Jun 27, 2022
Dr. Rachna Shroff, of the University of Arizona Cancer Center, tells guest host, Dr. Shaalan Beg, of UT Southwestern’s Harold C. Simmons Comprehensive Cancer Center and Science 37, about advances in precision medicine for pancreatic cancer featured at the 2022 ASCO Annual Meeting. She also highlights compelling new data from the FOLFOX, FOENIX-CCA2, and HERB trials in hepatocellular carcinoma, cholangiocarcinoma, and biliary tract cancer.
Dr. Shaalan Beg: Hello and welcome to the ASCO Daily News podcast. I'm Dr. Shaalan Beg, your guest host of the ASCO Daily News podcast today. I'm an adjunct associate professor at UT Southwestern Simmons Comprehensive Cancer Center and vice president of oncology at Science 37.
I'm delighted to welcome Dr. Rachna Shroff, the associate dean for clinical and translational research and the chief of gastrointestinal (GI) medical oncology at the University of Arizona Cancer Center where she's also the interim chief of Hematology-Oncology.
Dr. Shroff is also the chair-elect for the Gastrointestinal Cancer Symposium. Today we'll be discussing key abstracts in GI cancer that were featured at the 2022 ASCO Annual Meeting.
Our full disclosures are available in the show notes and disclosures of all our guests on the podcast can be found on our transcripts at asco.org/podcasts.
Dr. Shroff, thank you for being on the podcast today.
Dr. Rachna Shroff: Thank you so much for having me.
Dr. Shaalan Beg: Let's begin by reviewing what is new in the realm of precision medicine in GI cancers. One of the diseases where precision medicine has not made adequate inroads is pancreatic cancer. One of the most common mutations in pancreas cancer is KRAS, but there haven't been a lot of treatments that can target the most common forms of KRAS. What did we hear at ASCO22 regarding precision medicine and pancreatic cancer?
Dr. Rachna Shroff: I agree, I think that the area of precision oncology is, unfortunately, lagging behind a little bit in pancreatic cancer. But I think as we have gotten better and better with our comprehensive genomic profiling, we are identifying subsets of patients within pancreas cancer who are potentially amenable to targeted therapies.
You already mentioned KRAS mutations, and we obviously have a number of inhibitors in development in that space, though, we are still missing that key G12D mutation that we see in pancreas cancer. But what I think was really interesting that came out of ASCO22, was a lot of interest and emphasis on better understanding the KRAS wild-type patients in pancreatic cancer.
Now, this is obviously a smaller subset of patients, given that the majority of patients have KRAS mutations. But there was a really interesting abstract, LBA4011, that looked at patients with locally advanced or metastatic pancreatic cancer, who were KRAS wild-type. They actually received gemcitabine in combination with a monoclonal antibody targeting EGFR and nimotuzumab.
This was a study that was done entirely in Asia. It involved 92 Chinese patients that were randomly assigned to receive the combination of nimotuzumab with gemcitabine. What was interesting in this study is that the patients were found in the full analysis set to have a significantly longer median overall survival of 10.9 months versus 8.5 months with a hazard ratio of 0.5.
So, that of course was intriguing and provocative for sure. Similarly, the other endpoints were also somewhat intriguing in terms of improvements in the median progression-free survival (PFS), etc. And specifically, patients without biliary obstruction had a longer PFS, which was an interesting finding as well.
The nimotuzumab overall was pretty well tolerated and not any sort of surprising treatment-related adverse events (TRAEs) were noted. And so, this is definitely a drug that, I think, piques our interest in terms of being able to target patients with KRAS wild-type pancreatic cancer.
I think that questions, however, that remain, and I think require further study is really understanding what this drug could do in combination with the chemotherapy combinations that we use more frequently in metastatic pancreatic cancers such as gemcitabine and paclitaxel or 5FU-based regimens like FOLFIRINOX.
I think given that it is a relatively well-tolerated drug, it would be a very reasonable thing to investigate this drug further in the KRAS wild-type population with the kind of modern-day chemotherapy regimens that we use. And I think, of course, we all know that it is useful to be able to look at these types of drugs in a more global population. And so, a larger patient set I think would be very useful as well, but at least it tells us that there is a way to think about our KRAS wild-type patients with pancreas cancer and that perhaps we really need to understand and identify those patients' potential for precision oncology.
Dr. Shaalan Beg: One of the GI cancers that has been a hotbed for precision medicine is cholangiocarcinoma, a disease that's very close to your heart. What updates did we hear at ASCO22 regarding cholangiocarcinoma and precision medicine?
Dr. Rachna Shroff: This space of targeted therapy and cholangiocarcinoma has been incredibly exciting for the last few years and I think drug development has been rapid-fire in that space.
