Eculizumab as a Fast-Acting Therapy in a Myasthenic Crisis Patient With Poor Response to Efgartigimod

INTRODUCTION: Myasthenic crisis (MC) is the most serious manifestation of myasthenia gravis (MG) and it poses a big challenge in clinical management. Plasma exchange and intravenous immunoglobulin are the first-line therapy for MC, but a subset of patients exhibit poor response. Recently, neonatal Fc receptor (FcRn) inhibitors and complement inhibitors showed great efficacy in MC. However, there is no report on whether eculizumab can serve as a rescue therapy for patients who have not responded to efgartigimod. CASE REPORT: This case report describes a Chinese patient with generalized MG who experienced an acute exacerbation and suffered from MC. Despite poor responsiveness to efgartigimod, the patient was successfully rescued with eculizumab. Under regular treatment with eculizumab once every 2 weeks, the patient achieved a status of minimal symptom expression. However, the efficacy of eculizumab in MC has yet to be confirmed through more clinical trials. CONCLUSIONS: This case report hints the potential of complement inhibitors as viable treatments alternative for MC patients who poorly respond to antibody-clearing therapy. Besides, further research is necessary to determine the preferred or suitable treatment option for specific patients.