The US Food and Drug Administration (FDA) approved enzalutamide for the treatment of patients with nonmetastatic castration-resistant prostate cancer (CRPC) as well as metastatic CRPC.1
This latest approval now makes enzalutamide the only FDA-approved oral medication indicated for both metastatic and nonmetastatic CRPC.
The FDA based its approval on results from the PROSPER phase 3 trial (ClinicalTrials.gov Identifier: NCT02003924), for which researchers randomly assigned 1401 men with nonmetastatic CRPC to receive enzalutamide plus androgen deprivation therapy (ADT) or placebo plus ADT.
Results showed that the median metastasis-free survival (MFS) was 36.6 months among men assigned to the enzalutamide arm compared with 14.7 months in the ADT alone arm (hazard ratio [HR], 0.29; 95% CI, 0.24-0.35; P < .0001). The time to first use of new antineoplastic therapy (TTA) was also improved among men treated with enzalutamide; the median TTA was 39.6 months versus 17.7 months among men in the enzalutamide group and ADT alone group, respectively (HR, 0.21; 95% CI, 0.17-0.26; P < .0001).
Overall survival data was not mature at the time of approval.
Grade 3 or higher adverse events (AE) occurred in 31% of men in the enzalutamide group versus 23% of men who received ADT alone. Commonly observed AEs that occurred more frequently in the enzalutamide arm compared with the placebo arm included asthenic conditions, hot flush, hypertension, dizziness, nausea, and falls.
- U.S. FDA Approves Xtandi® (enzalutamide) for the Treatment of Men with Non-Metastatic Castration-Resistant Prostate Cancer (CRPC) [news release]. Tokyo, Japan, New York, New York: PR Newswire; July 13, 2018. https://prnmedia.prnewswire.com/news-releases/us-fda-approves-xtandi-enzalutamide-for-the-treatment-of-men-with-non-metastatic-castration-resistant-prostate-cancer-crpc-300680822.html. Accessed July 13, 2018.