Abstract: Objective To investigate the clinical features, causality, and management strategies of myasthenia gravis (MG) combined with acute myocarditis induced by toripalimab injection so as to provide references for safe clinical use of the drug. Methods The diagnosis and treatment process of a patient with clear cell renal cell carcinoma (ccRCC) who developed MG and acute myocarditis after receiving toripalimab injection was analyzed. The correlation of adverse reactions was determined, related literature was reviewed, and the pathogenesis, clinical features, and major interve-ntions were discussed. Results Both causality assessment tools indicated a “probable” association. Upon discontinuation of toripalimab, the patient received methylprednisolone pulse therapy, intravenous immunoglobulin, tacrolimus, and pyridos-tigmine, leading to complete symptom resolution. There was no recurrence during the 6-month follow-up. Conclusion MG combined with acute myocarditis induced by toripalimab injection is a rare but fatal immune-related adverse events (irAEs). Monitoring is required during medication. Early identification and quick interventions can improve prognosis.

Key words: Toripalimab Injection, Immune Checkpoint Inhibitor, Myasthenia Gravis (MG), Acute Myocarditis, Adverse Drug Reaction