Histopathologic Characterization of Myocarditis Associated With Immune Checkpoint Inhibitor Therapy

Chinese Society of Cardiology guidelines on the diagnosis and treatment of adult fulminant myocarditis

Fulminant myocarditis is an acute diffuse inflammatory disease of myocardium. It is characterized by acute onset, rapid progress and high risk of death. Its pathogenesis involves excessive immune activation of the innate immune system and formation of inflammatory storm. According to China's practical experience, the adoption of the "life support-based comprehensive treatment regimen" (with mechanical circulation support and immunomodulation therapy as the core) can significantly improve the survival rate and long-term prognosis. Special emphasis is placed on very early identification,very early diagnosis,very early prediction and very early treatment.

Predominant CD8+ cell infiltration and low accumulation of regulatory T cells in immune checkpoint inhibitor-induced tubulointerstitial nephritis

Immune checkpoint inhibitors (ICIs) can provide survival benefits to cancer patients; however, they sometimes result in the development of renal immune-related adverse events (irAEs). Tubulointerstitial nephritis (TIN) is the most representative pathological feature of renal irAEs. However, the clinicopathological entity and underlying pathogenesis of ICI-induced TIN are unclear. Therefore, we compared the clinical and histological features of this condition with those of non-ICI drug-induced TIN. Age and C-reactive protein levels were significantly higher in ICI-induced TIN, but there were no significant differences in renal function. Immunophenotyping of ICI-induced TIN showed massive T cell and macrophage infiltration with fewer B cells, plasma cells, neutrophils, and eosinophils. Compared with those in non-ICI drug-induced TIN, CD4+ cell numbers were significantly lower in ICI-induced TIN but CD8+ cell numbers were not significantly different. However, CD8/CD3 and CD8/CD4 ratios were higher in ICI-induced TIN. Moreover, CD25+ and FOXP3+ cells, namely regulatory T cells, were less abundant in ICI-induced TIN. In conclusion, T cell, B cell, plasma cell, neutrophil, and eosinophil numbers proved useful for differentiating ICI-induced and non-ICI drug-induced TIN. Furthermore, the predominant distribution of CD8+ cells and low accumulation of regulatory T cells might be associated with ICI-induced TIN development.

The role of circulating biomarkers in predicting the 30-day mortality of immune checkpoint inhibitors-related myocarditis: a retrospective cohort study

Immune checkpoint inhibitors-related myocarditis (ICIs-M) is a rare and highly lethal immune-related adverse events (irAEs) in common irAEs. This study aims to find circulating biomarkers that can reflect disease state and prognosis accurately. 48 patients with ICIs-M were enrolled according to the diagnostic criteria for ICIs-related myocarditis. For all enrolled patients, valuable information was extracted retrospectively from the medical system, mainly including demographic information, tumor information and laboratory examination. The follow-up period was defined as 30 days after the first diagnosis of ICIs-M. In this study, the 30-day mortality rate of ICIs-M was 24.4%. After adjusting for potential confounding factors using multivariate analysis tools, we demonstrated the excellent performance of biomarkers in predicting 30-day mortality in patients with ICIs-M, including PLT (hazard ratio (HR), 1.07; 95% confidence interval (95%CI), 1.01-1.14; p = 0.028), ALT (HR, 1.23; 95%CI, 1.06-1.41; p = 0.005), AST(HR, 1.06; 95%CI, 1.01-1.10; p = 0.015), LDH (HR, 1.15; 95%CI, 1.04-1.26; p = 0.004), troponin I(HR, 1.44; 95%CI, 1.09-1.89; p = 0.009), PLR (blood plate/lymphocyte) (HR, 1.04; 95% CI, 1.01-1.07; p = 0.024), LAR (lactate dehydrogenase/albumin) (HR, 1.05; 95%CI, 1.01-1.09; p = 0.012), and AAR (aspartate transaminase/albumin) (HR, 1.18; 95%CI, 1.00-1.39; p = 0.048). The analysis of the receiver operating characteristic showed that biomarkers with area under curve (AUC) greater than or equal to 0.80 were LDH (cutoff value, 724.5; AUC, 0.86; 95%CI, 0.75-0.97), LAR (cutoff value, 18.11; AUC, 0.87; 95%CI, 0.76-0.97), troponin I (cutoff value, 0.87; AUC, 0.80; 95%CI, 0.62-0.99), and AAR(cutoff value, 1.52; AUC, 0.80; 95%CI, 0.61-0.98). LDH, LAR, troponin I, and AAR are a group of promising biomarkers that demonstrate excellent predictive ability in predicting the 30-day mortality rate of immune-related myocarditis.

