Efficacy and Safety of Anti-cancer Biosimilars Compared to Reference Biologics in Oncology: A Systematic Review and Meta-Analysis of Randomized Controlled Trials

Background: Many biosimilars of monoclonal antibodies (mAbs) are becoming increasingly available as anticancer therapies, such as the rituximab, bevacizumab, and trastuzumab biosimilars. However, no comprehensive summary of their efficacy and safety is available. Objective: This study synthesized current evidence on the efficacy and safety of mAb biosimilars relative to their reference biologics among cancer patients. Methods: We searched PubMed, Embase, the Cochrane library, ClinicalTrials.gov, the ISI Web of Science, and several Chinese databases from their inception dates to December 31, 2018, for randomized controlled trials (RCTs) or comparative observational studies that compared the efficacy and safety of biosimilars with reference biologics used in oncology. The binary outcomes were pooled using risk ratio (RR) with 95% confidence intervals (CIs), continuous outcomes using weighted mean difference (WMD) with 95% CIs, and time-to-event outcomes using hazard ratios (HRs). Subgroup and sensitivity analyses were conducted following this. We used the Grading of Recommendations, Assessment, Development and Evaluations (GRADE) approach to rate the quality of the evidence. Results: We did not find any comparative observational studies that fit the criteria. Twenty-three RCTs were identified for biosimilars of three mAbs, of which eight RCTs examined rituximab biosimilars (total N = 1534), six RCTs were for bevacizumab biosimilars (total N = 1897), and nine were for trastuzumab biosimilars (total N = 4953), respectively. The quality of the GRADE evidence for efficacy and safety outcomes was moderate or low. The findings were robust for all pre-specified subgroup and sensitivity analyses. Conclusion: The existing evidence suggests highly comparable efficacy and safety profiles between mAb biosimilars and their reference biologics in oncological drugs.