Exelixis Completes Enrollment in mCRPC Trial

Exelixis has reached the enrollment target of 960 patients has been reached for COMET-1, the company’s Phase III trial of cabozantinib in patients with metastatic castration-resistant prostate cancer (mCRPC). The primary endpoint of COMET-1 is overall survival. Exelixis expects top-line data from COMET-1 and a second pivotal trial in mCRPC, COMET-2, in 2014.

COMET-1 is a randomized, double-blind, placebo-controlled trial designed to enroll  patients with mCRPC who have previously been treated with docetaxel, abiraterone acetate and/or enzalutamide. All patients in the trial have bone metastases and there is no limit to the number or type of prior treatments. Patients are randomized 2:1 to receive cabozantinib or prednisone. The trial is event-driven and has 90% power to detect a 25% reduction in the risk of death at the time of final analysis, which requires 578 events. A single interim analysis after 387 events is also planned and will assess if the trial achieved its primary endpoint; it will not include a futility analysis. The secondary endpoint of the trial is bone scan response as assessed by an independent radiology facility (IRF).