Swept ahead of schedule by a summer protocol amendment, a positive phase III trial of Xtandi (enzalutamide) in men with early stage castration-resistant prostate cancer (CRPC) is now providing key evidence that could back their inclusion in the drug's label. Long desired by Astellas Pharma Inc. and Pfizer Inc., the partners behind Xtandi, the change could make about 20,000 more men eligible for on-label use of the drug in the U.S. each year alone, bolstering sales and further validating Pfizer's $14.3 billion acquisition of Medivation Inc.