Abstract: Background：Case reports and case series from abroad have suggested that tocilizumab (TCZ) may be effective in treating refractory myelin oligodendrocyte glycoprotein antibody-associated disease (MOGAD) that does not respond well to other immunosuppressants, primarily in adults. However, there are no related reports in children in China. Objective：To analyze the clinical characteristics and of TCZ in two children with MOGAD, and to review the literature on the efficacy and safety of TCZ in treating MOGAD. Design：Case report and literature review. Methods：The clinical data of two pediatric patients with MOGAD treated with TCZ were reported, summarizing their clinical characteristics and the efficacy and safety of TCZ. English and Chinese articles published up to November 2023 were searched in PubMed, Embase, Web of Science, Cochrane, Wanfang Data, China National Knowledge Infrastructure (CNKI),and China Science and Technology Journal Database (CQVIP). The search terms include "MOGAD," "myelin oligodendrocyte glycoprotein antibody," "TCZ," "tocilizumab," and "interleukin-6 receptor antagonist". Main outcome measures：Efficacy and safety of TCZ. Results：The two pediatric patients with MOGAD had onset at 6 years and 6 months, and 3 years and 7 months, respectively. The duration of illness at the time of TCZ treatment was 9 years and 3 months, and 6 years and 6 months, with 11 and 5 prior acute demyelinating events, respectively. One patient did not experience relapse during 14 months of regular TCZ use, relapsed after stopping, and had one relapse during another 10 months of intermittent use. The other patient had no relapses during 2 years and 4 months of regular TCZ use. Neither of them experienced serious adverse reactions during treatment. A literature review included 9 studies with a total of 27 MOGAD patients (including two reported in this article). Four patients (14.8%) experienced relapse, and the annual relapse rate decreased significantly after treatment in 27 cases. The most common adverse reactions during TCZ treatment were infections and hyperlipidemia. No patients discontinued treatment due to serious adverse reactions. A meta-analysis including 5 studies with 23 patients(including two reported in this article) showed a relapse-free rate of 87% (95%CI: 72%-100%) for TCZ in treating MOGAD. Conclusion：TCZ is effective and well tolerated in patients with MOGAD who have failed to respond to other traditional immunosuppressant medications. Prospective studies with large sample sizes are needed to further confirm its efficacy.

Key words: Myelin oligodendrocyte glycoprotein antibody-associated disease, Relapse, Children, Tocilizumab