Exelixis, Inc. (NASDAQ:EXEL) today announced that the enrollment target of 960 patients has been reached for COMET-1, the company’s phase 3 pivotal trial of cabozantinib in patients with metastatic castration-resistant prostate cancer (mCRPC). The primary endpoint of COMET-1 is overall survival, and Exelixis continues to expect 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 960 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 (60 mg daily) or prednisone (5 mg twice daily). The trial is event-driven and has 90% power to detect a 25% reduction in the risk of death (HR = 0.75) 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).
“Reaching the COMET-1 enrollment target is a significant milestone for the cabozantinib clinical development program,” said Michael M. Morrissey, Ph.D., president and chief executive officer of Exelixis. “2014 will be an important year for Exelixis as we anticipate top-line data from four pivotal trials of compounds discovered and developed by the company: along with expected data from both COMET trials, we anticipate overall survival data from EXAM, the phase 3 pivotal trial of cabozantinib that served as the basis for its approval to treat progressive, metastatic medullary thyroid cancer. In addition, our partner Genentech, a member of the Roche Group, has guided that it expects data from the pivotal trial of cobimetinib (GDC-0973/XL518), an Exelixis-discovered compound, in combination with vemurafenib as a potential treatment for B-RAF V600 mutation positive, locally advanced or metastatic melanoma.”