Inflammatory Myositis in Cancer Patients Receiving Immune Checkpoint Inhibitors

Peripheral nervous system immune-related adverse events due to checkpoint inhibition

Immune checkpoint inhibitors have revolutionized cancer therapy and are increasingly used to treat a wide range of oncological conditions, with dramatic benefits for many patients. Unfortunately, the resulting increase in T cell effector function often results in immune-related adverse events (irAEs), which can involve any organ system, including the central nervous system (CNS) and peripheral nervous system (PNS). Neurological irAEs involve the PNS in two-thirds of affected patients. Muscle involvement (immune-related myopathy) is the most common PNS irAE and can be associated with neuromuscular junction involvement. Immune-related peripheral neuropathy most commonly takes the form of polyradiculoneuropathy or cranial neuropathies. Immune-related myopathy (with or without neuromuscular junction involvement) often occurs along with immune-related myocarditis, and this overlap syndrome is associated with substantially increased mortality. This Review focuses on PNS adverse events associated with immune checkpoint inhibition. Underlying pathophysiological mechanisms are discussed, including antigen homology between self and tumour, epitope spreading and activation of pre-existing autoreactive T cells. An overview of current approaches to clinical management is provided, including cytokine-directed therapies that aim to decouple anticancer immunity from autoimmunity and emerging treatments for patients with severe (life-threatening) presentations.

Rheumatic adverse events of immune checkpoint inhibitors in cancer immunotherapy

INTRODUCTION

The advent of immune checkpoint inhibitors (ICIs) in cancer treatment has marked a transformative era, albeit tempered by immune-related adverse events (irAEs), including those impacting the musculoskeletal system. The lack of precise epidemiologic data on rheumatic irAEs is attributed to factors such as potential underrecognition, underreporting in clinical trials, and the tendency to overlook manifestations without immediate life-threatening implications, further complicating the determination of accurate incidence rates, while the complete understanding of the mechanisms driving rheumatic irAEs remains elusive.

AREAS COVERED

This literature review comprehensively examines rheumatic irAEs in cancer patients undergoing ICI therapy, encompassing epidemiology, risk factors, mechanisms, clinical manifestations, and current management guidance for prevalent conditions such as inflammatory arthritis, polymyalgia rheumatica, and myositis. Less frequent rheumatic and musculoskeletal irAEs are also explored, alongside insights into ongoing clinical trials testing therapeutic and preventive strategies for irAEs. A thorough literature search on Medline and the National Cancer Institute Clinical Trials Database was conducted up to October 2023 to compile relevant information.

EXPERT OPINION

In light of the evolving landscape of cancer immunotherapy, there is a compelling need for prospective longitudinal studies to enhance understanding and inform clinical management strategies for rheumatic irAEs.

Neurological Immune-Related Adverse Events Induced by Immune Checkpoint Inhibitors

The use of immune checkpoint inhibitors (ICIs) for the treatment of various advanced and aggressive types of malignancy has significantly increased both survival and long-term remission rates. ICIs block crucial inhibitory pathways of the immune system, in order to trigger an aggravated immune response against the tumor. However, this enhanced immune activation leads to the development of numerous immune-related adverse events (irAEs), which may affect any system. Although severe neurological irAEs are relatively rare, they carry a high disability burden, and they can be potentially life-threatening. Therefore, clinicians must be alert and act promptly when individuals receiving ICIs present with new-onset neurological symptoms. In this narrative review, we have collected all the currently available data regarding the epidemiology, pathogenesis, clinical manifestations, diagnosis, and treatment of post-ICI neurological irAEs. This review aims to raise physicians' awareness, enrich their knowledge regarding disease pathogenesis, and guide them through the diagnosis and management of post-ICI neurological irAEs.

The Utility of Laboratory Investigations for the Assessment and Management of Rheumatic Immune Related Adverse Events

Immune checkpoint inhibitors (ICIs) have greatly improved survival of several cancers with historically very poor prognosis. ICIs act by stimulating the patient's own immune system to fight cancer. Simultaneously, this immune activation can lead to immune-related adverse events (irAEs), including rheumatic manifestations (Rh-irAEs). Rh-irAEs mimic primary rheumatic diseases including arthritis, polymyalgia rheumatica, myositis, vasculitis, sarcoidosis, and sicca. This article summarizes the latest evidence regarding the utility of laboratory investigations in Rh-irAEs.

