Study of Relugolix in Men With Metastatic Castration-Sensitive Prostate Cancer or Non-Metastatic or Metastatic Castration-Resistant Prostate Cancer

This is a three-part, open-label, parallel-cohort study to assess the safety and tolerability of relugolix as the ADT component in combination treatment with abiraterone acetate plus a corticosteroid in patients with mCSPC or mCRPC (Part 1), apalutamide in patients with mCSPC or nmCRPC (Part 2), or docetaxel with or without prednisone in patients with mCSPC or mCRPC (Part 3). The study will consist of a 45-day screening period followed by a 12-week treatment period with one of the three combination treatments (Parts 1, 2, or 3). All participants are required to be currently or previously treated with a GnRH receptor antagonist (analog), leuprolide acetate or triptorelin, or a GnRH receptor antagonist, degarelix or relugolix, in combination with either abiraterone plus prednisone (Part 1), apalutamide (Part 2), or docetaxel (Part 3). The study consists of a 12-week primary study treatment period in which safety and tolerability, including assessment of vital sign measurements, ECGs, clinical laboratory tests and reporting of adverse events every 2 to 4 weeks, followed by a 40-week safety extension treatment period during which adverse events and changes to concomitant medications will be reported. The total treatment duration is 52 weeks.