Key clinical finding: Adding atezolizumab to enzalutamide offers no survival benefit compared with enzalutamide alone in patients with metastatic castration-resistant prostate cancer (CRPC) having disease progression after treatment with abiraterone and docetaxel or who could not receive a taxane regimen.

Major finding: Median overall survival was 15.2 months with the combination therapy vs 16.6 months with monotherapy, with no statistically significant difference (stratified hazard ratio, 1.12; P = .28). Patients receiving combination therapy vs. monotherapy reported more treatment-related adverse events (77.8% vs. 51.1%).

Study details: In the phase 3 IMbassador250 trial, 759 patients with metastatic CRPC were randomly assigned to atezolizumab plus enzalutamide (n = 379) or enzalutamide alone (n = 380).

Disclosures: Funding information was not available. The authors declared relationships with one or more pharmaceutical companies.