s already partially impairing cell cycle pathways, and then you further hit the cell cycle pathway. So tends to synergize better with other targeted drugs.

Manju George  26:37 
Yeah, I think there’s another question about the combination of the ERK inhibitor with KRAS-G12C inhibitors, do you know anything about it?

Speaker 1  26:49 
That would obviously be very exciting. There are a range of trials that are ongoing, obviously, specifically for the G12C patients. If you hypothetically had a KRAS-G12C  inhibitor, you could go on this study in the KRAS arm. With that being said, there are a wealth of studies that are specifically looking at direct KRAS-G12C inhibitors, as we’re all aware of. And it’s actually there’s an increasing number of compounds and an increasing number of combination approaches. And frankly, that would be a really good option. And something that’d be more unique to you if you had a KRAS-G12C mutation. So while you certainly could consider the study, and I would consider it, I would also look very hard into KRAS-G12C  inhibitor based combinations, because, there is a rationale to look at G12C plus other inhibitors of the EGFR MAP kinase pathway that is being studied in colorectal cancer. The exact best strategy remains to be seen, but most of the studies we have we’ve enrolled a number of patients on on other G12C  inhibitor trials, and they’re looking at an ever increasing number of potential new combinations to look to see, is there a signal of being more active while remaining tolerable compared to just single agent? So there’s a lot more options if you do have a G12C  mutation.

Manju George  28:13 
Yeah, and the other one question here is about EGFR inhibitors. So prior EGFR inhibitors don’t affect being on the trial at all right?

Speaker 1  28:24 
Well, if you have a KRAS, or NRAS mutation, you should not have gotten a prior EGFR antibody. So it would be a moot point. For the BRAF arm, it’s more relevant about if you’ve had prior BRAF in general, I wouldn’t expect you to be getting an EGFR antibody alone. But even if you hypothetically did, it will really depend on whether the trials at that phase of whether it’s enrolling patients with prior BRAF and or EGFR antibody therapy or not. But I would say if you have a BRAF mutation, even if you’re getting standard of care, it really should be in combination with another targeted agent, like the BRAF.

Manju George  29:07 
Okay. Okay. And then so the exclusion or  you prefer to have people who don’t have prior BRAF inhibitor exposure, right?

Speaker 1  29:20 
The study actually, the reason I phrase it that way is actually different phases of the study, it may allow or may specifically prohibit prior therapy. So generally, it will be safer if you haven’t had prior therapy, because at some point, the study will reach a phase where if you’ve had prior therapy it will actually probably be an exclusion criterion for this study.

Manju George  29:42 
Okay, so that means that for right now, prior BRAF inhibition is not an exclusion but it could be later. Yes, okay. Okay. And then we have one question from a patient she’s currently on FOLFOXIRI plus Avastin. And then she’s asked she’s got an HAI pump and to get to the liver resection and she’s asking, this would be the best time to think about this trial, right? For her?

Speaker 1  30:07 
I would think about it for sure, I think the biggest question for you specifically is going to be do you in fact, get to the point of a liver resection happening. Because if you have, what it would mean is that your liver metastases have responded very well, and that you’re actually having your shot at surgery. So, if you actually do have surgery and have all visible, known tumors removed with no evidence of radiographic disease remaining, then frankly, wouldn’t really be a candidate for this study. But that’d be great. So I would think about it just in case it doesn’t happen. But obviously, the hope would be that you would get to resection.

Manju George  30:46 
Okay. How can a BRAF V600 patient decide between Beacon doublet and this trial and which is more likely to help?

Dr. Michael Lee  30:57 
Well, Beacon is your standard of care doublet, right? That’s always available to you, as a standard of care with your local oncologist. I think but knowing what we know, about expected response rate, progression free survival and wanting to continue to push things forward, improve outcomes, I do think there’s an important role for novel therapies, looking at trying to see if the addition of the ERK inhibitor will build on the Beacon kind of backbone. So, ultimately, I think, if you’re willing to go on a trial and kind of have the logistical bandwidth to go on a study, I would highly encourage you to at least look into it. I think if for other reasons lifestyle, quality of life, it just doesn’t make sense, that’s totally understandable. And the Beacon regimen is going to be totally reasonable to get as your standard of care and is obviously the best standard care approach you could take.

