Astellas Pharma Inc., of Tokyo, said it obtained marketing approval of oral androgen receptor signaling inhibitor Xtandi (enzalutamide) for the treatment of patients with castration-resistant prostate cancer in Japan. Xtandi is approved in the U.S. and Europe and is being jointly developed and commercialized by Medivation Inc., of San Francisco. Under the companies’ deal, Medivation is entitled to a $15 million milestone payment upon Japanese approval. (See BioWorld Today, Oct. 28, 2009.)