Comparing the clinical efficacy and safety of abiraterone and enzalutamide in metastatic castration-resistant prostate cancer: A systematic review and meta-analysis

Background Two new drugs, abiraterone and enzalutamide, had recently shown beneficial effects on survival in patients with metastatic castration-resistant prostate cancer. We systematically reviewed the efficacy and safety of abiraterone and enzalutamide in metastatic castration-resistant prostate cancer in real-world practice. Methods A search from PubMed, Web of Science, Cochrane, Embase was conducted up to 6 March 2019. Available articles from conferences were searched. The endpoint was prostate-specific antigen response, overall survival, progression-free survival, number of patients with any adverse event. Results Fourteen cohort studies involving 3469 participants were included. Pooled result showed that prostate-specific antigen response was higher for patients receiving enzalutamide than abiraterone (790 patients, odds ratio (OR) 0.47, 95% confidence interval (CI) 0.29–0.77, P = 0.003, I 2 =59%). Enzalutamide was significantly associated with increased adverse events rate in comparison with abiraterone (730 patients, OR 0.35, 95%CI 0.13–0.92, P = 0.03, I 2 =65%). There was no statistical difference between abiraterone and enzalutamide with respect to perceived cognitive impairments (1856 patients, OR 0.90, 95%CI 0.29–2.76, P = 0.85, I 2 =5%). Enzalutamide was significantly associated with increased fatigue risk in comparison with abiraterone (2477 patients, OR 0.46, 95%CI 0.34–0.63, P＜0.00001, I 2 =0%). Conclusions Our results demonstrated that enzalutamide was more efficacious than abiraterone for patients with metastatic castration-resistant prostate cancer, but was associated with a significantly elevated risk of side effects, particularly fatigue.