Immune checkpoint inhibitor-related myositis and myocarditis in patients with cancer

Immune Related Adverse Events: Classification and Management Approaches in Advanced Kidney Cancer

Recent therapeutic advancements have incorporated immune checkpoint inhibitors (ICIs) into the management of metastatic renal cell carcinoma. Pivotal phase III trials have resulted in Food and Drug Administration approval for anti-programmed death 1/programmed death ligand 1 ICIs, either in combination with anti-cytotoxic T-lymphocyte antigen 4 ICIs or with vascular endothelial growth factor-directed targeted therapies, as standard-of-care frontline regimens. Immune checkpoint inhibitors offer improved clinical outcomes when compared to previous treatment options. However, these agents also present unique toxicity profiles collectively referred to as immune-related adverse events. Common immune-related adverse events include colitis, hepatitis, dermatitis, and thyroiditis. Rare toxicities, such as myocarditis and pneumonitis, have the potential for causing severe harm. Herein, we provide a case-based discussion of how to identify, grade, and manage irAEs in metastatic renal cell carcinoma.

Adverse Effects of Anti-PD-1/PD-L1 Therapy in Non-small Cell Lung Cancer

Currently, immunotherapy has shown great efficacy in clinical trials, and monoclonal antibodies directed against immune checkpoint PD-1/PD-L1 have shown encouraging results in first-line or second-line treatment of non-small cell lung cancer patients. Meanwhile, anti-PD-1/PD-L1 immune checkpoint drugs combined with other treatments, such as chemotherapy, targeted therapy as well as anti-CTLA-4 checkpoint therapy, are considered an attractive treatment with higher efficacy. However, toxicity associated with PD-1/PD-L1 blockade is worth attention. Understanding the adverse effects caused by anti-PD-1/PD-L1 immunosuppressive agents is vital to guide the clinical rational use of drug. In this review, we summarized the adverse effects that occurred during the clinical use of anti-PD-1/PD-L1 inhibitors in the treatment of non-small cell lung cancer and discussed how to effectively manage and respond to these adverse reactions.

[Prevalence and treatment of rheumatological adverse events due to immune checkpoint inhibitor therapy]

BACKGROUND

Immune checkpoint inhibitors (ICI) have essentially improved the treatment options for various malignant diseases. They lead to an activation of the immune system and subsequent attack of tumor cells by affecting the immune system and preventing tumor cells from avoiding detection. In addition to this desired effect, immune-related adverse events (irAE) can occur in nearly all organ systems and therefore also rheumatological irAE (rh-irAE).

OBJECTIVE

The occurrence of rh-irAE has been described in various publications and is specifically investigated in this review. The aim is to provide an overview on the prevalence, severity, treatment options and altered tumor response in patients with rh-irAE.

MATERIAL AND METHODS

We conducted a literature search for studies and case reports on rh-irAE under ICI therapy in PubMed up to January 2020 using the PICO model.

RESULTS

A total of 18 publications were included, most of which were clinical studies (n = 13) and the rest case reports (n = 5). Several rh-irAE can occur with a wide variety of manifestations of which arthralgia, arthritis and myositis were the most common. Other rheumatic diseases, such as vasculitis, connective tissue diseases and sarcoidosis were less frequently described. The published prevalence of rh-irAE varied with a prevalence between 2.3% and 6.6%. Treatment of rh-irAE depends on the severity and most patients receive nonsteroidal anti-inflammatory drugs and glucocorticosteroids. In some cases, conventional DMARDs, such as methotrexate and biological DMARDs, were administered. Patients with rh-irAE in general had a higher tumor response rate compared to patients without side effects.

CONCLUSION

A close observation of patients and early detection of rh-irAE are important in order to treat these side effects in time. Further prospective studies are necessary to systematically investigate rh-irAE.

Toxin-Induced Channelopathies, Neuromuscular Junction Disorders, and Myopathy

Channelopathies, neuromuscular junction disorders, and myopathies represent multiple mechanisms by which toxins can affect the peripheral nervous system. These toxins include ciguatoxin, tetrodotoxin, botulinum toxin, metabolic poisons, venomous snake bites, and several medications. These toxins are important to be aware of because they can lead to serious symptoms, disability, or even death, and many can be treated if recognized ear.

Immune checkpoint inhibitor-induced inflammatory arthritis: identification and management

INTRODUCTION

Immune checkpoint inhibitors (ICIs) have proved to be groundbreaking in the field of oncology. However, immune system overactivation from ICIs has introduced a novel medical entity known as immune-related adverse events (irAEs), that can affect any organ or tissue. ICI-induced inflammatory arthritis (ICI-IIA) is the most common musculoskeletal irAE and can lead to significant morbidity and limitation in anti-cancer therapy.

AREAS COVERED

In this review, the authors focus on ICI-IIA. Relevant articles were identified through PubMed searches, spanning 2010 to the present. The authors detail the current understanding of its pathogenesis, diagnostic evaluation, and management strategies.

EXPERT OPINION

ICI-IIA is a complex irAE that we are just beginning to understand mechanistically and pathologically. It often presents later in the disease course than other irAEs and, due to various reasons, is under-recognized. In some patients, ICI-IIA may become a chronic disease, which distinguishes it from most irAEs that resolve after ICI discontinuation. Multiple important questions still demand further research including which patients may develop ICI-IIA? What are possible diagnostic and prognostic markers? Do anti-arthritis therapies interfere with the anti-tumor response? and when should steroid-sparing agents be initiated? Close collaboration and shared decision-making between oncologists, rheumatologists, and the patient are essential when managing this particular irAE.

Neurologic autoimmunity and immune checkpoint inhibitors: Autoantibody profiles and outcomes

OBJECTIVE

To describe neural autoantibody profiles and outcomes in patients with neurologic autoimmunity associated with immune checkpoint inhibitor (ICI) cancer immunotherapy.

METHODS

In this retrospective descriptive study, 63 patients with ICI-related neurologic autoimmunity were included: 39 seen at the Mayo Clinic Neurology Department (clinical cohort) and 24 whose serum/CSF was referred to the Mayo Clinic Neuroimmunology Laboratory for autoantibody testing. Serum/CSF samples were tested for neural-specific autoantibodies. Predictors of unfavorable outcome (residual adverse event severity grade ≥3) were explored (logistic regression).

