Astellas Pharma US, Inc., a U.S. subsidiary of Tokyo-based Astellas Pharma Inc., and Medivation, Inc. (NASDAQ: MDVN) reported positive results form the Phase III PREVAIL trial of enzalutamide in men with progressive chemotherapy-naïve metastatic prostate cancer following luteinizing hormone-releasing hormone therapy or bilateral orchiectomy.
“The PREVAIL study results demonstrate that treatment with enzalutamide in men with metastatic castration resistant prostate cancer can decrease the risk of death, delay the growth or spread of metastatic prostate cancer, and delay the time to initiation of chemotherapy,” said Tomasz M. Beer, co-principal investigator of the PREVAIL study and professor of medicine and deputy director of the Knight Cancer Institute at Oregon Health & Science University. Professor Beer added that the company was pleased at the trial results’ online publication in the New England Journal of Medicine.
Enzalutamide is an androgen receptor inhibitor that has been found to hinder androgen binding to its receptors. The drug also inhibits androgen receptor nuclear translocation and interaction with DNA. Astellas and Medivation have applied for FDA approval of Xtandi (enzalutamide) for the treatment of male patients with progressing metastatic prostate cancer in spite of LHRH therapy or after bilateral orchiectomy.
The randomized, placebo controlled, double blind, multi-national Phase III trial PREVAIL showed that men treated with enzalutamide experienced a statistically meaningful delay in disease progression. The drug also reduced the risk of death compared to those who took placebo. The trial’s co-primary endpoints included overall survival and radiographic progression-free survival, the latter of which 65 percent of the enzalutamide-treated group achieved at 12 months. The drug also reduced risk of death by 29 percent versus placebo. As of September 16, 2013, a total of 626 patients (72 percent) who received enzalutamide were alive compared to 532 patients (63 percent) in the placebo group.
The FDA granted priority Review designation in response to Medivation and Astellas’ supplemental New Drug Application (sNDA) for enzalutamide. The agency has set a Prescription Drug User Fee Act (PDUFA) for the sNDA of September 18, 2014.