On July 13, the FDA approved enzalutamide (Xtandi©, Astellas), for use in patients with castration-resistant prostate cancer (CRPC). Enzalutamide previously was granted FDA approval for the treatment of patients with metastatic CRPC. This approval expands the patient population to now include patients with both non-metastatic CRPC and metastatic CRPC.

The expansion of indication by the FDA was based on the randomised, multicenter PROSPER study (NCT020032924) in 1,401 men with non-metastatic CRPC at high risk of developing metastasis (defined as a PSA doubling time ≤10 months and PSA ≥2 ng/mL). Patients were randomised 2:1 to receive either enzalutamide or placebo orally once daily. All patients continued on androgen deprivation therapy (ADT) by gonadotropin-releasing hormone (GnRH) therapy or had undergone prior bilateral orchiectomy.

The primary efficacy outcome (metastasis-free survival [MFS]) by blinded, independent central review) was met. Patients treated with enzalutamide had a significant improvement in MFS compared to those receiving placebo; median MFS 36.6 months for the enzalutamide group and 14.7 months in the placebo group (HR=0.29; 95% CI, 0.24-0.35; P<0.0001). Common adverse reactions in ≥10% of patients that occurred more frequently (≥2% compared to placebo) in the enzalutamide-arm were asthenia/fatigue, hot flush, hypertension, dizziness, nausea, and falls. More Information.

View full prescribing information for XTANDI.