Perimyocarditis Associated with Immune Checkpoint Inhibitors: A Case Report and Review of the Literature

Patient prognoses have been significantly enhanced by immune checkpoint inhibitors (ICIs), altering the standard of care in cancer treatment. These novel antibodies have become a mainstay of care for metastatic non-small-cell lung cancer (mNSCLC) patients. Several types of adverse events related to ICIs have been identified and documented as a result of the launch of these innovative medicines. We present here a 74-year-old female patient with a stage IV lung adenocarcinoma, treated with nivolumab plus ipilimumab, who developed perimyocarditis two weeks after receiving the third cycle of immune checkpoint inhibitor therapy. The patient was diagnosed using troponin levels, computed tomography (CT) angiography, and echocardiography. After hospitalization, her cardiac condition was successfully resolved with corticosteroids, colchicine, and symptomatic treatment. To the best of our knowledge, this is one of the rarest cases to be reported of perimyocarditis as a toxicity of immunotherapy in a patient treated for adenocarcinoma of the lung.

Mediators and mechanisms of immune checkpoint inhibitor-associated myocarditis: Insights from mouse and human

The broad application of immune checkpoint inhibitors (ICIs) has led to significant gains in cancer outcomes. By abrogating inhibitory signals, ICIs promote T cell targeting of cancer cells but can frequently trigger autoimmune manifestations, termed immune-related adverse events (irAEs), affecting essentially any organ system. Among cardiovascular irAEs, immune-related myocarditis (irMyocarditis) is the most described and carries the highest morbidity. The currently recommended treatment for irMyocarditis is potent immunosuppression with corticosteroids and other agents, but this has limited evidence basis. The cellular pathophysiology of irMyocarditis remains poorly understood, though mouse models and human data have both implicated effector CD8+ T cells, some of which are specific for the cardiomyocyte protein α-myosin. While the driving molecular signals and transcriptional programs are not well defined, the involvement of chemokine receptors such as CCR5 and CXCR3 has been proposed. Fundamental questions regarding why only approximately 1% of ICI recipients develop irMyocarditis and why irMyocarditis carries a much worse prognosis than other forms of lymphocytic myocarditis remain unanswered. Further work in both murine systems and with human samples are needed to identify better tools for diagnosis, risk-stratification, and treatment.

Pembrolizumab-Induced Fatal Myasthenia, Myocarditis, and Myositis in a Patient with Metastatic Melanoma: Autopsy, Histological, and Immunohistochemical Findings-A Case Report and Literature Review

Immune checkpoint inhibitors (ICIs) represent a major advance in cancer treatment. The lowered immune tolerance induced by ICIs brought to light a series of immune-related adverse events (irAEs). Pembrolizumab belongs to the ICI class and is a humanized IgG4 anti-PD-1 antibody that blocks the interaction between PD-1 and PD-L1. The ICI-related irAEs involving various organ systems and myocarditis are uncommon (incidence of 0.04% to 1.14%), but they are associated with a high reported mortality. Unlike idiopathic inflammatory myositis, ICI-related myositis has been reported to frequently co-occur with myocarditis. The triad of myasthenia, myositis, and myocarditis must not be underestimated as they can rapidly deteriorate, leading to death. Herein we report a case of a patient with metastatic melanoma who fatally developed myasthenia gravis, myocarditis, and myositis, after a single cycle of pembrolizumab. Considering evidence from the literature review, autopsy, histological, and immunohistochemical investigations on heart and skeletal muscle are presented and discussed, also from a medical-legal perspective.

