When immunotherapy strikes the heart: A multimodal approach to immune checkpoint inhibitors induced myocarditis: A case series and literature review

Background

Immune checkpoint inhibitors (ICI) use is associated with potentially life-threatening cardiovascular complication including myocarditis. This case series aims to evaluate the different management approaches and outcomes of ICI-induced myocarditis with a comparative review with international benchmarks.

Methods

This retrospective case series analyzed patients diagnosed with ICI-induced myocarditis at Sultan Qaboos Comprehensive Cancer Care and Research Center (SQCCCRC). The diagnosis of ICI-induced myocarditis was based on clinical presentation, cardiac biomarkers, and cardiac imaging after the exclusion of other differential diagnoses. Management strategies included corticosteroids and immunosuppressive therapy. Clinical outcomes and mortality were monitored longitudinally compared with a literature review of international benchmarks.

Results

A total of 6 cases were identified over 2 years, with a myocarditis prevalence of 1.8 %. Myocarditis onset occurred anytime between the first and the ninth cycle, with clinical presentations varying from mild symptoms to severe presentations with stroke, steroid resistance, and cardiogenic shock. Multimodality imaging, particularly cardiac magnetic resonance, was utilized; the mainstay therapy included corticosteroids, with one refractory case requiring mycophenolate mofetil (MMF). Complete recovery occurred in five patients.

Conclusion

The study outcome showed that the incidence of ICI-induced myocarditis may be under-reported due to underdiagnosis and the absence of risk stratification protocols in many cancer centers. For treatment of non-fulminant or Grade I/II cases, oral steroids should be considered, while steroid resistance may necessitate alternative immunosuppressive therapies. Multidisciplinary team discussions are essential to assess the continuation of ICI therapy in possible cases. Protocols enhancing early detection and timely steroid therapy initiation improve outcomes.