Astellas Pharma Inc. (TSE: 4503, President and CEO: Kenji Yasukawa, Ph.D., “Astellas”) and Pfizer Inc. (NYSE: PFE) today announced the U.S. Food and Drug Administration (FDA) approved a supplemental New Drug Application (sNDA) for XTANDI® (enzalutamide), following FDA Priority Review designation, based on results from the Phase 3 PROSPER trial. The FDA action broadens the indication for XTANDI to men with castration-resistant prostate cancer (CRPC), now including men with non-metastatic CRPC. This approval makes XTANDI the first and only oral medication FDA-approved for both non-metastatic and metastatic CRPC. XTANDI was first approved by the FDA in 2012 for the treatment of patients with metastatic CRPC who had previously received docetaxel and was granted approval in 2014 for chemotherapy-naïve men with metastatic CRPC.
"With today’s approval, there is now a new option for men with non-metastatic CRPC, who are in between the failure of androgen deprivation therapy resulting in CRPC and the onset of metastatic disease,” said Jonathan Simons, M.D., Prostate Cancer Foundation President and CEO. “As a foundation that drives research aimed at improving patient outcomes, it is exciting to see approvals like this, which are vital to help address unmet patient needs.”
The updated label is based on results from the Phase 3 PROSPER trial, which demonstrated that the use of XTANDI plus androgen deprivation therapy (ADT) significantly reduced the risk of developing metastasis or death compared to ADT alone in men with non-metastatic CRPC. The median for the primary endpoint, metastasis-free survival (MFS), was 36.6 months for men who received XTANDI plus ADT compared to 14.7 months with ADT alone (N=1401; HR=0.29 [95% CI: 0.24-0.35]; p<0.0001). The most common adverse reactions (greater than or equal to 10%) that occurred more frequently (greater than or equal to 2% over placebo) in XTANDI plus ADT-treated patients were: asthenic conditions (40% vs 20%), hot flush (13% vs 7.7%), hypertension (12% vs 5.2%), dizziness (12% vs 5.2%), nausea (11% vs 8.6%) and fall (11% vs 4.1%). Grade 3 or higher adverse reactions were reported in 31 percent of men treated with XTANDI plus ADT and in 23 percent of men treated with ADT alone. Data from the PROSPER study were presented at the 2018 Genitourinary Cancers Symposium (ASCO GU) in February and published in the New England Journal of Medicine in June.