An integrative review of nonobvious puzzles of cellular and molecular cardiooncology

Oncologic patients are subjected to four major treatment types: surgery, radiotherapy, chemotherapy, and immunotherapy. All nonsurgical forms of cancer management are known to potentially violate the structural and functional integrity of the cardiovascular system. The prevalence and severity of cardiotoxicity and vascular abnormalities led to the emergence of a clinical subdiscipline, called cardiooncology. This relatively new, but rapidly expanding area of knowledge, primarily focuses on clinical observations linking the adverse effects of cancer therapy with deteriorated quality of life of cancer survivors and their increased morbidity and mortality. Cellular and molecular determinants of these relations are far less understood, mainly because of several unsolved paths and contradicting findings in the literature. In this article, we provide a comprehensive view of the cellular and molecular etiology of cardiooncology. We pay particular attention to various intracellular processes that arise in cardiomyocytes, vascular endothelial cells, and smooth muscle cells treated in experimentally-controlled conditions in vitro and in vivo with ionizing radiation and drugs representing diverse modes of anti-cancer activity.

Immune checkpoint inhibitor sintilimab-induced lethal myocarditis overlapping with myasthenia gravis in thymoma patient: A case report

RATIONALE

Immune checkpoint inhibitors have been extensively used and significantly improved the clinical outcomes in multiple types of cancer. But the immune-related adverse events occur frequently, particularly in thymoma. The cardiac immune-related adverse, which is relatively rare but fatal, have been increasing reported.

PATIENT CONCERNS

A 45-year-old thymoma patient was admitted to our hospital after receiving anti-programmed cell death-1 treatment with sintilimab 14 days later, accompanied by abdominal pain, intermittent chest tightness and dizziness.

DIAGNOSES

The laboratory tests revealed elevated serum troponin I. Electrocardiogram reported the prolongation of QTc interval. Echocardiography showed small amount of pericardial effusion, a left ventricular ejection fraction of 71%. Coronary artery computed tomography angiography revealed localized noncalcified plaque in the middle of the left anterior descending artery and mild stenosis of the lumen. Enhanced computed tomography scanning of the whole abdomen showed no abnormal signs in the parenchyma organs. Combining the results of the examinations, the Immune checkpoint inhibitor induced myocarditis was diagnosed.

INTERVENTIONS

The patient was treated with glucocorticoids (120 mg/day, IV, methylprednisolone) within 24 hours of admission. Seven days later, the patient experienced tachy ventricular arrhythmia and cardiogenic shock and was transferred to intensive care unit after electrical cardioversion, tracheal intubation and cardiopulmonary resuscitation. Intravenous immunoglobulin therapy at 25 g/day was given and methylprednisolone was reduced to 40 mg/day for the next 3 days. Intravenous esmolol and lidocaine were used for correcting arrhythmias. Ventilator positive pressure ventilation was used for respiratory support. She was administrated with plasmapheresis when the electrocardiogram monitoring showed ventricular arrhythmia storms.

OUTCOME

The patient progressed to ventricular arrhythmia storms and cardiac failure, which eventually resulted in death.

LESSONS

The case aims to raise awareness of immune-mediated cardiotoxicity and bring thoughts to the prospects of immunotherapy in thymoma.

Neuromuscular and cardiac adverse events associated with immune checkpoint inhibitors: pooled analysis of individual cases from multiple institutions and literature

BACKGROUND

Immune checkpoint inhibitors (ICIs) have revolutionized the management of multiple tumors, due to improved efficacy, quality of life, and safety. While most immune-related adverse events (irAEs) are mild and easily managed, in rare cases such events may be life-threatening, especially those affecting the neuromuscular and cardiac system. The management of neuromuscular/cardiac irAEs is not clear due to the lack of consistent data. Therefore, we carried out a pooled analysis of collected cases from selected Italian centers and individual data from published case reports and case series, in order to improve our understanding of these irAEs.

