Key Posters on Advances in GU Cancers at ASCO22

Guest host Dr. Neeraj Agarwal, of the University of Utah Huntsman Cancer Institute and the ASCO Daily News editor-in-chief, discusses key therapeutic advances in mRCC and mUC, as well as new research that proposes periodic scans to monitor patients with mCSPC for disease progression, with Dr. Jeanny-Aragon-Ching of the Inova Schar Cancer Institute.  Transcript:  Dr. Neeraj Agarwal: Hello and welcome to the ASCO Daily News podcast. I'm Dr. Neeraj Agarwal, the director of the Genitourinary Oncology Program, a professor of medicine at the University of Utah Huntsman Cancer Institute, and editor-in-chief of the ASCO Daily News.  My guest today is Dr. Jeanny Aragon-Ching, who is a medical oncologist and the Clinical Program Director of Genitourinary Cancers at the Inova Schar Cancer Institute in Virginia.  Today, we will be discussing key posters in genitourinary (GU) oncology that will be featured at the 2022 ASCO Annual Meeting. Our full disclosures are available in the show notes and disclosures of all guests on the podcast can be found on our transcripts at asco.org/podcast.  Jeanny, it is great to have you on the podcast today.  Dr. Jeanny Aragon-Ching: Thanks, Neeraj. It's a pleasure for me to be here as well.  Dr. Neeraj Agarwal: Jeanny, let's begin with Abstract 4510. This is a trial that represents a growing interest among researchers worldwide in the microbiome and how it is impacted by antibiotics and how it modulates immune checkpoint inhibitor response. Can you tell us about this study?  Dr. Jeanny Aragon-Ching: Thanks, Neeraj, I would be happy to. So, the title of the abstract is, “Characterization of the Microbial Resistome in a Prospective Trial of CBM 588 in Metastatic Renal Cell Carcinoma Offers Mechanism for Interplay Between Antibiotic Use and Immune Checkpoint Inhibitor Activity.”  So, this is an interesting abstract that originated likely from the observation that getting antibiotics while on checkpoint inhibitors typically results in worse outcomes, perhaps because antibiotics can clear the normal gut flora and thereby increase these pathogenic antibiotic-resistant bacteria.  Now, on the other hand, there were some retrospective studies using a live microbial product called CBM 588, which seems to improve outcomes in patients on checkpoint inhibitors and getting antibiotics.  So, the idea, therefore, is that shifting the genes encoding antimicrobial resistance could result in a better checkpoint inhibitor response. So, this Abstract 4510 is a small study conducted by Dr. Nazli Dizman and Dr. Sumanta (Monty) Kumar Pal, and colleagues, and enrolled 29 metastatic clear cell RCC patients with intermediate or poorest disease. And they were stratified into receiving either nivolumab or ipilimumab compared to nivo/IPI with CBM 588.  Now stool samples were collected at baseline in week 12. And they did this whole metagenome sequencing to analyze a stool microbiome composition, and they also looked at the antibiotic resistance genes for the most common classes of antibiotics.  The results showed an astounding improvement in objective responses. So, 58%, for instance, in nivo/IPI and the CBM 588 arm compared to only 20% in the nivo/IPI arm. And it seems like also the antibiotics resistance genes were also decreased in those getting the CBM 588 alongside nivo/IPI. Therefore, responses were improved by shifting the gut microbiome alone. So, these findings were published actually recently by these authors in Nature Medicine. So, in case anyone wants to take a deep dive, it would be a good interesting read for this dataset.  Dr. Neeraj Agarwal: Very interesting, indeed. Jeanny, what is the main message here for our colleagues?  Dr. Jeanny Aragon-Ching: I think, Neeraj, the key takeaway message is that this is a very provocative proof of concept trial that suggests shifting the gut microbiome has the potential to improve responses to checkpoint inhibitors and outcomes. So, this is a very up-and-coming trial and is seen also across the board in other cancers.  Dr. Neeraj Agarwal: Thanks, Jeanny. Moving on to urothelial cancer, there is a poster that I think is a must-see for our colleagues. This is Abstract 4577 titled, “Defining Platinum Ineligible Patients with Metastatic Urothelial Carcinoma.”  Dr. Jeanny Aragon-Ching: So, Neeraj, what can you tell us about this abstract?  Dr. Neeraj Agarwal: So, over the past few years, there has been a tremendous evolution in the treatment landscape for patients with metastatic urothelial carcinoma. For over 40 years the standard of care for these patients has been cisplatin-based chemotherapy.  