Immune checkpoint inhibitor associated myocarditis occurs in both high-grade and low-grade forms

Immune checkpoint inhibitor myocarditis: a call for standardized histopathologic criteria

Histopathologic criteria for the diagnosis of myocarditis at endomyocardial biopsy: from the Dallas criteria to those recently proposed for immune checkpoint inhibitor (ICI) myocarditis. DCM, dilated cardiomyopathy; DCMI, inflammatory dilated cardiomyopathy; WHF, World Heart Federation.

Myocarditis Induced by Immune Checkpoint Inhibitors: Mechanisms and Therapeutic Prospects

Under physiological conditions, immune checkpoint molecules downregulate the activation and effector function of myocardial antigen-reactive T cells through an immunosuppressive pathway, thus enabling myocardial T cells to maintain immune homeostasis under the action of central and peripheral tolerance mechanisms. The PD-1/PD-L1 signalling pathway is particularly important for limiting the ability of T cells to attack the heart. Immune checkpoint inhibitors (ICIs) specifically block this PD-1/PD-L1-mediated restriction of T cell activation and other immunosuppressive pathways by targeting immune checkpoints. In recent years, with the wide use of ICIs in cancer treatment, even though the incidence of immunomyocarditis is low, it has attracted increasing attention because of its complex clinical symptoms, rapid progression of disease and high mortality rates. The pathogenesis, genetic susceptibility factors and predictive biomarkers of immunomyocarditis still need to be understood, and multidisciplinary cooperation in the clinical treatment of this complication is necessary.

Clinical Strategy for the Diagnosis and Treatment of Immune Checkpoint Inhibitor-Associated Myocarditis: A Narrative Review

Importance

In the last decade, immune checkpoint inhibitors (ICIs) have been approved for the treatment of many cancer types. Immune checkpoint inhibitor-associated myocarditis has emerged as a significant and potentially fatal adverse effect. Recognizing, diagnosing, and treating ICI-associated myocarditis poses new challenges for the practicing clinician. Here, the current literature on ICI-associated myocarditis is reviewed.

Observations

Clinical presentation and cardiac pathological findings are highly variable in patients with ICI-associated myocarditis. Although endomyocardial biopsy is the criterion standard diagnostic test, a combination of clinical suspicion, cardiac biomarkers (specifically troponin), and cardiac imaging, in addition to biopsy, is often needed to support the diagnosis. Importantly, the combination of a cytotoxic T-lymphocyte-associated protein 4 inhibitor with a programmed cell death protein 1 or programmed death-ligand 1 inhibitor increases the risk of developing ICI-associated myocarditis.

Conclusion and Relevance

This review aims to provide a standardized diagnostic and therapeutic approach for patients with suspected ICI-associated myocarditis. A complete history of recent cancer treatments and physical examination in combination with cardiac biomarkers, cardiac imaging, and endomyocardial biopsy represent a pragmatic diagnostic approach for most cases of ICI-associated myocarditis. The addition of novel biomarkers or imaging modalities is an area of active research and should be evaluated in larger cohorts.

Factors associated with myocardial SARS-CoV-2 infection, myocarditis, and cardiac inflammation in patients with COVID-19

COVID-19 has been associated with cardiac injury and dysfunction. While both myocardial inflammatory cell infiltration and myocarditis with myocyte injury have been reported in patients with fatal COVID-19, clinical-pathologic correlations remain limited. The objective was to determine the relationships between cardiac pathological changes in patients dying from COVID-19 and cardiac infection by SARS-CoV-2, laboratory measurements, clinical features, and treatments. In a retrospective study, 41 consecutive autopsies of patients with fatal COVID-19 were analyzed for the associations between cardiac inflammation, myocarditis, cardiac infection by SARS-CoV-2, clinical features, laboratory measurements, and treatments. Cardiac infection was assessed by in situ hybridization and NanoString transcriptomic profiling. Cardiac infection by SARS-CoV-2 was present in 30/41 cases: virus+ with myocarditis (n = 4), virus+ without myocarditis (n = 26), and virus- without myocarditis (n = 11). In the cases with cardiac infection, SARS-CoV-2+ cells in the myocardium were rare, with a median density of 1 cell/cm2. Virus+ cases showed higher densities of myocardial CD68+ macrophages and CD3+ lymphocytes, as well as more electrocardiographic changes (23/27 vs 4/10; P = 0.01). Myocarditis was more prevalent with IL-6 blockade than with nonbiologic immunosuppression, primarily glucocorticoids (2/3 vs 0/14; P = 0.02). Overall, SARS-CoV-2 cardiac infection was less prevalent in patients treated with nonbiologic immunosuppression (7/14 vs 21/24; P = 0.02). Myocardial macrophage and lymphocyte densities overall were positively correlated with the duration of symptoms but not with underlying comorbidities. In summary, cardiac infection with SARS-CoV-2 is common among patients dying from COVID-19 but often with only rare infected cells. Cardiac infection by SARS-CoV-2 is associated with more cardiac inflammation and electrocardiographic changes. Nonbiologic immunosuppression is associated with lower incidences of myocarditis and cardiac infection by SARS-CoV-2.

