Immune checkpoint inhibitor therapy and myocarditis: a systematic review of reported cases

Immune Checkpoint Inhibitor-induced Myositis

Myositis induced by immune checkpoint inhibitors (ICIs) is an infrequent, potentially fatal, immune-related adverse event. It has higher incidence in patients who receive combination ICI therapy compared to monotherapy. Patients can present with clinical manifestation symptoms of myositis alone or in combination with myocarditis and/or myasthenia gravis, which significantly worsens the course and prognosis. Diagnosis can generally be made on the basis of clinical presentation, elevation of muscle enzymes, and electromyographic changes, but some patients may require a muscle biopsy. The first line of therapy is high-dose corticosteroids, followed by immunosuppression, plasmapheresis, or intravenous immunoglobulin in patients with severe disease.

Pembrolizumab-induced myocarditis with complete atrioventricular block and concomitant myositis in a metastatic bladder cancer patient: a case report and review of the literature

BACKGROUND

The cardiovascular system is among the least systems affected by immune-related adverse events. We report a rare life-threatening case of pembrolizumab-induced myocarditis with complete atrioventricular block and concomitant myositis in a metastatic bladder cancer patient.

CASE PRESENTATION

An 82-year-old Caucasian female with invasive urothelial carcinoma, started on first-line pembrolizumab, was admitted four days after receiving her second dose for severe asthenia, diffuse muscle aches, neck pain, and lethargy. In the emergency department, she had several episodes of bradycardia reaching 40 beats per minute associated with general discomfort and fatigue. Electrocardiography showed a third-degree atrioventricular heart block, while the patient remained normotensive. Cardiac damage parameters were altered with elevated levels of creatine phosphokinase of 8930 U/L, suggestive of immune checkpoint inhibitor-induced myositis, and troponin T of 1.060 ng/mL. Transthoracic echocardiography showed a preserved ejection fraction. Pembrolizumab-induced myocarditis was suspected. Therefore, treatment was initiated with high-dose glucocorticoids for 5 days, followed by a long oral steroid taper. A pacemaker was also implanted. Treatment resulted in the resolution of heart block and a decrease in creatine phosphokinase to the normal range.

CONCLUSION

Life-threatening cardiac adverse events in the form of myocarditis may occur with pembrolizumab use, warranting vigilant cardiac monitoring. Troponin monitoring in high-risk patients, along with baseline echocardiography may help identify this complication promptly to prevent life-threatening consequences.

Clinical characteristics, diagnosis and management of nivolumab-induced myocarditis

Nivolumab can cause fatal myocarditis. We aimed to analyze the clinical characteristics of nivolumab-induced myocarditis and provide evidence for clinical diagnosis, treatment, and prevention. Studies involving nivolumab-induced myocarditis were identified in electronic databases from 2000 to 2023 for retrospective analysis. A total of 66 patients were included, with a median age of 68 years. The median onset time of myocarditis is 11.5 days. The main organs affected in persons presented with myocarditis are heart (100.0%) and skeletal muscle (22.7%). The main clinical manifestations are dyspnea (49.2%), fatigue (47.6%), and myalgias (25.4%). The levels of troponin, troponin T, troponin I, creatine kinase, creatine kinase myocardial band, creatine phosphokinase, C-reactive protein, brain natriuretic peptide, and N-terminal brain natriuretic peptide precursor were significantly increased. Histopathology often shows lymphocyte infiltration, myocardial necrosis, and fibrosis. Myocardial immunological parameters usually present positive. Cardiac imaging often suggests complete heart block, intraventricular conduction delay, arrhythmia, myocardial infarction, edema, left ventricular ejection fractions reduction, ventricular dysfunction, and other symptoms of myocarditis. Forty-two (63.6%) patients achieved remission within a median time of 8 days after discontinuation of nivolumab and treatment with systemic corticosteroids, immunoglobulins, plasmapheresis, and immunosuppressant. Thirty-five patients eventually died attributed to myocarditis (68.6%), cancer (20.0%), respiratory failure (5.7%), and other reasons (5.7%). Nivolumab-induced myocarditis should be comprehensively diagnosed based on clinical symptoms, histopathological manifestations, immunological parameters, and cardiac function imaging examinations. Nivolumab should be discontinued immediately, plasmapheresis and systemic corticosteroids combined with immunoglobulins or immunosuppressants may be an effective treatment.

Role of Biomarkers in the Management of Immune-Checkpoint Inhibitor-Related Myocarditis

PURPOSE OF REVIEW

Immune checkpoint inhibitor (ICI)-related myocarditis poses a major clinical challenge given its non-specific presentation, rapid progression, and high mortality rate. Here, we review the role of blood-based biomarkers in the clinical management of patients with ICI-related myocarditis.

RECENT FINDINGS

Myocardial injury, its unique pattern, and the co-occurrence with myositis are defining features of ICI-related myocarditis. Non-cardiac biomarkers, specifically creatinine phosphokinase, precedes the symptomatic presentation and is highly sensitive for diagnosing ICI-related myocarditis, making them useful screening biomarkers. Combined elevations in cardiac troponins and non-cardiac biomarkers improve the confidence of an ICI myocarditis diagnosis. High troponin and creatinine phosphokinase levels are strongly associated with severe outcomes. We propose biomarker-based algorithms for the monitoring and diagnosis of ICI-related myocarditis. Biomarkers, such as cardiac troponins and creatine phosphokinase, can be used in combination in the monitoring, diagnosis, and prognostication of patients with ICI-related myocarditis.

Combined Nivolumab and Ipilimumab in Octogenarian and Nonagenarian Melanoma Patients

Data regarding elderly melanoma patients treated with anti-PD-1 or anti-CTLA-4 antibodies are in favor of tolerability outcomes that are similar to those of younger counterparts. However, there are very few studies focusing on elderly patients receiving nivolumab combined with ipilimumab (NIVO + IPI). Here, we ask what are the current prescribing patterns of NIVO + IPI in the very elderly population and analyze the tolerance profile. This French multicenter retrospective study was conducted on 60 melanoma patients aged 80 years and older treated with NIVO + IPI between January 2011 and June 2022. The mean age at first NIVO + IPI administration was 83.7 years (range: 79.3-93.3 years). Fifty-five patients (92%) were in good general condition and lived at home. Two dosing regimens were used: NIVO 1 mg/kg + IPI 3 mg/kg Q3W (NIVO1 + IPI3) in 27 patients (45%) and NIVO 3 mg/kg + IPI 1 mg/kg Q3W (NIVO3 + IPI1) in 33 patients (55%). NIVO + IPI was a first-line treatment in 39 patients (65%). The global prevalence of immune-related adverse events was 63% (38/60), with 27% (16/60) being of grade 3 or higher. Grade ≥ 3 adverse events were less frequent in patients treated with NIVO3 + IPI1 compared with those treated with NIVO1 + IPI3 (12% versus 44%, p = 0.04). In conclusion, the prescribing patterns of NIVO + IPI in very elderly patients are heterogeneous in terms of the dosing regimen and line of treatment. The safety profile of NIVO + IPI is reassuring; whether or not the low-dose regimen NIVO3 + IPI1 should be preferred over NIVO1 + IPI3 in patients aged 80 years or older remains an open question.