RESULTS

Median age at neurologic symptom onset was 65 years (range 31-86); 40% were female. Neurologic manifestations were CNS-restricted (n = 26), neuromuscular (n = 30), combined (n = 5), or isolated retinopathy (n = 2). Neural-specific autoantibodies were common in patients with CNS involvement (7/13 [54%] in the unbiased clinical cohort) and included known or unidentified neural-restricted specificities. Only 11/31 patients with CNS manifestations had neuroendocrine malignancies typically associated with paraneoplastic autoimmunity. Small-cell lung cancer (SCLC)-predictive antibodies were seen in 3 patients with non-neuroendocrine tumors (neuronal intermediate filament immunoglobulin G [IgG] and antineuronal nuclear antibody 1 with melanoma; amphiphysin IgG with non-SCLC). A median of 10 months from onset (range, 0.5-46), 14/39 in the clinical cohort (36%) had unfavorable outcomes; their characteristics were age ≥70 years, female, CNS involvement, lung cancer, higher initial severity grade, and lack of systemic autoimmunity. By multivariate analysis, only age remained independently associated with poor outcome (p = 0.01). Four of 5 patients with preexistent neurologic autoimmunity experienced irreversible worsening after ICI.

CONCLUSIONS

Neural-specific autoantibodies are not uncommon in patients with ICI-related CNS neurologic autoimmunity. Outcomes mostly depend on the pre-ICI treatment characteristics and clinical phenotype.

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

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

Diagnosis and Treatment of Rheumatic Adverse Events Related to Immune Checkpoint Inhibitors

Immune checkpoint inhibitors (ICIs) have completely changed the treatment of cancer, and they also can cause multiple organ immune-related adverse reactions (irAEs). Among them, rheumatic irAE is less common, mainly including inflammatory arthritis, rheumatic myalgia/giant cell arteritis, inflammatory myopathy, and Sjogren's syndrome. For oncologists, rheumatism is a relatively new field, and early diagnosis and treatment is very important, and we need to work closely with experienced rheumatologists. In this review, we focused on the incidence, clinical characteristics, and treatment strategies of rheumatic irAE.

Pembrolizumab-related Bilateral Ocular Hypotony, Uveitis, Cataracts, Exudative Retinal, and Choroidal Detachments: An Unusual Success Story

Here, we report the presentation and management of a rare case of sight-threatening bilateral panuveitis with secondary chronic hypotony, subcapsular cataracts, exudative retinal detachments, and choroidal detachments, following initiation of pembrolizumab immunotherapy for metastatic melanoma. An 82-year-old white woman presented with painful, blurry vision 3 days after initiation of pembrolizumab immunotherapy. She had developed a marked panuveitis causing secondary hypotony. The fundal view was entirely limited by acutely dense cataracts and small, uveitic pupils unresponsive to topical dilation. Urgent cataract surgery with intravitreal dexamethasone implant (Ozurdex) was completed successfully and allowed a fundal examination. This revealed bilateral, symmetrical, inferior exudative retinal detachments, and choroidal detachments secondary to chronic hypotony. After 3 months of observation and cessation of oral steroids, the panuveitis remains quiescent, hypotony persists, and the choroidal and retinal detachments are showing progressive self-resolution. The current best-corrected visual acuity is 6/24 OU. She remains under close monitoring. The immune checkpoint inhibitor, pembrolizumab, has been reported to cause sight-threatening adverse effects. We report a rare case of profound bilateral complications treated successfully with oral and intravitreal steroids. To the authors' knowledge, this has not previously been reported in the literature. Ophthalmologists and oncologists should be aware of the ocular effects of pembrolizumab and be able to identify various complications early. Here, cataract surgery with a steroid implant has been an effective sight-saving intervention. The promising visual outcome makes this an unusual success story.

Rheumatic immune-related adverse events induced by immune checkpoint inhibitors

Immune checkpoint inhibitors (ICIs) block the major inhibitory pathways in T cells, resulting in an augmented antitumor response. Immune‐related adverse events (irAEs) are a new class of side effects caused by ICIs and tend to be more prevalent in patients with preexisting autoantibodies and autoimmune diseases. The rheumatic subset of irAEs mainly includes arthralgia, arthritis, myalgia, myositis, vasculitis, sicca syndrome, scleroderma and systemic lupus erythematosus. The most common classification system for AEs, the Common Terminology Criteria for Adverse Events, is of limited use for irAEs, especially rheumatic irAEs. Therapy with glucocorticoid and temporary or permanent discontinuation of ICIs are the cornerstones of irAE treatment, and can be complemented with immunosuppressants (e.g., methotrexate), biologic agents (e.g., tumor necrosis factor inhibitors and interleukin‐6 receptor antagonists), intravenous immunoglobin and plasma exchange. Thus, the evaluation and treatment of rheumatic irAEs require multidisciplinary cooperation among physicians. Here, we review the most prevalent ICI‐associated rheumatic irAEs.

Immune checkpoint inhibitor induces cardiac injury through polarizing macrophages via modulating microRNA-34a/Kruppel-like factor 4 signaling

Cancer immunotherapy has become a well-established treatment option for some cancers; however, its use is hampered by its cardiovascular adverse effects. Immune checkpoint inhibitors (ICIs)-related cardiac toxicity took place in kinds of different forms, such as myocarditis, acute coronary syndrome, and pericardial disease, with high mortality rates. This study aimed to investigate the roles of programmed death-1 (PD-1) inhibitor, one of widespread used ICIs, in the development of murine cardiac injury. PD-1 inhibitor is known to transduce immunoregulatory signals that modulate macrophages polarization to attack tumor cells. Hence, this study explored whether the cardiovascular adverse effects of PD-1 inhibitor were related to macrophage polarization. MicroRNA-34a (miR-34a), which appears to regulate the polarization of cultured macrophages to induce inflammation, is examined in cardiac injury and macrophage polarization induced by the PD-1 inhibitor. As a target of miR-34a, Krüppel-like factor 4 (KLF4) acted as an anti-inflammation effector to take cardiac protective effect. Further, it investigated whether modulating the miR-34a/KLF4-signaling pathway could influence macrophage polarization. The PD-1 inhibitor markedly induced M1 phenotype macrophage polarization with impaired cardiac function, whereas miR-34a inhibitor transfection treatment reversed M1 polarization and cardiac injury in vivo. In vitro, PD-1 inhibitor-induced M1 polarization was accompanied by an increase in the expression of miR-34a but a decrease in the expression of KLF4. TargetScan and luciferase assay showed that miR-34a targeted the KLF4 3′-untranslated region. Either miR-34a inhibition or KLF4 overexpression could abolish M1 polarization induced by the PD-1 inhibitor. The findings strongly suggested that the PD-1 inhibitor exerted its effect in promoting M1 polarization and cardiac injury by modulating the miR-34a/KLF4-signaling pathway and inducing myocardial inflammation. These findings might help us to understand the pathogenesis of cardiac injury during immunotherapy, and provide new targets in ameliorating cardiac injury in patients with cancer receiving PD-1 inhibitor treatment.

