OBJECTIVES: Abiraterone acetate plus predniso(lo)ne (AA) and enzalutamide (E) are novel therapies for the treatment of metastatic castration-resistant prostate cancer in chemotherapy naïve patients. Pivotal trials have been conducted evaluating the efficacy of the drugs using different comparators. In the COU-AA-302 trial, patients were randomised between AA and active comparator predniso(lo)ne whereas in the PREVAIL trial, E was compared against placebo. For health economic purposes, the mean overall survival (OS) and radiographic progression-free survival (rPFS) of both novel agents need to be compared in the absence of head-to-head trial data. METHODS: Due to the difference in the comparator arms, only survival data from AA and E were used for the comparison. Observed individual level survival data with baseline patient characteristics were available for AA. Individual survival data were simulated for E to replicate the rPFS and OS curves published for the pivotal trial. rPFS and OS were modeled and extrapolated by fitting parametric survival functions. The Weibull, exponential, and lognormal models were evaluated based on statistical and clinical considerations, i.e. assessing the model fit and the implied hazard profiles, respectively. To control for differences in baseline patient characteristics (PSA, ECOG, Gleason score, BPI, LDH, metastasis, age, race) rPFS and OS estimates for AA were adjusted using a matching algorithm. RESULTS: The Weibull models were selected for extrapolation of both OS and rPFS. The mean rPFS was estimated to be 23.9 (95% CI: 21.5-26.3) and 19.5 (95% CI: 16.0-23.9) months for AA and E respectively. Mean OS was estimated to be 38.7 (95% CI: 36.4-40.7) and 34.6 (95% CI: 31.8-37.8) months respectively. CONCLUSIONS: Based on currently available data and the presented modeling approach, these findings suggest that AA is associated with longer mean rPFS and OS than E.