23 August 2019 - - The US Food and Drug Administration has accepted for review the filing of a supplemental New Drug Application for XTANDI (enzalutamide) to add an indication for the treatment of men with metastatic hormone-sensitive prostate cancer (mHSPC), Japan-based Astellas Pharma Inc. (TSX: 4503) and US-based drugmaker Pfizer Inc. (NYSE: PFE) said.

The application has also been granted Priority Review, a designation given to those applications for drugs that, if approved, may offer significant improvements in the safety or effectiveness of the treatment, diagnosis or prevention of serious conditions when compared to standard applications.

XTANDI is currently indicated in the US for the treatment of patients with castration-resistant prostate cancer.

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 in July 2019.

The study evaluated the efficacy and safety of XTANDI plus androgen deprivation therapy versus ADT plus placebo in men with mHSPC. The primary endpoint of radiographic progression-free survival 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 an active control.

The results were presented during the Plenary Session at the 2019 American Society of Clinical Oncology annual meeting in June and simultaneously published in The New England Journal of Medicine. The primary endpoint of overall survival was met in the ENZAMET trial.

The safety analyses of the ARCHES and ENZAMET trials appear consistent with the safety profile of enzalutamide in previous clinical trials in CRPC.

Data from the ARCHES and ENZAMET studies have also been submitted to the European Medicines Agency and to the Pharmaceuticals and Medical Devices Agency in Japan to potentially support an indication for XTANDI that includes men with mHSPC.

The FDA has set a Prescription Drug User Fee Act (PDUFA) date, or target action date, in 4Q19.