Dr. Pedro Barata and Dr. Rana McKay discuss the integration of innovative advances in molecular imaging and therapeutics to personalize treatment for patients with renal cell and urothelial carcinomas.

TRANSCRIPT

Dr. Pedro Barata: Hello, I'm Dr. Pedro Barata, your guest host of By the Book, a podcast series featuring insightful conversations between authors and editors of the ASCO Educational Book. I'm a medical oncologist at University Hospitals Seidman Cancer Center and an associate professor of medicine at Case Western Reserve University in Cleveland, Ohio. I'm also an associate editor of the ASCO Educational Book.

Now, we all know the field of genitourinary cancers (GU) is evolving quite rapidly, and we have new innovations in molecular imaging as well as targeted therapeutics. Today's episode will be exploring novel approaches that are transforming the management of renal cell and urothelial carcinomas and also their potential to offer a more personalized treatment to patients.

For that, joining for today's discussion is Dr. Rana McKay, a GU medical oncologist and professor at University of California San Diego. Dr. McKay will discuss her recently published article titled, "Emerging Paradigms in Genitourinary Cancers: Integrating Molecular Imaging, Hypoxia-Inducible Factor-Targeted Therapies, and Antibody-Drug Conjugates in Renal Cell and Urothelial Carcinomas."

Our full disclosures are available in the transcript of this episode.

And with that, Rana McKay, great to have you on the podcast today.

Dr. Rana McKay: Oh, thank you so much, Dr. Barata. It's really wonderful to be here with you. So, thanks for hosting.

Dr. Pedro Barata: No, thanks for taking the time, and I'm looking forward to this conversation. And by the way, let me start by saying congrats on a great article in the Educational Book. Really super helpful paper. I'm recommending it to a lot of the residents and fellows at my own institution.

I would like to first ask you to kind of give our listeners some context of how novel approaches in the molecular imaging as well as targeted therapeutics are actually changing the way we're managing patients with GU, but specifically with renal cell carcinoma and urothelial carcinoma. So, what are the areas you would call out as like being big areas for innovation in this context, and why are they important?

Dr. Rana McKay: Very good question. And I think this is really what this article highlights. It highlights where are we going from an imaging diagnostics standpoint? Where are we going from a therapeutic standpoint? And I think if we have to step back, from the standpoint of diagnostics, we've seen PET imaging really transform diagnostics in prostate cancer with the advent of PSMA PET imaging, and now PSMA PET imaging is used as a biomarker for selection for theranostics therapy.

And so, we're starting to see that enter into the RCC landscape, enter into the urothelial cancer landscape to a lesser extent. And I think it's going to potentially be transformative as these tools get more refined. I think when we think about therapeutics, what's been transformative most recently in the renal cell carcinoma landscape has been the advent of HIF2α inhibition to improve outcomes for patients. And we have seen the approval of belzutifan most recently that has reshaped the landscape. And now there's other HIF2α inhibitors that are being developed that are going to be further important as they get refined.

And lastly, I think when we think about urothelial carcinoma, the greatest transformation to treatment in that context has been the displacement of cisplatin and platinum-based chemotherapy as a frontline standard with the combination of enfortumab vedotin plus pembrolizumab. And we've seen antibody-drug conjugates really reshape treatment and tremendously improve outcomes for patients. So, I think those are the three key areas of interest.

Dr. Pedro Barata: So with that, let's focus first on the imaging and then we'll get to the therapeutic area. So, we know there's been a paradigm shift, really, when prostate-specific targets emerged as tracers for PET scanning. And so, we now commonly use prostate-specific membrane antigen, or PSMA-based PET scanning, and really transform how we manage prostate cancer. Now, it appears that we're kind of seeing a similar wave in renal cell carcinoma with the new radiotracer against the target carbonic anhydrase IX. What can you tell us about this? And is this going to be available to us anytime soon? And how do you think that might potentially change the way we're managing patients with RCC today?

