Astellas Pharma Inc. announced that it has submitted a supplemental new drug application for the oral androgen receptor signaling inhibitor XTANDI® (generic name: enzalutamide) to add the indication for the treatment of men with metastatic hormone-sensitive prostate cancer (mHSPC) in Japan. XTANDI is currently indicated for the treatment of men castration-resistant prostate cancer (CRPC) in Japan.
The submission is based on results from the Phase 3 ARCHES trial presented at the 2019 Genitourinary Cancers Symposium (ASCO GU) in February and published in The Journal of Clinical Oncology. The study evaluated the efficacy and safety of XTANDI plus androgen deprivation therapy (ADT) versus ADT plus placebo in men with mHSPC. The primary endpoint of radiographic progression-free survival (rPFS) was met in the study.
Additionally, the submission is supported by data from ENZAMET, an Astellas-supported, investigator-sponsored Phase 3 research study led by the Australian and New Zealand Urogenital and Prostate Cancer Trials Group (ANZUP) and sponsored by the University of Sydney. The ENZAMET trial evaluated XTANDI plus ADT versus ADT plus a standard nonsteroidal antiandrogen therapy (bicalutamide, nilutamide or flutamide) in men with mHSPC to provide active control.
The results were presented during the Plenary Session at the 2019 American Society of Clinical Oncology (ASCO) Annual Meeting in June and simultaneously published in the New England Journal of Medicine. The primary endpoint of overall survival (OS) was met in the ENZAMET trial. The safety analysis of the ARCHES and ENZAMET trials appear consistent with the safety profile of enzalutamide in previous clinical trials in CRPC.
Enzalutamide is currently indicated for the treatment of CRPC in the U.S. and Europe. Data from the ARCHES and ENZAMET studies have also been submitted to the European Medicines Agency (EMA) and to the U.S. Food & Drug Administration (FDA) to potentially support an indication for XTANDI that includes men with mHSPC.