Multiorgan Failure From Nivolumab and Ipilimumab: A Case Report and Literature Review

Immune checkpoint inhibitors (ICIs) as standard of care have revolutionized the treatment of patients with metastatic melanoma. The combination of nivolumab and ipilimumab improves treatment efficacy and prolongs survival compared to monotherapy alone. However, combination therapy is also associated with an increased incidence of adverse events. We report an uncommon yet important case of multi-organ failure in a patient following a single dose of nivolumab plus ipilimumab. A 60-year-old male with a history of ulcerative colitis in remission and metastatic melanoma was admitted on February 25, 2021, for presumed sepsis, after presenting with neutropenic fever. His brain metastases were previously resected on January 14, 2021, and he was started on dexamethasone 4 mg BID for six weeks. On February 11, 2021, he received one dose of nivolumab plus ipilimumab, per the CheckMate-067 protocol. He presented 14 days later with fever, diarrhea, pancytopenia, renal failure, drug-induced hepatitis, and myocarditis. The infectious workup was negative. His neutropenia responded to growth factors. He was diagnosed with interstitial nephritis due to immunotherapy and treated with corticosteroids. His symptoms resolved with concomitant improvement of his renal, hepatic, and cardiac function. He was discharged home in a stable condition. Although these specific immune-related adverse events (irAEs) are uncommon and rarely occur simultaneously, ICIs can trigger non-specific immune system activation, resulting in widespread inflammatory effects. Since irAEs can lead to multi-organ failure, as evidenced in this case, early recognition and institution of high-dose steroids are critical to preventing rapid deterioration. Given that ICI therapy is the standard of care for several cancers and is often studied in clinical trials, increased education on irAE toxicity and updated algorithms on the management of febrile cancer patients are warranted.

A Systematic Review of Myocarditis Induced by Immune Checkpoint Inhibitors: How Concerning Is the Most Common Cardiotoxicity of Immune Checkpoint Inhibitors?

Novel cancer therapies have revolutionized the management of various cancers. An immune checkpoint inhibitor (ICI) is one of these antitumor medications. ICIs, which are immune therapies, enhance the immune system's capacity to fight cancer cells. Based on the receptors that they inhibit, such as PD-1, PD-L1, and CTLA-4, ICIs are subdivided. Although this class of drugs is extremely beneficial for cancer patients, their adverse effects can be fatal. Multiple organs, such as the cardiovascular system, may be impacted by immune-related adverse effects (irAEs). These cardiotoxic irAEs can occur at a rate of up to 1% and can be fatal. Myocarditis is the most prevalent of all cardiotoxicities. The purpose of this systematic review is to assess the seriousness of myocarditis, the most prevalent cardiotoxicity of ICIs, and the importance of screening. We chose studies based on the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) 2020 criteria. Therefore, from 2018 to 2023, we gathered articles from databases such as PubMed, ScienceDirect, Web of Science, the Cochrane Library, and Google Scholar. Of the 665 studies identified based on various screening methods and quality assessment tools, 13 were selected for inclusion in the study. This study shows that although the risk of myocarditis in ICI therapy is low and the majority of cases are asymptomatic or mild, some cases can be deadly and disastrous, and physicians should be aware that if myocarditis is suspected based on clinical symptoms, troponin, electrocardiogram, and echocardiogram, treatment should be initiated accordingly.

Evaluation of Cardiac Adverse Events with Nivolumab Using a Japanese Real-World Database

BACKGROUND

Nivolumab has been used for the treatment of various types of cancers and has achieved improvements in overall survival. However, nivolumab can cause a variety of adverse events (AEs). Among these, cardiac-specific AEs have received little attention in clinical trials, despite their life-threatening potential.

OBJECTIVE

The present study aimed to determine the risk of nivolumab-induced cardiac AEs, time to onset, incidence rates, and post hoc outcomes using the Japanese Adverse Drug Event Report database.

METHODS

We analyzed data for the period between April 2004 and March 2021. Data on cardiac AEs were extracted and relative risk of AEs was estimated using the reporting odds ratio (ROR).

RESULTS

We analyzed 1,772,494 reports and identified 18,721 reports of AEs caused by nivolumab. Of these, 409 reports involved cardiac AEs. Signals were detected for four cardiac AEs: myocarditis; pericardial effusion; pericarditis; and immune-mediated myocarditis. Among these, myocarditis was the most frequently reported (35.0%) and included fatal cases. A histogram of times to onset showed nivolumab-associated AEs occurring 41-127 days after starting administration, with outlier cases of myocarditis or pericardial effusion occurring after more than one year, both with catastrophic consequences.

CONCLUSION

This study focused on cardiac AEs caused by nivolumab as post-marketing AEs. Myocarditis and pericardial effusion have been associated with some fatal cases after administration of nivolumab. Patients should be monitored for signs of onset for these AEs, not only at the start of administration, but also over an extended period after nivolumab administration.

Fulminant Myocarditis Complicated with Immune Checkpoint Inhibitor in Patients with Thymoma: Report of Three Cases

: Immune checkpoint inhibitors (ICIs) prevent the immune escape of tumor cells, which helps immune cells such as T lymphocytes to continuously monitor and kill tumor cells, and play powerful anti-tumor role. Immune checkpoint inhibitor-associated myocarditis has been rarely reported; however, its latent, rapidly developed, and lethal onset has gradually attracted the attention of clinicians. This study aimed to report cases of fulminant myocarditis in three patients with thymoma who were treated with pembrolizumab, one of the programmed cell death protein 1 inhibitors (PD-1 inhibitors).

Comparative efficacy and pharmacological mechanism of Chinese patent medicines against anthracycline-induced cardiotoxicity: An integrated study of network meta-analysis and network pharmacology approach

Background

This study aimed to evaluate the efficacy of Chinese patent medicines (CPMs) combined with dexrazoxane (DEX) against anthracycline-induced cardiotoxicity (AIC) and further explore their pharmacological mechanism by integrating the network meta-analysis (NMA) and network pharmacology approach.