Immune checkpoint inhibitor myocarditis: elucidating the spectrum of disease through endomyocardial biopsy

AIMS

Although immune checkpoint inhibitor (ICI) myocarditis carries a high reported mortality, increasing reports of smoldering myocarditis suggest a clinical spectrum of disease. Endomyocardial biopsy (EMB) remains the gold standard for diagnosis of ICI myocarditis, but different pathologic diagnostic criteria exist. The objective of this study was to classify the spectrum of ICI myocarditis and myocardial inflammation by pathology findings on EMB and correlate this with clinical outcomes.

METHODS AND RESULTS

All patients who had EMB at MD Anderson Cancer Center between January 2018 and August 2019 for suspected ICI myocarditis were retrospectively reviewed. A grading system (Grades 0-2) based on the degree of inflammatory infiltrate was developed by pathologists. Cardiovascular outcomes and treatment were compared between grades of pathology. We identified 28 patients who had EMB for suspected ICI myocarditis, of which 18 were positive for myocarditis/inflammation. There were four deaths (two in Grade 2 and two in Grade 1), but only one was attributable to myocarditis. Grade 2 patients had no myocarditis-associated deaths despite having the highest troponin T values (median 2063 pg/mL). Four patients with Grade 1 myocardial inflammation continued ICI without any immunomodulation, and all were alive without adverse cardiovascular events at follow-up.

CONCLUSION

We defined an EMB grading system for ICI myocarditis encompassing a spectrum of histologic findings of inflammatory infiltrates. A subset of low-grade myocardial inflammation patients were able to continue ICI without immunosuppressive therapy. Further studies are needed to identify low-risk patients who can be safely treated with ICI.

What the Cardiologist Needs to Know About Cancer Immunotherapies and Complications

OPINION STATEMENT

Immunotherapies have transformed the current landscape for cancer treatment and demonstrated unparalleled improvements in survival rates. Now, a third of cancer patients are eligible for treatment with the most widely used class of immunotherapy, immune checkpoint inhibitors (ICIs). As more patients are treated with these novel agents, it is critical for both oncologists and subspecialists to establish a better understanding of the adverse events which can occur. The incidence of myocarditis associated with ICI therapy has been reported to be between 0.27 and 1.14%, 5 times that of myocarditis from other cancer therapies, and, of those patients, 20-50% develop a fulminant form. However, because of unclear risk factors, a broad clinical spectrum, and lack of specific noninvasive studies for diagnosis, the care of patients with ICI-associated cardiotoxicity can be challenging. Here, we have provided a brief overview of the current immunotherapy agents with a focus on the emerging evidence regarding diagnosis and management of cardiac adverse events.

Comparative Transcriptomics of Immune Checkpoint Inhibitor Myocarditis Identifies Guanylate Binding Protein 5 and 6 Dysregulation

