Treatment of corticosteroid refractory immune checkpoint inhibitor myocarditis with Infliximab: a case series

BACKGROUND: Glucocorticoid treatment remains the cornerstone of therapy for immune checkpoint inhibitor (ICI) myocarditis, but data supporting the use of additional immunotherapy for steroid refractory cases remains limited. We investigate the safety and efficacy of infliximab in patients with ICI myocarditis who are refractory to corticosteroids. Additionally, we highlight the importance of a multi-disciplinary approach in the care for these complex patients. METHODS: We retrospectively identified consecutive patients who developed ICI myocarditis at our institution between January 2017 and January 2020. Baseline characteristics, laboratory data and clinical outcomes were compared between patients who received infliximab and those who did not. RESULTS: Of a total of 11 patients who developed ICI myocarditis, 4 were treated with infliximab. Aside from age, there were no significant differences in baseline patient characteristics between the two groups including total number of ICI doses received and duration from initial ICI dose to onset of symptoms. The time to troponin normalization was 58 vs. 151.5 days (p = 0.25). The duration of prednisone taper was longer in the infliximab group (90 vs. 150 days p = 0.32). All patients survived initial hospital admission. Over a median follow-up period of 287 days, two of the 4 patients died from sepsis 2 and 3 months after initial treatment of their myocarditis; one of these patients was on a steroid taper and the other patient had just completed a steroid taper. CONCLUSIONS: Infliximab, despite its black box warning in patients with heart failure, may be a safe and effective treatment for ICI myocarditis.