Systemic Therapy Update on 177Lutetium-PSMA-617 for Metastatic Castration-Resistant Prostate Cancer: ASCO Rapid Recommendation Update

Dr. Rohan Garje reviews the latest rapid recommendation update for the ASCO guideline on systemic therapy in men with metastatic castration-resistant prostate cancer (mCRPC). He reviews what prompted the guideline update and the latest recommendation from the expert panel. Dr. Garje also discusses future updates to the guideline that are currently underway, and outstanding questions regarding systemic therapy for mCRPC. Read the latest update, "Systemic Therapy Update on 177Lutetium-PSMA-617 for Metastatic Castration-Resistant Prostate Cancer: ASCO Guideline Rapid Recommendation Update" at www.asco.org/genitourinary-cancer-guidelines. TRANSCRIPT This guideline, clinical tools, and resources are available at http://www.asco.org/genitourinary-cancer-guidelines. Read the full text of the guideline and review authors' disclosures of potential conflicts of interest disclosures in the Journal of Clinical Oncology, https://ascopubs.org/doi/10.1200/JCO.23.02128  Brittany Harvey: Hello, and welcome to the ASCO Guidelines podcast, one of ASCO's podcasts delivering timely information to keep you up to date on the latest changes, challenges, and advances in oncology. You can find all the shows, including this one at asco.org/podcasts. My name is Brittany Harvey, and today I'm interviewing Dr. Rohan Garje from Miami Cancer Institute Baptist Health South Florida, lead author on "Systemic Therapy Update on 177Lutetium-PSMA-617 for Metastatic Castration-Resistant Prostate Cancer: ASCO Guideline Rapid Recommendation Update.  Thank you for being here today, Dr. Garje. Dr. Rohan Garje: Thank you so much for having me, Brittany. Brittany Harvey: And then, just before we discuss this guideline, I'd like to note that ASCO takes great care in the development of its guidelines in ensuring that the ASCO Conflict of Interest policy is followed for each guideline. The disclosures of potential conflicts of interest for the guideline panel, including Dr. Garje, who has joined us on this episode today, are available online with the publication of the update in the Journal of Clinical Oncology, which is linked in the show notes.  So then, to dive into the content of this rapid update, first, Dr. Garje, what prompted this rapid update to the guideline on Systemic Therapy for Metastatic Castration Resistant Prostate Cancer? Dr. Rohan Garje: So, last year, when we did a rapid update on ASCO prostate cancer guidelines, we recommended the addition of 177Lutetium-PSMA-617, also called as PLUVICTO, as a treatment choice for patients who have PSMA-positive metastatic castrate-resistant prostate cancer. After that approval, the primary imaging modality at the time of this initial drug approval was based on gallium-68, which was used in that clinical trial, which was VISION. Since then, we have access to a couple of new radiotracers, one of them being piflufolastat, also called as PYLARIFY, and the newer one called flotuflastat F-18, which is also called as POSLUMA, as additional imaging agents to detect PSMA-positive lesions. So, our expert panel group, along with my co-chairs, we thought to add these additional choices for patient selection because this provides the treating physicians additional options because there really are nuances involved in these imaging agents. So this helps broaden the access to  177Lutetium-PSMA-617 for patients. Brittany Harvey: Excellent. I appreciate you providing that background that the panel was reviewing.   So then, based on this updated information, what is the updated recommendation from the expert panel? Dr. Rohan Garje: So, for the new recommendation, the guideline expert panel recommends use of one of these three radio tracers, that is Ga-68PSMA-11, or piflufolastat F-18, or flotufolastat F-18 as one of the radiotracer choices to screen for PSMA-positive lesions on a PSMA scan, and potentially select the patients for PSMA 177lutetium. This way, we can use one of these three agents rather than previously recommended, as per FDA approval of gallium 68. Now, the reason behind these additional agents, as I was just alluding in my initial comment, is each institution may have access to one of these agents. For example, if a patient had a testing done by piflofolastat or flotufolastat, if they are PSMA-positive, it has shown PSMA-positive lesions as per VISION criteria, we do not suggest the patients to undergo gallium-68 assisted imaging again to have selection for PSMA lutetium therapy. This is unnecessary imaging. We have evidence now, based on the studies which were done with PYLARIFY, which is the piflofolastat, or the flotufolastat, which is POSLUMA, that they are equally good in detecting PSMA-positive lesions. This way we can avoid additional imagings for patients who are being screened for lutetium therapy. Brittany Harvey: Understood. Thank you for reviewing the expansion of this recommendation to avoid additional or unnecessary screening.  