Immunotherapy with Sipuleucel-T (APC8015) in patients with metastatic castration-refractory prostate cancer (mCRPC): a systematic review and meta-analysis

Objective: To perform a systematic review and meta-analysis of all randomized controlled trials comparing the efficacy of Sipuleucel-T versus placebo for asymptomatic or minimally symptomatic metastatic castration-refractory prostate cancer (mCRPC). Materials ans Methods: Several databases were searched, including MEDLINE, EMBASE, LILACS, and CENTRAL. The endpoints were overall survival (OS), time to progression (TTP) and side effects. We performed a meta-analysis (MA) of the published data. The results are expressed as Hazard Ratio (HR) or Risk Ratio (RR), with their corresponding 95% confidence intervals (CI 95%). Results: The final analysis included 3 trials comprising 737 patients. The TTP was similar in patients who received Sipuleucel-T or placebo (fixed effect: HR = 0.89; CI 95% = 0.75 to 1.05; p = 0.16), with no heterogeneity detected on this analysis (Chi2 = 2.14, df = 2 (P = 0.34); I2 = 6%). The results showed a higher overall survival in patients treated with Sipuleucel-T (fixed effect: HR = 0.74; CI 95% = 0.61 to 0.89; p = 0.001; NNT = 3). We found no heterogeneity on this analysis either (Chi2 = 1.46, df = 2 (P = 0.48); I2 = 0%). The incidence of adverse events (grade > 3) was the same in both groups. Conclusion: Sipuleucel-T prolongs overall survival in patients with asymptomatic or minimally symptomatic mCRPC.