Innovative Immunotherapy Approaches in GI Malignancies

Drs. Shaalan Beg and Rachna Shroff discuss key abstracts on GI cancers that were featured at the 2024 ASCO Gastrointestinal Cancers Symposium, including SKYSCRAPER-08, EMERALD-1, and NEST-1 in esophageal squamous cell carcinoma, hepatocellular carcinoma, and colorectal cancer, respectively.

TRANSCRIPT

Dr. Shaalan Beg: Hello, and welcome to the ASCO Daily News Podcast. I'm Dr. Shaalan Beg, your guest host of the podcast today. I'm an adjunct associate professor at UT Southwestern's Simmons Comprehensive Cancer Center and vice president of oncology at Science 37. Today, we'll be discussing key abstracts and other exciting highlights from the 2024 ASCO Gastrointestinal Cancers Symposium. Joining me to discuss some key takeaways from the meeting is the chair of this year's Symposium, Dr. Rachna Shroff. Dr. Shroff is the division chief of Hematology Oncology and chief of GI Medical Oncology at the University of Arizona Cancer Center. She also serves as the associate dean for clinical and translational research at the University of Arizona College of Medicine – Tucson.

Our full disclosures are available in the transcript of this episode, and disclosures related to all episodes of the podcast are available at asco.org/DNpod.

Dr. Shroff, welcome back to the ASCO Daily News Podcast, and congratulations on a great Symposium. The scientific advances and innovative, multidisciplinary approaches that were featured throughout the meeting were really inspiring and reflect the incredible strides we're making in GI cancer research.

Dr. Rachna Shroff: Thank you so much for having me back. I am delighted to be here.

Dr. Shaalan Beg: Dr. Shroff, the theme of this year's symposium was "Taking Personalized Care to the Next Level." I'd love to hear your reflections on the sessions that you found most exciting and really resonated with the attendees.

Dr. Rachna Shroff: Yes, thank you. We were really excited about this theme because we really felt that "Taking Personalized Care to the Next Level" translated to thinking through personalized approaches to patient care, not just in the traditional ways that we think of with precision oncology and genomics driving our care, but also how we can think through multidisciplinary approaches and an individualized care plan. Thinking through how artificial intelligence and novel clinical trial designs can and should be implemented to meet the needs of our individual patients. And so we really highlighted that in what was a somewhat new reboot of a session called "Intersections," which were every day and were really more cross-tumor; they were tumor agnostic but were thematic focused. As I mentioned, those themes were really based on feedback that we had from prior attendees, as well as from the program committee's feeling on what are really the questions that we are dealing with and that are burning in the clinic today and that includes the emerging role of artificial intelligence and machine learning and how we integrate that into our clinical care, approaches to oligometastatic disease, and it's not really just something that we think of in colorectal cancer but haven't fully used that paradigm to really apply it to other GI malignancies. And then the art and science of clinical trial design where, again, traditional randomized phase 3 trials might not be the best and most innovative and most expedient way of bringing novel therapeutics to our patients. And so, I thought that all of those sessions were really highlighting different important topics that we deal with day to day.

Additionally, we had a really fantastic keynote lecture from Dr. Kimmie Ng of the Dana-Farber Cancer Institute. She is a world-renowned expert in the early-onset colorectal cancer space, and the timing of her keynote was perfect with the new cancer statistics that came out literally days before GI ASCO that demonstrated this just dramatic rise in early onset GI malignancies as a whole, not just colorectal. And she spoke really in a comprehensive manner not just on clinical approaches, screening approaches, and how to find these patients at an earlier stage, but also kind of gave us a call to action, if you will, in terms of public health initiatives, as well as like I said, clinical care and really thinking outside of the box for how to reach these patients.

And then, of course, we always have what I think is one of my favorite aspects of the meeting, which are the networking opportunities that include the Trainee and Early Career Networking Luncheon, the Women's Networking Reception, and the Meet the Experts Luncheon where, especially as junior career investigators, you have an opportunity to meet what we think of as the "big names" in GI cancer.

Dr. Shaalan Beg: Absolutely, I remember my first couple of GI ASCO meetings and those were probably the most memorable sessions that I attended as junior faculty as well.

