Results show enzalutamide plus androgen deprivation therapy significantly reduced the risk of developing metastases or death by 71 percent compared to placebo plus androgen deprivation therapy

TOKYO, June 29, 2018 – Astellas Pharma Inc. (TSE: 4503, President and CEO: Kenji Yasukawa, Ph.D., “Astellas”) today announced that results from the pivotal Phase 3 PROSPER trial, which evaluated enzalutamide plus androgen deprivation therapy (ADT) versus placebo plus ADT in patients with non-metastatic castration-resistant prostate cancer (CRPC), were published in the New England Journal of Medicine. The paper, “Enzalutamide in Men with Nonmetastatic, Castration-Resistant Prostate Cancer," appears in the June 28 print edition of the Journal.

In the study, enzalutamide plus ADT significantly reduced the risk of developing metastases or death compared to ADT alone, 23% of patients in enzalutamide and ADT arm had metastasis or had died, vs 49% in the ADT alone arm. The primary endpoint of metastasis-free survival (MFS), was 36.6 months for men who received enzalutamide compared to 14.7 months with ADT alone (n=1401; HR=0.29 [95% CI: 0.24-0.35]; p<0.001).

“I’m pleased with the PROSPER trial results, which confirm that men with non-metastatic CRPC receiving enzalutamide plus androgen deprivation therapy (ADT) had an almost two year delay in appearance of prostate cancer metastasis or death as compared to those taking ADT” said Maha Hussain, M.D.FACP,FASCO,Genevieve Teuton Professor of Medecine, Robert H. Lurie Comprehensive Cancer Center of Northwestern University, and lead study investigator.

The U.S. Food and Drug Administration (FDA) also recently accepted for Priority Review a supplemental New Drug Application (sNDA) for enzalutamide based on the results of the Phase 3 PROSPER study; the Prescription Drug User Fee Act (PDUFA) goal date assigned by the FDA is July 2018. In March 2018, the European Medicines Agency (EMA) validated and started the review process for Astellas’ application for a Type II Variation to extend the overall indication for enzalutamide to include patients with non-metastatic castration-resistant prostate cancer (CRPC) based on results from the PROSPER study. Enzalutamide is already approved for CRPC in Japan.

Results from the Phase 3 PROSPER data were previously presented at the Genitourinary Cancers Symposium (ASCO GU) in San Francisco in February 2018.