Manju George  32:05 
The next question is about washouts. So if somebody is on chemo, how long do they have to wait till they get on the trial?

Speaker 1  32:13 
I believe it’s three weeks,  let me confirm it. It would. It would be in the clinical trials. I believe it’s three weeks though.

Manju George  32:24 
Okay. So not too much of a wait time. Yes. Yeah. Okay. Any other questions? When you showed the figure with the mouse models, you had some wild type animals in there, too. Right?

Dr. Michael Lee  32:43 
In the mouse models, there were wild type as well. Yes.

Manju George  32:47 
So it’s responding to people who don’t have the cancers which don’t have mutations in the BRAF and KRAF too?

Speaker 1  32:58 
So at least from the mouse data, it did look like that was the case now. Certainly, that the potential future area of investigation, because we obviously know that all patients with a range of kind of mutation profiles, we want to push things forward and have new trial options. So, but I think the study was designed with this priority for now, because we know there’s a particular need for patients with these mutations. I think I saw a question about what is the known toxicity profile. The study has started enrolling, but it’s actually quite early in its course, there haven’t been any major unexpected toxicity so far. But this is with a very small handful of patients. And certainly hasn’t been, like, reported at a meeting or anything, just because it’s still so small. I can assure you there are very regular safety calls ongoing to make sure all investigators in the study are staying abreast of any updated safety kind of in real time, which we do standardly for any new combination of drugs, and that’s certainly happening with this as well.

Steve Schwarze  34:01 
Manju, can I jump in? Sorry. Yeah, just I mean, obviously, we know something or like we have some data about CDK 4/6 for KRAS patients. Do we have any sort of evidence about what that would do for BRAF patients?

Speaker 1  34:25 
The CDK 4/6? Yeah. It’s a great question. We are increasingly looking, we’ve been looking at CDK 4/6 in a range of mouse models, actually. And while there certainly is kind of some promising preclinical data, I think. It certainly would be another realm of investigation for us to want to look into. There are a lot of really promising BRAF trials right now actually, that are trying to build on Beacon so really the question has been a matter of what is the most promising way to go? So CDK 4/6, certainly there’s a lot of interest in it. I will tell you at our center, my colleague, Van Morris, who I’m sure you all are very familiar with, has probably talked to you about some other emerging data about kind of the Beacon regimen plus immune checkpoint inhibitor therapy, and that he’ll actually be discussing those outcomes at the upcoming GI ASCO meeting. With the early data, and, there’s ongoing discussions about that becoming a larger, kind of much larger study. So I think we’re very excited about that data, in particular for BRAF patients.

Manju George  35:44 
Okay. Again, going back to the mouse data, so you had the HCT 119 cell lines right? In that figure, so is that like a subcutaneous model? Or do you have you checked in like a PDX model or something?

Speaker 1  35:59 
So it’s looked both kind of traditional cell line models, right. But on the right side of that figure was actually a range of colorectal PDX , is specifically patient derived xenografts. So it was looking both at kind of traditional cell line models plus PDXs.

Manju George  36:18 
What else? This is very useful. Thank you so much for your time. And we’ll probably give like one or two minutes, if anybody has any other questions.

Speaker 1  36:29 
I think someone had asked about efficacy even in the last few months. I wish I could tell you something more concrete. But right now, it’s still extremely early in the course of the study. We’re still even kind of at a point of getting dosing or firming up the dosing and the tolerability. So it’s very hard to say right now anything broadly with just a handful of patients.

Steve Schwarze  36:58 
Can I ask one, Manju? That dosing question is really important. I mean, so I was on a Beacon doublet, on the trial arm,  like four years ago, and then over the past year, I did it again with ulixertinib, through their expanded access program, and like I ended up getting eight months, I got twice as long on this combo with ERK inhibitor –I got four months on the trial, even though I’m much farther out. But it was a real challenge to try to juggle those doses, because we really didn’t know how much and I had a lot of toxicities related to it. So, yeah, I don’t really have a question. It’s just more of an n of 1 example, that it was figuring out what those right dosage was gonna be.

