Severe immune-mediated myocarditis caused by sintilimab combined with gemcitabine: a case report and literature review.

Following the approval of sintilimab for lung cancer immunotherapy in China in June 2021, real-world clinical practice has confirmed its efficacy and safety. Although there have been limited reports of immune-related myocarditis associated with sintilimab, no fatal cases have been reported to date. This case report focuses on a 71-year-old male patient with lung squamous cell carcinoma who developed severe immune-mediated myocarditis after receiving sintilimab in combination with gemcitabine. The patient presented with immune myocarditis combined with acute myocardial infarction. Due to delayed diagnosis, the outcome was unfavorable. This case is a warning to clinicians for early identification, rapid diagnosis and standardized use of glucocorticoids and immunosuppressants in sindilizumab induced myocarditis and emphasize the importance of multidisciplinary collaboration in managing such rare but serious adverse events.