Immune Checkpoint Inhibitors and Myocarditis

Immune checkpoint inhibitors (ICI) are a promising group of novel anti cancer drugs. They are monoclonal antibodies targeting cytotoxic T lymphocyte-associated antigen 4 (CTLA-4), programmed cell death 1 (PD-1) and its ligand (PD-L1). This group of drugs have been useful in a wide variety of malignancies with an otherwise poor prognosis. Important drugs in this class are ipilimumab, nivolumab, pembrolizumab and atezolizumab. Though they are excellent therapeutic options in several malignancies, some immune-related adverse effects have been noted, of which autoimmune myocarditis is potentially life threatening. Pathology of ICI‐associated myocarditis is characterized by intense infiltration by T lymphocytes and macrophages. Severe myocarditis will mandate suspension of ICI treatment and initiation of high dose corticosteroids (prednisolone or methylprednisolone).