The U.S. Food and Drug Administration (FDA) approved a supplemental new drug application for Xtandi® (enzalutamide) for the treatment of metastatic castration-sensitive prostate cancer.
This is the only oral treatment approved by the FDA for three distinct types of advanced prostate cancer: non-metastatic and metastatic castration-resistant prostate cancer, as well as metastatic castration-sensitive prostate cancer.
The approval was based on results from the randomized, double-blind, placebo-controlled, multinational, phase III ARCHES trial that included 1,150 patients with metastatic castration-sensitive prostate cancer from the United States, Canada, Europe, South America, and the Asia-Pacific region. Patients were randomized to receive enzalutamide 160 mg daily or placebo plus androgen deprivation therapy (ADT).
Improved survival with enzalutamide
The study found that enzalutamide significantly reduced the risk of radiographic progression-free survival (rPFS; primary endpoint) by 61% compared with placebo plus ADT (hazard ratio, 0.39; 95% CI, 0.30-0.50; P<0.0001). The rPFS was not reached in the enzalutamide plus ADT group compared with 19.45 months in the placebo group. Overall survival data were not mature at the time of analysis.
Common treatment-related adverse events that occurred more frequently in patients treated with enzalutamide plus ADT versus placebo and were hot flush (27% vs. 22%), asthenic conditions (24% vs. 20%), hypertension (8.0% vs. 5.6%), fractures (6.5% vs. 4.2%), and musculoskeletal pain (6.3% vs. 4.0%).