Immune Checkpoint Inhibition-Does It Cause Rheumatic Diseases? Mechanisms of Cancer-Associated Loss of Tolerance and Pathogenesis of Autoimmunity

Mechanisms of immune checkpoints and their role in autoimmunity are discussed in the context of immune checkpoint inhibitor (ICI) therapy for cancer. The updated clinical spectrum of immune-related adverse events (irAEs), with an in-depth discussion of rheumatic irAEs, is presented. The relationship between ICI-induced loss of self-tolerance in cancer and the implications for understanding of irAEs, rheumatic irAEs in particular, is overviewed.

The Terrible Triad of Checkpoint Inhibition: A Case Report of Myasthenia Gravis, Myocarditis, and Myositis Induced by Cemiplimab in a Patient with Metastatic Cutaneous Squamous Cell Carcinoma

Background

We report a case of a patient with squamous cell carcinoma (SCC) who developed myasthenia gravis (MG), myositis, and myocarditis after receiving cemiplimab, an anti-PD-1 immune checkpoint inhibitor (ICI). Case Presentation. An 86-year-old man with metastatic periocular SCC presented with decreased vision in the left eye, severe fatigue, and lower back and bilateral hip pain 3 weeks after receiving cemiplimab. Within hours, he developed dysphonia, pharyngeal secretions, and dysphagia, necessitating intubation. Endomyocardial biopsy revealed active lymphocyte-mediated necrosis consistent with ICI-induced myocarditis. Anti-striated muscle and anti-acetylcholine receptor antibodies were elevated, consistent with myositis and myasthenia gravis. Despite plasma exchange therapy, steroids, and intravenous immunoglobulin, he died from cardiac arrest.

Conclusions

The presence of myasthenia gravis, myocarditis, or myositis should prompt evaluation for all three toxicities as they may represent an overlap syndrome. The severity of these immunotoxicities highlights the need for clinicians to suspect multiple simultaneous adverse effects of ICIs.

Hepatotoxicity From Immune Checkpoint Inhibitors: A Systematic Review and Management Recommendation

Immune checkpoint inhibitors (ICIs) are monoclonal antibodies targeting immune checkpoint molecules. ICIs are an immunotherapy for the treatment of many advanced malignancies. The advent of ICIs has been a major breakthrough in the field of oncology, a fact recognized by the 2018 Nobel Prize in Physiology or Medicine being awarded for the discovery. The Food and Drug Administration approved the first ICI, ipilimumab, in 2011 for the treatment of metastatic melanoma. Seven ICIs are now used in clinical practice, including nivolumab and pembrolizumab for treatment of advanced hepatocellular carcinoma. ICIs are increasingly used across the spectrum of hepatobiliary neoplasia. The utility of ICI therapy has been limited by immune-related adverse reactions (irAEs) affecting multiple organ systems. Hepatotoxicity is an important irAE, occurring in up to 16% of patients receiving ICIs. Optimizing outcomes in patients receiving ICI therapy requires awareness of and familiarity with diagnosing and management of ICI-induced immune-mediated hepatotoxicity (IMH), including approaches to treatment and ICI dose management. The aim of this review article is to (1) provide a comprehensive, evidence-based review of IMH; (2) perform a systematic review of the management of IMH; and (3) present algorithms for the diagnosis and management of IMH.

Central nervous system complications associated with immune checkpoint inhibitors

OBJECTIVE

To describe the spectrum and outcome of central nervous system complications associated with immune checkpoint inhibitors (CNS-ICI).

METHODS

Patients with CNS-ICI were identified and their characteristics compared with ICI-related peripheral neuropathy (PN-ICI).

RESULTS

We identified 19 patients with CNS-ICI. The patients were receiving nivolumab (n=8), pembrolizumab (n=6), a combination of ipilimumab-nivolumab (n=3), ipilimumab-durvalumab (n=1), or atezolizumab (n=1). Underlying malignancies included non-small-cell lung cancer (n=8), melanoma (n=3), and other less common tumours (n=8). Neurological phenotypes were limbic encephalitis (n=8), meningoencephalitis (n=4) and cerebellitis (n=4). Two patients developed isolated confusion and one parkinsonism. Associated autoantibodies included onconeural (Ma2, n=7; Hu, n=1), astrocytic (glial fibrillar acidic protein, n=2) and neuronal surface (contactin-associated protein-like 2, n=1) specificities. ICIs were withheld and corticosteroid treatment was given in all cases. Five patients received intravenous immunoglobulin, two rituximab, one plasmapheresis and one infliximab. Overall, six patients died. Readministration of ICI was attempted in three patients, without further relapses. Non-small-cell lung cancer was significantly more frequent in patients with CNS-ICI (p<0.01), while melanoma and ipilimumab treatment were more common in PN-ICI (p<0.01 and p=0.01). Conversely, CNS-ICI cases were more frequently antibody-positive than PN-ICI (p<0.01) and showed a strong trend towards poorer outcome (p=0.053).

CONCLUSION

Three main clinical phenotypes characterise CNS complications of ICIs, each with distinct immunological background, disease course and response to treatment. Other clinical manifestations (including parkinsonism and steroid-responsive confusion) are also possible. Underlying cancers, antibody prevalence and outcome appear different from those of patients with PN-ICI.

