Enzalutamide Demonstrates Significant Improvement in Overall Survival in Phase 3 PROSPER Trial of Patients with nmCRPC

San Francisco, CA (UroToday.com) -- Astellas Pharma Inc. and Pfizer Inc. announced the 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 Medicine.1

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.

PROSPER Trial
The Phase 3 randomized, double-blind, placebo-controlled, multi-national trial enrolled approximately 1,400 patients with nmCRPC at sites in the United States, Canada, Europe, South America, and the Asia-Pacific region. PROSPER enrolled patients with prostate cancer that had progressed, based on a rising PSA level despite ADT, but who had no symptoms and no prior or present evidence of metastatic disease. The trial evaluated enzalutamide at a dose of 160 mg taken orally once daily plus ADT, versus placebo plus ADT.  

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.

References: 
1. Hussain M, Fizazi K, Saad F, et al. Enzalutamide in Men with Nonmetastatic, Castration-Resistant Prostate Cancer. New England Journal of Medicine. 2018;378(26):2465-2474. doi:10.1056/nejmoa1800536. 

Source: "XTANDI® (Enzalutamide) Demonstrates Significant Improvement In Overall Survival In Phase 3 PROSPER Trial Of Patients With Nmcrpc - Feb 11, 2020". 2020. Astellas Pharma US, Inc. | News Room