Astellas Pharma Inc, a pharmaceutical company dedicated to improving the health of people around the world, has announced that Medivation Inc., a biopharmaceutical company focused on the rapid development of novel small molecule drugs to treat serious diseases, has submitted a New Drug Application (NDA) to the US Food and Drug Administration (FDA) for enzalutamide (formerly MDV3100). The compound has been studied in patients with castration-resistant prostate cancer who have received docetaxel therapy.

Pursuant to the Prescription Drug User Fee Act (PDUFA), the FDA is expected to determine within 60 days whether to accept the filing for review. Medivation has requested Priority Review, a designation given to drugs that offer a significant improvement in treatment or provide treatment where no satisfactory alternative therapy exists. If a Priority Review is granted, the FDA goal for completing a review is six months.

Enzalutamide is an oral, once-daily investigational agent that is an androgen receptor signaling inhibitor. Enzalutamide inhibits androgen receptor signaling in three distinct ways: it inhibits testosterone binding to androgen receptors; nuclear translocation of androgen receptors; and DNA binding and activation by androgen receptors.

In the phase III AFFIRM trial, enzalutamide was well tolerated. Common side effects observed more frequently in enzalutamide as compared with placebo-treated patients included fatigue, diarrhoea and hot flush. Seizure was reported in <1% of enzalutamide-treated patients. Serious adverse events, adverse events causing patients to stop treatment, and adverse events causing death all were lower in the enzalutamide group than in the placebo group.