PATIENTS AND METHODS

We collected retrospective data from patients treated in six Italian centers with ICIs (programmed cell death protein 1 or programmed death-ligand 1 and/or cytotoxic T-lymphocyte antigen 4 inhibitor) for any solid tumor who experienced neuromuscular and/or cardiovascular toxicity. Then, we carried out a search of case reports and series of neuromuscular/cardiac irAEs from ICIs with any solid tumor.

RESULTS

This analysis includes cases from Italian institutions (n = 18) and the case reports identified in our systematic literature search (n = 120), for a total of 138 patients. Among these patients, 50 (36.2%) had complete resolution of their neuromuscular/cardiac irAEs, in 21 (15.2%) cases there was a clinical improvement with mild sequelae, and 53 (38.4%) patients died as a result of the irAEs. Factors significantly associated with worse outcomes were early irAE onset, within the first two cycles of ICI (Fisher P < 0.0001), clinical manifestation of both myositis and myocarditis when compared with patients who developed only myositis or myocarditis (chi-square P = 0.0045), and the development of arrhythmia (Fisher P = 0.0070).

CONCLUSIONS

To the best of our knowledge, this is the largest collection of individual cases of immune-related myocarditis/myositis. Early irAE onset, concurrent development of myositis and myocarditis, as well as occurrence of arrhythmias are associated with worse outcomes and should encourage an aggressive immunomodulatory treatment.

Case report: Electrocardiographic changes in pembrolizumab-induced fatal myocarditis

Immune checkpoint inhibitor (ICI)-induced myocarditis is rare but fatal. Because of the rapid course of ICI-induced myocarditis, understanding of clinical course is only possible through information from case reports. We report a case of pembrolizumab-induced myocarditis in which we were able to document the course of electrocardiographic changes from onset to death. A 58-year-old woman with stage IV lung adenocarcinoma, who had completed her first cycle of pembrolizumab, carboplatin, and pemetrexed, was admitted with pericardial effusion. She underwent pericardiocentesis after admission. A second cycle of chemotherapy was administered 3 weeks after the first cycle. Twenty-two days after admission, she developed a mild sore throat and tested positive for SARS-CoV-2 antigen. She was diagnosed with mild coronavirus disease 2019 (COVID-19), isolated, and treated with sotrovimab. Thirty-two days after admission, an electrocardiogram showed monomorphic ventricular tachycardia (VT). Suspecting myocarditis caused by pembrolizumab, the patient was started on daily methylprednisolone after coronary angiography and endocardial biopsy. Eight days after the start of methylprednisolone administration, she was considered to have passed the acute stage. However, four days later, R-on-T phenomenon triggered polymorphic VT and she died. The impact of viral infections such as COVID-19 on patients be treated with immune checkpoint inhibitors is still unknown and we need to be careful with systemic management after viral infections.

Immunopathogenesis of Immune Checkpoint Inhibitor Induced Myocarditis: Insights from Experimental Models and Treatment Implications

Despite the extraordinary success of immune checkpoint inhibitors (ICIs) in cancer treatment, their use is associated with a high incidence of immune-related adverse events (IRAEs), resulting from therapy-related autoimmunity against various target organs. ICI-induced myocarditis is one of the most severe forms of IRAE, which is associated with risk of hemodynamic compromise and mortality. Despite increasing recognition and prompt treatment by clinicians, there remain significant gaps in knowledge regarding the pathophysiology, diagnosis and treatment of ICI-induced myocarditis. As the newly emerged disease entity is relatively rare, it is challenging for researchers to perform studies involving patients at scale. Alternatively, mouse models have been developed to facilitate research understanding of the pathogenesis of ICI-induced myocarditis and drug discovery. Transgenic mice with immune checkpoint genes knocked out allow induction of myocarditis in a highly reproducible manner. On the other hand, it has not been possible to induce ICI-induced myocarditis in wild type mice by injecting ICIs monotherapy alone. Additional interventions such as combinational ICI, tumor inoculation, cardiac sarcomere immunization, or cardiac irradiation are necessary to mimic the underlying pathophysiology in human cancer patients and to induce ICI-induced myocarditis successfully. This review focuses on the immunopathogenesis of ICI-induced myocarditis, drawing insights from human studies and animal models, and discusses the potential implications for treatment.