However, approximately 50% of patients are cisplatin-ineligible, due to underlying comorbidities, and are offered carboplatin as an alternative. So, although the checkpoint inhibitors pembrolizumab and atezolizumab were approved as first-line therapy for these patients in 2017, the U.S. Food and Drug Administration (FDA) has now restricted the use of first-line pembrolizumab to platinum ineligible patients with metastatic urothelial carcinoma.  The challenge we face as oncologists since the FDA restriction is the absence of a formal definition of platinum ineligibility and the inclusion of this definition in the guidelines. So, in Abstract 4577, Drs. Shilpa Gupta and Jonathan Rosenberg, along with the team present an updated consensus definition for platinum ineligibility based on an online survey of 60 genitourinary oncologists in the United States.  Based on the results from this survey, any patient with metastatic urothelial carcinoma, meeting 1 of the following 5 clinical and or laboratory parameters should be considered platinum ineligible, and these are 1 of the following: an ECOG performance status of 3 or more, creatinine clearance of fewer than 30 mils per minute, or peripheral neuropathy of grade 2 or more, or heart failure class of 3 or more—so, this is NYHA heart failure class of 3 or more—and lastly, the combination of performance status of 2 or more, plus a creatinine clearance of less than 30 mils per minute.  Dr. Jeanny Aragon-Ching: Well, this is a timely update, Neeraj. So, what do you think is a key takeaway from this abstract?  Dr. Neeraj Agarwal: These criteria based on simple and easily available clinical and or laboratory parameters will now allow us to readily define platinum ineligibility in our patients with metastatic urothelial carcinoma, which is a need in busy clinics, both in academic and community settings.  So, I think once published and obviously once endorsed by guidelines, we really would like to be able to use this criterion to quickly define platinum ineligibility in our clinics.  Dr. Jeanny Aragon-Ching: Agree. Yeah.  Dr. Neeraj Agarwal: So, Jeanny, let me switch the gears. PSMA testing is a hot topic this year. And there is an abstract that could potentially have an impact on future guidelines, and how we will practice further down the road.  So, I'm referring to the Abstract 5088 titled, “Predictive Value of Extra Prostatic Disease Detection by Preoperative PSMAPET for Biochemical Recurrence-free Survival in Patients with Otherwise Localized Prostate Cancer and Who are Treated with Radical Prostatectomy.”  So, this is a follow-up analysis of a multicenter prospective phase 3 imaging trial. So, could you please tell us more about this abstract where they are using PSMA PET scan in the preoperative localized prostate cancer setting?  Dr. Jeanny Aragon-Ching: Absolutely, Neeraj. So, you may recall that the multicenter prospective phase 3 imaging trial that garnered gallium PSMA approval by the FDA was actually based on this study that looked at the intermediate and high-risk patients with prostate cancer undergoing radical prostatectomy and lymph node dissection, and they underwent prior gallium PSMA PET scanning for pelvic nodal metastases prior to surgery.  So, this was actually previously reported by Dr. Calais and group. Now they are reporting on Abstract 5088 as a post hoc analysis of the same population and group of patients looking for extraprostatic disease. And the final pathology was also correlated to look at nodal disease in these patients in order to predict biochemical recurrence, so they follow these patients for biochemical recurrence occurrence.  So, of the 36% of patients who did undergo radical prostatectomy after they underwent PSMA PET scan, about 41% of them recurred with biochemical recurrence, and 40% of them underwent some kind of salvage therapy or some treatment.  What was very interesting was when they looked at the biochemical recurrence-free survival. It was better in those who were PSMA negative, and that recurrence-free survival was easily about 33 months, compared to only about 7.3 months in those who were PSMA-positive scans.  Furthermore, the ones who had the longest and the highest biochemical recurrence-free survival, intuitively, were those who were node-negative and PSMA PET-negative, so probably not surprisingly. And that rate was about 46 months—close to 4 years. Whereas those who are node-positive on final pathology and their PSMA PET was also positive, they only had about 3 months of biochemical recurrence-free survival.  