Tocilizumab treatment in neuromyelitis optica spectrum disorders: Updated meta-analysis of efficacy and safety

•In comparison to the previous meta-analysis, our study not only confirmed that tocilizumab can effectively reduce the ARR ratio of NMOSD patients but also can significantly improve patients’ clinical disability.•Tocilizumab's efficacy in reducing the ARR ratio in patients with NMOSD is related to gender, ethnicity, and the dose of tocilizumab used, but the above factors are not related to tocilizumab's efficacy in improving the EDSS score in patients with NMOSD.•Compared to the AQP4-IgG negative NMOSD patients, tocilizumab demonstrates a more pronounced efficacy in AQP4-IgG positive NMOSD patients.•Serious adverse reactions in patients with NMOSD treated with tocilizumab are uncommon, and the drug is considered safe. This systematic review and meta-analysis summarize the efficacy and safety of Tocilizumab (TCZ) in treating NMOSD and investigates the factors that affect its efficacy. TCZ is the first monoclonal antibody against the IL-6 receptor for treating NMOSD, and its efficacy and safety vary in different studies. We collected English-language research literature until January 1, 2023, by searching databases such as PubMed, MEDLINE, Embase, Cochrane Library, and clinicaltrials.gov, and identified 9 studies involving 153 patients (139 female and 14 male) that met our inclusion criteria. In these studies, the average ARR ratio and EDSS score reduction values in the TCZ treatment group were -1.34 (95 % CI, -1.60 to -1.09) and -0.81 (95 % CI, -1.04 to -0.58), respectively. Based on the data we have collected, compared to the AQP4-IgG negative NMOSD patients, TCZ demonstrates a more pronounced effectiveness in AQP4-IgG positive NMOSD patients. The study also found that the effectiveness of TCZ in reducing NMOSD patients' ARR ratio was related to gender, race, and TCZ dosage, while the effectiveness of reducing EDSS score was not related to these factors. Among the 153 patients receiving TCZ treatment, 101 (66 %) experienced mild adverse reactions, and one patient experienced a severe adverse reaction (facial cellulitis). The comprehensive data indicate that TCZ treatment can reduce the frequency of NMOSD relapses, improve patients' neurological function, and have good safety. The effectiveness of TCZ in reducing NMOSD patients' ARR ratio is related to multiple factors.