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

The purpose of this study is to investigate safety and efficacy of abiraterone in participants with metastatic castration-resistant prostate cancer (mCRPC) and who have not received prior chemotherapy (treatment of disease, usually cancer, by chemical agents).

This is a multi-center (conducted in more than one center), open-label (all people know the identity of the intervention), single-arm study to investigate safety and efficacy of abiraterone. The study consists of 3 phases: Screening phase (consists of 14 days before study commences on Day -1); Treatment phase (consists of 28-daily dosing cycles wherein abiraterone 1000 milligram \[mg\] once daily along with 5 mg prednisolone twice daily will be given until disease progression or unacceptable toxicity is observed); and Follow-up phase (up to 5 years or until survival after the first dose of study drug). Abiraterone will be orally administered daily as at least 1 hour before the meal or 2 hours after the meal. Dose reduction will be allowed at the Investigator's discretion but not lower than 500 mg per day. Participants will discontinue study treatment at disease progression unless, in the Investigator's opinion, it is deemed that the participants will continue to derive benefit from abiraterone. Efficacy will be evaluated primarily through decline in prostate-specific antigen (substance in blood that is measured to check for prostate cancer) after 12 weeks of therapy. Participants' safety will be monitored throughout the study.

Eligibility Criteria:
Inclusion Criteria:

* In-patients or out-patients with histologically or cytologically confirmed adenocarcinoma of the prostate without neuroendocrine differentiation or small cell histology
* Have surgically or medically castrated, with testosterone levels of less than 50 nanogram per deciliter
* Have prostate-specific antigen (PSA) level of at least 5 nanogram per milliliter
* Be under PSA progression according to Prostate-Specific Antigen Working Group (PSAWG) eligibility criteria or objective progression by Response Evaluation Criteria in Solid Tumors (RECIST) Version 1.0 criteria for participants with measurable disease after androgen deprivation
* Have Eastern Cooperative Oncology Group Performance Status (ECOG PS) score of 0 or 1

Exclusion Criteria:

* Has received other hormonal therapy, including any dose of finasteride, dutasteride, any herbal product known to decrease PSA levels or any systemic corticosteroid within 4 weeks prior to Cycle 1 Day 1 or has received ketoconazole for prostate cancer
* Has received radiotherapy, chemotherapy (including estramustine) or immunotherapy (including provenge) within 4 weeks, or single fraction of palliative radiotherapy within 2 weeks prior to Cycle 1 Day 1
* Has had surgery or local prostatic intervention within 4 weeks prior to Cycle 1 Day 1. In addition, any clinically relevant sequel from the surgery must have resolved prior to Cycle 1 Day 1
* Has clinically significant heart disease as evidenced by myocardial infarction, or arterial thrombotic events, severe or unstable angina, or New York Heart Association (NYHA) Class 3 to 4 heart disease or cardiac ejection fraction measurement of less than 50 percent within 6 months prior to Cycle 1 Day 1
* Has uncontrolled hypertension (systolic blood pressure greater than or equal to 160 millimeter of mercury or diastolic blood pressure greater than or equal to 95 millimeter of mercury)