So let's take a deeper dive into some key abstracts from the meeting. I'd like to begin with Abstract 245. This is the SKYSCRAPER-08 study. It's first-line tiragolumab and atezolizumab with chemotherapy in an Asian patient population with esophageal squamous cell carcinoma. What are your key takeaways from this study?

Dr. Rachna Shroff: Yeah. This was an exciting study in my opinion in the sense that thinking through how we can build on immunotherapy backbones is obviously a pressing question across the GI cancer space. So this was a phase 3 randomized, double-blinded, placebo-controlled trial that looked specifically at patients with esophageal squamous cell carcinomas. And the study was enrolled fully with an Asian population. It looked at taking the traditional chemotherapy backbone and adding to it an anti-PD-L1 with atezolizumab and an anti-TIGIT with tiragolumab. Again, that proof of principle of using anti-TIGIT and PD-L1 has been looked at across a lot of different GI cancer spaces and we know that the esophageal squamous cell cancers tend to be very immunotherapy responsive. So this was a really important question.

This involved a number of patients, a little over 460 patients, who were randomized one-to-one to receive the tiragolumab with atezolizumab with the standard paclitaxel and cisplatin, that's used for esophageal squamous versus chemotherapy alone with placebo. And the primary endpoint was independent review of progression-free survival, and overall survival. And so, out of the 461 patients randomized, there was at the primary analysis, a median improvement in progression free survival, from 5.4 months in the control arm to 6.2 months with a tira-paclitaxel plus chemo arm with a hazard ratio of 0.56, highly statistically significant. Similarly the median overall survival was also improved from 11.1 months to 15.7 months again with a hazard ratio of 0.7 and some of the other key efficacy endpoints were also improved with the addition of the anti-TIGIT PD-L1 approach. And importantly, there was not really safety signals that jumped out at us.

And so, to me, what this means is that, in our patients with esophageal squamous cell carcinoma, we really should be thinking about chemotherapy with immunotherapy as a backbone and how we can build on it. And, you know, I would imagine that it's hard to argue with both the PFS and OS endpoint that adding anti-TIGIT won't necessarily be kind of the new approach to these patients. And importantly, I'll point out that it seems to be a benefit across the subgroups, including PD-1 status, which is always our big question here. I think the only thing to keep in mind is this was an all-Asian population and whether or not that kind of immune profile of the immune responsiveness is different in those patients, but regardless, a positive phase 3 trial.

Dr. Shaalan Beg: It's really exciting to see immune checkpoint inhibitors or immunotherapy beyond PD-1 targeted, CTLA-4 targeted treatments making their way into GI Cancers.

Dr. Rachna Shroff: Absolutely.

Dr. Shaalan Beg: Sticking with the immunotherapy theme, let's focus on hepatocellular carcinoma. So LBA432, the EMERALD-1 study of transarterial chemoembolization combined with durva with or without bevacizumab looked at people with unresectable hepatocellular carcinoma eligible for embolization. So really a highly anticipated study, I'm wondering what your thoughts are and whether it'll be practice-changing for this field.

Dr. Rachna Shroff: I was excited to see the press release when it showed that the study was positive, and I think it's because now that we're using immunotherapy in the advanced HCC space, our obvious question is, can we integrate it into multimodality approaches? There are a lot of smaller studies looking at neoadjuvant IO approaches, and in this intermediate stage, unresectable hepatocellular carcinoma patients. We wanted to know if there was a utility to liver directed therapy with immunotherapy.

So, this was a large study. It was a global study looking at unresectable HCC with preserved Child-Pugh function. But it was Child-Pugh A and up to B7, importantly. And there were 616 patients randomized in a 1:1:1 fashion, with the control arm being just TACE alone. But then, there was also an opportunity for durvalumab with TACE, as well as durvalumab plus bevacizumab with TACE. The patients would receive durvalumab during their TACE treatments and could receive up to four TACE treatments and then subsequently were either continued on durvalumab alone, durvalumab plus bevacizumab, or the placebo. The primary endpoint was progression-free survival, powered specifically to look at TACE versus durvalumab plus TACE. In this study, the primary endpoint was met with a significant improvement in PFS. Median PFS was 15 months versus 8.2 months, with a hazard ratio of 0.77. Most prespecified subgroups demonstrated this benefit.

