TOKYO and NEW YORK, February 11, 2020 – Astellas Pharma Inc. (TSE: 4503, President and CEO: Kenji Yasukawa, Ph.D., “Astellas”) and Pfizer Inc. (NYSE: PFE) announced today results of the final overall survival (OS) analysis from the Phase 3 PROSPER trial, which evaluated XTANDI® (enzalutamide) plus androgen deprivation therapy (ADT) versus placebo plus ADT in men with non-metastatic castration-resistant prostate cancer (nmCRPC).

The results demonstrated a statistically significant improvement in OS in patients with nmCRPC who were treated with XTANDI plus ADT. OS was a key secondary endpoint of the trial. In a preliminary analysis, adverse events were generally consistent with those previously reported from PROSPER. Detailed efficacy and safety results from the final PROSPER OS analysis will be shared at a later date.

In 2018, Astellas and Pfizer announced that the PROSPER trial met its primary endpoint of metastasis-free survival (MFS). These results were presented at the Genitourinary Cancers Symposium (ASCO GU) and later published in the New England Journal of Medicine1.

PROSPER efficacy and safety data at the time of the MFS analysis are included in the XTANDI labels in the U.S., Europe and Japan and are currently under review in China.


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