Multisystem inflammatory syndrome and lymphohistiocytic myocarditis after Covid‐19 vaccine in a middle‐aged woman

We describe a 51-year-old otherwise healthy woman hospitalized for hypotension, fever, and weakness 4 days after the second-dose Covid-19 mRNA vaccine. Elevated inflammatory markers, natriuretic peptide levels and troponin levels, and slightly reduced left ventricular ejection fraction of 50% were noted. We also found the multiple organ damage, including mucocutaneous, gastrointestinal, and neurologic systems. In addition, we revealed the positive results for anti-nucleocapsid SARS-CoV-2 IgG, albeit negative for SARS-CoV-2 polymerase chain reaction testing, suggesting the prior asymptomatic Covid-19 infection. We finally diagnosed her as multisystem inflammatory syndrome after vaccination. Of note, we obtained myocardial specimen from the patients and demonstrated the lymphohistiocytic myocarditis, which is a rare form of myocarditis.

Overcoming the cardiac toxicities of cancer therapy immune checkpoint inhibitors

Immune checkpoint inhibitors (ICIs) have led recent advances in the field of cancer immunotherapy improving overall survival in multiple malignancies with abysmal prognoses prior to their introduction. The remarkable efficacy of ICIs is however limited by their potential for systemic and organ specific immune-related adverse events (irAEs), most of which present with mild to moderate symptoms that can resolve spontaneously, with discontinuation of therapy or glucocorticoid therapy. Cardiac irAEs however are potentially fatal. The understanding of autoimmune cardiotoxicity remains limited due to its rareness. In this paper, we provide an updated review of the literature on the pathologic mechanisms, diagnosis, and management of autoimmune cardiotoxicity resulting from ICIs and their combinations and provide perspective on potential strategies and ongoing research developments to prevent and mitigate their occurrence.

Cardiovascular toxicities associated with immune checkpoint inhibitors: An updated comprehensive disproportionality analysis of the FDA adverse event reporting system

WHAT IS KNOWN AND OBJECTIVE

Immune checkpoint inhibitors (ICIs) have significantly improved clinical outcomes for a wide range of cancers but can also lead to cardiovascular toxicities. This study was to scientifically and systematically explore the association between cardiovascular toxicities and immune checkpoint inhibitors (ICIs) and also to characterize the main features of ICI-related cardiovascular toxicities.

METHODS

From January 2012 to December 2020, data in the Food and Drug Administration Adverse Event Reporting System (FAERS) database were retrieved for disproportionality analysis. The definition of adverse events (AEs) relied on the Medical Dictionary for Regulatory Activities (MedDRA). We used the reporting odds ratio (ROR) with 95% confidence intervals (CIs) to evaluate the association between ICIs and cardiovascular AEs. Clinical characteristics of patients with ICI-associated cardiovascular toxicities were collected, and the time to onset following different ICI regimens was further investigated.

