BOT+BAL trial for MSS CRC: Dr. DeVito (2025)

Manju George 0:00
Hello everyone. Welcome to COLONTOWN Doc talks. I’m Dr Manju George the Scientific Director at PALTOWN Development Foundation, the nonprofit that supports COLONTOWN. So today for our doc talk, 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.