Efficacy and safety of tocilizumab in patients with refractory generalized myasthenia gravis

Abstract Background We aimed to compare the efficacy of tocilizumab with conventional immunotherapy in refractory patients with acetylcholine receptor antibody‐positive (AChR‐Ab+) generalized myasthenia gravis (gMG). Methods This single‐center prospective cohort study was based on patients from an MG registry study in China and conducted from February 10, 2021 to March 31, 2022. Adult refractory patients with AChR‐Ab+ gMG were assigned to tocilizumab or conventional immunotherapy groups. The primary efficacy outcome was the mean difference of MG activities of daily living (MG‐ADL) change at weeks 4, 8, 12, 16, 20, 24 corresponding to that at the baseline between the two groups. A generalized estimating equation model was used for the primary outcome analysis. Safety was assessed based on adverse events. Results Of 34 eligible patients, 20 (mean standard deviation age, 53.8 21.9 years; 12 60.0% female) received tocilizumab and 14 received conventional immunotherapy (45.8 18.0 years; 8 57.1% female). The tocilizumab group had greater reduction in MG‐ADL score at week 4 (adjusted mean difference, −3.4; 95% CI, −4.7 to −2.0; p < 0.001) than the conventional immunotherapy group, with significant differences sustained through week 24 (adjusted mean difference, −4.5; 95% CI, −6.4 to −2.6; p < 0.001). At week 24, the proportion of patients achieving higher levels of MG‐ADL (up to 7‐point reduction) and QMG (up to 11‐point reduction) scores improvement was significantly greater with tocilizumab. Tocilizumab had acceptable safety profiles without severe or unexpected safety issues. Conclusion Tocilizumab is safe and effective in improving the MG‐ADL score and reducing prednisone dose in refractory AChR‐Ab+ gMG, suggesting tocilizumab has the potential to be a valuable therapeutic option for such patients.