The oldest, if you will, target that we've been thinking about for some time is the FGFR2 fusion patient population. And in Abstract 4009 by Dr. Goyal and colleagues, we saw the results of the FOENIX-CCA 2 trial which was looking at an oral FGFR inhibitor (futibatinib) in patients with intrahepatic cholangiocarcinoma, who harbor FGFR2 fusions and gene rearrangements.
We had initially seen some of this data presented a few years back, but this was the updated data set. It was a single-arm phase 2 study that involved patients with advanced intrahepatic cholangiocarcinoma who had identified FGFR2 gene fusions, and they received futibatinib daily until progression.
This was a traditional single-arm phase 2 study with a primary endpoint of overall response rate. At the final data cut, with a median follow-up of 25 months, there's actually a confirmed overall response rate of 41.7%. And I think that what was really exciting about this is this is a refractory patient population.
So, in patients who have refractory cholangiocarcinoma, the other drugs, the non-targeted therapy drugs that we think through, really have response rates more in the single-digit to 10% range and so to have a confirmed overall response (OR) over 40% is truly exciting.
The duration of the response was also exciting. This is not just a drug that works briefly, it has a duration of response of 9.5 months. And the mature median overall survival was 20 months. And in a disease which we talk about with the ABC-02 data of GemCis, a median OS in advanced disease of 11.7 months. This is really, really exciting for patients who harbor this fusion or gene rearrangement.
We know that that's seen in about 10 to 15% of patients. So, again, we're dealing with a smaller subset, but it clearly demonstrates the need to identify FGFR2 gene fusions, so that we can offer these types of targeted therapies.
This was not the first FGFR inhibitor that we have seen data on and in fact, we have 2 drugs already U.S. Food and Drug Administration (FDA) approved. And so, when we look at the common treatment-related adverse events that were identified with the futibatinib, there are really class effects related to FGFR inhibition like hyperphosphatemia, alopecia, dry mouth, nothing that really stood out or that was concerning.
And so, I think this final analysis for the FOENIX study really just reaffirms the utility of futibatinib in patients with FGFR2 gene fusions, and the mature OS data, the duration of response, all of this really aligns with the need to identify patients with this alteration so that we can, post-gemcitabine based therapies, offer this targeted therapy or an FGFR inhibitor in general to these patients.
I think the other really exciting abstract in the glandular carcinoma or biliary tract cancer space was Abstract 4006. This was the updated data from the HERB trial, which was an investigator-initiated multicenter phase 2 trial looking at trastuzumab deruxtecan (T-DXd) in patients who have HER2 expressing unresectable or recurrent biliary tract cancer.
Trastuzumab deruxtecan, I'm sure everybody has been hearing about because it has been incredibly effective in HER2 alterations across a myriad of different disease sites. And so, not wanting to be left out, biliary tract cancers were investigated in this study with patients who had HER2 expression, so, that was HER2-positive IHC3+ or IHC2+/ISH+, and they also looked at HER2-low expressing patients, and [whose disease] were refractory or intolerant to gemcitabine-based therapy with the primary endpoint of overall response rate.
So, in the HERB trial, a total of 32 patients were enrolled. 24 of them were HER2-positive and 8 were HER2-low and they all received trastuzumab deruxtecan. When you look at the efficacy data, the confirmed overall response rate in the patients with HER2-positive was 36.4%, which again, as I said, in a refractory patient population is certainly very exciting data. And the overall disease control median, PFS, and median OS were all pretty encouraging in terms of efficacy.
What was also kind of intriguing was that there was some efficacy seen even in the patients who are HER2-low. Now, this is, in my opinion, a slightly less exciting amount of efficacy, but still important to note that the overall response rate in HER2-low was 12.5% with a median PFS that was also somewhat exciting at 4.2 months.
And so, there is a potential clearly for targeting patients with HER2-high or HER2-positive with trastuzumab deruxtecan, and I think in the patients who are HER2-low, we need to better understand the potential utility.
The common treatment-related adverse events that we see were the typical things that we've heard about with trastuzumab deruxtecan, but I think the one thing that was really worth noting was 8 patients or 25% of patients had interstitial lung disease (ILD), which we know is an important identified safety concern for patients who receive trastuzumab deruxtecan, and I think that's a pretty sizable number of 25%, so, I think that's going to really require a little bit more fleshing out for us to understand the safety for these patients.
One question that a lot of us have had is whether these are patients who have received gemcitabine, which we know can also cause pneumonitis. And so, I don't know if we're seeing a higher percentage of ILD because of, 'priming' with prior gemcitabine.