RESULTS AND DISCUSSION

We identified a total of 13,713 ICI-associated cardiovascular toxicities which appeared to influence more men (56.90%) than women (36.79%), with a median age of 67 (interquartile range [IQR] 58-74) years. ICI-associated cardiovascular AEs were most frequently reported in lung, pleura, thymus and heart cancer patients (34.49%). Compared with the full database, ICI therapies were detected with pharmacovigilance of myocardial disorders (ROR: 2.64; 95% CI: 2.55-2.75) and pericardial disorders (ROR: 4.51; 95% CI: 4.30-4.74). Concerning myocardial and pericardial disorders, a significant increased ROR was found for all anti-PD-1 and anti-PD-L1 monotherapies, with the exception of anti-CTLA-4 monotherapies. Regarding cardiac arrhythmias, only tremelimumab among ICI monotherapies was associated with an increased ROR (1.92, 1.09-4.72; 4 cases). Compared with ICI monotherapy, ICI combination therapy detected an increase in cardiovascular toxicity spectrum, but did not prolong the onset time.

WHAT IS NEW AND CONCLUSION

We observed that the spectrum and risk of ICI-associated cardiovascular AEs differed between therapeutic regimens. The poor clinical outcome and early onset of these events should attract clinical attention.

PD-1/PD-L1 Inhibitor-Associated Myocarditis: Epidemiology, Characteristics, Diagnosis, Treatment, and Potential Mechanism

Immune checkpoint inhibitors (ICIs) induce T-cell activation against cancer cells, and due to their anti-tumor function in multiple cancers, ICIs have been considered an important option for oncotherapy. PD-1/PD-L1 inhibitors are now widely used as ICIs for many types of cancers in clinical practices. Myocarditis induced by anti-PD-1/PD-L1 agents is uncommon but shows potentially fatal toxicity. In this review, we attempted to conclude the incidence, characteristics, diagnosis, and treatments, as well as illustrate the potential pathogenesis from the perspectives of T-lymphocyte infiltration, disturbance of regulatory T cells, cytokines, macrophage-mediated inflammatory response, and synergistic effect of PD-1/PD-L1 and CTLA4.

Balancing the good and the bad: controlling immune related adverse events versus anti-tumor responses in cancer patients treated with immune checkpoint inhibitors

Immune checkpoint inhibitors (ICI) have provided new hope for cancer patients, and in particular for patients with tumors that are immunologically active and classified as hot tumors. These tumors express antigenic and tumor microenvironment (TME) characteristics that make them potential candidates for therapy with checkpoint inhibitors that aim to reactivate the immune response such as anti-PD-1 and anti-CTLA-4. Examples of potentially responsive cancers are, melanoma, non-small cell lung cancer and several other metastatic or unresectable tumors with genetic instability: DNA mismatch repair deficiency (dMMR), microsatellite instability-high (MSI-H), or with a high tumor mutational burden (TMB). Immunotherapy using checkpoint inhibitors is typically associated with adverse events (AEs) that are milder than those with chemotherapy. However, a significant percentage of patients develop short-term immune-related AEs (irAEs) which range from mild (~70%) to severe cases (~13%) that can lead to modifications of the checkpoint inhibitor therapy and in some cases, death. While some studies have investigated immune mechanisms behind the development of irAEs, much more research is needed to understand the mechanisms and to develop interventions that could attenuate severe irAEs, while maintaining the anti-tumor response intact. Moreover, studies to identify biomarkers that can predict the likelihood of a patient developing severe irAEs would be of great clinical importance. Here we discuss some of the clinical ramifications of irAEs, potential immune mechanisms behind their development and studies that have investigated potentially useful biomarkers of irAEs development.

[Research Progress of Immune Checkpoint Inhibitor-associated Myocarditis]

免疫检查点抑制剂（immune checkpoint inhibitors, ICIs）是一种负性调节因子抗体，激活T细胞发挥免疫治疗抗肿瘤作用的同时，也可引起免疫相关的不良应答，从而诱导出一系列免疫相关不良反应（immune related adverse events, irAEs）。在这些irAEs中，ICIs相关心肌炎的发病率虽然很低，但致死率却明显高于其他不良反应，接近50%，临床医生应用ICIs时应提高警惕，但目前ICIs相关心肌炎的发病机制仍不明确。本文结合近期ICIs的研究成果对ICIs相关性心肌炎的发生机制及临床表现等方面作一综述，以提高临床医生对该不良反应的认识。