Methods

We searched for clinical trials on the efficacy of DEX + CPMs for AIC until March 10, 2023 (Database: PubMed, Embase, Cochrane Library, Chinese National Knowledge Infrastructure, China Science and Technology Journal and China Online Journals). The evaluating outcomes were cardiac troponin I (cTnI) level, creatine kinase MB (CK-MB) level, left ventricular ejection fraction (LVEF) value, and electrocardiogram (ECG) abnormal rate. Subsequently, the results of NMA were further analyzed in combination with network pharmacology.

Results

We included 14 randomized controlled trials (RCTs) and 1 retrospective cohort study (n = 1,214), containing six CPMs: Wenxinkeli (WXKL), Cinobufotalin injection (CI), Shenqifuzheng injection (SQFZ), Shenmai injection (SM), Astragalus injection (AI) and AI + CI. The NMA was implemented in Stata (16.0) using the mvmeta package. Compared with using DEX only, DEX + SM displayed the best effective for lowering cTnI level (MD = -0.44, 95%CI [-0.56, -0.33], SUCRA 93.4%) and improving LVEF value (MD = 14.64, 95%CI [9.36, 19.91], SUCRA 98.4%). DEX + SQFZ showed the most effectiveness for lowering CK-MB level (MD = -11.57, 95%CI [-15.79, -7.35], SUCRA 97.3%). And DEX + AI + CI has the highest effectiveness for alleviating ECG abnormalities (MD = -2.51, 95%CI [-4.06, -0.96], SUCRA 96.8%). So that we recommended SM + DEX, SQFZ + DEX, and DEX + AI + CI as the top three effective interventions against AIC. Then, we explored their pharmacological mechanism respectively. The CPMs' active components and AIC-related targets were screened to construct the component-target network. The potential pathways related to CPMs against AIC were determined by KEGG. For SM, we identified 118 co-targeted genes of active components and AIC, which were significantly enriched in pathways of cancer pathways, EGFR tyrosine kinase inhibitor resistance and AGE-RAGE signaling pathway in diabetic complications. For SQFZ, 41 co-targeted genes involving pathways of microRNAs in cancer, Rap1 signaling pathway, MAPK signaling pathway, and lipid and atherosclerosis. As for AI + CI, 224 co-targeted genes were obtained, and KEGG analysis showed that the calcium signaling pathway plays an important role except for the consistent pathways of SM and SQFZ in anti-AIC.

Conclusions

DEX + CPMs might be positive efficacious interventions from which patients with AIC will derive benefits. DEX + SM, DEX + SQFZ, and DEX + AI + CI might be the preferred intervention for improving LVEF value, CK-MB level, and ECG abnormalities, respectively. And these CPMs play different advantages in alleviating AIC by targeting multiple biological processes.

Pacemakers and methylprednisolone pulse therapy in immune-related myocarditis concomitant with complete heart block

Immune-related cardiotoxicities are uncommon but potentially fatal. The study aims to evaluate the value of pacemakers and methylprednisolone pulse therapy (MPPT) to patients with immune-related myocarditis concomitant with complete heart block (CHB). We first reviewed medical records of three patients with immune-related myocarditis concomitant with CHB. For the pooled analysis, we searched related cases with immune-related myocarditis in the PubMed database and screened the patients. Clinical characteristics, management, and outcomes were summarized. Our three patients developed immune-related myocarditis concomitant with CHB about 2 weeks after receiving pembrolizumab, and were successfully treated with pacemaker implantation and high-dose steroids (two received MPPT). In the pooled analysis, 21 cases were eligible with an overall fatality rate of 52%. Patients with pacemakers had a fatality rate of 38%, significantly lower than patients without them (38% vs 100%; p = 0.035), particularly the MPPT subgroup (25% vs 100%; p = 0.019). All five patients without pacemakers expired. Among patients with pacemakers, MPPT patients tended to have an inferior rate compared with non-MPPT patients. Timely pacemaker implantation played a crucial role in improving the outcomes of patients with immune-related myocarditis concomitant with CHB. Patients receiving MPPT appeared to have a better prognosis. Additionally, multidisciplinary consultation should be recommended for better management.

Biomarker Trends, Incidence, and Outcomes of Immune Checkpoint Inhibitor-Induced Myocarditis

Background

Myocarditis is a dreaded and unpredictable complication of immune checkpoint inhibitors (ICI). We sought to determine whether routinely measured biomarkers could be helpful in monitoring for ICI myocarditis.

Objectives

The authors examined biomarker trends of patients on ICI and their association with the incidence of ICI myocarditis and outcomes.

Methods

We conducted an observational cohort study of adults who received at least one dose of ICI at Michigan Medicine between June 2014 and December 2021 and underwent systematic serial testing for aspartate aminotransferase (AST) and alanine aminotransferase (ALT), creatine phosphokinase (CPK), and lactate dehydrogenase during ICI therapy.

Results

Among 2,606 patients (mean age 64 ± 13 years; 60.7% men), 27 (1.0%) were diagnosed with ICI myocarditis. At diagnosis, patients with myocarditis had an elevated high-sensitivity troponin T (100%), ALT (88.9%), AST (85.2%), CPK (88.9%), and lactate dehydrogenase (92.6%). Findings were confirmed in an independent cohort of 30 patients with biopsy-confirmed ICI myocarditis. A total of 95% of patients with ICI myocarditis had elevations in at least 3 biomarkers compared with 5% of patients without myocarditis. Among the noncardiac biomarkers, only CPK was associated (per 100% increase) with the development of myocarditis (HR: 1.83; 95% CI: 1.59-2.10) and all-cause mortality (HR: 1.10; 95% CI: 1.01-1.20) in multivariable analysis. Elevations in CPK had a sensitivity of 99% and specificity of 23% for identifying myocarditis.

Conclusions

ICI myocarditis is associated with changes in AST, ALT, and CPK. An increase in noncardiac biomarkers during ICI treatment, notably CPK, should prompt further evaluation for ICI myocarditis.

