Ortho Biotech unblinded abiraterone acetate Phase 3 study for prostate cancer patients

Ortho Biotech Oncology Research & Development, a unit of Cougar Biotechnology, Inc., today announced that it has unblinded the Phase 3 study of abiraterone acetate plus prednisone for the treatment of patients with metastatic advanced prostate cancer (also referred to as castration-resistant prostate cancer) whose disease has progressed following treatment with one or two chemotherapy regimens at least one of which contained docetaxel.  

Study COU-AA-301 included 1,195 patients who were randomized to receive abiraterone acetate plus prednisone or placebo plus prednisone.

The Independent Data Monitoring Committee's (IDMC) recommendation to unblind the study was based on a pre-specified interim analysis, which demonstrated a statistically significant improvement in overall survival and an acceptable safety profile.  Based on these results, the IDMC also recommended that patients in the placebo arm be offered treatment with abiraterone acetate.

A program that will provide early access to abiraterone acetate to patients who meet specified medical criteria is being initiated.  Participating centers will be listed on www.clinicaltrials.gov when they are ready to enroll patients. The company anticipates opening the program in the United States in October and in sites outside the United States in the months following, contingent on local health authority and ethics committee approvals.

These results will be presented at the upcoming European Society for Medical Oncology congress, which is held in Milan, October 8-12, 2010.  They will also be submitted for publication in a peer-reviewed journal.

Abiraterone acetate is an investigational drug; its safety and efficacy have not yet been established.  The company is evaluating the filing strategy for abiraterone acetate, based on the IDMC's recommendation to unblind this study.