Correlation between radiographic progression-free survival (rPFS) and overall survival (OS): Results from PREVAIL.

182 Background: In PREVAIL, enzalutamide (ENZA) significantly improved OS (hazard ratio [HR] 0.71; P < 0.0001) and rPFS (HR 0.19; P < 0.0001) compared with placebo in chemotherapy-naive metastatic castration-resistant prostate cancer (mCRPC). Using data from the final analysis at 439 rPFS events we showed a strong correlation between investigator and central review. Here we report sensitivity analyses (SAs) from the final analysis of investigator-assessed rPFS and the association between investigator-assessed rPFS and OS. Methods: The coprimary endpoint of rPFS was defined as time from randomization to the earliest objective evidence of centrally assessed radiographic progression, defined by PCWG2 guidelines for bone disease and RECIST v1.1 for soft-tissue disease, or death within 168 days of treatment discontinuation. Bone progression was captured using a validated bone scan data capture assay. Four SAs were performed on investigator-assessed rPFS to evaluate the impact of: (1) progression in bone, (2) c...