Dr. Rana McKay: First, I'll step back and say that in the context of PSMA PET imaging, we have actually been able to better understand RCC as well. So, we know that PSMA is expressed in the neovasculature of tumors, and it can actually be used to detect renal cell carcinoma tumors. It has a detection rate of about 84% when used for detection. And so, you know, I don't think it's just restricted to carbonic anhydrase IX, but we will talk about that. So, PSMA expressed in the neovasculature has a detection rate of around 84%, particularly if we're looking at clear cell RCC.

CAlX is overexpressed in clear cell RCC, and it's actually used in diagnosing renal cell carcinoma when we think of CAlX IHC for diagnosing clear cell RCC. And now there are CAlX PET tracers. The first foray was with the ZIRCON study that was actually an interestingly designed study because it was designed to detect the likelihood of PET imaging to identify clear cell RCC. So, it was actually used in the early diagnostics setting when somebody presents with a renal mass to discriminate that renal mass from a clear cell versus a non-clear cell, and it was a positive study.

But when I think about the potential application for these agents, you know, I think about the entire landscape of renal cell carcinoma. This is a disease that we do treat with metastasis-directed therapy. We have certainly seen patients who've undergone metastasectomy have long, durable remissions from such an approach. And I think if we can detect very early onset oligometastatic disease where a metastasis-directed therapy or SABR could be introduced - obviously tested in a trial to demonstrate its efficacy - I think it could potentially be transformative.

Dr. Pedro Barata: Wonderful. It's a great summary, and I should highlight you are involved in some of those ongoing studies testing the performance of this specific PET scanning for RCC against conventional imaging, right? And to remind the listeners, thus far, for the most part, we don't really do FDG-PET for RCC. There are some specific cases we do, but in general, they're not a standard scanning. But maybe that will change in the future. Maybe RCC will have their own PSMA-PET. And to your point, there's also emerging data about the role of PSMA-PET scanning in RCC as well, as you very elegantly summarized. Wonderful.

So, let me shift gears a little bit because you did, in your introduction, you did highlight a novel MOA that we have in renal cell carcinoma, approved for use, initially for VHL disease, and after that for sporadic clear cell renal cell carcinoma. We're talking about hypoxia-inducible factor 2-alpha inhibitors, or HIF2α inhibitors, such as belzutifan. But there's also others coming up.

So, as a way to kind of summarize that, what can you tell us about this breakthrough in terms of therapeutic class, this MOA that got to our toolbox of options for patients with advanced RCC? Tell us a little bit what is being utilized currently in the management of advanced RCC. And where do you see the future going, as far as, is it moving early on? Is it getting monotherapy versus combinations? Maybe other therapies? What are your thoughts about that? What can you tell us about it?

Dr. Rana McKay: Belzutifan is a first-in-class HIF2α inhibitor that really established clinical validation for HIF2α as a therapeutic target. When we think about the activity of this agent, the pivotal LITESPARK-005 trial really led to the approval of belzutifan in patients who were really heavily pretreated. It was patients who had received prior IO therapy, patients who had received prior VEGF-targeted therapy. And in the context of this study, we saw a median PFS of 5.6 months, and there did seem to be a tail on the curve when you looked at the 12-month PFS rate with belzutifan. It was 33.7% compared to 17.6% with everolimus. And then when we look at the response rate, it was higher with belzutifan on the order of 22-23%, and very low with everolimus, as we've previously seen.

I think one of the Achilles heels of this regimen is the primary PD rate, which was 34% when used in later line. There are multiple studies that are testing belzutifan in combination across the treatment landscape. So, we have LITESPARK-011, which is looking at the combination of belzutifan plus lenvatinib in the second-line setting. We've got the MK-012 [LITESPARK-012] study, which is looking at belzutifan in various combinations in the frontline setting. So there is a combination with IO plus belzutifan. And ...