A closer look at immune-mediated myocarditis in the era of combined checkpoint blockade and targeted therapies

Immune checkpoint inhibitors (ICI) and tyrosine kinase inhibitors (TKI) have transformed the management of many malignancies. Although rare, immune-mediated myocarditis presents unique clinical challenges due to heterogenous presentation, potential life-threatening consequences, and the time-critical need to differentiate it from other causes of cardiac dysfunction. Increasingly, TKI are being combined with ICI to promote immune modulation and improve efficacy. However, these combinations are associated with more toxicities. This series describes six patients with advanced melanoma who developed immune-mediated myocarditis while receiving an anti-PD-1 antibody or an anti-PD-L1 antibody plus a mitogen-activated protein kinase inhibitor. It provides a review of their heterogenous clinical presentations, investigational findings and treatment outcomes. Presentations ranged from asymptomatic cardiac enzyme elevation to death due to heart failure. We highlight the role of cardiac MRI (CMRI), a sensitive and non-invasive tool for the early detection and subsequent monitoring of myocardial inflammation. Five of the six patients exhibited CMRI changes characteristic of myocarditis, including mid-wall myocardial oedema and late gadolinium enhancement in a non-coronary distribution. Critically, two of these patients had normal findings on echocardiogram. Of the five patients who received immunosuppression, four recovered from myocarditis and one died of cardiac failure. The sixth patient improved with cardiac failure management alone. Three of the four patients responding to ICI derived long-term benefit. Clinical vigilance, prompt multimodal diagnosis and multidisciplinary management are paramount for the treatment of immune-mediated myocarditis.

Management of immune-related adverse events associated with immune checkpoint inhibitors in cancer patients: a patient-centred approach

Immune checkpoint inhibitors (ICIs) have revolutionized cancer treatment. The number of indications is increasing and antibodies targeting the CTLA-4 and PD-1/PD-L1 pathways are now also prescribed in adjuvant settings and for metastatic cancer. However, ICIs reactivate autoreactive immune cells as well as tumour-specific T cells, which lead to immune-related adverse events (irAEs) in around 70% of treated patients. Although all organs can potentially be involved, the skin, gut, thyroid, lungs, liver, and joints are most frequently affected. Most irAEs occur in the first few months of treatment but late-onset toxicity-even after the ICI has been discontinued-is also possible. In terms of severity, most irAEs are grade 1-2. Some irAEs (especially myocarditis, pneumonitis, and encephalitis) are potentially fatal; in patients with highly suggestive clinical signs, treatment should be initiated before the diagnostic work-up has been completed. When confronted with an unexpected clinical sign, the physician must differentiate rapidly between an irAE, cancer progression, and another (unrelated) cause. The management of irAEs is based on the temporary or permanent discontinuation of the ICI and (for grade ≥ 2 events) the administration of steroids.

Investigational Biomarkers for Checkpoint Inhibitor Immune-Related Adverse Event Prediction and Diagnosis

BACKGROUND

Immune checkpoint inhibitors (ICIs) have revolutionized the treatment of multiple cancers. However, these promising therapies may also cause immune-related adverse events (irAEs) in a substantial proportion of patients. These autoimmune phenomena may affect almost any organ system and may occur at almost any point in therapy. In some instances, these toxicities are life-threatening and potentially permanent. Diverse clinical presentation and unpredictable timing further complicate their anticipation and diagnosis.

CONTENT

To improve patient safety and selection for ICI use, biomarkers for irAE diagnosis and prediction are under development. Clinicians may use traditional laboratory markers such as routine chemistries, creatinine clearance, thyroid function tests, and serum cortisol/adrenocorticotrophic hormone to monitor for specific irAEs, but noted aberrations may not necessarily represent an immune-mediated etiology. Novel biomarkers have the potential to be more specific to assist in the diagnosis of irAEs. The prediction of irAEs is more challenging. Apart from a history of autoimmune disease, no other clinical parameters are routinely used to project risk. Biomarker candidates under investigation for irAE diagnosis and prediction include blood cell analysis, chemokines/cytokines, autoantibodies, and genetic predisposition, such as human leukocyte antigen haplotype. Among other emerging candidates are immune-cell subsets, T-cell repertoire, fecal microbiome, tumor genomics, and radiomic characterization.

SUMMARY

Several conventional laboratory indexes of end-organ dysfunction are currently in routine clinical use for irAE monitoring and diagnosis. Novel biomarkers for the prediction and diagnosis of these irAEs, which primarily characterize patient immune function, represent an area of active investigation.

Rheumatic Manifestations in Patients Treated with Immune Checkpoint Inhibitors

Immune checkpoint inhibitors (ICIs) are monoclonal antibodies that activate the immune system, aiming at enhancing antitumor immunity. Their clinical efficacy is well-documented, but the side effects associated with their use are still under investigation. These drugs cause several immune-related adverse events (ir-AEs), some of which stand within the field of rheumatology. Herein, we present a literature review performed in an effort to evaluate all publicly available clinical data regarding rheumatic manifestations associated with ICIs. The most common musculoskeletal ir-AEs are inflammatory arthritis, polymyalgia rheumatica and myositis. Non-musculoskeletal rheumatic manifestations are less frequent, with the most prominent being sicca, vasculitides and sarcoidosis. Cases of systemic lupus erythematosus or scleroderma are extremely rare. The majority of musculoskeletal ir-AEs are of mild/moderate severity and can be managed with steroids with no need for ICI discontinuation. In severe cases, more intense immunosuppressive therapy and permanent ICI discontinuation may be employed. Oncologists should periodically screen patients receiving ICIs for new-onset inflammatory musculoskeletal complaints and seek a rheumatology consultation in cases of persisting symptoms.

