Sudden and severe cardiotoxicity induced with pembrolizumab, its clinical course, therapeutic intervention, and outcome.

Immune checkpoint inhibitors (ICIs), including cytotoxic T-lymphocyte associated antigen-4 inhibitors, and inhibitors of programmed cell death 1 and its ligand, are widely used in the treatment of several malignant tumors. Immune-related adverse events occur in two-thirds of recipients. Among them, cardiotoxicities are very rare (about 1%), albeit fatal. Pembrolizumab-induced cardiotoxicity in a patient was successfully treated with high-dose corticosteroids, and his cardiac function was maintained by adrenergic drugs and intra-aortic balloon pumping in the intensive care unit for 1 week. Cardiotoxicity with ICIs is an oncologic emergency, and should be managed in a pluridisciplinary setting involving cardiologists. © The Japan Society of Clinical Oncology 2021.