Abstract
BACKGROUND: Noninfectious, inflammatory myocarditis is a rare but serious side effect of immune checkpoint inhibitor (ICI) therapy. In severe cases, mortality rates are high and prompt multidisciplinary management, often including intensive care unit admission. CASE SUMMARY: This is a report focusing on a 54-year-old-man diagnosed with ICI myocarditis that highlights a treatment regimen which prolonged life in a fulminant steroid-refractory case. DISCUSSION: By combining immunosuppressive drugs from multiple therapeutic classes (antithymoglobulin and mycophenolate), cardiac inflammation was mitigated, with significant improvement in clinical condition. Debilitating symptoms resolved, and the patient was able to be weaned from inotropic agents. TAKE-HOME MESSAGE: Rabbit thymocyte antiglobulin and mycophenolate are useful rescue therapies in severe cases of steroid-refractory ICI myocarditis.