T cell checkpoint regulators in the heart

T lymphocyte-mediated immune responses in the heart are potentially dangerous because they can interfere with the electromechanical function. Furthermore, the myocardium has limited regenerative capacity to repair damage caused by effector T cells. Myocardial T cell responses are normally suppressed by multiple mechanisms of central and peripheral tolerance. T cell inhibitory molecules, so called immune checkpoints, limit the activation and effector function of heart antigen-reactive T cells that escape deletion during development in the thymus. Programmed cell protein death-1 (PD-1) and cytotoxic T-lymphocyte-associated protein-4 (CTLA-4) are checkpoint molecules homologous to the costimulatory receptor CD28, and they work to block activating signals from the T cell antigen receptor and CD28. Nonetheless, PD-1 and CTLA-4 function in different ways and at different steps in a T cell response to antigen. Studies in mice have established that genetic deficiencies of checkpoint molecules, including PD-1, PD-L1, CTLA-4, and lymphocyte activation gene-3, result in enhanced risk of autoimmune T cell-mediated myocarditis and increased pathogenicity of heart antigen-specific effector T cells. The PD-1/PD-L1 pathway appears to be particularly important in cardiac protection from T cells. PD-L1 is markedly up-regulated on myocardial cells by interferon-gamma secreted by T cells and PD-1 or PD-L1 deficiency synergizes with other defects in immune regulation in promoting myocarditis. Consistent with these studies, myocarditis has emerged as a serious adverse reaction of cancer therapies that target checkpoint molecules to enhance anti-tumour T cell responses. Histopathology and immunohistochemical analyses of myocardial tissue from immune checkpoint blockade (ICB)-treated patients echoes findings in checkpoint-deficient mice. Many questions about myocarditis in the setting of cancer immunotherapy still need to be answered, including the nature of the target antigens, genetic risk factors, and variations in the disease with combined therapies. Addressing these questions will require further immunological analyses of blood and heart tissue from patients treated with ICB.

Immune-related adverse events of checkpoint inhibitors

Cancer immunotherapies have changed the landscape of cancer treatment during the past few decades. Among them, immune checkpoint inhibitors, which target PD-1, PD-L1 and CTLA-4, are increasingly used for certain cancers; however, this increased use has resulted in increased reports of immune-related adverse events (irAEs). These irAEs are unique and are different to those of traditional cancer therapies, and typically have a delayed onset and prolonged duration. IrAEs can involve any organ or system. These effects are frequently low grade and are treatable and reversible; however, some adverse effects can be severe and lead to permanent disorders. Management is primarily based on corticosteroids and other immunomodulatory agents, which should be prescribed carefully to reduce the potential of short-term and long-term complications. Thoughtful management of irAEs is important in optimizing quality of life and long-term outcomes.

Immune Checkpoint Inhibitor-Related Myositis: From Biology to Bedside

Immune checkpoint inhibitor (ICI)-related inflammatory diseases, including polymyositis (PM) and dermatomyositis (DM), in patients suffering from neoplastic disorders represent a medical challenge. The treatment of these conditions has taken on new urgency due to the successful and broad development of cancer-directed immunological-based therapeutic strategies. While primary and secondary PM/DM phenotypes have been pathophysiologically characterized, a rational, stepwise approach to the treatment of patients with ICI-related disease is lacking. In the absence of high-quality evidence to guide clinical judgment, the available data must be critically assessed. In this literature review, we examine partially neglected immunological and clinical findings to obtain insights into the biological profiles of ICI-related PM/DM and potential treatment options. We show that differential diagnosis is essential to stratifying patients according to prognosis and therapeutic impact. Finally, we provide a comprehensive assessment of druggable targets and suggest a stepwise patient-oriented approach for the treatment of ICI-related PM/DM.

Immune checkpoint inhibitors-induced neuromuscular toxicity: From pathogenesis to treatment

Immune checkpoint inhibitors (ICIs) are increasingly used and are becoming the standard of care in the treatment of various tumor types. Despite the favorable results in terms of oncological outcomes, these treatments have been associated with a variety of immune-related adverse events (irAEs). Neurological irAEs are rare but potentially severe. Neuromuscular disorders represent the most common neurological irAEs following anti-PD-1, anti-PD-L1, and anti-CTLA-4 treatment, and include myositis, myasthenia gravis, and demyelinating polyradiculoneuropathy. Instrumental findings may differ from typical neuromuscular disorders occurring outside ICIs treatment. Despite initial severity, neurological irAEs often respond to immune-modulating therapies. Prompt irAEs diagnosis, ICIs discontinuation, and early treatment with corticosteroids, together with patient education and a multi-disciplinary approach, are important for optimizing clinical outcomes. Intravenous immunoglobulin, plasma exchange, and other immune-modulating treatments should be considered in more severe cases. Consideration of re-challenging with the same immunotherapy drug may be given in some cases, based on clinical picture and initial severity of irAEs.

Toxic Myopathies

PURPOSE OF REVIEW

This article reviews the pathogenesis, clinical features, and management of toxic myopathy related to common medications, critical illness, and illicit substances.

RECENT FINDINGS

Muscle symptoms are common among statin users and are usually reversible after discontinuation of the statin; rarely, however, statins trigger an immune-mediated necrotizing myopathy that persists and requires immunomodulatory therapy. Autoantibodies targeting 3-hydroxy-3-methylglutaryl coenzyme A reductase can distinguish the toxic and immune-mediated forms. Immune checkpoint inhibitors, increasingly used in the treatment of advanced cancer, have recently been associated with the development of inflammatory myositis. A reversible mitochondrial myopathy has long been associated with zidovudine, but recent reports elucidate the risk of myopathy with newer antivirals, such as telbivudine and raltegravir.

SUMMARY

The medications most commonly associated with myopathy include statins, amiodarone, chloroquine, hydroxychloroquine, colchicine, certain antivirals, and corticosteroids, and myopathy can occur with chronic alcoholism. Certain clinical, electrodiagnostic, and histologic features can aid in early recognition. Stopping the use of the offending agent reverses symptoms in most cases, but specific and timely treatment may be required in cases related to agents that trigger immune-mediated muscle injury.

