Application for pre-chemo use of prostate cancer agent submitted
Astellas Pharma Inc. and Medivation Inc. have submitted a supplemental new drug application to the FDA seeking approval of enzalutamide (XTANDI) capsules for the treatment of men with metastatic castration-resistant prostate cancer (mCRPC) who have not received chemotherapy.
Enzalutamide is currently approved for the treatment of patients with mCRPC who have previously received docetaxel (Taxotere) chemotherapy.
The supplemental new drug application is based on the results from the phase III PREVAIL trial evaluating enzalutamide as compared to placebo in more than 1,700 chemotherapy-naïve mCRPC patients.
“The study was stopped early by the independent data safety monitoring committee [DSMC] for superior efficacy and overall benefit-to-risk ratio, and the DSMC recommended that placebo patients be crossed over to enzalutamide,” said PREVAIL first author Tomasz Beer, MD, of the Knight Cancer Institute at Oregon Health & Science University, Portland. Dr. Beer presented findings from PREVAIL at the Genitourinary Cancers Symposium in San Francisco.
At the time of the interim analysis at a median follow-up of 22 months, enzalutamide was associated with a 29% reduction in the risk of death, with an estimated median overall survival of 32.4 months in the enzalutamide arm versus 30.2 months in the placebo arm (p<.0001). Because the median follow-up was approximately 10 months shorter than the estimated median survival—and 72% of enzalutamide-treated patients were still alive at the time of the analysis—the estimate of median survival is not robust and the hazard ratio is a more accurate expression of the survival differences seen in the trial.
Dr. Beer has received research funding from Astellas Pharma, Cougar Biotechnology, Janssen Biotech, and Medivation. Several PREVAIL trial co-authors have received honoraria and/or research funding from, own stock in, serve as consultants/advisers for, and/or have an employment or leadership position with Astellas Pharma, Janssen Biotech, Medivation, and/or Sanofi.