Efficacy and safety of abiraterone and enzalutamide for castration-resistant prostate cancer A systematic review and meta-analysis of randomized controlled trials

Background: Previous evidence directly evaluating the efficacy and safety of abiraterone and enzalutamide treatment for castration-resistant prostate cancer (CRPC) is limited. We aim to include more randomized controlled trials (RCTs) to comprehensively assess the efficacy and safety of abiraterone and enzalutamide treatment. Methods: PubMed, Embase, and ClinicalTrial.gov were systematically searched. Pooled hazard ratios (HRs) were calculated using Stata 12.0 software. The comparison of the prostate-specific antigen (PSA) response rate and adverse events (AEs) between the treatment and control groups were performed using RevMan 5.3 software. Results: Eight eligible RCTs with 6,490 patients were selected. Pooled HRs were 0.72 for overall survival, 0.45 for radiographic progression-free survival (rPFS), and 0.36 for PSA PFS. abiraterone and enzalutamide could significantly increase the PSA response rate OR = 8.67, 95%CI 4.42-17.04) and any AE occurrence (OR = 1.98, 95%CI 1.46-2.68). The treatment group had more occurrence of fatigue (OR = 1.34, 95%CI 1.20-1.49), back pain (OR = 1.15, 95%CI 1.01-1.15), hot flush (OR = 1.76, 95%CI 1.50-R2.06), diarrhea (OR=1.22, 95%CI 1.07-2.40) and arthralgia (OR = 1.34, 95%CI 1.16-1.54). Particularly, AEs of special interest including any grade hypertension (OR = 2.06, 95%CI 1.71-2.47), hypokalemia (OR = 1.80, 95%CI 1.42-2.30) and fluid retention or edema (OR = 1.38, 95%CI 1.17-1.63) also occurred less in the control group. Moreover, a higher incidence of high-grade hypertension (OR = 2.60, 95%CI 1.79-3.79) and extremity pain (OR = 4.46, 95%CI 2.81-7.07) was observed in the treatment group. Conclusion: The survival benefits of abiraterone and enzalutamide for CRPC were evident and promising, while the risk of AE occurrence was also acceptably higher in the treatment group than in the placebo group.