Final overall survival data for phase III PROSPER trial of Xtandi shows significant improvement in prostate cancer.- Astellas Pharma + Pfizer

Astellas Pharma and Pfizer announced results of the final overall survival (OS) analysis from the Phase III 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. The primary endpoint of the PROSPER trial, metastasis-free survival (MFS), was measured as the time from patients entering the trial until their cancer was radiographically detected as having metastasized, or until death, within 112 days of treatment discontinuation. Key secondary endpoints included overall survival, time to PSA progression and time to first use of antineoplastic therapy.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 Medicine. 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.