Immune checkpoint inhibitors (ICIs) are revolutionizing cancer treatment. Nevertheless, their increasing use leads to an increase of immune-related adverse events (irAEs). Among them, ICI-associated myocarditis (ICIM) is a rare irAE with a high mortality rate. We aimed to characterize the transcriptional changes of ICIM myocardial biopsies and their possible implications. Patients suspected for ICIM were assessed in the cardio-oncology units of University Hospitals Heidelberg and Kiel. Via RNA sequencing of myocardial biopsies, we compared transcriptional changes of ICIM (n = 9) with samples from dilated cardiomyopathy (DCM, n = 11), virus-induced myocarditis (VIM, n = 5), and with samples of patients receiving ICIs without any evidence of myocarditis (n = 4). Patients with ICIM (n = 19) showed an inconsistent clinical presentation, e.g., asymptomatic elevation of cardiac biomarkers (hs-cTnT, NT-proBNP, CK), a drop in left ventricular ejection fraction, or late gadolinium enhancement in cMRI. We found 3784 upregulated genes in ICIM (FDR < 0.05). In the overrepresented pathway 'response to interferon-gamma', we found guanylate binding protein 5 and 6 (compared with VIM: GBP5 (log2 fc 3.21), GBP6 (log2 fc 5.37)) to be significantly increased in ICIM on RNA- and protein-level. We conclude that interferon-gamma and inflammasome-regulating proteins, such as GBP5, may be of unrecognized significance in the pathophysiology of ICIM.

How can we manage the cardiac toxicity of immune checkpoint inhibitors?

Introduction: Cancer immunotherapies with monoclonal antibodies (mAbs) against immune checkpoints (i.e. CTLA-4 and PD-1/PD-L1) have revolutionized antineoplastic treatments. Immune checkpoint inhibitors (ICIs) approved for cancer immunotherapy are mAbs anti-CTLA-4 (ipilimumab), anti-PD-1 (nivolumab, pembrolizumab, and cemiplimab), and anti-PD-L1 (atezolizumab, avelumab, and durvalumab). Treatment with ICIs can be associated with immune-related adverse events (irAEs), including an increased risk of developing myocarditis. These findings are compatible with the observation that, CTLA-4, PD-1, and PD-L1 pathways play a central role in the modulation of autoimmunity.Areas covered: In this paper, we start from examining the pathogenesis of cardiovascular adverse events from ICIs, and then we focus on risk factors and strategies to prevent and manage this cardiotoxicity.Expert opinion: There is a growing need for a multidisciplinary approach of ICI-associated cardiotoxicity, involving oncologists, cardiologists, and immunologists. Prevention and effective management of ICIs cardiotoxicity starts with an in-depth screening and surveillance strategies of high-risk patients, in order to improve early detection and appropriate management in a personalized approach.

Immune checkpoint inhibitor cardiotoxicity: what can we learn from real life data on CMR as a diagnostic tool?

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The Evolving Immunotherapy Landscape and the Epidemiology, Diagnosis, and Management of Cardiotoxicity: JACC: CardioOncology Primer

Immune checkpoint inhibitors (ICIs) are newer therapies being applied to an increasing number of patients with cancer. Data suggest that up to 36% of cancer patients may be eligible for immunotherapy and, in late 2019, there were more than 3,362 clinical trials initiated to evaluate the effectiveness of immunotherapy, either as single agents or in combination with other immunotherapy, targeted therapies, or traditional cytotoxic or radiation therapy. With the combination of both immune and non-immune treatment approaches, the complexity in making the diagnosis of cardiotoxicity related to an ICI will increase substantially. Here, we summarize the published data on the epidemiology, diagnosis, and management of cardiotoxicity of ICIs. This is a rapidly evolving field, and as our understanding continues to evolve, previously considered hypotheses may not prove to be entirely correct. Research and continued collaborations are urgently needed to provide evidence-based cardiovascular care for this rapidly expanding and vulnerable cohort of patients. (J Am Coll Cardiol CardioOnc 2021;3:35-47) © 2021 The Authors. Published by Elsevier on behalf of the American College of Cardiology Foundation. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).

Pathological features of COVID-19-associated myocardial injury: a multicentre cardiovascular pathology study

Aims

Coronavirus disease 2019 (COVID-19) due to severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) has been associated with cardiovascular features of myocardial involvement including elevated serum troponin levels and acute heart failure with reduced ejection fraction. The cardiac pathological changes in these patients with COVID-19 have yet to be well described.

