Dr. Agarwal on the COSMIC-021 Trial Design in Castration-Resistant Prostate Cancer

Neeraj Agarwal, MD, director of the Genitourinary Oncology Program, Oncology Division, professor of medicine, physician, and investigator, at Huntsman Cancer Institute, discusses the design of cohort 6 in the phase Ib COSMIC-021 trial in metastatic castration-resistant prostate cancer (mCRPC).

The COSMIC-021 trial began as a multi-cohort, phase I trial evaluating the early efficacy and safety of cabozantinib (Cabometyx) in combination with atezolizumab (Tecentriq) in multiple tumor types, explains Agarwal. Based on laboratory and preclinical data, investigators postulated that cabozantinib could have potential synergy with a PD-L1 inhibitor, which was atezolizumab in this case, says Agarwal.

The study began in 30 patients with mCRPC. After the efficacy data of the combination was evaluated, the cohort was expanded to 130 patients. A phase III trial is currently being planned as well, says Agarwal.

Patients entering the phase Ib trial were required to have mCRPC and progressive measurable disease. Nearly half of the patients received both abiraterone acetate (Zytiga) and enzalutamide (Xtandi). Furthermore, one-third of patients received prior docetaxel in the castration-sensitive prostate cancer setting, concludes Agarwal.