Autoimmune complications of immunotherapy: pathophysiology and management

Immune checkpoint inhibitors (ICIs) are monoclonal antibodies that target inhibitory molecules, such as cytotoxic T-lymphocyte-associated protein 4 (CTLA-4), programmed cell death protein 1 (PD-1), or its ligand, programmed cell death protein ligand 1 (PD-L1), and lead to immune activation in the tumor micro-environment. ICIs can induce durable treatment responses in patients with advanced cancers, but they are commonly associated with immune related adverse events (irAEs) such as rash, colitis, hepatitis, pneumonitis, and endocrine and musculoskeletal disorders. Almost all patients experience some form of irAE, but high grade irAEs occur in approximately half of those on combination therapy (eg, anti-CTLA-4 plus anti-PD-1), and up to one quarter receiving ICI monotherapy. Fatal irAEs occur in approximately 1.2% of patients on CTLA-4 blockade and 0.4% of patients receiving PD-1 or PD-L1 blockade, and case fatality rates are highest for myocarditis and myositis. IrAEs typically occur in the first three months after ICI initiation, but can occur as early as one day after the first dose to years after ICI initiation. The mainstay of treatment is with corticosteroids, but tumor necrosis factor inhibitors are commonly used for refractory irAEs. Although ICIs are generally discontinued when high grade irAEs occur, ICI discontinuation alone is rarely adequate to resolve irAEs. Consensus guidelines have been published to help guide management, but will likely be modified as our understanding of irAEs grows.

Clinical characteristics of rheumatic syndromes associated with checkpoint inhibitors therapy

Compared with conventional cancer therapies, the spectrum of toxicities observed with checkpoint inhibitors is unique and can affect any organ system. Arthralgia and myalgia were by far the most commonly reported rheumatic immune-related adverse events in clinical trials, and there is now a growing number of case series and reports describing clinical features of de novo rheumatic immune-related adverse events, which will be the focus of this review. Some patients develop genuine classic rheumatic and musculoskeletal diseases, but a number of rheumatic immune-related adverse events mimic rheumatic and musculoskeletal diseases with atypical features, mainly polymyalgia rheumatica, rheumatoid arthritis and myositis, as well as several systemic conditions, including sicca syndrome, vasculitis, sarcoidosis, systemic sclerosis and lupus.

Myositis as a neuromuscular complication of immune checkpoint inhibitors

Immune checkpoint inhibitors (ICI) induce improved clinical outcomes associated with numerous cancers, but immune-related adverse events can occur, including neuromuscular complications. We searched for all muscle biopsies from the patient data system of University Hospitals Leuven (UZ Leuven) from January 2014 to July 2018 (n = 686) and collected clinical data of patients with a biopsy-proven ICI-related myositis and expanded the pathological examinations. We identified three cases of ICI-related myositis in patients with malignant melanoma. The clinical phenotype ranged from mild to life threatening. Two patients had a myositis-myasthenia gravis overlap syndrome and one had a co-occurring myocarditis. Pathological examination showed a necrotizing and/or inflammatory myopathy with CD4 + and CD8 + T cells and CD68 + macrophages. IgG staining was positive in all cases. PD-1 and PD-L1 reactions were negative for inhibitors of the PD-1/PD-L1 pathway (nivolumab, atezolizumab) and positive for CTLA-4 inhibitors (ipilimumab). With increasing usage of ICI, clinicians must be aware of rare but potentially serious adverse events such as myositis. Early detection by inquiring about complaints and clinical signs of weakness and monitoring the creatine phosphokinase level in serum are recommended. Our histological findings are in line with other reports. The IgG positivity suggests a local role of the ICI in the pathophysiology of the myositis. Further research must be performed to identify patients at risk and to optimize treatment of the complications.

Neurologic complications of immune checkpoint inhibitors

Introduction: Immune checkpoint inhibitors (ICI) are associated with a wide spectrum of neurologic immune-related adverse events (irAEs) including meningo-encephalitis, myasthenia gravis and various neuropathies. Although relatively rare, they often present significant diagnostic complexity and may be under-recognized. Permanent neurologic deficits and/or fatality have been described but improvement is noted in most cases with ICI discontinuation and immunosuppressive therapy.Areas covered: This review highlights the most frequently reported ICI-associated neurologic toxicities with a particular focus on those that may be more severe and/or fatal. Data from case series and pharmacovigilance studies is leveraged to provide an overview of associated clinical features, expected outcomes and appropriate management. Various immunobiologic triggers have been proposed to explain why certain patients might develop neurologic irAEs and are also briefly discussed.Expert opinion: All providers who care for patients with cancer should be made aware of common neurologic irAEs and able to recognize when prompt evaluation and consultation with appropriate specialists are indicated. Symptoms suggestive of encephalitis, myasthenia-gravis or an acute polyradiculopathy such as Guillain-Barre Syndrome (GBS) in patients exposed to these agents warrant immediate attention with a low threshold for hospitalization to expedite work-up and monitor for severe and/or life-threatening manifestations.

Nivolumab resulting in persistently elevated troponin levels despite clinical remission of myocarditis and myositis in a patient with malignant pleural mesothelioma: case report

Malignant pleural mesothelioma (MPM) remains a deadly disease with limited therapeutic options beyond platinum/pemetrexed chemotherapy. Immune checkpoint inhibitors have demonstrated modest benefit in the second to later-line settings. An MPM patient from our institute developed myocarditis and myositis after 2 cycles of second-line nivolumab. Despite immunosuppression with corticosteroids and mycophenolate mofetil, there was ongoing rise in troponin levels which remained elevated for months. The patient developed an impressive but brief response following cessation of nivolumab. Myocarditis and myositis are rare complications of immune checkpoint inhibitors. Clinicians should be aware of these possible complications as myocarditis can result in mortality.

Incidence and characteristics of neurotoxicity in immune checkpoint inhibitors with focus on neuromuscular events: Experience beyond the clinical trials

Immune checkpoint inhibitors (ICIs) are associated with various neurological adverse events (NAEs). We herein explored the incidence and clinical phenotype of immune-related NAEs in cancer patients. Medical records of ICI-treated cancer patients were reviewed between the years 2010 and 2018, with an aim to characterize immuno-related NAEs. A total of 1185 ICIs-treated patients were identified, 63.7% of which were males and 36.3% were females, with a mean age of 63.4 ± 7.3 years. Twenty-four from the overall ICIs-treated patients (2%) developed NAEs. No differences were identified in terms of age, sex, tumor type and class of ICIs between the patients who developed NAEs and those who did not. The median number of cycles of ICI treatment before NAEs onset were 4.5 (1-10), and the median time was 102 days. Peripheral nervous system (PNS) involvement was present in 14 patients (58.4%) and central nervous system (CNS) involvement in 10 (33.3%), including 2 patients with aseptic meningitis and polyradicular involvement. Amongst PNS complications, there were five (20.8%) with axonal sensory neuropathies, four (16.7%) with Guillain-Barre-like syndromes, and four (16.7%) with myositis and/or myasthenic syndromes. The majority of patients with PNS-related NAEs (n = 11; 78.6%) improved after ICIs discontinuation and treatment with immune-modulating therapies. The time to neuromuscular toxicities onset was significantly shorter, compared to CNS NAEs (median 70 vs 119 days, P = .037). Immune-related NAEs mostly present with neuromuscular complications. Discontinuation of ICIs and appropriate treatment should be commenced early throughout the process, in order to maximize a favorable outcome.

