External validation of a prognostic model predicting overall survival in metastatic castrate-resistant prostate cancer patients treated with abiraterone

A prognostic model was derived from the population of the COU-AA-301 phase 3 trial for metastatic castrate-resistant prostate cancer patients treated with abiraterone after docetaxel, and it stratifies patients into three risk groups based on clinical parameters. We validated this model in an independent cohort of patients treated with abiraterone after docetaxel outside a clinical trial (group A; n=94) and explored its utility in patients treated with abiraterone in the prechemotherapy setting (group B; n=64). For group A, median overall survival (mOS) was significantly different across the three prognostic groups (good: n=39, mOS: 21.8 mo; intermediate: n=44, mOS: 10.6 mo; poor: n=7, mOS: 6.8 mo; p