Dr. Neeraj Agarwal: Very interesting. So, it looks like the PSMA PET scan is predicting biochemical recurrence-free survival in localized prostate cancer settings. So, Jeanny, what is the key takeaway from this trial?  Dr. Jeanny Aragon-Ching: I think, Neeraj, the bottom line is that patients with extraprostatic disease that is detected by their preoperative PSMA PET scan does predict strongly a high risk of biochemical relapse, and this can really be an additional tool that clinicians can use to help inform and guide future therapy.  Dr. Neeraj Agarwal: Thanks, Jeanny. The research on preoperative PSMA testing and its implications on future treatment strategies in the setting is going to be really interesting to watch in the very near future.  Dr. Jeanny Aragon-Ching: Yes, absolutely. I really think we should also discuss Abstract 5072, along those lines, the importance really of radiographic monitoring for disease progression in patients with metastatic hormone-sensitive prostate cancer.  Dr. Neeraj Agarwal: Yes, thanks for reminding and this is Abstract 5072. This is a post hoc analysis of the ARCHES trial, titled, “Radiographic Progression in the Absence of PSA Progression in Patients with Metastatic Hormone-sensitive Prostate Cancer.”  During the last several years, we have seen many of these agents typically given for gastric resistant prostate cancer moving upfront to the castration-sensitive prostate cancer setting. This is especially true for androgen receptor access targeting agents such as abiraterone, enzalutamide, and apalutamide, all being now approved for patients with metastatic castration-sensitive prostate cancer.  What is noteworthy from all these trials, and is reported in Abstract 5072, is the use of imaging studies to evaluate disease progression. So, in Abstract 5072, Dr. Andrew Armstrong and Dr. Arun Azad performed a post hoc analysis of the ARCHES trial to investigate the concordance between radiographic progression and the PSA Progression as defined by PCWG2 criteria, or between radiographic progression and any rise in the PSA above nadir, in patients who were being treated with this novel hormonal therapies, in this case, enzalutamide for metastatic castration sensitive prostate cancer.  And as a quick reminder, ARCHES was a phase 3 trial that showed a significant reduction and radiographic progression-free survival and improved overall survival for patients with metastatic castration sensitive prostate cancer treated with enzalutamide plus androgen deprivation therapy (ADT) versus those treated with placebo plus androgen deprivation therapy.  So, very interestingly, the findings from this study indicate that 67% of patients on the enzalutamide plus ADT arm did not have [Prostate Cancer Clinical Trials Working Group 2 criteria] PCWG2-defined prostate-specific antigen (PSA) progression at the time of radiographic progression. And discordance was present in the ADT-only arm as well, where they found 42% of patients on the ADT-only arm had radiographic progression but did not have PCWG2-defined PSA progression.  Interestingly, this discordance of radiographic disease progression was also seen with any rise in the PSA above nadir. And I personally found this information to be very clinically relevant when we are seeing the majority of patients actually experiencing radiographic disease progression, not experiencing PSA progression at the same time.  Dr. Jeanny Aragon-Ching: Yeah, absolutely. I agree with that, Neeraj. So, very interesting data. So, what do you think is the key takeaway message for the clinicians listening to us?  Dr. Neeraj Agarwal: I'll make the message very simple. I think the message is that patients with metastatic castration-sensitive prostate cancer need to be monitored for disease progression with periodic scans, and PSA monitoring alone is not sufficient in the majority of these patients.  Again, we cannot undervalue the role of periodic imaging studies in these patients so that we can timely diagnose them to have disease progression.  Dr. Jeanny Aragon-Ching: I agree with that.  Dr. Neeraj Agarwal: Jeanny, the last abstract I would like to mention before we wrap up the podcast is Abstract 4509, the results from the phase1 live SPARC 001 study. So, can you please tell us more about this study titled, “Phase-1 Live SPARC 001: The Study of Belzutifan in Advanced Solid Tumors,” which is an update of the renal cell carcinoma cohort with more than 3 years of total follow up?  