Cabozantinib (Cometriq) Fails to Meet Primary Endpoint in Pivotal Study of Men With Metastatic Prostate Cancer
Drug currently approved for thyroid cancer
Disappointing results have been reported from the final analysis of a pivotal phase III trial of cabozantinib (Cometriq, Exelixis, Inc.) in men with metastatic castration-resistant prostate cancer (mCRPC) whose disease progressed after treatment with docetaxel plus abiraterone and/or enzalutamide.
The study did not meet its primary efficacy endpoint of demonstrating a statistically significant increase in overall survival (OS) for patients treated with cabozantinib compared with those given prednisone. The median OS for the cabozantinib arm was 11.0 months compared with 9.8 months for the prednisone arm (hazard ratio [HR], 0.90; P = 0.212).
However, median progression-free survival was 5.5 months for the cabozantinib-treated patients compared with 2.8 months for the prednisone-treated patients (HR, 0.50; P < 0.0001).
Based on the primary outcome of this study, enrollment in COMET-2 — the second pivotal trial of cabozantinib in mCRPC — has been halted.
COMET-1 was a randomized, double-blind, controlled trial that enrolled 960 patients with mCRPC who had progressed after treatment with docetaxel, abiraterone, and/or enzalutamide. The study’s primary endpoint was OS, and the secondary endpoint was the bone scan response.
All of the patients in the trial had bone metastases, and there was no limit to the number or type of prior treatments. The patients were randomly assigned to receive cabozantinib (60 mg daily) or prednisone (5 mg twice daily).
Cabozantinib inhibits the activity of tyrosine kinases, including vascular endothelial growth factor receptors (VEGFRs) as well as MET and RET. These receptor tyrosine kinases are involved both in normal cellular function and in pathologic processes, such as oncogenesis, metastasis, tumor angiogenesis, and maintenance of the tumor microenvironment.
Cometriq (cabozantinib) is approved by the FDA for the treatment of progressive, metastatic medullary thyroid cancer.
Source: Exelixis, Inc.; September 1, 2014.