Phase 3 Study Update of Zytiga Plus Prednisone for Chemotherapy-Naive Patients with Metastatic Castration-Resistant Prostate Cancer

Janssen Research & Development announced that it has unblinded the Phase 3 study of Zytiga (abiraterone acetate) 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 was an international, randomized, double-blind, placebo controlled study that included 1,088 patients who were randomized to receive ZYTIGA 1,000mg administered once daily plus prednisone 5mg administered twice daily or placebo plus prednisone 5mg administered twice daily. The co-primary endpoints of the study were radiographic progression-free survival and overall survival.

The Independent Data Monitoring Committee (IDMC) 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 acetate plus prednisone as compared to those receiving placebo plus prednisone.  Based on these results, the IDMC also recommended that patients in the placebo arm be offered treatment with Zytiga.

Zytiga in combination with prednisone is indicated for the treatment of patients with metastatic castration-resistant prostate cancer (CRPC) who have received prior chemotherapy containing docetaxel.

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