Efficacy and safety of different dosages of rituximab for refractory generalized AChR myasthenia gravis: A meta-analysis

Background: Rituximab (RTX) is a mouse-human chimeric anti-CD20 monoclonal antibody and has been increasingly used for preventing relapses in myasthenia gravis (MG). However, the appropriate dose for maximizing the beneficial effects in refractory MG with acetylcholine receptor (AChR) autoantibody is a long-standing and critical debating question. Methods: We performed a meta-analysis to evaluate the efficacy and safety of the different doses of RTX in 260 refractory AChR-MG patients. Results: The AChR-MG patients were divided into low or routine RTX dose groups. An overall proportion of 77% (p = 0.000) AChR-MG patients demonstrated improved clinical status as indicated by the Myasthenia Gravis Foundation of America post-intervention scale (MGFA-PIS). There were 77.1% patients showed improved clinical status in lower dose of RTX group (p = 0.000) and 76.8% in routine protocol group (p = 0.000). Although we found there was no significant difference in the proportion of AChRMG patients with improved clinical status or adverse reactions between the two groups, adverse reactions might be lower in the lower dose RTX group. Conclusion: Most of refractory MG patients with anti-AChR autoantibody were well responsive and tolerated to RTX treatment. Repeated application of lower dose of RTX was effective and might be more appropriate for refractory AChR-MG patients with potential lower side effects. (C) 2020 Published by Elsevier Ltd.