Immune checkpoint inhibitor treatment induces colitis with heavy infiltration of CD8 + T cells and an infiltration pattern that resembles ulcerative colitis

Colitis is a common, but poorly understood, adverse event of immune checkpoint inhibitors that are standard-of-care for an expanding range of cancer types. This explorative study aimed to describe the immune infiltrates in the colon from individuals developing checkpoint inhibitor colitis and compare them to well-known immunophenotypes of acute graft-versus-host disease, ulcerative colitis, and Crohn’s disease. Colon biopsies (n = 20 per group) of patients with checkpoint inhibitor colitis, acute graft-versus-host disease, ulcerative colitis and Crohn’s disease, all colitis treatment-naïve, and of individuals with a normal colon were analyzed using immunohistochemistry: CD8 for cytotoxic T cells, CD4 for T helper cells, and CD68 to identify cells of macrophage lineage. CD8 + T cell, CD4 + T cell, and CD68 + cell counts were performed. Cell infiltration was scored as scattered/patchy or band-like in the superficial and deep gut mucosa. Checkpoint inhibitor colitis was found to be heavily infiltrated by CD8 + T cells. Comparative analysis between groups showed that both CD8 + T cell counts (P < 0.01) and immune cell infiltration patterns in checkpoint inhibitor colitis were most similar to those observed in ulcerative colitis, with a deep band-like CD4 + T cell infiltration pattern and a superficial band-like CD68 + cell infiltration pattern in both. In conclusion, this is the first immunohistopathological study comparing infiltrate characteristics of checkpoint inhibitor colitis, acute graft-versus-host disease, ulcerative colitis, and Crohn’s disease. Checkpoint inhibitor colitis samples are heterogeneous, heavily infiltrated by CD8 + T cells, and show an immune cell infiltration pattern that is more similar to ulcerative colitis than to colonic acute graft-versus-host disease or colonic Crohn’s disease.

Immune Myocarditis Overlapping With Myasthenia Gravis Due to Anti-PD-1 Treatment for a Chordoma Patient: A Case Report and Literature Review

Immunotherapy begins to be widely used due to the increasing exploration and gratifying effects in multiple cancers. Chordoma, as a rare bone malignant tumor, often recurs and metastasizes after undergoing surgery and radiotherapy. Therefore, immunotherapy can be explored as an emerging, potentially effective treatment to improve the survival rate and clinical benefit of patients. However, a variety of immune-related adverse events (irAEs) cannot be avoided completely. And the immunotherapy-induced myocarditis, as a rare but fatal irAE, has been increasingly reported. Understanding the mechanism involved in irAEs can inform best practices for side effects management. Here, we firstly reported a case of immune myocarditis and subsequent myasthenia gravis (MG) following anti-PD-1 treatment for chordoma.

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.

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.

Mechanisms and Management of Immune Checkpoint Inhibitor-Related Cardiac Adverse Events

Onco-cardiology recently emerged as a novel discipline to provide effective cardioprotective care against cancer therapeutics-related cardiac adverse events (CAEs) and support the continuity of optimal cancer treatment. Immune checkpoint inhibitors (ICIs) have revolutionized cancer therapy and dramatically improved outcomes in patients with advanced or refractory cancers. However, ICIs intrinsically stimulate systemic immune responses and can potentially induce a spectrum of immune-related adverse events (irAEs), which can affect any organs of the body. The manifestation of cardiac irAEs includes myocarditis, arrhythmias and conduction abnormalities, and pericardial diseases. Takotsubo-like cardiomyopathy is also included as a manifestation of ICI-related CAEs, but the pathophysiological relevance is unclear. Although the incidence is rare, ICI-related CAEs are life-threatening and potentially fatal. Elucidating pathophysiology and establishing management measures of ICI-related CAEs are one of the most urgent challenges in the field of onco-cardiology.

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/).