Multisystem immune-related adverse events due to toripalimab: Two cases-based review

Immune checkpoint inhibitors (ICIs) have significantly improved the survival of patients with advanced tumors. However, immune-related adverse events (irAEs) caused by ICIs, especially high-grade irAEs, are of growing concern. High-grade multisystem irAEs due to toripalimab, a programmed cell death-1 (PD-1) inhibitor, have been rarely reported. Two patients with malignant metastatic tumors were treated with anti-PD-1 immunotherapy. However, both patients developed high-grade multisystem irAEs based on myocarditis, with chest discomfort and malaise as the main clinical manifestation. Both patients had an elevation of cardiac enzymes, abnormal electrocardiography and left ventricular wall motion. Patient 2 was also diagnosed with organizing pneumonia. Immunotherapy was suspended. High-dose intravenous methylprednisolone was immediately initiated. The patients' symptoms were significantly relieved in a short period of time. Immunosuppressants were discontinued at the 6th month follow-up in patient 1 without relapse. However, patient 2 was lost to follow up due to financial reasons. To the best of our knowledge, this is the first report regarding ICI-associated myocarditis-pneumonia due to toripalimab, indicating the significance of early recognition and management of high-grade multisystem irAEs in clinical practice.

Prevalence and characteristics of immune checkpoint inhibitor-related myocardial damage: A prospective observational study

An increasing number of patients with cancer are being treated with immune checkpoint inhibitors. Consequently, the incidence of immune checkpoint inhibitor-related myocarditis has been increasing. Nonetheless, the diagnostic criteria for the immune checkpoint inhibitor-related myocarditis have not been sufficiently established. Therefore, the real-world incidence or prevalence of immune checkpoint inhibitor-related myocardial damage remains unknown. This was a single-center cohort study that included 100 patients admitted for immune checkpoint inhibitor therapy for any type of cancer. The patients underwent monthly measurement of cardiac troponin I and N-terminal pro-brain natriuretic peptide levels with electrocardiography. Additionally, echocardiography was performed every 3 months. Our protocol was continued until 6 months after the initiation of immune checkpoint inhibitors. We defined immune checkpoint inhibitor-related myocardial damage as an increase in cardiac troponin I levels by >0.026 ng/mL and/or a decrease in the left ventricular ejection fraction by >10% to <53% on echocardiography. The mean patient age was 64 years; 71% were men. The most commonly used immune checkpoint inhibitor was nivolumab (47%), followed by pembrolizumab (29%). Overall, 5% of patients received combination therapy. Among 100 patients, 10 (10%) were diagnosed with immune checkpoint inhibitor-related myocardial damage. Among them, five patients underwent endomyocardial biopsy. Of these patients, four were histopathologically observed to have lymphocyte infiltration in their myocardium. In conclusion, serial cardiac troponin I measurement during immune checkpoint inhibitor treatment could help detect early-phase myocardial damage. The prevalence of myocardial damage was much higher than previously expected.

Immune checkpoint inhibitor-induced myocarditis, myositis, myasthenia gravis and transaminitis: a case series and review

Immune checkpoint inhibitors have been incorporated into the treatment of various malignancies. An increasing body of literature is reporting rare but potentially fatal adverse events associated with these agents. In this case series, the authors report the clinical features and outcomes of seven patients who received immune checkpoint inhibitors for different solid organ malignancies and developed a tetrad of immune-related myocarditis, myositis, myasthenia gravis and transaminitis. Herein the authors review the literature and describe the current diagnostic and management approach for this overlapping syndrome. The authors' series highlights the importance of a high index of clinical suspicion, prompt comprehensive investigations, early multidisciplinary team involvement and initiation of immunosuppressive therapy when immune-related adverse events are suspected.

Durvalumab-associated Late-onset Myocarditis Successfully Treated with Corticosteroid Therapy

We herein report a 66-year-old man with locally advanced non-small-cell lung cancer (NSCLC) who developed durvalumab-associated myocarditis. The patient underwent durvalumab administration every two weeks following concurrent chemoradiotherapy, without any adverse events or apparent disease progression. He presented with fatigue and dyspnea on exertion seven months after the first administration. Myocarditis was suspected based on laboratory data, an electrocardiogram, echocardiography, and magnetic resonance imaging findings. The definitive diagnosis was confirmed by a myocardial biopsy. Myocarditis was alleviated by cessation of durvalumab and corticosteroid therapy. This is a noteworthy case to describe late-onset myocarditis following the administration of durvalumab for NSCLC.

Immune checkpoint inhibitor-associated myocarditis : Case reports and a review of the literature

Immune checkpoint inhibitors (ICIs) are increasingly recognised to effectuate long-lasting therapeutic responses in solid tumours. However, ICI therapy can also result in various immune-related adverse events, such as ICI-associated myocarditis, a rare but serious complication. The clinical spectrum is wide and includes asymptomatic patients and patients with fulminant heart failure, making it challenging to diagnose this condition. Furthermore, the optimal diagnostic algorithm and treatment of ICI-associated myocarditis is unknown. In this review, we describe two cases on both ends of the spectrum and discuss the challenges in recognising, diagnosing and treating ICI-associated myocarditis.

Pro-BNP in the differential diagnosis of dyspnea in patients treated with immune-checkpoint inhibitors: Case Report

INTRODUCTION

Immune checkpoint inhibitors (ICI) induced cardiac toxicity can present with non-specific symptoms and signs. Early recognition and treatment are important; however, diagnosis can be challenging.

CASE REPORT

We describe a 67-year-old woman with a history of ICI induced pneumonitis who presented with dyspnea, hypoxemia and pulmonary infiltrates while treated with pembrolizumab for lung cancer, initially diagnoses with relapssed pneumonitis. When her condition did not improve with steroids, NT-pro-BNP level was tested and was markedly high, prompting additional tests for heart failure.

MANAGEMENT AND OUTCOME

The patient was diagnosed with ICI induced left ventricular dysfunction and treated with steroids, beta blockers, diuretics, and ACE inhibitors. Her symptoms and imaging studies markedly improved.

DISCUSSION

Here, we review the literature on ICI induced cardiac toxicity and the role of NT-pro -BNP in triage of patients presenting with dyspnea in the emergency setting. We suggest that measurement of NT-pro -BNP be utilized in patients receiving ICI's and presenting with respiratory abnormalities, to rapidly assess for possible cardiac toxicity.

