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-an