So then, Dr. Garje, the article mentions complete updates to the metastatic castration-resistant prostate cancer guideline are underway. At a high level, could you review what new evidence the panel will look at to update their evidence-based recommendations? Dr. Rohan Garje: There have been a lot of developments in the last year, at least, in the treatment strategies for patients with metastatic castration-resistant prostate cancer. Earlier this year, we have seen three big updates about the first-line metastatic CRPC setting, where the combination of PARP inhibitors and androgen receptor pathway inhibitors were tested. For example, in the TALAPRO-2 study talazoparib and enzalutamide, and in the MAGNITUDE study, it was niraparib along with abiraterone. And in the PROpel study, the combination of olaparib and abiraterone was studied. Now, all these combinations have recently received FDA approval with specific nuances with regards to folks who have biomarker positive disease, specifically BRCA1 and BRCA2 mutations. So it is very important to refine this information so that it is utilized by practicing oncologists so that it is widely adapted in their day to day practice. Now, in addition, we also are focusing on addressing the need for utilizing biomarkers. The biggest thing for us to offer a biomarker driven therapy is to do biomarker testing. So we are focusing on making sure patients with advanced prostate cancer get biomarker testing so that we can identify who are the patients who get selected. So this particular guideline update is addressing those needs.  And then most recently at the recent ESMO meeting, we also noted the positive data from a study called PSMAfore, which evaluated PSMA 177lutetium prior to chemotherapy. This study showed positive data based on progression free survival benefit. So we will review additional data from that and see if a guideline update can be done based on this. So it is very exciting. Now, obviously, we are also waiting on survival data on all the studies. So we are closely monitoring all the updates on these studies so that we can provide more rational guidance based on not only progression-free survival benefit in a specific cohort and also to see if it helps with overall survival improvement. Brittany Harvey: Absolutely. We'll look forward to the panel's review of this evidence and then future updates to this full guideline.  So then, finally, Dr. Garje, you've alluded to awaiting some data. So could you expand on what are some of the outstanding questions regarding systemic therapy for metastatic castration-resistant prostate cancer? Dr. Rohan Garje: I would put that in two boxes. Number one, sequencing. So we are excited that we have a broad spectrum of options; androgen receptor pathway inhibitors, chemotherapy options, radium-223. We have lutetium based options and then biomarker selected patients with PARP inhibitor combinations and select patients with benefit for checkpoint inhibitors. Now, the biggest question we need to answer is how to sequence them, which drug or which combination strategy is ideal for one particular patient. Now, obviously, when we do not have clinical trials which have addressed sequencing, we as an expert panel would want to come up with some mechanism of consensus to identify what treatment sequence would work best for patients. So that is an important question this guideline panel wants to address where we can give some generic information as a consensus, based on the experience of the panel to give guidance for practicing physicians the best sequencing.  Now, second thing, very equally important, is biomarkers. This particular guideline update is also focusing on making sure biomarker testing is universal. There has been a lot of evidence that biomarker testing happens very late in the course of the disease, which precludes a lot of patients from these combination strategies. So this particular guideline also is focusing on what biomarkers to be tested and at what time frame, so that they can be optimally utilized for the patient treatment so that the patients will have the best cancer outcomes. Brittany Harvey: Definitely, those are important questions for personalized care for people with prostate cancer.   I want to thank you so much for your work on this rapid update and your ongoing work on the updates to the full guideline, Dr. Garje, and thank you for your time today. Dr. Rohan Garje: Sure, thank you so much. Brittany Harvey: And thank you to all of our listeners for tuning in to the ASCO Guidelines podcast. To read the full guideline update, go to www.asco.org/genitourinary-cancer-guidelines.  You can also find many of our guidelines and interactive resources in the free ASCO Guidelines app, which is available in the Apple App Store or the Google Play Store. 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