Comparative efficacy and safety of trastuzumab biosimilars to the reference drug: a systematic review and meta-analysis of randomized clinical trials

Purpose: To assess efficacy and safety of trastuzumab biosimilars in comparison to the reference drug through a systematic review and meta-analysis of randomized controlled trials (RCTs). Methods: A comprehensive search was conducted using PubMed, Web of Science, Cochrane library, Open Grey and ClinicalTrials.gov databases. Dichotomous data for efficacy and safety outcomes were pooled to obtain the relative risk (RR) and 95% confidence intervals (CIs). Meta-analysis was performed with the Mantel–Haenszel method using Revman 5.3 software. Results: Eight phase III RCTs including a total of 3913 patients with HER2 + breast cancer were identified that met the inclusion criteria. The pooled results for the comparison of trastuzumab biosimilars to the reference drug showed no differences of objective response rate (ORR) (RR 1.05, 95% CI 0.98–1.12, P = 0.20) or overall survival (RR 0.82, 95% CI 0.61–1.09, P = 0.17) in the intention-to-treat population, as well as no difference of ORR (RR 1.03, 95% CI 0.97–1.10, P = 0.30) in the per-protocol population. Similarly, no significant difference was detected in any type of adverse event reported in at least three RCTs, including any serious treatment-emergent adverse effects (RR 0.97, 95% CI 0.76–1.25, P = 0.83), heart failure (RR 1.47, 95% CI 0.69–3.14, P = 0.32), neutropenia (RR 1.05, 95% CI 0.96–1.15, P = 0.26), and infusion-related reaction (RR 1.10, 95% CI 0.89–1.36, P = 0.38). Conclusion: This meta-analysis provides compelling evidence of clinical comparability between trastuzumab biosimilars and the originator product in terms of both efficacy and safety for the treatment of HER2 + breast cancer.