A Phase 2 Study to Evaluate Safety and Efficacy of Abiraterone Acetate in Male Participants With Prostate Cancer

The purpose of this study is to evaluate safety and efficacy of abiraterone acetate plus leuprolide acetate and prednisone, versus leuprolide acetate alone in male participants with prostate cancer (a disease in which cells in the prostate gland become abnormal and start to grow uncontrollably, forming tumors) who are suitable candidates for prostatectomy (surgery to remove all or part of the prostate gland).

This is an open-label (all people know the identity of the intervention), randomized (the study drug is assigned by chance), and multi-center (conducted in more than one center) study of abiraterone in male participants with prostate cancer. The duration of study will be approximately 24-32 weeks per participant. The study consists of 4 parts: Screening (that is, 30 days before study commences on Day 1); Treatment (abiraterone acetate 1000 milligram per day or leuprolide acetate as 22.5 milligram intramuscular injection \[injection of a substance into a muscle\] or prednisone 5 mg once daily); Prostatectomy (Week 24); and Follow-up ( 4-8 weeks after prostatectomy). Participants will receive either abiraterone, leuprolide and prednisone for 24 weeks (that is, Group 1) or leuprolide once every 12 weeks up to Week 24 then abiraterone and prednisone from Week 13 to 24 (that is, Group 2). All the eligible participants will be randomly assigned to 1 of the 2 treatment groups. Efficacy will be evaluated primarily through the concentrations of testosterone and dihydrotestosterone from prostate tissues at Week 12. Participants' safety will be monitored throughout the study.