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

A Phase 2 Open-Label, Randomized, Multi-center Study of Neoadjuvant Abiraterone Acetate (CB7630) Plus Leuprolide Acetate and Prednisone Versus Leuprolide Acetate Alone in Men With Localized High Risk 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.

Inclusion Criteria:

• Histologically or cytologically confirmed adenocarcinoma of the prostate
• At least three core biopsies positive for prostate cancer (a minimum of 6 core biopsies must be obtained at baseline). A prostate biopsy within 6 months from Screening is allowed for entry requirements
• At least one of the following features: prostate specific antigen (PSA) greater than (>) 10 nanogram per milliliter (ng/ml); PSA velocity >2 ng/ml per /year (defined as a rise in PSA of >2 ng/ml in the preceding 12 month period); Gleason score greater than or equal to (>=) 7 (4+3); Gleason score 6 if either PSA >=10 ng/ml or PSA velocity >=2 ng/ml/year
• Serum testosterone >200 nanogram/deciliter
• Participant and urologist must agree that participant is suitable for prostatectomy

Exclusion Criteria:

• Serious or uncontrolled co-existent, non-malignant disease, including active and uncontrolled infection
• Abnormal liver function consisting of any of the following: serum bilirubin >= 1.5 * upper limit of normal (ULN); aspartate aminotransferase or alanine aminotransferase >=2.5 * ULN
• Uncontrolled hypertension within the Screening period (systolic blood pressure >= 160 millimeter of mercury [mmHg] or diastolic BP >= 95 mmHg)
• Requirement for corticosteroids greater than the equivalent of 5 milligram of prednisone daily
• Participants with active or symptomatic viral hepatitis or chronic liver disease or clinically significant heart disease or as evidenced by myocardial infarction, or arterial thrombotic events in the past 6 months, severe or unstable angina, or New York Heart Association (NYHA) Class II-IV heart disease or cardiac ejection fraction measurement of < 50 percent at Baseline or history of gastrointestinal disorders (medical disorders or extensive surgery) which may interfere with the absorption of the study drug or history of pituitary or adrenal dysfunction