Eculizumab in Myasthenia Gravis: A Multicenter Retrospective Real-World Study in China

Abstract

Introduction: Myasthenia gravis (MG) is a chronic autoimmune neuromuscular disorder needing long-term immunosuppressive therapy. Eculizumab is a promising treatment, but real-world evidence on its efficacy and safety is limited. Methods: This retrospective cohort study across six medical centers enrolled 60 patients with MG on eculizumab. Clinical data, including MG-Activities of Daily Living (MG-ADL) scores, quantitative MG scores (QMG), and oral corticosteroid dosage at baseline, weeks 1, 4, and 8, and final follow-up were obtained. Outcomes included score changes, post-intervention status (PIS), and safety profile. Results: By week 8, 30.95% of patients achieved minimal manifestation status (MMS) or better, increasing to 32.69% at final follow-up. Mean ADL scores significantly dropped from 8.18 ± 3.99 at baseline to 5.59 ± 3.72 at week 1, 3.78 ± 3.42 at week 4, 3.50 ± 2.92 at week 8, and 3.33 ± 3.56 during final follow-up (p < 0.0001). Clinically meaningful improvement (CMI) was observed in 56.9%, 70.0%, 85.0%, and 76.27% at the respective time points. Both thymoma-associated and non-thymoma subgroups showed significant ADL improvement (p ≤ 0.026) with mixed-effects modeling revealing significant group × time interaction (p = 0.01).The thymoma-associated MG (TAMG) group had a faster initial response, with subsequent outcomes comparable between the two groups. Among the 37 patients (61.67%) who switched from FcRn inhibitor therapy to eculizumab, clinical outcomes were non-inferior to those of direct eculizumab recipients and the magnitude of MG-ADL improvement was comparable to that of the overall treatment group. The mean daily corticosteroid dose decreased from 21.21 ± 13.68 mg at baseline to 13.32 ± 10.42 mg at final follow-up (p < 0.0001) Adverse events were rare, with no treatment-related serious events. Conclusion: Eculizumab provides rapid and sustained clinical improvement in patients with MG, with a favorable safety profile. Patients with TAMG show a faster initial response. For patients with an inadequate response to FcRn inhibitors, eculizumab remains an effective rescue strategy.