Pembrolizumab and epacadostat induced fatal myocarditis and myositis presenting as a case of ptosis and ophthalmoplegia.

We report the first case of fatal myocarditis presenting as bilateral ptosis in a patient on combination therapy with pembrolizumab and epacadostat. An 83 year-old man with stage III high-grade urothelial carcinoma presented with acute onset droopy eyelids one month after starting pembrolizumab and epacadostat. Exam showed myogenic ptosis and ophthalmoplegia. He was later found to have acute myocarditis with complete heart block and subsequently passed away. Pembrolizumab in combination with epacadostat can induce a potentially fatal myocarditis. Although immune mediated myocarditis is a rare established side effect, more reported fatalities are needed in the literature to highlight the urgency for standardized cardiac monitoring of even asymptomatic patients to prevent fatal outcomes, as well as a consensus on treatment protocols. Cancer immunotherapy complications are not well known to ophthalmologists. This case is unique in that the presenting sign was ptosis, which prompted the patient to call his ophthalmologist first.