Drug maker unblinds phase III study of advanced prostate Ca therapy

Janssen Research & Development, LLC, recently has unblinded the phase III study of the androgen biosynthesis inhibitor abiraterone acetate (ZYTIGA) plus prednisone for the treatment of asymptomatic or mildly symptomatic patients with metastatic castration-resistant prostate cancer (CRPC) who have not received chemotherapy.

Study COU-AA-302 is an international, randomized, double-blind, placebo-controlled trial that included 1,088 patients who were randomized to receive abiraterone, 1,000 mg administered once daily, plus prednisone, 5 mg twice daily, or placebo plus prednisone, 5 mg twice daily. The co-primary endpoints of the study are radiographic progression-free survival and overall survival.

The Independent Data Monitoring Committee unanimously recommended unblinding the study based on a planned interim analysis in which differences in radiographic progression-free survival, overall survival, and secondary endpoints were observed that constitute evidence of clinical benefit as well as continued evidence of favorable safety in patients receiving abiraterone plus prednisone as compared with those receiving placebo plus prednisone. Based on these results, the committee also recommended that patients in the placebo arm be offered treatment with abiraterone.

"The COU-AA-302 study has been a key priority for us as we expand our understanding of the utility of abiraterone acetate in metastatic prostate cancer," said William N. Hait, MD, PhD, of Janssen Research & Development. "We’re delighted that these data will soon be added to the growing body of literature about this important medication."

ZYTIGA is currently indicated in combination with prednisone for the treatment of CRPC in patients who have received prior chemotherapy containing docetaxel (Taxotere). It has not been approved for use in men with metastatic CRPC who have not yet received chemotherapy. Janssen plans to submit for regulatory approval in the United States and around the world beginning in the second half of 2012.

Results from COU-AA-302 will be presented at an upcoming medical meeting and also submitted for publication in a peer-reviewed journal.

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