US Pharm. 2012;37(9)(Oncology/Hematology suppl):19.

Men with late-stage prostate cancer following chemotherapy lived nearly 5 months longer when treated with enzalutamide, which targets multiple steps in the androgen receptor–signaling pathway, the major cause of prostate-cancer growth. In the phase 3 double-blind, placebo-controlled trial, researchers at Memorial Sloan-Kettering Cancer Center stratified 1,199 men with castration-resistant prostate cancer after chemotherapy, then randomly assigned them, in a 2 to 1 ratio, to receive oral enzalutamide at a dose of 160 mg per day (800 patients) or placebo (399 patients). The primary endpoint was overall survival.

The median overall survival was 18.4 months in the enzalutamide group versus 13.6 months in the placebo group. The superiority of enzalutamide over placebo was shown with respect to all secondary end- points: the proportion of patients with a reduction in the prostate-specific antigen (PSA) level by 50% or more (54% vs. 2%, P < .001); the soft-tissue response rate (29% vs. 4%, P < .001); the quality-of-life response rate (43% vs. 18%, P < .001); the time to PSA progression (8.3 vs. 3.0 months, hazard ratio 0.25, P < .001); radiographic progression-free survival (8.3 vs. 2.9 months, hazard ratio 0.40; P < .001); and the time to the first skeletal-related event (16.7 vs. 13.3 months, hazard ratio 0.69, P < .001).