Medivation/Astellas' Xtandi beats Casodex in prostate cancer trial

US drugmaker Medivation (Nasdaq: MDVN) and Japanese major Astellas Pharma (TYO: 4503) have released positive new top-line results from the Phase III STRIVE trial comparing their already marketed Xtandi (enzalutamide) with bicalutamide, AstraZeneca's (LSE: AZN) Casodex, in a study population of men with non-metastatic or metastatic castration-resistant prostate cancer.

The study achieved its primary endpoint demonstrating a statistically-significant increase in progression-free survival (PFS) for enzalutamide compared with bicalutamide (Hazard Ratio = 0.24; 95% Confidence Interval, 0.18-0.32; p < 0.0001). Median PFS was 19.4 months in the enzalutamide group compared with 5.7 months in the bicalutamide group.

The median time on treatment in the STRIVE trial was 14.7 months in the enzalutamide group versus 8.4 months in the bicalutamide group. Serious adverse events were reported in 29.4% of enzalutamide-treated patients and 28.3% of bicalutamide-treated patients. Grade 3 or higher cardiac adverse events were reported in 5.1% of enzalutamide-treated patients versus 4.0% of bicalutamide-treated patients. One seizure was reported in the trial in the enzalutamide-treated group and none in the bicalutamide-treated group.