Exelixis Presents Results Of Cabozantinib On Metastatic Castration-Resistant Prostate Cancer

(RTTNews) - Exelixis Inc. (EXEL) said that it presented detailed results from the expanded cohort 6 of the phase 1b COSMIC-021 trial of cabozantinib or CABOMETYX in combination with atezolizumab in patients with metastatic castration-resistant prostate cancer or CRPC at the 2021 European Society of Medical Oncology or ESMO Congress.

Cohort 6 included patients with metastatic CRPC who had been previously treated with the novel hormone therapies (NHT) enzalutamide and/or abiraterone acetate used along with prednisone.

New detailed results demonstrated that median progression-free survival per RECIST 1.1 for the high-risk population was 5.6 months as assessed by investigators and 6.8 months as assessed by Blinded Independent Radiology Committee. The exploratory endpoint of overall survival for the high-risk patient population was 18.4 months. Tumor PD-L1 status, which was known for 75 patients, was not associated with response.

The company noted that the detailed results confirmed previous findings from cohort 6 of COSMIC-021, further suggesting the promise cabozantinib in combination with atezolizumab may hold for patients with high-risk metastatic castration-resistant prostate cancer whose disease progressed following treatment with novel hormone therapy.

Exelixis said that, following discussions with the U.S. Food and Drug Administration, the company will not pursue a regulatory submission for the combination regimen based on cohort 6 of the COSMIC-021 trial.

The CONTACT-02 study, a global phase 3 pivotal trial, initiated enrollment in June 2020 and is evaluating cabozantinib in combination with atezolizumab versus a second NHT in patients with metastatic CRPC who have been previously treated with one NHT. Pending results, CONTACT-02 may serve as a basis for future regulatory applications in this setting.