ASCO GU 2021: Key Studies
An Expert’s Guide to the 2021 ASCO Genitourinary Cancers Symposium: A Preview of the Top Abstracts

Released: February 04, 2021

Expiration: February 03, 2022

Robert Motzer
Robert Motzer, MD
Daniel P. Petrylak
Daniel P. Petrylak, MD

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During the ASCO Genitourinary (GU) Cancers Symposium, which is being held virtually February 11-13, 2021, important results from many clinical trials in genitourinary malignancies will be reported. Below, experts have highlighted their most anticipated abstracts, which will be covered online as a part of CCO’s Independent Conference Coverage of ASCO GU 2021. After the meeting, remember to check back on the CCO Web site for a downloadable highlights slideset summarizing the data from these studies and a CME-certified online expert analysis featuring discussions and perspectives on the clinical implications of the new data.

Here are the top studies to watch for at ASCO GU 2021, as chosen by our experts Robert J. Motzer, MD, and Daniel P. Petrylak, MD, as well as additional studies that may be of clinical interest.

Urothelial Carcinoma
One ongoing question in caring for patients with urothelial carcinoma (UC) is whether we should consider systemic therapy earlier in the disease course. At ASCO GU 2021, Bajorin and colleagues will report first results from the phase III CheckMate 274 trial of adjuvant nivolumab vs placebo in patients with disease-free status who underwent radical surgery for high-risk muscle-invasive UC in the previous 120 days. The planned enrollment of CheckMate 274 is approximately 700 patients, with a primary endpoint of disease-free survival at 5 years following randomization and planned biomarker analysis on resected tissue.

In locally advanced or metastatic UC, Powles and colleagues will present primary results from the phase III EV-301 trial exploring the use of enfortumab vedotin, an antibody–drug conjugate against Nectin-4, vs chemotherapy in patients with previously treated locally advanced or metastatic UC. In a related abstract, Balar and colleagues will report results from cohort 2 of the EV-201 study examining the safety and antitumor activity of enfortumab vedotin in 100 cisplatin-ineligible patients who have locally advanced or metastatic UC that has been previously treated with PD-1 or PD-L1 inhibitors.

Prostate Cancer
Although there are somewhat limited data on the efficacy of immune checkpoint inhibitors in prostate cancer, recent data have shown modest activity for single agent therapy. In castration-resistant prostate cancer (CRPC), Appleman and colleagues will report data from cohort B of the phase I KEYNOTE-365 study—with 1 year of additional follow-up—evaluating pembrolizumab plus docetaxel and prednisone in metastatic CRPC previously treated with abiraterone or enzalutamide. The primary endpoints for that study include a reduction of ≥ 50% in prostate-specific antigen from baseline, the number of patients who experience an adverse event or who discontinue treatment due to an adverse event, and ORR based on Response Evaluation Criteria in Solid Tumors v1.1. Fizazi and colleagues will report a final analysis for arm B from the phase III CheckMate 9KD study, which evaluated nivolumab plus docetaxel in chemotherapy-naive metastatic CRPC. In addition to trial exploring the use of immune checkpoint inhibitors, Rathkopf and colleagues will present final results from the randomized, placebo-controlled phase III ACIS study evaluating apalutamide, abiraterone, and prednisone vs abiraterone and prednisone in patients with chemotherapy-naive metastatic CRPC.

Finally, in nonmetastatic CRPC, Feng and colleagues will report data on molecular determinants associated with long-term response to apalutamide.

Kidney Cancer
In advanced renal cell carcinoma (RCC), Motzer and colleagues will report data from the phase III CLEAR study evaluating the antitumor activity of lenvatinib plus pembrolizumab or everolimus vs sunitinib monotherapy as frontline therapy for patients with advanced RCC. In this abstract, Motzer and colleagues report results suggesting improved outcomes with frontline lenvatinib plus pembrolizumab vs sunitinib—in terms of ORR, PFS, and OS—and for lenvatinib plus everolimus vs sunitinib—for ORR and PFS, but not OS. There will also be new data presented on the use of different starting doses of lenvatinib in combination with everolimus. Pal and colleagues will present results from a phase II trial of lenvatinib at 2 starting doses plus everolimus in patients with RCC. In a related abstract, Bergerot and colleagues will present Health-Related Quality of Life outcomes from the phase II of lenvatinib at 2 different starting doses in combination with everolimus as well.

Choueiri and colleagues will report data from a phase II study of MK-6482 (belzutifan), a novel oral inhibitor of HIF-2α, plus cabozantinib (a VEGF TKI), and exploring efficacy for the combination in 118 patients with advanced clear-cell RCC. This abstract is the first to report efficacy of combining the novel HIF-2α inhibitor with a VEGF TKI in advanced RCC, with a primary endpoint of ORR by investigator and secondary endpoints of PFS, duration of response, time to response, and OS. In a related abstract, Bauer and colleagues will present data for an updated follow-up of a phase I/II study of belzutifan as a single agent as well. In a previous analysis of the dose-expansion cohort of that study, treatment with belzutifan was associated with clinical activity in heavily pretreated clear-cell RCC across risk categories, with notable on-target toxicities of anemia and hypoxia.

Pal and colleagues will report results from the randomized phase II SWOG 1500 study evaluating sunitinib vs cabozantinib, crizotinib, or dacomitinib in 180 patients with metastatic papillary RCC following progression. The primary endpoint of that study is to compare PFS in patients with metastatic papillary RCC treated with sunitinib, a VEGFR TKI, with that of patients treated with MET kinase inhibitors (cabozantinib, crizotinib, or savolitinib).

Finally, Plimack and colleagues will report outcomes in patients with advanced RCC who completed 2 years of treatment in the pembrolizumab plus axitinib arm of the phase III KEYNOTE-426 study, which has coprimary endpoints of PFS and OS. In previous reports of KEYNOTE-426, investigators showed that pembrolizumab plus axitinib prolonged OS and PFS vs sunitinib in patients with treatment-naive advanced RCC.

Remember to Check the CCO Web Site After the 2021 ASCO GU Cancers Symposium!
These are just a few of the interesting and important abstracts selected by our expert faculty from the 2021 GU Cancers Symposium. A downloadable highlight slideset of these studies will be available on our Web site after the data are presented. Also, after the meeting, a comprehensive analysis by our expert faculty members will explore the clinical implications of the data in a CME-certified text-based module.

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Which of the following clinical trials are you most looking forward to seeing presented at ASCO GU 2021?
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