Case Report: Fatal myocarditis after combination of immune checkpoint inhibitor and platinum doublet chemotherapy [version 1; peer review: 1 not approved]

Myocarditis is a rare but feared adverse event of treatment with immune checkpoint inhibitors. The incidence is about 1%, while the mortality rate is up to 50%. Many physicians treating lung cancer do not have experience with this serious adverse event, and few hospitals in Scandinavia have routines for baseline assessments that may help detect early signs of inflammation of the myocard. Early onset of anti-inflammatory treatment is associated with favourable outcome. We present a case report of fatal myocarditis after treatment with check-point inhibitor. The patient was admitted with severe dyspnoea, general body ache, weakness, dysphagia, palpitations and diplopia two weeks after her second infusion of systemic treatment combining chemotherapy and immunotherapy. She had presented vague symptoms at time of the second infusion that were not identified as related to myocarditis/myositis. Upon aggressive treatment with methylprednisolone, mycophenolate mofetil, abatacept and plasmapheresis, her troponins and pro-BNP were reduced, but clinically she deteriorated and her life could not be saved. We present this case report to increase awareness of the condition and to raise discussion about the role of routine baseline assessments to aid early diagnosis and anti-inflammatory treatment to prevent treatment-related deaths.