Medivation and Astellas Announce New Enzalutamide Data Presented During Plenary Presentations at the 2015 European Association of Urology Congress

SAN FRANCISCO, CA and TOKYO, JAPAN--(Marketwired - Mar 24, 2015) - Medivation, Inc. (NASDAQ: MDVN) and Astellas Pharma Inc. (Tokyo: 4503) today announced new data from the Phase 2 TERRAIN trial of enzalutamide compared to bicalutamide in metastatic castration-resistant prostate cancer (CRPC), as well as an updated overall survival analysis from the placebo-controlled Phase 3 PREVAIL trial of enzalutamide in chemotherapy-naive metastatic CRPC. The data were presented during a plenary session at the 2015 European Association of Urology (EAU) Congress in Madrid, Spain.

Highlights of Key Enzalutamide Data

Title: A randomized, double-blind, phase 2, efficacy and safety study of enzalutamide vs. bicalutamide in metastatic castrate resistant prostate cancer: TERRAIN trial

The Phase 2 TERRAIN trial enrolled 375 patients in North America and Europe. The trial enrolled patients with metastatic prostate cancer whose disease progressed despite treatment with a luteinizing hormone-releasing hormone (LHRH) analogue therapy or following surgical castration. The primary endpoint of the trial was progression-free survival (PFS), defined as time from randomization to centrally confirmed radiographic progression, skeletal-related event, initiation of new anti-neoplastic therapy or death, whichever occurred first. The trial was designed to evaluate enzalutamide at a dose of 160 mg taken orally once daily versus bicalutamide at a dose of 50 mg taken once daily, the approved dose in combination with an LHRH analogue.

"The results of the TERRAIN trial, if confirmed, have the potential to impact the treatment landscape of metastatic castration-resistant prostate cancer," said Axel Heidenreich, M.D., Ph.D., professor and director, Department of Urology, University hospital, Aachen, Germany. "The study demonstrated an improvement with enzalutamide over the standard practice of the addition of bicalutamide to a luteinizing hormone-releasing hormone therapy."

• The study achieved its primary objective of a statistically significant increase in PFS for enzalutamide compared to bicalutamide. The median PFS in the enzalutamide arm was 9.9 months longer compared to that in the bicalutamide arm (15.7 vs. 5.8 months, respectively) with a Hazard Ratio (HR) of 0.44 (95% confidence interval [CI], 0.34-0.57; p < 0.0001);
• The median time to PSA progression was 13.6 months longer with enzalutamide (19.4 months) relative to bicalutamide treatment (5.8 months) with an HR of 0.28 (p < 0.0001);
• 82% of enzalutamide-treated patients achieved ≥ 50% PSA reduction from baseline by week 13 vs. 21% of bicalutamide-treated patients;
• The median time on enzalutamide treatment was 11.7 months compared to 5.8 months on bicalutamide;
• The safety profile of the enzalutamide-treated patients in TERRAIN is consistent with the known safety profile of enzalutamide.
  • Serious adverse events (AEs) were reported in 31.1% of enzalutamide vs. 23.3% of bicalutamide patients and Grade 3 or higher cardiac AEs were observed in 5.5% of enzalutamide vs. 2.1% of bicalutamide patients. Two seizures were reported with enzalutamide and one with bicalutamide;
  • The common (≥10%) AEs reported more frequently with enzalutamide vs. bicalutamide were fatigue (27.9% vs. 20.1%), back pain (19.1% vs. 18.0%), hot flush (14.8% vs. 11.1%), hypertension (14.2% vs. 7.4%), diarrhea (11.5% vs. 9.0%), weight decreased (10.9% vs. 7.9%) and pain in extremities (10.9% vs. 5.3%).

Title: Enzalutamide in men with chemotherapy-naïve metastatic castration-resistant prostate cancer (mCRPC): Final overall survival analysis of the phase 3 PREVAIL study