San Francisco, CA and Tokyo – June 26, 2013 – Medivation, Inc. (Nasdaq: MDVN) and Astellas Pharma Inc. (TSE: 4503) today announced enrollment of the first patient in a global Phase 2 clinical trial evaluating enzalutamide as a single agent for the treatment of advanced, androgen receptor (AR)-positive, triple-negative breast cancer (TNBC).  Medivation is conducting this study under its agreement with Astellas.

“The initiation of this Phase 2 study marks an important milestone as we expand our enzalutamide development program beyond prostate cancer to explore the clinical efficacy of enzalutamide in triple-negative breast cancer, where there is a significant unmet medical need,” said David Hung, M.D., president and chief executive officer of Medivation, Inc. “We plan to present the results from the Phase 1 study in breast cancer at an upcoming scientific conference.”

The Phase 2 open label, single-arm, multicenter trial plans to enroll approximately 80 patients with AR-positive, TNBC at sites in the United States, Canada and Europe. The primary endpoint of the trial is clinical benefit rate, defined as the proportion of patients with a best response of complete response, partial response or stable disease at ≥ 16 weeks.  All patients will receive enzalutamide at a dose of 160 mg to be taken orally once daily.  Information about patient eligibility and enrollment can be obtained by calling 800-888-7704 ext. 5473 or e-mailing [email protected].

TNBC is a type of cancer which does not express any of the three most commonly targeted receptors in breast cancer: estrogen, progesterone and HER2.  TNBC remains an area of significant unmet medical need. Currently, there are no approved targeted therapies for these patients, who are typically treated with multiple regimens of chemotherapy.  AR-positive breast cancer is a recently-identified subtype of TNBC that can express high levels of the androgen receptor.