Enzalutamide is significantly more efficacious than bicalutamide in the treatment of metastatic castration-resistant prostate cancer (mCRPC), according to study findings presented at the Canadian Urological Association annual meeting in Ottawa.

A randomized double-blind phase 2 trial comparing the medications in 375 mCRPC patients showed that the 184 patients treated with enzalutamide had a significantly longer median progression-free survival (the primary trial endpoint) than the 191 bicalutamide recipients (15.7 vs. 5.8 months), reported investigator D. Robert Siemens, MD, of Queen's University in Kingston, Ontario. This difference translated into a 56% decreased risk of progression. In addition, the median time to PSA progression was significantly longer in the enzalutamide than bicalutamide group (19.4 vs. 5.8 months). A 50% or greater PSAresponse was achieved in 82.1% of the enzalutamide group compared with 20.9% of the bicalutamide group. The enzalutamide group had a higher rate of serious adverse events (31.1% vs. 23.3%).

In the study, the dosages of enzalutamide and bicalutamide were 160 mg per day and 50 mg per day, respectively.

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