CHICAGO—Abiraterone acetate (Zytiga) shows significant improvement in radiographic progression-free survival (rPFS) among patients with metastatic castration-resistant prostate cancer (mCRPC), according to findings presented at the American Society of Clinical Oncology 2012 annual meeting.

In a randomized, placebo-controlled phase 3 study, mCRPC patients treated with abiraterone acetate plus prednisone had not yet reached a progression event and had a 33% improvement in survival whereas patients treated with a placebo plus prednisone had a median rPFS of 8.3 months. The study included 1,088 asymptomatic or mildly symptomatic mCRPC patients who had not received chemotherapy.

“This is an important study with all clinically relevant endpoints favoring treatment with abiraterone acetate plus prednisone, and is also the first to suggest that inhibiting androgen production significantly delays initiation of cytotoxic chemotherapy,” said lead investigator Charles J. Ryan, MD, Associate Professor of Clinical Medicine at the University of California-San Francisco Helen Diller Family Comprehensive Cancer Center.

Continue Reading

In addition, patients treated with abiraterone acetate plus prednisone had a longer median time to secondary endpoints such as cancer pain requiring opiate use, initial cytotoxic chemotherapy for prostate cancer, deterioration in performance status, and PSA progression.