A Safety and Efficacy Study of Abiraterone Acetate in Participants With Prostate Cancer Who Have Failed Hormone Therapy

A Phase I/II Open Label Study of the 17α-Hydroxylase/ C17,20 Lyase Inhibitor, Abiraterone Acetate in Patients With Prostate Cancer Who Have Failed Hormone Therapy

The purpose of this study is to determine the maximum tolerated dose and evaluate the safety, tolerability, and activity at the recommended dose (maximum tolerated dose [MTD]) of abiraterone acetate (also known as CB7630) in participants with hormone refractory prostate (gland that makes fluid that aids movement of sperm) cancer (HRPC).

This is an open-label (all people know the identity of the intervention) study to evaluate the safety, tolerability, and recommended dose of abiraterone acetate taken orally (by mouth), once daily in participants with HRPC. The study will consist of a dose escalation stage (Phase 1) that will be conducted to determine the MTD of abiraterone and an activity evaluation stage (Phase 2) to evaluate the activity of abiraterone in participants with HRPC. Escalated doses of abiraterone (starting at 250 milligram [mg] up to a maximum of 2000 mg) will be given for 28-day treatment periods to determine the MTD. Participants will be given MTD of abiraterone for up to 12 cycles (28 day each) in Phase 2 of the study. Participants' safety will be monitored throughout the study.

Inclusion Criteria:

• Histologically (pertaining to the disease status of body tissues or cells) documented adenocarcinoma of the prostate, clinically refractory (not responding to treatment) or resistant to hormone therapy, as documented by progression following at least one hormonal therapy
• Prostate specific antigen (PSA) evidence for progressive prostate cancer
• Participants who were withdrawn from anti-androgen therapy less than 6 months prior to inclusion in the study require one PSA higher than the last pre-withdrawal PSA or 2 increases in PSA documented after the post-withdrawal nadir(value) greater than or equal to 4 weeks from treatment withdrawal if treated with flutamide and greater than or equal to 6 weeks if treated with bicalutamide or nilutamide
• Eastern Cooperative Oncology Group (ECOG) performance status score equal to 0 or 1
• Life expectancy of greater than or equal to12 week

Exclusion Criteria:

• Participants with central nervous system (the brain and spinal cord) disease and/or brain metastases
• No currently active second malignancy (cancer or other progressively enlarging and spreading tumor) other than non-melanoma skin cancer
• Myocardial infarction within the 6 months prior to start of study
• No active or uncontrolled autoimmune disease (disorder in which a person's immune system attacks parts of his or her own body) that may require corticosteroid therapy during protocol treatment
• Major surgery or significant traumatic injury within 4 weeks of start of study