A Study to Evaluate the Safety and Efficacy of Relugolix in Men With Advanced Prostate Cancer

This is a phase 3, multinational, randomized, open-label, parallel group study to evaluate the efficacy and safety of oral daily relugolix 120 mg in participants with androgen-sensitive advanced prostate cancer who require at least 1 year of continuous androgen-deprivation therapy. Relugolix 120 mg orally once daily or leuprolide acetate depot suspension, 22.5 mg (or 11.25 mg in Japan and Taiwan based on local labels), every 3 months by subcutaneous injection will be administered to participants. There are 2 analyses for this study, a primary analysis and a final analysis. Primary Analysis: The primary analysis of efficacy and safety has been completed (N=934). Participants were randomized 2:1 to receive relugolix or leuprolide for 48 weeks, followed by a 30-day safety follow-up visit or early termination 30-day safety follow-up. Final Analysis: The final analysis will occur after additional participants with metastatic disease (approximately 130) have been enrolled and randomized from any sites to the study, and have completed the 48-week treatment period. A cohort of participants enrolled in China and Taiwan will be analyzed separately once they have completed treatment to support registration in China. Eligible participants were randomized 2:1 to relugolix or leuprolide arm and will attend visits monthly (every 4 weeks) where serum testosterone and prostate-specific antigen will be assessed. Safety will be assessed throughout the study by monitoring adverse events, vital signs, physical examinations, clinical laboratory tests, and 12-lead electrocardiograms. Castration resistance-free survival will be assessed up to Week 49, Day 1 of the study and reported as part of the final analysis. The study enrolled 1134 participants, including 139 participants with metastatic advanced prostate cancer to support the analysis of the secondary endpoint of castration resistance-free survival and 93 Chinese participants (enrolled in China and Taiwan) to support registration in China.