Trial Information

A Phase 3, Randomized, Double-blind, Placebo-Controlled Study of Abiraterone Acetate (CB7630) Plus Prednisone in Asymptomatic or Mildly Symptomatic Patients With Metastatic Castration-Resistant Prostate Cancer

This is a randomized (individuals will be assigned by chance to study treatments),
double-blind (individuals and study personnel will not know the identity of study
treatments), placebo (an inactive substance that is compared with a drug to test whether the
drug has a real effect in a clinical trial)-controlled study in approximately 1,000
medically or surgically castrated male patients with metastatic CRPC who have shown tumor
progression and are asymptomatic or mildly symptomatic. The study period will consist of
screening, treatment, and follow-up phases. Patients will receive study treatment
(abiraterone acetate or placebo) plus prednisone until radiographic progression of disease
and/or unequivocal clinical progression. Efficacy evaluations will be performed and safety
will be assessed throughout the study. Follow-up will continue for 60 months (5 years) or
until patient dies, is lost to follow-up, or withdraws informed consent.

At the interim analysis of overall survival (OS; 43% of death events), the independent data
monitoring committee (IDMC) reviewed the efficacy and safety data and concluded that all of
the data pointed to a significant advantage for patients in one arm of the study compared
with the other arm thereby unanimously recommending unblinding the study and allowing
crossover from the placebo arm to active therapy. Patients currently receiving placebo will
be offered crossover therapy to abiraterone acetate. Treatment for patients who were
originally randomized to the abiraterone acetate treatment group will not change.