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.

Neurological Adverse Events Related to Immune Checkpoint Inhibitors: A Practical Review

The increasing use of immune checkpoint inhibitors (ICI) in cancer therapy has brought attention to their associated neurotoxicities, termed neurological immune-related adverse events (n-irAEs). Despite their relatively rare incidence, n-irAEs pose a significant risk, potentially leading to severe, long-lasting disabilities or even fatal outcomes. This narrative review aims to provide a comprehensive overview of n-irAEs, focusing on their recognition and management. The review addresses a spectrum of n-irAEs, encompassing myositis, myasthenia gravis, various neuropathies, and central nervous system complications, such as encephalitis, meningitis, and demyelinating diseases. The key features of n-irAEs are emphasized in this review, including their early onset after initiation of ICIs, potential association with non-neurological irAEs and/or concurrent oncological response, the significance of ruling out other etiologies, and the expected improvement upon discontinuation of ICIs and/or immunosuppression. Furthermore, this review delves into considerations for ICI re-challenge and the intricate nature of n-irAEs within the context of pre-existing autoimmune and paraneoplastic syndromes. It underscores the importance of a multidisciplinary approach to diagnosis and treatment, highlighting the pivotal role of severity grading in guiding treatment decisions.

Immune-Related Adverse Events Due to Cancer Immunotherapy: Immune Mechanisms and Clinical Manifestations

The landscape of cancer treatment has undergone a significant transformation with the introduction of Immune Checkpoint Inhibitors (ICIs). Patients undergoing these treatments often report prolonged clinical and radiological responses, albeit with a potential risk of developing immune-related adverse events (irAEs). Here, we reviewed and discussed the mechanisms of action of ICIs and their pivotal role in regulating the immune system to enhance the anti-tumor immune response. We scrutinized the intricate pathogenic mechanisms responsible for irAEs, arising from the evasion of self-tolerance checkpoints due to drug-induced immune modulation. We also summarized the main clinical manifestations due to irAEs categorized by organ types, detailing their incidence and associated risk factors. The occurrence of irAEs is more frequent when ICIs are combined; with neurological, cardiovascular, hematological, and rheumatic irAEs more commonly linked to PD1/PD-L1 inhibitors and cutaneous and gastrointestinal irAEs more prevalent with CTLA4 inhibitors. Due to the often-nonspecific signs and symptoms, the diagnosis of irAEs (especially for those rare ones) can be challenging. The differential with primary autoimmune disorders becomes sometimes intricate, given the clinical and pathophysiological similarities. In conclusion, considering the escalating use of ICIs, this area of research necessitates additional clinical studies and practical insights, especially the development of biomarkers for predicting immune toxicities. In addition, there is a need for heightened education for both clinicians and patients to enhance understanding and awareness.

Neurologic manifestations of autoimmunity with immune checkpoint inhibitors

Immune checkpoint inhibitors (ICIs) are cancer immunotherapies that enhance the body's own immune system to treat cancer. ICI treatment, however, can cause immune-related adverse events (irAEs) that can affect any organ, resulting in significant morbidity and mortality. Neurologic irAEs (nirAEs) are rare and can affect the peripheral nervous system more commonly than the central nervous system. Treatment is dependent on the severity of the neurologic manifestations and often includs discontinuation of the ICI and initiation of steroid therapy as the first line; other treatments have also been used. NirAEs and cardiac irAEs have higher fatality rates underlying the importance of early recognition and appropriate management. This chapter reviews the clinical manifestations of neurologic immune-related adverse events associated with ICI treatment as well as diagnostic and therapeutic modalities.

Neurological adverse events of immune checkpoint inhibitors and the development of paraneoplastic neurological syndromes

Immune checkpoint inhibitors, a class of oncological treatments that enhance antitumour immunity, can trigger neurological adverse events closely resembling paraneoplastic neurological syndromes. Unlike other neurological adverse events caused by these drugs, post-immune checkpoint inhibitor paraneoplastic neurological syndromes predominantly affect the CNS and are associated with neural antibodies and cancer types commonly found also in spontaneous paraneoplastic neurological syndromes. Furthermore, post-immune checkpoint inhibitor paraneoplastic neurological syndromes have poorer neurological outcomes than other neurological adverse events of immune checkpoint inhibitors. Early diagnosis and initiation of immunosuppressive therapy are likely to be crucial in preventing the accumulation of neurological disability. Importantly, the neural antibodies found in patients with post-immune checkpoint inhibitor paraneoplastic neurological syndromes are sometimes detected before treatment, indicating that these antibodies might help to predict the development of neurological adverse events. Experimental and clinical evidence suggests that post-immune checkpoint inhibitor paraneoplastic neurological syndromes probably share immunological features with spontaneous paraneoplastic syndromes. Hence, the study of post-immune checkpoint inhibitor paraneoplastic neurological syndromes can help in deciphering the immunopathogenesis of paraneoplastic neurological syndromes and in identifying novel therapeutic targets.

