Medivation, Inc. ( MDVN - Analyst Report ) and Astellas Pharma Inc. recently launched their prostate cancer treatment, Xtandi (enzalutamide) which gained US Food and Drug Administration (FDA) approval in late August 2012.

The FDA approved Xtandi for the treatment of patients with metastatic castration-resistant prostate cancer who have previously received docetaxel. Approval came well ahead of the Prescription Drug User Fee Act (PDUFA) action date of November 22, 2012.

Besides making Xtandi available through specialty pharmacies and specialty distributors, Medivation and Astellas have also launched a comprehensive patient access support program so that patients requiring Xtandi have timely access to the drug.

Meanwhile, Xtandi is currently under review in the EU. Xtandi could very well be a game-changer for Medivation. The prostate cancer market represents huge commercial potential. According to the American Cancer Society, prostate cancer is the most commonly diagnosed cancer among men in the US, other than skin cancer.

Medivation and Astellas have priced Xtandi at $7,450 (wholesale acquisition cost) for a 30-day supply. While Medivation has a 60-person sales force in place for promoting Xtandi, Astellas will be using a 90-person sales force to promote the product.

Per the requirements of the FDA, Medivation and Astellas have agreed to conduct an open label safety study of Xtandi at the approved dose of 160 mg per day in patients who are at high risk for seizure. The companies have agreed to provide results from this study, which will involve about 350 patients, in 2019. We note that the “warnings and precautions” section of the product label mentions that about 0.9% of patients in the Xtandi arm experienced a seizure compared to none in the placebo arm of a randomized study.

Currently approved prostate cancer treatments include Sanofi’s ( SNY - Analyst Report ) Jevtana and Johnson and Johnson’s ( JNJ - Analyst Report ) Zytiga among others.