Bradyarrhythmias in Cardio-Oncology

The relationship between bradyarrhythmias and cancer therapies has not been well described but is increasingly recognized. There have been extensive advances in oncological pharmacotherapy, with several new classes of drugs available including targeted agents, immune checkpoint inhibitors and CAR T cell therapy. This increasing repertoire of available drugs has revolutionized overall prognosis and survival of cancer patients but the true extent of their cardiovascular toxicity is only beginning to be understood. Previous studies and published reviews have traditionally focused on conventional chemotherapies and in arrhythmias in general, particularly tachyarrhythmias. The number of patients with both cancer and cardiovascular problems is increasing globally and oncologists and cardiologists need to be adept at managing arrythmia based scenarios. Greater collaboration between the two specialties including studies with prospective data collection in Cardio-Oncology are much needed to fill in knowledge gaps in this arena. This case-based review summarizes current available evidence of cancer treatment-related bradyarrhythmia incidence (including its different subtypes), possible mechanisms and outcomes. Furthermore, we propose a stepwise surveillance and management protocol for patients with suspected bradyarrhythmia related to cancer treatment.

Cardiotoxicity in cancer immune-checkpoint therapy: Mechanisms, clinical evidence, and management strategies

Immune-checkpoint inhibitors (ICIs), a unique antibody-based therapeutic strategy, have revolutionized the treatment landscape of solid and hematological cancers. Despite the proven benefits of ICIs, the cardiotoxicity from unspecific immune activation (uncommon but potentially fatal) is a continuing concern. Accumulating preclinical research has demonstrated that ICIs initiate inflammation in the myocardium, while clinically significant cardiotoxicity were reported in few patients receiving ICI therapy, probably due to the low incidence and unspecific symptoms. The subtle signs and symptoms (e.g., chest pain, dizziness, and dyspnea) were likely attributed to cancer and/or non-cardiac events by previous studies, thus limiting the understanding of the incidence, outcomes, risk factors, and management of ICI-related cardiotoxicity. The heterogeneous clinical presentation and complex diagnostic procedure further make it challenging to accurately identify ICI-related cardiac events in clinical trials. Therefore, ICI-related cardiotoxicity, whose incidence is probably underestimated, has not been well recognized. In this article, we provide an overview of potential mechanisms underlying ICI-related cardiotoxicity and review accumulating clinical evidence of ICI-related cardiotoxicity, with a focus on myocarditis. Moreover, we discuss possible strategies to manage ICI-related cardiotoxicity and highlight the importance of developing cardio-oncology.

Immune checkpoint inhibitors and cardiotoxicity: possible mechanisms, manifestations, diagnosis and management

INTRODUCTION

Immune checkpoint inhibitors (ICIs) are a new class of anticancer drugs that enhance the immune system function and activate T cells against cancerous cells. Although cardiac complications are not common, they could be accompanied with high morbidity and mortality.

AREAS COVERED

Regarding the importance of cardiac complications and their subsequent burden on individuals and the healthcare system, this review attempts to discuss the mechanism, diagnosis, and management of myocarditis, besides recapitulating the possible mechanism of other cardiac adverse events. Moreover, we briefly discuss the concurrent administration of other chemotherapeutic agents.

EXPERT OPINION

Due to insufficient knowledge concerning the physiopathology of immune-related adverse events (irAEs) and their potential further complications, cardiovascular complications in particular and in the context of this paper's focus, cooperation of oncologists, immunologists, and cardiologists is necessary for the management of patients. Experimental approaches such as using corticosteroids are becoming a part of guidelines for managing cardiac irAEs. However, a unique algorithm for diagnosis and management is necessary, especially in myocarditis cases. Furthermore, more studies are required to resolve current challenges, including prevention of myocarditis, concurrent administration of other chemotherapeutic agents, and re-introducing patients with ICIs.

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.

Fulminant myocarditis induced by immune checkpoint inhibitor nivolumab: a case report and review of the literature

Background

Nivolumab, an anti-programmed cell death protein 1 antibody, is commonly used as an immune checkpoint inhibitor in various cancers. Various adverse events are associated with these therapies, including hepatitis, dermatitis, and myocarditis. Myocarditis is a relatively rare but potentially fatal immune-mediated adverse reaction.

Case presentation

We report a case of colon cancer in a 56-year-old Chinese patient with lung and liver metastasis who developed fulminant myocarditis by nivolumab and survived with the support of extracorporeal membrane oxygenation. After six cycles (within 3 months) of nivolumab treatment, the patient developed chest tightness and was hospitalized. A diagnosis of fulminant myocarditis associated with immunotherapy was confirmed based on the clinical manifestations and laboratory examinations. He recovered well and was discharged on day 45 after management with extracorporeal membrane oxygenation, intravenous methylprednisolone, and immunoglobulin.

Conclusions

This case illustrates a severe cardiovascular complication of immunotherapy, strongly suggesting the necessity of close monitoring for outpatient usage of nivolumab. Additionally, our experience provided an efficient management strategy of extracorporeal membrane oxygenation in terms of life-threatening conditions.

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.

An Emergent Form of Cardiotoxicity: Acute Myocarditis Induced by Immune Checkpoint Inhibitors

Immune checkpoint inhibitors (ICIs) are monoclonal antibodies that activate the immune system, aiming at enhancing antitumor immunity. ICIs have shown great promise in the treatment of several advanced malignancies. However, therapy with these immunomodulatory antibodies may lead to a wide spectrum of immune-related adverse events in any organ and any tissue. Cardiologic immune-related events include pericarditis, pericardial effusion, various types of arrhythmias including the occurrence of complete atrioventricular block, myocardial infarction, heart failure, and myocarditis. Although relatively rare, myocarditis is associated with a very high reported mortality in comparison to other adverse events. Myocarditis often presents significant diagnostic complexity and may be under-recognized. When confronted with an unexpected change in the clinical picture, the physician must differentiate between immune-related adverse events, cancer worsening, or other causes unrelated to the cancer or its therapy. However, this is not always easy. Therefore, with the increasing use of checkpoint inhibitors in cancer, all providers who care for patients with cancer should be made aware of this rare, but potentially fatal, cardiologic immune-related adverse event, and able to recognize when prompt consultation with a cardiologist specialist is indicated. In this review, we evaluate currently available scientific evidence and discuss clinical manifestations and new potential approaches to the diagnosis and therapy of acute myocarditis induced by ICIs. Temporary or permanent discontinuation of the ICIs and high-dose steroids have been administered to treat myocarditis, but symptoms may worsen in some patients despite therapy.

Left ventricular myocardial strain and tissue characterization by cardiac magnetic resonance imaging in immune checkpoint inhibitor associated cardiotoxicity

Background

Immune checkpoint inhibitors (ICIs) are highly effective in treating cancer; however, cardiotoxicity can occur, including myocarditis. Cardiac magnetic resonance (CMR) imaging is useful for evaluation of myocarditis, although it has not been well studied in ICI cardiotoxicity.