Speaker 1  37:52 
And I think that’s really important, because it’s exactly what we’re getting at. And I will say that targeted therapies, some patients think, oh, targeted therapies are not going to have any side effects like cytotoxic chemotherapy. And that’s, of course, not the case. It’s a different side effect profile, right? It’s more not like the really bad toxicity that gets better. It’s more like we have to learn how to live with these toxicities over a long time. So like a moderate toxicity that just never goes away, is quite bothersome as well, and perhaps arguably more so than a more significant toxicity that goes away in a couple of days. Right? And so part of the study is looking very carefully at what is the best dosing schedule along with dosing there are. That’s all kind of being pre specified, and still active discussion, and that’s kind of a key point of the early phase of the study. So we know what is the best strategy to go to before we kind of go into a larger expansion phase where the slots aren’t going to be so limited, we will have a better handle so that other clinicians, the investigators on the study, have a better sense instead of feeling like they’re having to go it alone to figure out the dosing, right?  which may have been your n of 1 experience.

Manju George  39:05 
Yeah, I think there’s a question. He’s asking, do you have a sense of how quickly you expect to see results or not? So are you going to have like interim results when you have the safety part done before you go into a dose expansion?

Speaker 1  39:21 
Yes, and no, I mean, so, of course there will be ongoing evaluation of the results, but it’s always very tricky when you have only like a handful of patients to make a firm conclusion about the efficacy of the study. Even the Beacon regimen, which as we all recognize was a major advance, had a response rate of about 20%. So hypothetically, I mean, I know actually, the earlier patients actually had a really high response rate, but hypothetically, if you’d had a treatment that had a one in five response rate and your first five patients you didn’t happen to see anyone have a response, you might prematurely say, “Oh, that’s not active” — and that wouldn’t really be accurate. So you do have to be really careful about that. We obviously do want to get the results as quickly as you can, but we also need to recognize that we need to get a large enough sample to know really what the true efficacy is.

Manju George  40:20 
Yeah. Okay. I have a question. So, in Dr. Corcoran’s trial, where he had the Spartalizumab with the MEK inhibitor and the BRAF inhibitor, he was using CtDNA to see whether the BRAF levels go down, and that would be an early indicator of effficacy, right? Are you planning to do something like that? What exploratory endpoints are you looking at?

Speaker 1  40:42 
Sure I mean, there are a range of –any early phase study has a lot of endpoints like, additional correlative studies, a lot of them are pharmacokinetic studies where they’re really looking to see what is the dosing level obtained by the drug and like, what is the level of the drug in your body at that time point that standard. It’s pretty cumbersome, honestly, for the patient to have, but that standard. CtDNA is built into practically every study at this point, I will tell you, it’s probably not like an immediate readout or necessarily going to be used to determine if it’s working or not–continue or stop. From that perspective, we’ll still be using the tried and true kind of radiographic imaging based endpoints. But, pharmacodynamics, and pharmacokinetics are a key point of what happens in these early studies. We’re very grateful that patients are so willing to take those steps, we can truly know was the drug working, was it doing what we intended it to do, because we really need patients to be willing to get extra blood draws or even biopsies and things as needed. So we’re very thankful for patients to be willing to do that.

Manju George  42:03 
Okay, thank you for that. Yeah, I think we covered all the questions. And this has been very useful. So what I’ll do is that I’ll have the video available in Colontown University as well as Colontown. And if you want, if you’re interested in having your patients watch it, or somebody who’s interested in the trial watching it, I’ll be happy to share a link so that you can have them watch it.

Dr. Michael Lee  42:31 
Yeah, that would be great. Thank you so much.

Manju George  42:34 
Yeah. Okay. Thank you very much for your time.

Dr. Michael Lee  42:37 
Thank you, everyone.

Steve Schwarze  42:38 
Thank you. Bye bye.

DocTalk
2021
Dr. Lee
BRAF
KRAS
MSS
Stage IV
Trials

Dr. Michael Lee of MD Anderson discusses the HERKULES-3 clinical trial for BRAF and RAS-mutated GI cancers. Recorded in December, 2021.

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