Cardiac Troponins for Diagnosis and Prognostic Assessment of Immune Checkpoint Inhibitor Myocarditis and Myositis: The Emerging Importance of Peripheral Vision

Prognosis of immune checkpoint inhibitor-related myocarditis: Retrospective experience of a single institution

BACKGROUND

Myocarditis related to immune checkpoint inhibitors (ICIs) treatment is a rare but potentially life-threatening adverse event. To gain insight into this condition, we analyzed the clinical characteristics and prognosis of patients with ICI-related myocarditis.

METHODS

Data on the clinical characteristics, management, and outcomes of patients diagnosed with ICI-related myocarditis between August 2018 and August 2023 in our institution were gathered retrospectively from medical records. Outcomes included the occurrence of major adverse cardiac events (MACE).

RESULTS

Among 8875 patients who received ICI therapy, 31 patients experienced ICI-related myocarditis. These 31 patients had a mean age of 62 ± 12 years and included 24 (77.4 %) males and 19 patients (61.3 %) with at least one risk factor for cardiovascular disease. The median duration from ICI initiation to the onset of myocarditis symptoms was 6.3 weeks (interquartile range, 4.3-8.1 weeks). Twenty-one patients (67.7 %) developed grade 3-4 myocarditis. Thirteen patients (42 %) experienced MACE after myocarditis onset, and 15 patients (48.4 %) showed a troponin rise > 4 times the maximum limit of the standard range. On receiver operating characteristic curve analysis, troponin level could predict MACE in patients with ICI-related myocarditis with an area under the curve of 0.82 (95 % confidence interval [CI]: 0.66-0.98, p = 0.003). From Kaplan-Meier analysis, the occurrence of MACE (p = 0.002) was an independent influencing factor on patients' overall survival.

CONCLUSIONS

ICI-related myocarditis frequently leads to MACE, which is associated with poor prognosis. Elevated troponin levels and electrocardiogram abnormalities in these patients may help predict the occurrence of MACE.

Circulating biomarkers in the diagnosis and prognosis of immune checkpoint inhibitor-related myocarditis: time for a risk-based approach

Immune checkpoint inhibitors (ICIs) are monoclonal antibodies that block immune checkpoints and therefore activate immune cells, allowing them to recognize and attack cancer cells. ICIs have revolutionized oncology practice, but their use has been complicated by immune-related adverse events (irAEs). Of cardiovascular (CV) irAEs, ICI-related myocarditis has received significant attention due to high mortality rates, ranging from 25% to 50%, despite its overall low incidence. Establishing the early diagnosis of ICI-myocarditis is important for early initiation of steroids and consideration of hospitalization in patients who are at risk for hemodynamic compromise and need high acuity care in a tertiary setting. In this review, we summarize the diagnostic and prognostic tools for ICI-myocarditis, including electrocardiography, echocardiography, cardiac magnetic resonance imaging, with emphasis on circulating biomarkers. Cardiac troponins (cTns) are an essential component of the diagnosis of ICI-myocarditis, and we provide a summary of the recent studies that utilized different assays (cTnI vs. cTnT) and outcomes (diagnosis vs. prognosis including major adverse cardiac outcomes). With the exponential increase in ICI use across different oncology indications, there is a major need to include biomarkers in risk stratification to guide diagnosis and treatment. Our review proposes a framework for future multisite registries, including cTn evaluation at baseline and at the time of irAE suspicion, with development of central biobanking to allow head-to-head evaluation and clinical validation of different biomarker assays in ICI-myocarditis. This approach, with the inclusion of CV biomarkers into clinical and pragmatic oncology trials, holds promise to improve the early recognition and management of ICI-myocarditis and CV irAEs, thus leading to better outcomes.

Immune Checkpoint Inhibitors-Associated Myocarditis: Diagnosis, Treatment and Current Status on Rechallenge

Immune checkpoint molecules like cytotoxic T-lymphocyte antigen 4 (CTLA-4), programmed cell death 1 (PD-1) or its ligand, programmed cell death ligand 1 (PD-L1), play a critical role in regulating the immune response, and immune checkpoint inhibitors (ICIs) targeting these checkpoints have shown clinical efficacy in cancer treatment; however, their use is associated with immune-related adverse events (irAEs), including cardiac complications. The prevalence of cardiac irAEs, particularly myocarditis, is relatively low, but they can become a severe and potentially life-threatening condition, usually occurring shortly after initiating ICI treatment; moreover, diagnosing ICI-related myocarditis can be challenging. Diagnostic tools include serum cardiac biomarkers, electrocardiography (ECG), echocardiography, cardiac magnetic resonance (CMR) and endomyocardial biopsy (EMB). The treatment of ICI-induced myocarditis involves high-dose corticosteroids, which have been shown to reduce the risk of major adverse cardiac events (MACE). In refractory cases, second-line immunosuppressive drugs may be considered, although their effectiveness is based on limited data. The mortality rates of ICI-induced myocarditis, particularly in severe cases, are high (38-46%). Therapy rechallenge after myocarditis is associated with a risk of recurrence and severe complications. The decision to rechallenge should be made on a case-by-case basis, involving a multidisciplinary team of cardiologists and oncologists. Further research and guidance are needed to optimize the management of cancer patients who have experienced such complications, evaluating the risks and benefits of therapy rechallenge. The purpose of this review is to summarize the available evidence on cardiovascular complications from ICI therapy, with a particular focus on myocarditis and, specifically, the rechallenge of immunotherapy after a cardiac adverse event.