Immune-mediated adverse effects of immune-checkpoint inhibitors and their management in cancer

Within the past decade, immune-checkpoint inhibitors (ICPIs), including anti-programmed cell death 1 (PD-1), anti-programmed cell death 1 ligand 1 (PD-L1), and anti-cytotoxic T lymphocyte antigen 4 (CTLA-4) antibodies, are undoubtfully the most remarkable advances in cancer therapy. The immune responses are modulated by these ICPIs via blocking the inhibitory PD-1/PD-L1 path and result in immune activation in the suppressive microenvironment of the tumor. While ICPIs result in benefits for numerous patients with malignancy and lead to disease control and survival, toxicity and safety problems have emerged as well. Although immune mediated adverse effects due to ICPIs could involve any organ system, skin, endocrine glands, and gastrointestinal tract, are one of the most commonly affected. Fortunately, in most of the cases, these immune‑mediated adverse effects (imAEs) are manageable, while in some cases these toxicities are fulminant and fatal and lead to the withdrawal of treatment. Numerous attempts have been started and are continuing to reduce the incidence rate of imAEs. Further studies are required for a better understanding of these imAEs, decrease the occurrence, and lighten the severity. In this work, we overview the imAEs and also, highlight the most important aspects of the imAEs management.

Neurotoxicity associated with cancer immunotherapy: immune checkpoint inhibitors and chimeric antigen receptor T-cell therapy

PURPOSE OF REVIEW

Immune checkpoint inhibitors (ICPI) and chimeric antigen receptor T cells (CAR-T) represent novel therapies recently approved to treat a number of human cancers. As both approaches modulate the immune system, they can generate a number of immune-related adverse events (irAEs), including a large spectrum of novel neurological toxicities. These are of special interest given their potential severity and risk of compromising further oncologic treatment. We aim to provide a comprehensive review of the literature and discuss their optimal management.

RECENT FINDINGS

In contrast to irAEs involving other organs, neurological complications of ICPI are uncommon, may present throughout the course of treatment and involve the peripheral and central nervous system, including polyneuropathy, myositis, myasthenia gravis, demyelinating polyradiculopathy, myelitis, encephalitis and others. If started early, ICPI-related neurologic irAEs are usually responsive to steroids. In contrast, as many as 40% of patients undergoing CAR-T therapy will develop neurologic complications in the form of a cytokine-release-associated encephalopathy. It includes delirium, aphasia, tremor/myoclonus, seizure and seizure-like activity.

SUMMARY

irAEs associated with CAR-T and ICPI therapy constitute new entities. Early identification and treatment are essential to optimize the functional outcome and further oncologic management of the patient.

[A case of myasthenia gravis developed during pembrolizumab administration, suggesting an excitation-contraction connection disorder]

The patient was a 50-year-old woman. Pembrolizumab was started for bladder cancer recurrence. From the day after the second administration, ptosis, diplopia, restriction of eye movement, muscle weakness, fatigue resistance, increase in serum creatine kinase (CK) level, and muscle pain were observed. Tests for anti-acetylcholine receptor (AChR) antibody and anti-muscle specific kinase (MuSK) antibody were negative. Electrophysiological examination of the neuromuscular junction showed negative results, and electromyography revealed no myogenic changes. We considered that the immune checkpoint inhibitor caused neuromuscular damage. The patient's symptoms were gradually improved by immunotherapy, such as steroid and plasma exchange. In this case, tests for the anti-titin antibody, an anti-striational antibody, were positive. We considered that myasthenia gravis-like symptoms and serum CK level elevation might have been caused by impairment of excitation-contraction coupling, and not the neuromuscular junction.

Checkpoint inhibitor myasthenia-like syndrome and myositis associated with extraocular muscle atrophy

A patient with metastatic melanoma developed myasthenia-like syndrome and paraspinal myositis with subsequent extraocular muscle atrophy associated with immune checkpoint inhibitor treatment. MRI scan of the ocular muscles on admission was normal, however 3 months later revealed significant extraocular muscle atrophy.

Emerging PD-1 and PD-1L inhibitors-associated myopathy with a characteristic histopathological pattern

BACKGROUND AND OBJECTIVE

Drug-induced myopathy is among the most common causes of muscle disease. An association has recently been described between programmed death-1 (PD-1)/PD-1 ligand (PD-L1) inhibitors and immune-related adverse events (irAE) affecting the muscle. Here, we report the clinical and pathological findings of nine unrelated patients with PD-1 and PD-L1 inhibitors-associated myopathy.

METHODS

We retrospectively analyzed 317 muscle biopsies performed for diagnostic purposes from January 2017 to June 2019. Patients were attended in two tertiary centers and muscle biopsies were performed and analyzed by two myology experts. Muscle biopsies were frozen in cooled isopenthane, cryostat sectioned and stained. Immunohistochemistry studies were also performed as a routine procedure in our lab.

RESULTS

We identified 9 patients receiving anti-PD-1 or PD-L1 inhibitors consulting for either muscle weakness, asthenia, myasthenic-like syndrome or other muscle related-symptoms, along with biopsy-proven inflammatory myopathy. One had concomitant myocarditis. In most of the cases muscle biopsy showed a marked phenomenon of necrosis, macrophagy and muscle regeneration with perivascular inflammatory infiltrates with a large component of macrophagic cells. A tendency to perifascicular atrophy was also noticed. The expression of MHC class I antigens predominated in the perifascicular zones. Raised muscle enzymes were detected in 7 patients.