Methods

We identified patients referred for CMR evaluation of ICI cardiotoxicity from September 2015 through September 2019. We assessed structural and functional parameters, feature tracking (FT) left ventricular and atrial strain, T2- weighted ratios and quantitative late gadolinium enhancement (LGE). We also applied the Updated Lake Louise Criteria for diagnosis of myocarditis.

Results

Of the 20 patients referred, the median left ventricular ejection fraction (LVEF) was 52.5% ± 19.1 and 50% had a normal LVEF (≥53%). FT strain analysis revealed an average abnormal global longitudinal strain (GLS) of −9.8%± 4.2%. In patients with a normal LVEF, the average GLS remained depressed at −12.3%± 2.4%. In all patients, GLS demonstrated a significant negative correlation with LVEF (r_s = −0.64, p 0.002). Sixteen patients (80%) had presence of LGE (14 non-ischemic pattern and 2 ischemic). Percent LGE did not correlate with any CMR parameters and notably did not correlate with LVEF (r_s = −0.29, p = 0.22) or GLS (r_s = 0.10, p = 0.67), highlighting the value of tissue characterization beyond functional assessment. Nine patients (45%) met full Updated Lake Louise Criteria and 85% met at least one criterion, suggestive of myocarditis in the correct clinical context. Thirteen patients (65%) were treated for ICI-associated myocarditis and, of these, 54% (n = 7) had recovery of LVEF to normal. There was no correlation between LVEF (p = 0.47), GLS (0.89), or % LGE (0.15) and recovery of LVEF with treatment.

Conclusion

In patients with suspected ICI cardiotoxicity, CMR is an important diagnostic tool, even in the absence of overt left ventricular dysfunction, as abnormalities in left ventricular strain, T2 signal and LGE can identifying disease.

Pembrolizumab-induced myocarditis in a patient with malignant mesothelioma: plasma exchange as a successful emerging therapy-case report

Malignant mesothelioma is an aggressive cancer associated with prior exposure to asbestos and dismal prognosis. Immune checkpoint inhibitor therapy is currently approved by the Food and Drug Administration for pre-treated malignant pleural mesothelioma. We describe a 75-year-old patient with disseminated, progressive malignant mesothelioma receiving 2 cycles of pembrolizumab who presented with generalized muscle weakness, shortness of breath, double vision and ptosis. There was no previous history of cardiovascular disease. The clinical picture, supported by the detection of anti-titin autoantibodies suggested myasthenia gravis (MG). Also, cardiac biomarkers were elevated. Echocardiography showed new severely reduced ejection fraction. A 12-lead resting electrocardiogram (ECG) revealed ST segment elevation in the posterior leads with polymorphic ventricular extrasystoles. Because cardiac catheterization revealed no relevant coronary lesions, immune checkpoint inhibitor-associated myocarditis and MG were suspected. Management and Outcome: The patient was started on steroids. Within a few days of presentation respiratory failure set in and the patient was intubated. Recurrent arrhythmias followed, which were treated by repeated emergency electrical cardioversion. In order to relieve myasthenic symptoms, plasma exchange was initiated and 10 cycles were carried out. This consequently also led to an improvement of myocarditis. Upon discharge, the ejection fraction recovered. The patient recovered and was alive at 1-year follow-up, without relevant limitations to his quality of life. Discussion and Conclusion: The article further discusses the use of plasma exchange for immune checkpoint inhibitor-associated myocarditis based on a review of literature. We conclude that patients showing no improvement after steroid therapy for immune checkpoint inhibitor-related myocarditis should be evaluated for plasma exchange, which appears to be an effective treatment option.

Immune Checkpoint Inhibitors and Cardiac Toxicity in Patients Treated for Non-Small Lung Cancer: A Review

Lung cancer is a major cause of cancer-related mortality worldwide, both in men and women. The vast majority of patients are diagnosed with non-small-cell lung cancer (NSCLC, 80-85% of lung cancer cases). Therapeutics named immune checkpoint inhibitors (ICIs) have revolutionized cancer treatment in the last decade. They are monoclonal antibodies, and those directed against PD-1 (programmed cell death protein 1) or PD-L1 (programmed cell death-ligand 1) have been used in the treatment of lung cancer and significantly improved the prognosis of NSCLC patients. However, during treatment with ICIs, immune-related adverse events (irAEs) can occur in any organ and any tissue. At the same time, although cardiac irAEs are relatively rare compared to irAEs in other organs, they have a high mortality rate. The two most common clinical manifestations of immunotherapy-related cardiotoxicity are myocarditis and pericarditis. Various types of arrhythmias have been reported in patients treated with ICIs, including the occurrence of life-threatening complete atrioventricular block or ventricular tachyarrhythmias. Here, we aim to summarize the incidence, clinical manifestations, underlying mechanisms, diagnosis, and treatment strategies for ICI-associated cardiotoxicity as these issues become very important in view of the increasing use of ICI in the treatment of lung cancer.

Concomitant development of neurologic and cardiac immune-related adverse effects in patients treated with immune checkpoint inhibitors for melanoma

Immune checkpoint inhibitors (ICI) have altered the prognosis of patients with melanoma over the past few years, with immune-related adverse effects (irAEs) being the only factor limiting their use. Neurologic and cardiac irAEs are rare, but usually severe. We reviewed the files of patients with melanoma treated with ICIs in one center to retrieve data from patients with neurologic irAEs. Patients with a combination of neurologic and cardiac manifestations were further analyzed. We also reviewed the literature for similar syndromes. Five out of 482 (1.01%) patients developed a neurologic syndrome and we present three patients with a constellation of neurologic and cardiac irAEs. A 66-year-old woman and a 68-year-old man presented with a constellation of findings after being treated with ipilimumab and nivolumab, respectively, for melanoma in the adjuvant setting and were eventually diagnosed with myasthenia gravis with cardiac involvement. An 80-year-old woman developed diffuse asymmetric muscle weakness, bilateral ptosis and asymptomatic high serum troponin levels after adjuvant treatment with nivolumab and ipilimumab for a stage IIIB melanoma. After excluding ischemic heart disease, she was diagnosed with axonal polyradiculoneuropathy and myocarditis. Neurologic or cardiac irAEs in patients treated with ICIs are uncommon (<1%), but usually severe, with high rates of morbidity and fatality. The co-development of neurologic and cardiac irAEs is even more rare and can arise soon after exposure to ICIs and escalate rapidly. Since more and more patients are now treated with ICIs in the adjuvant setting, prompt identification and management are essential to avoid serious complications or death.

