A Novel Sequential Regimen of Efgartigimod and Telitacicept as Fast‐Acting Treatment for Impeding Crisis of MuSK‐MG

Abstract

ABSTRACT Background Myasthenia gravis (MG) is an autoimmune disorder of the neuromuscular junction. The muscle‐specific kinase (MuSK) antibody‐positive subtype often involves bulbar and respiratory muscles, conferring a high risk of myasthenic crisis. Method We report a very late‐onset MuSK‐MG case complicated by lung infection and acute heart failure, with a history of peptic ulcer. The patient was sequentially treated with efgartigimod and telitacicept, achieving minimal symptom expression (MSE) within 1.5 months. Discussion Following the first efgartigimod infusion, QMG and MG‐ADL scores improved from 31 to 23 and 22 to 12, respectively. After five injections of telitacicept, symptoms resolved completely on day 47, with scores further reducing to 2 (QMG) and 0 (MG‐ADL). Treatment also reduced IgG levels and MuSK‐Ab titers, while IgM remained stable. Conclusion This case demonstrates the successful sequential use of efgartigimod and telitacicept in managing complicated, late‐onset MuSK‐MG in a state of impeding crisis.