Introduction: There is paucity of data on management of steroid refractory, immune checkpoint induced (ICI) myocarditis.
Case: We present the case of a 65-year-old gentleman diagnosed with metastatic melanoma (BRAF mutated, LDH elevated) with disease confined to spleen and para-aortic lymph nodes but no primary skin lesion was identifiable. He was commenced on dual immunotherapy with ipilimumab and nivolumab. Within few days of initiation of immunotherapy, he was diagnosed with ICI pneumonitis and concurrent ICI hepatitis was started on methylprednisolone, followed by prednisolone. Mycophenolate 500mg twice daily was added as steroid sparing agent.
He represented within a week with central chest pain and palpitations. His initial ECGs were normal, but he later developed ventricular ectopics and left bundle branch block. His cardiac troponin was elevated at 549. Initial echocardiogram was normal. A coronary angiogram excluded significant coronary artery disease. Cardiac MRI found features of ICI myocarditis with late gadolinium enhancement and a diagnosis of ICI myocarditis was made. He was recommenced on methylprednisolone followed by high dose prednisolone and mycophenolate was increased to 1g twice daily.
But despite this treatment, he remained symptomatic, cardiac enzymes were persistently elevated and there were short runs of non-sustained ventricular tachycardia on telemetry. His subsequent echo also showed mild deterioration in LV function with regional wall motion abnormalities. After literature review and expert opinion, he was given single dose of abatacept of 200mg. Following this treatment, he clinically improved, cardiac enzymes normalised and there was significant improvement in ECG and LV function on echocardiogram.
Discussion: Out of the options for management of steroid refractory ICI myocarditis, abatacept appears more specific given its direct action as CTLA-4 agonist in reversing pathways activated by immune checkpoint inhibition.
Conclusion: This case highlights abatacept as an option in steroid refractory ICI myocarditis which otherwise has high mortality.