Myocarditis associated with immune checkpoint inhibitors: Practical considerations in diagnosis and management

Immune checkpoint inhibitors (ICI) have caused radical changes in the treatment scheme of many types of cancer in the past 10 years. ICIs are specific monoclonal antibodies that increase T-cell mediated immune response against cancer cells. Despite important advances in cancer treatment, uncontrolled activation of cytotoxic T cells has brought along many autoimmune clinical side effects, especially acute myocarditis. Although the incidence of ICI-related myocarditis is about 1%, it is remarkable in terms of mortality rate reaching 46% and demonstrating the necessity of rapid diagnosis and multidisciplinary approach. The present review aimed to summarize the heterogeneous symptomatology of ICI-associated myocarditis, clinical presentation ranging from elevated asymptomatic cardiac enzyme levels to cardiogenic shock, prominent diagnostic value of cardiac magnetic resonance imaging, and current information on the effectiveness of immunosuppressants in therapy.

Cardiovascular toxicity induced by anti-VEGF/VEGFR agents: a special focus on definitions, diagnoses, mechanisms and management

INTRODUCTION

Vascular endothelial growth factor (VEGF) is a key target in cancer therapy. However, cardiovascular safety has been one of the most challenging aspects of anti-VEGF/VEGF receptor (VEGFR) agent development and therapy. While accurate diagnostic modalities for assessment of cardiac function have been developed over the past few decades, a lack of an optimal definition and precise mechanism still places a significant limit on the effective management of cardiovascular toxicity.

AREAS COVERED

Here, we report the cardiovascular toxicity profile associated with anti-VEGF/VEGFR agents and summarize the clinical diagnoses as well as management that are already performed in clinical practice or are currently being investigated. Furthermore, the review discusses the potential molecular toxicological mechanisms, which may provide strategies to prevent toxicity and drive drug discovery.

EXPERT OPINION

Cardiovascular toxicity associated with anti-VEGF/VEGFR agents has been a substantial risk for cancer treatment. To improve its management, the development of guidelines for prevention, monitoring and treatment of cardiovascular toxicity has become a hot topic. The summary of cardiovascular toxicity profile, mechanisms and management given in this review is not only significant for the optimal use of existing anti-VEGF/VEGFR agents to protect patients predisposed to cardiovascular toxicity but is also beneficial for drug development.

A Case of Acute Heart Failure Following Immunotherapy for Metastatic Lung Cancer

Inhibitors of cytotoxic T-lymphocyte-associated antigen-4, programmed cell death protein-1, and programmed death-ligand 1 have been shown to produce significant antitumor activity in multiple malignancies, and have become essential oncology standard-of-care therapies. Despite their success, the checkpoint inhibitors’ ability to amplify the immune system response against tumor cells has been associated with a unique panel of side effects known as immune-related adverse events. The involvement of the myocardium has been reported previously, but it’s remarkably uncommon. Even more noteworthy is that secondary autoimmune myocarditis and heart failure due to these medications are typically fatal.

Immune Checkpoint Inhibitor-Associated Myocarditis: A Run of Bad Luck or Rather Deficient-Monitoring Protocol?

Immune checkpoint inhibitors (ICIs) can induce immunity-related adverse events. We demonstrate the clinical use of cardiac magnetic resonance and endomyocardial biopsy in the diagnosis and subsequent monitoring of ICI-associated myocarditis, suggesting the need to establish and evaluate a cardiac monitoring protocol for patients under ICI therapy. (Level of Difficulty: Intermediate.)

Evolution of Immune Checkpoint Blockade-Induced Myocarditis Over 2 Years

Ipilimumab and nivolumab for melanoma induced smoldering myocarditis remitting with steroids. Rechallenge with nivolumab produced steroid-refractory myocarditis confirmed by electron microscopy. Tacrolimus and mycophenolate transiently reduced inflammation, but antithymocyte globulin induced remission. Cardiomyopathy with fatty infiltration ensued, but the patient succumbed to rampant melanoma progression after lymphocyte depletion. (Level of Difficulty: Advanced.).

Gastrointestinal adverse events associated with immune checkpoint inhibitor therapy

Immunotherapy with checkpoint inhibitors has revolutionized cancer therapy and is now the standard treatment for several different types of cancer, supported by favorable outcomes and good tolerance. However, it is linked to multiple immune manifestations, referred to as immune-related adverse events (irAEs). These adverse events frequently affect the skin, colon, endocrine glands, lungs, and liver. The gastrointestinal system is one of the most commonly affected organ systems and is responsible for the most frequent emergency visits resulting from irAEs. However, because immune checkpoint inhibitors are a recent addition to our arsenal of cancer drugs, many health-care providers remain unfamiliar with the management of irAEs. Gastroenterologists involved in the treatment of oncology patients who have received checkpoint inhibitors are currently encountering cases of abdominal pain, diarrhea, and other nonspecific symptoms that may be challenging to manage. This article reviews the gastrointestinal, hepatic, and pancreatic toxicities of checkpoint inhibitors and provides an approach to their diagnosis and recommended workup. It also highlights the management of irAEs according to their toxicity grading and specifically discusses the instances in which corticosteroids should be administered and/or the immune checkpoint inhibitors should be withheld.

[Third degree atrio-ventricular blockade during a myocarditis occurring under anti-PD1 : Case report and literature review]

INTRODUCTION

Immune Checkpoint Inhibitor (ICI) therapy is now a standard of care in numerous cancers with very promising results. Nevertheless, adverse events, and especially immune-related adverse events (irAEs) not reported during clinical trials, are emerging and can be life-threatening.

OBSERVATION

We report here a teachable case of a 80 year-old man, of third-degree atrioventricular block consecutive to myocarditis associated with the administration of nivolumab (anti-PD1) monotherapy.

CONCLUSION

Myocarditis occurring during ICI treatment is a rare but potentially lethal event. Daily serum troponin level seems to predict ICI-related myocarditis but interpretation could be difficult in the context of associated myositis. Echocardiography and cardiac MRI are also useful but can remain negative. Electrocardiogram is a cornerstone of myocarditis diagnosis. In case of cardiac involvement, continuous heart rhythm monitoring should be performed in addition to the administration of high-dose corticosteroids therapy and the cessation of ICI therapy. Add-on treatments should be discussed with a well-trained multidisciplinary team.