Importantly, there was a secondary endpoint looking at durvalumab plus TACE versus TACE alone, and that actually did not show a statistically significant improvement in median PFS from 8.2 months in the control arm to 10.0 months. The overall response rates were slightly higher with the durvalumab plus bevacizumab approach at 43.6%. And importantly in these patients, who oftentimes have a higher burden of disease in the liver, median time to progression is a really important and clinically meaningful endpoint. That was 22 months with the durvalumab plus bevacizumab and TACE versus 10 months for TACE alone.

I would just point out that the overall concern we always have with bevacizumab is the increased risk of bleeding and the treatment-related adverse event profile. Overall, there were no safety signals that emerged from this, with nothing that really, especially in that bleeding risk category, jumped out at us. Of course, we haven't seen the overall survival data yet because we have not seen enough follow-up to really see that number.

I do think that this is potentially practice-changing, and I think it just demonstrates that there's probably some synergy between anti-VEGF with anti-PD-1, and then the liver-directed treatments. The obvious question for us in the United States is that the vast majority of people are moving away from TACE and towards more radioembolization and what can we extrapolate from this? Does this really tell us much if people are using more of a Y90-based approach? I think those are a lot of the burning questions that most of us have.

Dr. Shaalan Beg: Yeah, and it's a very interesting direction that the HCC space is taking because we heard in previous meetings, the role of PD-1 inhibition as adjuvant therapy after resection. Now, we have data for local-regionally advanced disease over local-regional treatments. And of course, you already mentioned the data for more advanced disease. So it sounds like immunotherapy may be impacting the management of anyone diagnosed with hepatocellular carcinoma.

Let's talk about the MONET trial, Abstract 249, which compared thoracoscopic esophagectomy and open esophagectomy for thoracic esophageal cancer. Do you think this is a study which may influence the treatment of patients with thoracic esophageal cancer?

Dr. Rachna Shroff: So, this was, again, I think, a really important question. It was a randomized, controlled phase 3 trial comparing a more minimally invasive approach with TE — thoracoscopic esophagectomy — versus an open approach. This had patients with clinical stage 1-3, excluding T4 thoracic esophageal squamous cell carcinomas. They were randomized 1:1 to the open versus the TE approach, with a primary endpoint of overall survival and an important secondary endpoint of relapse-free survival. 300 patients were randomized, and at the second planned interim analysis, the median follow-up was a little over two and a half years. The 3-year overall survival was 82% in the TE group versus 70.9% in the open group. The DSMC of this trial actually recommended early termination based on the non-inferiority, which is what they were specifically looking at. There was a very statistically significant one-sided p-value for non-inferiority.

Importantly, the 3-year recurrence-free survival was also markedly better in the TE group versus the open group, with no real notable differences in R0 resection, or a large percentage of patients who needed to be converted from a TE to an open approach, and really not any significant difference in overall postoperative morbidity. I think this just supports the concept that minimally invasive approaches for our patients with GI malignancies can and should be considered. Again, esophageal squamous because they tend to be seen a lot more in Asia, this study was conducted in Japan, but I think that being said, a lot of our surgeons in Europe and in the U.S. are also very amenable to minimally invasive approaches. And I think this just supports the fact that an open approach is not necessary. So, I would think again, that this is something that is implementable and I think will affect the field.

Dr. Shaalan Beg: Moving on to metastatic cholangiocarcinoma, there have been many FGFR inhibitors that have shown activity and promise and are approved for the management of cholangiocarcinoma with FGFR alteration. But at this ASCO GI, we heard the results of the safety and efficacy of an FGFR1, 2, and 3 inhibitor, tinengotinib, as monotherapy for advanced metastatic cholangiocarcinoma (Abstract 434). How do you see this fitting into the broad picture?

Dr. Rachna Shroff: Yeah, so this was highly anticipated data, primarily because at this point, the FGFR space in cholangiocarcinoma is quite crowded. And so a lot of us were getting sick of the "me-too" drugs. What is really unique about tinengotinib is that, not only is it a selective multikinase inhibitor, but it also, in preclinical models as well as in early phase one trials, demonstrated potent inhibition of patients with FGFR2 fusions and rearrangements who had acquired resistance mutations. So, as we better understand the first generation of FGFR inhibitors and note the resistance mechanisms, these drugs are now being developed to try to circumvent or overcome those.