Methods and results

In an international multicentre study, cardiac tissue from the autopsies of 21 consecutive COVID-19 patients was assessed by cardiovascular pathologists. The presence of myocarditis, as defined by the presence of multiple foci of inflammation with associated myocyte injury, was determined, and the inflammatory cell composition analysed by immunohistochemistry. Other forms of acute myocyte injury and inflammation were also described, as well as coronary artery, endocardium, and pericardium involvement. Lymphocytic myocarditis was present in 3 (14%) of the cases. In two of these cases, the T lymphocytes were CD4 predominant and in one case the T lymphocytes were CD8 predominant. Increased interstitial macrophage infiltration was present in 18 (86%) of the cases. A mild pericarditis was present in four cases. Acute myocyte injury in the right ventricle, most probably due to strain/overload, was present in four cases. There was a non-significant trend toward higher serum troponin levels in the patients with myocarditis compared with those without myocarditis. Disrupted coronary artery plaques, coronary artery aneurysms, and large pulmonary emboli were not identified.

Conclusions

In SARS-CoV-2 there are increased interstitial macrophages in a majority of the cases and multifocal lymphocytic myocarditis in a small fraction of the cases. Other forms of myocardial injury are also present in these patients. The macrophage infiltration may reflect underlying diseases rather than COVID-19.

Cardiovascular Toxicity of Immune Checkpoint Inhibitors: Clinical Risk Factors

Purpose of Review

Immune checkpoint inhibitors, such as monoclonal antibodies targeting CTLA-4, PD-1, and PD-L1, have improved the outcome of many malignancies, but serious immune-related cardiovascular adverse events have been observed. Patients’ risk factors for these toxicities are currently being investigated.

Recent Findings

Interfering with the CTLA-4 and PD-1 axes can bring to several immune-related adverse events, including cardiotoxic events such as autoimmune myocarditis, pericarditis, and vasculitis, suggesting that these molecules play an important role in preventing autoimmunity.

Summary

Risk factors (such as pre-existing cardiovascular conditions, previous and concomitant cardiotoxic treatments, underlying autoimmune diseases, tumor-related factors, simultaneous immune-related toxic effects, and genetic factors) should be always recognized for the correct management of these toxicities.

Cardiovascular Health during and after Cancer Therapy

Certain cancer treatments have been linked to specific cardiovascular toxicities, including (but not limited to) cardiomyopathy, atrial fibrillation, arterial hypertension, and myocarditis. Radiation, anthracyclines, human epidermal growth factor receptor 2 (Her2)-directed therapies, fluoropyrimidines, platinums, tyrosine kinase inhibitors and proteasome inhibitors, immune checkpoint inhibitors, and chimeric antigen-presenting (CAR)-T cell therapy can all cause cardiovascular side effects. Management of cardiovascular dysfunction that occurs during cancer therapy often requires temporary or permanent cessation of the risk-potentiating anti-neoplastic drug as well as optimization of medical management from a cardiovascular standpoint. Stem cell or bone marrow transplant recipients face unique cardiovascular challenges, as do patients at extremes of age.

Fulminant myocarditis: a comprehensive review from etiology to treatments and outcomes

Fulminant myocarditis (FM) is characterized by a rapid progressive decline in cardiac function and a high mortality rate. Since the first report of FM patients in the 1980s, several clinical trials and research studies have been published increasing our knowledge regarding FM. Currently, the diagnosis of FM depends on various techniques including electrocardiography, echocardiography, endomyocardial biopsy, and cardiac magnetic resonance. The development of mechanical circulation support (MCS) devices and progress in our understanding of the pathophysiological mechanisms underlying FM, treatment regimens have evolved from simple symptomatic treatment to a life support-based comprehensive treatment approach. The core mechanism underlying the development of FM is the occurrence of an inflammatory cytokine storm. This review provides a comprehensive account of the current understanding of FM pathophysiology and knowledge regarding its etiology, pathophysiology, treatments, and outcomes.

Clinical Pharmacology and Interplay of Immune Checkpoint Agents: A Yin-Yang Balance

T cells have a central role in immune system balance. When activated, they may lead to autoimmune diseases. When too anergic, they contribute to infection spread and cancer proliferation. Immune checkpoint proteins regulate T cell function, including cytotoxic T lymphocyte antigen-4 (CTLA-4) and programmed cell death-1 (PD-1) and its ligand (PD-L1). These nodes of self-tolerance may be exploited pharmacologically to downregulate (CTLA-4 agonists) and activate [CTLA-4 and PD-1/PD-L1 antagonists, also called immune checkpoint inhibitors (ICIs)] the immune system.CTLA-4 agonists are used to treat rheumatologic immune disorders and graft rejection. CTLA-4, PD-1, and PD-L1 antagonists are approved for multiple cancer types and are being investigated for chronic viral infections. Notably, ICIs may be associated with immune-related adverse events (irAEs), which can be highly morbid or fatal. CTLA-4 agonism has been a promising method to reverse such life-threatening irAEs. Herein, we review the clinical pharmacology of these immune checkpoint agents with a focus on their interplay in human diseases.

