Hormonal therapeutics enzalutamide and abiraterone acetate in the treatment of metastatic castration-resistant prostate cancer (mCRPC) post-docetaxel-an indirect comparison

Introduction: This study aims to make an indirect comparison between enzalutamide and abiraterone acetate for mCRPC post-docetaxel. Methods: A search for published phase 3 trials was performed with PubMed. Indirect comparisons of enzalutamide (AFFIRM) to abiraterone acetate (COU-AA-301) on outcomes overall survival (OS), time to prostate-specific-antigen (PSA) progression, radiographic progression-free survival (PFS), and PSA response were constructed in the context of log-linear regression models. Results: There was no statistically significant difference in OS (hazard ratio (HR) 0.85, 95% CI 0.68-1.07). However, there was some evidence that enzalutamide may outperform abiraterone acetate with respect to secondary outcomes: time to PSA progression (HR 0.40, 95% CI 0.30-0.53), radiographic PFS (HR 0.61, 95% CI 0.50-0.74), and PSA response rates (RRs) (OR 10.69, 95% CI 3.92-29.20). Conclusion: While there was no statistically significant difference in OS, enzalutamide may be advantageous for secondary endpoints. Findings of this indirect comparison serve to be hypothesis-generating for future head-to-head trials.