FDA Approval Summary: Belzutifan for Patients with Advanced Renal Cell Carcinoma

On December 14, 2023, the U.S. FDA approved belzutifan (Welireg, Merck & Co., Inc.) for patients with advanced renal cell carcinoma (RCC) following treatment with a PD-1/PD-L1 inhibitor and a VEGF tyrosine kinase inhibitor. The FDA granted traditional approval based on LITESPARK-005 (NCT04195750), an open-label, randomized, head-to-head trial of 746 patients with advanced RCC that progressed following treatment with both a PD-1/PD-L1 inhibitor and a VEGF tyrosine kinase inhibitor. Patients were randomized (1:1) to receive belzutifan or everolimus. The primary endpoints were progression-free survival (PFS) assessed by blinded independent central review and overall survival. A statistically significant improvement in PFS was demonstrated for belzutifan compared with everolimus [HR = 0.75; 95% confidence interval (CI), 0.63-0.90; one-sided P value = 0.0008]. Kaplan-Meier curves reflected nonproportional hazards with similar median PFS estimates of 5.6 months (95% CI, 3.9-7.0) in the belzutifan arm and 5.6 months (95% CI, 4.8-5.8) in the everolimus arm. Although not reaching full maturity, the overall survival results seemed to show a favorable trend in the belzutifan arm compared with the everolimus arm (HR, 0.88; 95% CI, 0.73-1.07). The confirmed objective response rate by blinded independent central review was 22% and 3.6% in the belzutifan and everolimus arms, respectively. Observed toxicities differed between treatment arms, but drug discontinuations and interruptions due to treatment-emergent adverse events were lower in the belzutifan arm compared with the everolimus arm, and a descriptive analysis of patient-reported symptom and functional outcomes was suggestive of favorable tolerability for belzutifan compared with everolimus.