This study looked at 4 different cohorts: 1 cohort with FGFR2 fusion patients who had primary progression who never responded to FGFR inhibitors, a second cohort with FGFR2 fusion patients who had progression after primary response, so those with acquired resistance, and then there was non-fusion FGFR alterations because we do know that a number of cholangiocarcinoma patients have other FGFR alterations that are not fusions, and then those with FGFR wild-type. The primary endpoint was objective response rate, with a total of 48 patients enrolled across the four cohorts. And so the 40 patients who were evaluable in the group that had primary resistance, which was the first cohort, there was a response rate was 9.1% and that was partial response, and 31% had tumor reduction with tinengotinib. And similarly in those with acquired resistance, 37.5%, 3 out of 8 patients had a partial response and tumor reductions were noted with an overall disease control rate between those patients with FGFR2 fusions of 94.7%, between those with primary and secondary resistance.

In the patients who had FGFR alterations, there was 3 out of 9 patients with a partial response and again, tumor reductions were notable across the board and the disease control rate was 88.9%. The FGFR wild-type group, not surprisingly, did not see any partial responses, but interestingly, 75% of these patients had at least disease control, and the median progression-free survival was 5.26 months, again, kind of most notably impressive in the 2 cohorts that included FGFR2 fusions. The toxicity profiles are what we come to expect for FGFR inhibitors and we've gotten better at managing those and mitigating some of those so there was really nothing to jump out there.

So there is now an ongoing randomized phase III trial specifically looking at tinengotinib versus physician's choice in patients with FGFR2-altered cholangiocarcinoma after having received prior FGFR inhibitors. So that's where I think it's in is for those of us who know that there are multiple drugs in the space, our big question is can we sequence through that? Can we offer multiple FGFR inhibitors in these patients? And I think we are all eagerly anticipating this data as well as the subsequent data to really justify the use of these novel second generation FGFR inhibitors.

Dr. Shaalan Beg: It's been fantastic to see the evolution of these compounds in precision medicine, or precision oncology at its finest, in terms of understanding mechanisms of resistance and treating refractory disease.

Let's focus on colorectal cancer. I'll tell you, there has been a lot of discussion, Dr. Shroff, on social media, on insurance companies sometimes rejecting one biologic or the other based on tumor sidedness. We have talked about tumor sidedness predicting response on this podcast based on data from previous studies. But this year in GI ASCO, Abstract 207 explored the role of tumor genomics and tumor sidedness and they said that it's tumor genomics, that tumor genomics better explains the differences on outcomes, and it explains it better than sidedness. What does this mean to the field? Because a lot of professional organizations have guidelines that are asking people to now incorporate sidedness. So how does that change based on these results?

Dr. Rachna Shroff: I really commend these authors on leveraging real-world data, and I think we're getting better and better at recognizing that real world data actually informs our clinical decision making, possibly better than sometimes some of these studies that lead to the guidelines and algorithms that we develop. So this is a perfect example of a little bit cart before horse in trying to understand the way that sidedness and genomics may interplay.

So this was a study that basically leveraged both the Foundation Medicine and Flatiron Health clinical genomic database and looked at patients with microsatellite stable metastatic colorectal cancer. There were a total of 3,845 patients included in a kind of two-thirds one-third split between left sided and right-sided colorectal cancer. And they found the typical genomic alterations that historically have been thought of more with left-sided colorectal cancer like APC and then more of the RAS BRAF alterations in the right-sided patients. But I think what they really thought and what I think was remarkable is they really looked at the patients and how they received chemotherapy with anti-EGFR or bevacizumab therapies, and they did a multivariate analysis to really see what is driving outcomes. And like you mentioned, what they found was patients in the RAS pathway, those classified as having alterations in the RAS pathway, had less favorable outcomes, while those with APC altered group had more favorable outcomes. And that was regardless of treatment received and sidedness.

And so when they did an analysis of what was called a "likelihood ratio test," they found that when genomics was added to the sidedness evaluation, there was an improvement in outcome prediction, but not when sidedness was added to genomics. Like you said, it kind of demonstrates, at least in this mining of real-world data from Flatiron that tumor genomics is probably a better driver and a more important driver in determining outcomes than sidedness.