But regardless, I think this is just proof of principle that again, we need to identify patients with biliary tract cancers that have HER2-positivity because we now have a number of drugs including potentially trastuzamab deruxtecan to target [their disease] with after gemcitabine-based treatments
Dr. Shaalan Beg: Absolutely. Any new biomarkers to keep on the radar for our listeners?
Dr. Rachna Shroff: I think there are a lot of really exciting targets. One that was talked about and that we saw data on at ASCO [Annual Meeting] was from Abstract 4048, which looked at claudin . Claudin is basically a transmembrane protein that kind of helps maintain the tight junctions between cells.
In gastric cancer, in particular, we look at claudin 18 isoform 2, and there are 18.1 and 18.2 gene expressions that have been identified in gastric cancer. So, there was a very comprehensive abstract that was presented of over 1,900 samples that underwent comprehensive profiling by next-generation sequencing.
And the patients were identified with claudin 18.1, and 18.2, high versus low. Claudin 18.2 expression was actually detected in 97% of the samples. It’s slightly lower with claudin 18.1 at 63%. It's important to note that the primary tumors had higher expression levels than the metastatic tumors, so those were really the tumors in which they did a deeper dive.
And in the process of doing this deeper dive, they did a really interesting kind of better understanding of the immune microenvironment and the immune profile in the samples that had claudin expression. And what was identified is that there was an inverse relationship basically between claudin 18.1 and 18.2 expression and correlation with PD-L1 positivity, tumor mutational burden (TMB)-high, M1 macrophages expression, NK cell presence, CD4 positive T-cells, myeloid dendritic cells.
And so, there's clearly something between the presence of this claudin expression and the effect it has on the immune microenvironment. I think that's very relevant to keep in mind because as we all know, there's a whole space of drug development focused right now on anti-claudin 18.2 monoclonal antibodies, as well as a target for antibody-drug conjugates (ADC) and cellular therapies with CAR T-cell therapies being developed specifically against claudin 18.
And so, understanding the immune microenvironment and the interaction between the claudin expression will be really important as we continue to charge forward in that space.
Dr. Shaalan Beg: Absolutely. Very, very exciting. Sticking with the liver pancreas theme, what other studies piqued your interest with regards to hepatocellular carcinoma (HCC)?
Dr. Rachna Shroff: It's a really exciting time in HCC. I mean, we actually have drugs that are working in the advanced space. And so, now there's a lot of interest in shifting to looking at preoperative neoadjuvant, and adjuvant approaches and what we can do to improve disease-free survival and overall survival in patients who are able to undergo prior resection.
So, Abstract 4013 looked specifically at the efficacy and safety of adjuvant hepatic arterial infusion chemotherapy with FOLFOX. And this was a randomized open-label phase 3 trial. It actually included a total of 315 patients between 5 different centers and patients were randomly assigned to receive either 1 to 2 cycles of adjuvant HAIC FOLFOX (Hepatic Arterial Infusion Chemotherapy FOLFOX) versus just follow up, the control group had no adjuvant treatment, and the primary endpoint was disease-free survival here and in the intention to treat population, there was a significantly improved median disease-free survival at 27 months versus 11 months in the patients who were on the control arm. And there was a protocol analysis, there were a number of other efficacy endpoints including disease-free survival rates at 1, 2, and 3 years.
And everything kind of leaned towards and or suggested an improvement with the utility of HAI FOLFOX in patients who undergo complete resection. It should be noted that this included patients specifically who had microvascular invasion on their resection. And so, these are patients who are at higher risk for recurrence as we know.
This to me suggests that there could be a role for adjuvant treatment in patients who undergo complete resection with microvascular invasion (MVI). HAI is a very specific technique and it requires a highly skilled center in the placement of HAI pumps. And we're seeing more and more trials across the U.S. as well investigating the role of HAI in advanced disease and in perioperative approaches.
And so, I think this is an area of much-needed continued research. There are, of course, a number of ongoing adjuvant studies looking at immunotherapy in the adjuvant setting. And so, it'll be really important to see how those read out and then to try to put all of these in context so that we can better understand local therapy like HAI FOLFOX versus more systemic adjuvant approaches like immunotherapy.
Dr. Shaalan Beg: Thank you very much, Dr. Shroff for sharing your valuable insights with us. I really appreciate you taking the time to spend with us and our listeners.
Dr. Rachna Shroff: Thanks so much. I enjoyed it.
Dr. Shaalan Beg: And thank you to our listeners for your time today. You will find links to the abstracts discussed today in the transcript of this episode. Finally, we'd really like to hear your feedback. If you could please take a moment to rate, review, and subscribe wherever you get your podcasts. Thank you very much!
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
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