Acute fatal myocarditis after a single dose of anti-PD-1 immunotherapy, autopsy findings: a case report

Nivolumab (PD-1 inhibitor) and Ipilimumab (CTLA-34 inhibitor) are both commonly used immune checkpoint inhibitor therapies for various cancers. Various adverse events are associated with these therapies, including hepatitis, nephritis, dermatitis, and myocarditis. It is believed these adverse events occur in part because modified cellular receptors lead to enhanced CD4 and CD8 lymphoproliferation. These events usually occur after several months and rounds of treatment. Here we present a case of an 81-year-old male with recurrent renal cell carcinoma (RCC) who experienced myocarditis after only a single dose of combination therapy with Nivolumab and Ipilimumab. He presented with elevated troponins and a third-degree heart block; three days after admission he died. Histologic examination revealed a predominance of CD3 T cells (CD4 > CD8) and CD68 macrophages, with occasional CD20 B cells. C4d staining was negative in the interstitial capillaries, suggesting that antibody-mediated injury of endothelial cells did not play a significant role in the pathogenesis of this myocarditis. Additional studies ruled out an infectious etiology. Immune checkpoint inhibitors are increasingly more common, and it is important clinicians are aware patients can present with myocarditis early in the course of treatment.

Clinical and Advanced MRI Techniques for Detection of Checkpoint Inhibitor Associated Myocarditis

Purpose of Review

With the advent of immune checkpoint inhibitors (ICIs), cancer treatment has been revolutionized; however, these agents are associated with immune-related adverse events, including myocarditis, which ranges from mild to fulminant in severity. Currently, there are no established guidelines in diagnosing ICI-associated myocarditis, and the gold standard test for diagnosis of myocarditis in general is invasive endomyocardial biopsy (EMB). Cardiac magnetic resonance (CMR) imaging is a noninvasive test with the advantage of providing structural, functional and tissue characterization information. Additionally, it provides high spatial and temporal resolution without exposure to ionizing radiation, iodinated contrast, or radioactive isotopes.

Recent Findings

With an increasing number of reported cases of ICI associated myocarditis, understanding of the disease process and associated CMR findings is growing. Diagnostic testing with cardiac biomarkers, electrocardiogram, and echocardiogram can be nonspecific and EMB can have sampling errors. CMR as a diagnostic tool can provide functional assessment of biventricular ejection fraction, myocardial strain, tissue characterization of myocardial edema and inflammation as well as fibrosis. Furthermore, with advanced parametric mapping techniques, CMR provides even more sensitive and quantitative information about myocardial inflammation and fibrosis, including measurements of extracellular volume.

Summary

ICI-associated myocarditis is a serious immune adverse event, and CMR plays a vital role in establishing its diagnosis, providing prognostic information, and has the potential for use as a tool for screening and serial monitoring in patients exposed to ICIs.

Pembrolizumab-induced myasthenia gravis with myositis and presumable myocarditis in a patient with bladder cancer

INTRODUCTION

Pembrolizumab cause immune-related adverse events. We herein report a case of advanced bladder cancer, who treated with pembrolizumab and exhibited intriguing clinical course.

CASE PRESENTATION

A 63-year-old man with bladder carcinoma was treated by radical cystectomy, however, the bladder carcinoma recurred and invaded to the rectum. He was treated by combination therapy using gemcitabine and cisplatin, which were not effective for the tumor. He subsequently underwent treatment with pembrolizumab. In several 30 days, he suffered from the symptoms of myasthenia gravis. Serum levels of creatine kinase, its isozyme creatine kinase-myocardial band, and troponin I were elevated. Electrocardiography showed a right bundle branch block. These findings suggested that he was myasthenia gravis with general myositis and presumable myocarditis. Oral prednisolone administration significantly attenuated these findings. The tumor drastically shrunk only by the single injection of pembrolizumab.

CONCLUSION

Early intervention with corticosteroid was effective for neuromuscular complications due to pembrolizumab.

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

Immune checkpoint inhibitor therapy for malignancy has been associated with adverse events including myocarditis. It has been unclear if there are distinct pathologic grades of this myocarditis that are associated with distinct clinical outcomes. Cardiac tissue from ten patients with immune checkpoint inhibitor myocarditis (nine biopsies and one autopsy) were evaluated using immunohistochemistry for CD3, CD8, CD68, tryptase, PD-L1, and C4D. The immune checkpoint inhibitor myocarditis cases were classified as either high grade (>50 CD3⁺ cells/hpf) or low grade (≤50 CD3⁺ cells/hpf). The densities of macrophages, T cells, eosinophils, necrotic myocytes, and PD-L1⁺ macrophages and myocytes were compared between the two groups and with 13 cases of grade 2R acute cellular allograft rejection. Three patients were classified as high-grade myocarditis and seven as low grade. There were higher densities of CD3⁺ cells and CD8⁺ cells in high-grade immune checkpoint inhibitor myocarditis and rejection compared with low-grade myocarditis. The number of CD68⁺ macrophages was higher in high-grade myocarditis compared with low-grade myocarditis and rejection. For both grades of myocarditis, there was a higher CD68/CD3 ratio and a higher density of PD-L1⁺ macrophages and myocytes compared with rejection. Clinically, there were trends toward higher serum troponin levels and shorter interval from first immune checkpoint inhibitor treatment in the high-grade myocarditis group compared with the low-grade group. All the patients with high-grade myocarditis died, while all the patients with low-grade myocarditis were still living. These data suggest that immune checkpoint inhibitor myocarditis occurs in two forms, a high-grade form with increased inflammatory cell infiltration and a more fulminant clinical course, and a low-grade form with a lower degree of inflammatory cell infiltration and a more indolent clinical course. Compared with acute cellular rejection, immune checkpoint inhibitor myocarditis is characterized by a more lymphohistiocytic inflammatory infiltrate with an increased CD68/CD3 ratio and increased PD-L1⁺ macrophages and myocytes.

Clinical manifestation and management of immune checkpoint inhibitor-associated cardiotoxicity

Immune checkpoint inhibitors (ICIs) targeting programmed death-1 (PD-1), its ligand (PD-L1), and cytotoxic T-lymphocyte-associated antigen 4 (CTLA4) have revolutionized cancer treatment by recovering the attack of T lymphocytes on the malignant cells. They have improved clinical outcomes dramatically in multiple types of advanced-stage malignancies. Even though the tolerance and safety profiles are generally good, it has been widely reported that ICIs can cause severe or fatal immune-related adverse events (irAEs), since the activated T lymphocytes are not specific for tumor cells. Cardiac irAEs appear to occur less frequently than irAEs in other organ systems but are notorious for high mortality. Here, we aim to identify and characterize the ICI-associated cardiotoxicity and summarize the optional diagnosis and treatment strategies.