Efficacy and safety of rituximab in autoimmune and microangiopathic hemolytic anemia: a systematic review and meta-analysis

Background The efficacy and safety of rituximab (RTX) on hemolytic anemia (HA) is unknown. Therefore we retrospectively analyze the efficacy and safety of RTX in autoimmune hemolytic anemia (AIHA) and microangiopathic hemolytic anemia (MAHA) from the previous literature. Methods Data in clinical trials and observational studies were collected from PubMed, Cochrane, Embase, and Google Scholar until Oct 15, 2018. The efficacy and safety of RTX in patients with AIHA or MAHA were assessed and overall response rates (ORRs), complete response rates (CRRs), adverse events (AEs) and relapse rates (RRs) were extracted if available. A meta-analysis was performed with a random-effects model, estimating mean proportions in all studies, and relative rates in comparative studies. Results After quality assessment, a total of 37 investigations encompassing 1057 patients eligible for meta-analysis were included. Pooled mean proportion of ORR was 0.84 (95% confidence interval [CI] 0.80-0.88), and that of CRR was 0.61 (95% CI 0.49-0.73). Mean AE rate was 0.14 (95% CI 0.10-0.17), and mean RR was 0.21 (95% CI 0.15-0.26). Relative ORR was 1.18 (95% CI 1.02-1.36), and relative CRR was 1.17 (95% CI 0.98-1.39) fold more than the respective non-RTX counter parts. Relative AE rate was 0.77 (95% CI 0.36-1.63), and relative RR was 0.93 (95% CI 0.56-1.55) fold less than the respective non-RTX counter parts. Conclusion RTX is more effective than the treatments without RTX for AIHA and MAHA and is well-tolerated.