Xtandi timeline speeds up in non-metastatic CRPC trial

Astellas Pharma Inc. (Tokyo:4503) and Pfizer Inc. (NYSE:PFE) said they now expect to report top-line data this year from the Phase III PROSPER trial of Xtandi enzalutamide to treat non-metastatic castration-resistant prostate cancer. The companies had previously expected first data in June 2019.

The partners will reduce PROSPER's target enrollment to 1,440 from 1,560. Astellas spokesperson Tyler Marciniak told BioCentury that based on recent clinical data in non-metastatic and chemotherapy-naïve metastatic CRPC, the partners have reduced the study's target hazard ratio and now believe they will need fewer metastasis-free survival events (MFS) to power the study. PROSPER's primary endpoint measures MFS. "This amendment will not negatively impact the strength of the data," Marciniak said...