The Food and Drug Administration has expanded the prostate cancer indication for enzalutamide to include nonmetastatic castration-resistant prostate cancer (CRPC). The androgen-receptor inhibitor was first approved in 2012 for the treatment of patients with metastatic CRPC who had previously received chemotherapy and was granted approval in 2014 for men with metastatic CRPC who had not received chemotherapy.
The current approval was based on a statistically significant improvement in metastasis-free survival for patients receiving enzalutamide in the phase 3 PROSPER trial, a trial that randomized 1,401 patients (2:1) with nonmetastatic CRPC to 160 mg of oral enzalutamide daily or to placebo. Median metastasis-free survival was 36.6 months for those receiving enzalutamide versus 14.7 months for those receiving placebo (hazard ratio, 0.29; 95% confidence interval, 0.24-0.35; P less than .0001), the FDA said in a press statement.
The most common adverse events were asthenia/fatigue, hot flush, hypertension, dizziness, nausea, and falls.
The recommended dose for enzalutamide, marketed as Xtandi by Astellas Pharma US, is 160 mg (four 40-mg capsules) administered orally once daily.