Immune Checkpoint Inhibitor Cardiotoxicity: Understanding Basic Mechanisms and Clinical Characteristics and Finding a Cure

Immune checkpoint inhibitors (ICIs) attenuate mechanisms of self-tolerance in the immune system, enabling T cell responses to cancerous tissues and revolutionizing care for cancer patients. However, by loweringbarriers against self-reactivity, ICIs often result in varying degrees of autoimmunity. Cardiovascular complications, particularly myocarditis but also arrhythmias, pericarditis, and vasculitis, have emerged as significant complications associated with ICIs. In this review, we examine the clinical aspects and basic science principles that underlie ICI-associated myocarditis and other cardiovascular toxicities. In addition, we discuss current therapeutic approaches. We believe a better mechanistic understanding of ICI-associated toxicities can lead to improved patient outcomes by reducing treatment-related morbidity.

Programmed cell death-1 (PD-1) and programmed death-ligand 1 (PD-L1) expression in PD-1 inhibitor-associated colitis and its mimics

AIMS

Immune checkpoint inhibitors (ICIs) have revolutionised the treatment of advanced malignancies by boosting immune-mediated destruction of neoplastic cells, but are associated with side effects stemming from generalised immune system activation against normal tissues. Checkpoint ligand expression in non-tumoral cells of tissues affected by immune-related adverse effects has been described in ICI-associated hypophysitis, myocarditis, and acute interstitial nephritis. We aimed to investigate the tissue expression of the immune checkpoint receptor programmed cell death-1 (PD-1) and its ligand, programmed death-ligand 1 (PD-L1), in PD-1 inhibitor-associated colitis (PD1i colitis).

METHODS AND RESULTS

PD-1 and PD-L1 immunohistochemical expression levels were analysed in 15 cases of PD1i colitis and potential mimics-infectious colitis and inflammatory bowel disease (IBD). Increased epithelial expression of PD-L1 was observed in PD1i colitis as compared with normal colon and infectious colitis, but the expression level was lower than that in IBD. Conversely, PD-1 expression in inflammatory cells was higher in infectious colitis, intermediate in IBD, and minimal or absent in normal colon and in patients receiving PD-1 inhibitors.

CONCLUSIONS

Although our results do not justify the use of PD-L1 as a discriminatory marker of PD1i colitis against other entities within the differential diagnosis, they support the concept that PD1i colitis and IBD have similar pathogenetic mechanisms. They also highlight the fact that PD-L1 epithelial overexpression is a commonly used mechanism of the gastrointestinal tract mucosa to protect itself from inflammatory-mediated damage resulting from different aetiologies, which probably underpins the high incidence of gastrointestinal immune-related adverse effects in patients receiving ICI therapies, in whom this mechanism is disrupted.

Targeting Negative and Positive Immune Checkpoints with Monoclonal Antibodies in Therapy of Cancer

The immune checkpoints are regulatory molecules that maintain immune homeostasis in physiological conditions. By sending T cells a series of co-stimulatory or co-inhibitory signals via receptors, immune checkpoints can both protect healthy tissues from adaptive immune response and activate lymphocytes to remove pathogens effectively. However, due to their mode of action, suppressive immune checkpoints may serve as unwanted protection for cancer cells. To restore the functioning of the immune system and make the patient’s immune cells able to recognize and destroy tumors, monoclonal antibodies are broadly used in cancer immunotherapy to block the suppressive or to stimulate the positive immune checkpoints. In this review, we aim to present the current state of application of monoclonal antibodies in clinics, used either as single agents or in a combined treatment. We discuss the limitations of these therapies and possible problem-solving with combined treatment approaches involving both non-biological and biological agents. We also highlight the most promising strategies based on the use of monoclonal or bispecific antibodies targeted on immune checkpoints other than currently implemented in clinics.