Phase 2 Study to Compare the Safety and Effectiveness of ASP5541 Injection Versus Abiraterone Acetate Tablets with PrednisonePrednisolone in Men with Advanced Prostate Cancer

What this Trial Is About

Researchers are evaluating a new form of hormone therapy called ASP5541 for men with advanced prostate cancer that has spread to other parts of the body. This phase 2 study compares ASP5541 given by injection with the standard abiraterone acetate tablets, both combined with a steroid called prednisone or prednisolone. The study aims to assess how well ASP5541 works and its safety in men who have not previously been treated with androgen receptor pathway inhibitors, including specific evaluation in Japanese men. Participants are divided into three groups based on their cancer type and treatment history. ASP5541 is given as a muscle injection every 12 weeks, while abiraterone acetate is taken as a daily tablet. Men with metastatic castration-resistant prostate cancer take prednisone or prednisolone twice daily, and men with metastatic hormone-sensitive prostate cancer take it once daily. All groups also receive standard care such as androgen deprivation therapy. Some participants will monitor blood pressure at home weekly. During the study, men visit the clinic regularly for health checks, safety monitoring, and scans to observe any changes in their cancer. The frequency and type of visits depend on each participants health and treatment stage. Researchers will measure prostate-specific antigen PSA levels, adverse events, physical exams, ECGs, and performance status to evaluate treatment effects and safety. The study may last up to about 3 years for some outcomes, with longer follow-up for certain measures.

A Phase 2 Study to Evaluate the Effects of ASP5541 in Participants With Prostate Cancer