I totally agree with you. I would push for us to really kind of bring a little bit of noise to this and to make insurance companies and other companies that are looking at this to think through this a little bit more and make sure that we're putting all of the data together in a comprehensive passion before making the treatment plans and determinations.

Dr. Shaalan Beg: The last abstract I'd like to ask you about is Abstract 117, the NEST-1 trial. This study looked at neoadjuvant botensilimab and balstilimab for resectable mismatch repair proficient and deficient colorectal cancer, both MSS and MSI. What are your key takeaways from this study?

Dr. Rachna Shroff: This is another study that is demonstrating that there may potentially be a role for immunotherapy in microsatellite stable patients. I will make the caveat that this was a single-arm study that really was looking at feasibility safety, with efficacy as a secondary endpoint. The combination of bot-bal in the neoadjuvant space for colorectal cancer patients, they received one dose of boten and two fixed doses of bal two weeks apart and then were taken to surgery. They limited the number of patients and out of the 12 patients that were enrolled, they limited the number of mismatch repair deficient patients. So to your point, they allowed both, but they wanted to make sure it was not just MSI-high patients.

What they basically found is that it was safe and did not delay surgery or increase risks of adverse events. But importantly, there was significant regression of tumor noted. And some interesting spatial biology analyses demonstrated potentially novel mechanisms of action, especially in the MSS population, and that ctDNA reductions correlated with pathologic response. There were a lot of different things that they were looking at, basically suggesting that bot-bal is safe and can be used in both mismatch repair–deficient and proficient patients with colorectal cancer. And now importantly, they've added some additional cohorts and expanding the study. As I mentioned, this is right now just 12 patients, but does definitely have a provocative result.

Dr. Shaalan Beg: Thanks so much, Dr. Shroff.

Finally, the role of cell-free DNA (cfDNA) in GI cancers has been an exciting and important development in our field. There's tremendous data that emerged at the GI meeting, and we have decided to do a separate ASCO Daily News Podcast dedicated to ctDNA. So listeners, please look out for our coverage of key studies on ctDNA in GI cancers very soon here on the ASCO Daily News Podcast.

Many thanks, Dr. Shroff, for sharing your insights with us today and for your great work in building a robust GI meeting this year. Thank you very much.

Dr. Rachna Shroff: Thank you so much.

Dr. Shaalan Beg: And thank you to all our listeners for your time today. You'll find links to the abstracts discussed on the transcript of this episode. Finally, if you value the insights that you hear on the ASCO Daily News Podcast, please take a moment to rate, review, and subscribe wherever you get your podcasts.

Disclaimer:

The purpose of this podcast is to educate and inform. It is not a substitute for professional medical care and is not intended for use in the diagnosis or treatment of individual conditions. Our guests on this podcast express their own opinions, experiences, and conclusions. These statements do not necessarily reflect the views of ASCO. The mention of any product, service, organization, activity, or therapy should not be construed as an endorsement by ASCO.

Find out more about today's speakers:

Dr. Shaalan Beg

@ShaalanBeg

Dr. Rachna Shroff

@rachnatshroff

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Disclosures:

Dr. Shaalan Beg:

Employment: Science 37

Consulting or Advisory Role: Ipsen, Array BioPharma, AstraZeneca/MedImmune, Cancer Commons, Legend Biotech, Foundation Medicine

Research Funding (Inst.): Bristol-Myers Squibb, AstraZeneca/MedImmune, Merck Serono, Five Prime Therapeutics, MedImmune, Genentech, Immunesensor, Tolero Pharmaceuticals

Dr. Rachna Shroff:

Consulting or Advisory Role: Exelixis, Merck, QED Therapeutics, Incyte, Astra Zeneca, Taiho Pharmaceutical, Boehringer Ingelheim, SERVIER, Genentech, Basilea

Research Funding: Pieris Pharmaceuticals, Taiho Pharmaceutical, Merck, Exelixis, QED Therapeutics, Rafael Pharmaceuticals, Bristol-Myers Squibb, Bayer, Immunovaccine, Seagen, Novocure, Nucana, Loxo/Lilly, Faeth Therapeutics