CONCLUSION

A characteristic clinic-pathological pattern, including a myasthenia gravis-like syndrome plus myositis was found in patients receiving PD-1 and PD-1 L inhibitors. A large component of macrophages resembling granulomas seems to be the pathological hallmark of the syndrome. Further information is required to understand the wide spectrum of immune-related adverse events involving the muscle during or after treatment with anti-PD-1 inhibitors, but the pathological picture seems to be characteristic.

Clinical diagnosis and treatment recommendations for immune checkpoint inhibitor-related adverse reactions in the nervous system

Immune checkpoint inhibitors (ICIs) can cause adverse reactions in the nervous system. The incidence rate is 0.1%–12% and 80% of nervous system adverse reactions occur within the first four months of application. ICIs can cause diseases of various parts of the nervous system including central nervous system diseases such as aseptic meningitis, meningeal encephalitis, necrotizing encephalitis, brainstem encephalitis, transverse myelitis, etc., and peripheral neuropathy such as cranial nerve peripheral neuropathy, multifocal nerve root neuropathy, Guillain‐Barré syndrome, spinal nerve root neuropathy, myasthenia gravis, myopathy, etc. For these complications of the nervous system, diagnosis could be difficult. Physicians require a specific collection of nervous system symptoms and signs, combined with supplementary examinations including imaging, cerebrospinal fluid cytology, EEG or electromyography in order to exclude infection or malignant tumor before reaching a final diagnosis. With regard to treatment, ICIs should be discontinued in severe cases, and large doses of glucocorticoid or gamma globulin administered, and supportive treatment may be necessary. If severe adverse reactions of the nervous system occur, the prognosis could be poor.

Neuropathology in Pitié-Salpêtrière hospital: Past, present and prospect

Pitié and La Salpêtrière, both founded in the17th century, were for long two distinct hospitals until they merged in 1964. The name La Salpêtrière is inherited from the initial purpose of the buildings designed to produce saltpeter for gun powder. But the place was soon transformed into an asylum to shelter the poor and the insane. From the care of this underprivileged population, alienists such as Pinel have paved the way for modern medicine for the mentally ill at the time of the French Revolution. In the second half of the 19th century, Jean-Martin Charcot and his students laid the foundations of modern neurology from the observation of the large population hosted in La Salpêtrière, mostly women with severe chronic diseases. Charcot led clinicopathological studies in almost all the fields of nervous system disorders. His successors (including Raymond, Dejerine, Pierre Marie) maintained the same close relationship between clinical neurology and neuropathology. In parallel with the development of neurosurgery at Pitié hospital, neuropathology first spread through small laboratories attached to clinical departments. The merger of the two hospitals in the early '60s coincided with the creation of a large university hospital in which the care and study of diseases of the nervous system were preponderant. An independent laboratory of neuropathology was created, led by Raymond Escourolle. This period was on the eve of important developments in neuroscience around the world. Today, the Pitié-Salpêtrière neuropathology laboratory still plays a central role between neurology and neurosurgery clinics and major research institutes such as the Brain Institute, callled Institut du Cerveau et de la Moelle (ICM), and the Institute of Myology.

Pathology of immune-mediated tissue lesions following treatment with immune checkpoint inhibitors

Immune check point inhibitor (CPI) therapy has revolutionized treatment paradigms for several cancers, but at the cost of triggering a diverse spectrum of immune-mediated injury to non-cancer tissues. The complex biology of these toxicities remains incompletely understood, partly because tissue acquisition from affected areas can be challenging to retrieve, thus hindering development of targeted therapy. Here, we review the literature describing pathology of immune-mediated tissue lesions including gastrointestinal, skin, rheumatic, pulmonary, cardiac, renal and hepatic lesions and highlight key immunological insights.

Frequency and distribution of various rheumatic disorders associated with checkpoint inhibitor therapy

Immune checkpoint inhibitors have advanced the treatment paradigm of various cancers, achieving remarkable survival benefits. However, a myriad of immune-related adverse events (irAE) has been recognized in almost every organ system, presumably because of persistent immune system activation. Rheumatic symptoms such as arthralgia or myalgia are very common. More specific irAE are increasingly being reported. The most frequent ones are inflammatory arthritis, polymyalgia-like syndromes, myositis and sicca manifestations. These rheumatic irAE can develop in ∼5-10% of patients treated with immune checkpoint inhibitors, although true incidence rates cannot be estimated given the lack of prospective cohort studies, and likely underreporting of rheumatic irAE in oncology trials. In this review, we will provide a summary of the epidemiologic data reported for these rheumatic irAE, until more robust prospective longitudinal studies become available to further define the true incidence rate of rheumatic irAE in patients receiving these novel cancer therapies.

Toxicities associated with checkpoint inhibitors-an overview

Immunotherapy has an increasing role in the management of cancer, both in metastatic disease and as an adjuvant therapy. However, sensitization of the immune system with checkpoint inhibitors comes with a unique side effect profile. Full appreciation of this can take some time to emerge as some adverse events are rare, or can be subtle and potentially overlooked. Clinician awareness of these side effects can be particularly important in patients with pre-existing autoimmune conditions. Here we describe common symptoms and diagnostic strategies for organ-specific side effects of anti-CTLA-4 and anti-PD-1/PD-L1 immunotherapy agents.

Nivolumab and Ipilimumab-induced myositis and myocarditis mimicking a myasthenia gravis presentation

The rapidly growing field of cancer immunotherapy has led to the development of new treatments such as immune checkpoint inhibitors. These agents are monoclonal antibodies that enable tumor-reactive T cells to overcome regulatory mechanisms and produce effective antitumor responses. The use of immune checkpoint inhibitors is expected to progressively increase because they have shown promising therapeutic outcomes in multiple types of cancer and clinicians should be aware of their possible side-effects. We report a case of a man diagnosed with a non-microcytic lung carcinoma who started treatment with a combination of immune checkpoint inhibitors (Nivolumab and Ipilimumab). He subsequently developed binocular diplopia, fatigue, mild dyspnea and upper back pain resembling a myasthenia gravis presentation. Finally, a diagnosis of immune checkpoint inhibitor-related myositis and myocarditis was made. The detection of GFAP antibodies in CSF has unclear clinical and pathogenic significance and they may rather represent an epiphenomenon of the immune inflammation process.