Prognosis of immune checkpoint inhibitor-related myocarditis: Retrospective experience of a single institution

Myocarditis related to immune checkpoint inhibitors (ICIs) treatment is a rare but potentially life-threatening adverse event. To gain insight into this condition, we analyzed the clinical characteristics and prognosis of patients with ICI-related myocarditis.

Data on the clinical characteristics, management, and outcomes of patients diagnosed with ICI-related myocarditis between August 2018 and August 2023 in our institution were gathered retrospectively from medical records. Outcomes included the occurrence of major adverse cardiac events (MACE).

Among 8875 patients who received ICI therapy, 31 patients experienced ICI-related myocarditis. These 31 patients had a mean age of 62 ± 12 years and included 24 (77.4 %) males and 19 patients (61.3 %) with at least one risk factor for cardiovascular disease. The median duration from ICI initiation to the onset of myocarditis symptoms was 6.3 weeks (interquartile range, 4.3-8.1 weeks). Twenty-one patients (67.7 %) developed grade 3-4 myocarditis. Thirteen patients (42 %) experienced MACE after myocarditis onset, and 15 patients (48.4 %) showed a troponin rise > 4 times the maximum limit of the standard range. On receiver operating characteristic curve analysis, troponin level could predict MACE in patients with ICI-related myocarditis with an area under the curve of 0.82 (95 % confidence interval [CI]: 0.66-0.98, p = 0.003). From Kaplan-Meier analysis, the occurrence of MACE (p = 0.002) was an independent influencing factor on patients' overall survival.

ICI-related myocarditis frequently leads to MACE, which is associated with poor prognosis. Elevated troponin levels and electrocardiogram abnormalities in these patients may help predict the occurrence of MACE.