Dr. Jeanny Aragon-Ching: Thanks, Neeraj. So, while the current therapeutic landscape for patients with metastatic clear cell renal cell carcinoma (RCC) has changed dramatically over the past several years, with significant improvement in patient outcomes. Most patients unfortunately still experience disease progression on current treatments.  So, in-depth molecular profiling of clear cell RCC has revealed recurrent loss of function mutations in VHL in actually greater than 90% of patients. So, the VHL protein, as you will recall, is part of the oxygen-sensing pathway, regulating levels of HIF which is hypoxia-inducible factor protein, it's a transcriptional activator that mediates the response to hypoxic conditions. So, HIF-2α is a key oncogenic driver in RCC.  So, previous data you may recall from the phase-1 Live SPARC 001 trial was designed to evaluate belzutifan so, this was a novel HIF-2α inhibitor which showed durable anti-tumor activity and acceptable safety profile in patients with metastatic clear cell RCC.  So, in Abstract 4509, Drs. Jonasch and Toni Choueiri presented updated results from this trial after more than 3 years of follow-up. Of the 55 patients enrolled 16% of patients remained in treatment. And 62% of patients had discontinued treatment because of, unfortunately, disease progression.  The median progression-free survival (PFS) for the total cohort was 14.5 months. And the overall disease control rate was 80%. Forty percent of patients experienced grade 3 treatment-related adverse events with the most frequent ones being anemia and hypoxia.  There were no great 4 or 5 treatment-related adverse events. And these results, therefore, show that belzutifan monotherapy continues to show a high rate of disease control and a safety profile in a heavily treated population of patients with metastatic RCC. So, it is great to see that there were no new safety signals.  Dr. Neeraj Agarwal: Very nice data indeed. So, Jeanny, what is the key takeaway message here for our listeners?  Dr. Jeanny Aragon-Ching: Yeah, I think the message here is that the use of belzutifan monotherapy continues to show efficacy and safety in patients with metastatic clear cell RCC, which have progressed on multiple prior contemporary therapies, and there are phase 3 trials currently underway.  Dr. Neeraj Agarwal: Jeanny, any final thoughts before we wrap up the podcast today?  Dr. Jeanny Aragon-Ching: Thanks, Neeraj. I think it's a really exciting time to be in genitourinary (GU) oncology, and I'm truly looking forward to seeing some great sessions at the 2022 ASCO Annual Meeting.  Dr. Neeraj Agarwal: Thank you, Jeanny, for sharing your insight with us today. It was a great conversation. And thank you to our listeners for joining us today. You will find links to the abstracts discussed today 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 podcast.    Disclosures:   Dr. Neeraj Agarwal:   Consulting or Advisory Role: Pfizer, Bristol-Myers Squibb, AstraZeneca, Nektar, Lilly, Bayer, Pharmacyclics, Foundation Medicine, Astellas Pharma, Lilly, Exelixis, AstraZeneca, Pfizer, Merck, Novartis, Eisai, Seattle Genetics, EMD Serono, Janssen Oncology, AVEO, Calithera Biosciences, MEI Pharma, Genentech, Astellas Pharma, Foundation Medicine, and Gilead Sciences  Research Funding (Institution): Bayer, Bristol-Myers Squibb, Takeda, Pfizer, Exelixis, Amgen, AstraZeneca, Calithera Biosciences, Celldex, Eisai, Genentech, Immunomedics, Janssen, Merck, Lilly, Nektar, ORIC Pharmaceuticals, crispr therapeutics, Arvinas  Dr. Jeanny Aragon-Ching:   Honoraria: Bristol-Myers Squibb, EMD Serono, Astellas Scientific and Medical Affairs Inc  Consulting or Advisory Role: Algeta/Bayer, Dendreon, AstraZeneca, Janssen Biotech, Sanofi, EMD Serono, AstraZeneca/MedImmune, Bayer, Merck, Seattle Genetics, Pfizer, Immunomedics, Amgen, AVEO, Pfizer/Myovant, Exelixis  Speakers' Bureau: Astellas Pharma, Janssen-Ortho, Bristol-Myers Squibb , Astellas/Seattle Genetics  Travel, Accommodations, Expenses: Dendreon, Algeta/Bayer, Bristol Myers Squibb, EMD Serono, Astellas Pharma  Disclaimer:   The purpose of this podcast is to educate and to inform. This is not a substitute for professional medical care and is not intended for use in the diagnosis or treatment of individual conditions.  Guests on this podcast expressed their own opinions, experience, and conclusions. Guest statements on the podcast do not express the opinions of ASCO. The mention of any product, service, organization, activity, or therapy should not be construed as an ASCO endorsement.