Pembrolizumab-induced Myopathy with Anti-striated Muscle Antibodies Successfully Treated by Plasma Exchange

A 70-year-old woman with advanced endometrial cancer developed right ptosis and muscle weakness in the right quadriceps after pembrolizumab administration. Serum creatine kinase (CK) levels were elevated, and anti-striated muscle antibodies were positive. On magnetic resonance imaging, the right vastus lateral muscle showed an abnormal signal. She was diagnosed with pembrolizumab-induced myopathy. We initiated plasma exchange (PE), and the ptosis immediately resolved. We then introduced oral corticosteroids, which improved her muscle weakness. We were able to rapidly diagnose her with ocular symptoms and serum CK level elevation. The early initiation of PE might prevent the exacerbation of pembrolizumab-induced myopathy.

The Role of Environmental Factors in the Development of Idiopathic Inflammatory Myopathies: a Narrative Review

PURPOSE OF REVIEW

This review aims to evaluate recent findings on the role of environmental factors in the development and clinical presentation of idiopathic inflammatory myopathies (IIMs).

RECENT FINDINGS

A targeted literature review was conducted to identify reports relevant to the association between environmental factors and IIMs published over the past three years. There has been an increasing number of publications dealing with the association of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection or vaccination with the development of IIMs, highlighting the significant role of the antiviral immune response in the pathogenesis of the disease. Traditional environmental factors associated with the pathogenic process of IIM subclassifications included drugs such as statins and immune checkpoint inhibitors, ultraviolet radiation, smoking, air pollutants, and vitamin D deficiency. Correlations of seasonality and residence with the onset of certain IIM subtypes suggest a potential role of environmental triggers in the pathogenic process. An interplay between genetic predisposition and various environmental factors might contribute to the development of IIMs as well as the heterogeneous clinical and serological presentation of IIMs. The growing evidence on the role of environmental factors in the development of IIMs provides important clues to elucidate the pathophysiology of these disease entities. The mechanisms underlying the interactions between genetic predisposition and environmental factors should be investigated in the future.

Immune Checkpoint Inhibitor-Induced Myositis/Myasthenia Gravis Overlap

Immune checkpoint inhibitors (ICIs) have considerably changed the management of several malignancies. Although these agents transformed the scope of management in oncology and proved long-term efficacy, they have been associated with numerous autoimmune-related adverse events. We presented a case of a 61-year-old male with a history of non-small cell lung cancer (NSCLC) who presented with respiratory failure requiring mechanical ventilation. He was discharged with a working diagnosis of myasthenia gravis crisis secondary to the use of pembrolizumab. On further evaluation, he was found to possibly have pembrolizumab-induced myositis. He was treated with plasmapheresis, methylprednisolone, and rituximab and achieved significant improvement. Pembrolizumab, a monoclonal antibody, is an ICI that targets programmed death protein 1 (PD-1), thereby blocking the interaction between PD-1 and PDL-1, leading to an enhancement of T-cell mediated immune response against tumor cells. Pembrolizumab has been used to treat a variety of malignancies including melanoma, NSCLC, and other solid tumors. Though ICIs have revolutionized the field of oncology, they should be used with caution. ICIs can cause immune-related adverse events (irAEs), including myasthenia gravis and myositis. Diagnosing irAEs is challenging due to their nonspecific presentations and lack of antibody markers. Therefore, patients and clinicians should be aware of irAEs in order to initiate timely intervention.

Infliximab for Treatment of Immune Adverse Events and Its Impact on Tumor Response

Background: Immune-related adverse events (irAEs) challenge the use of immune checkpoint inhibitors (ICIs). We performed a retrospective study to evaluate response to infliximab for immune-related adverse event management, and infliximab's effect on progression-free survival (PFS) and overall survival (OS) with a focus on melanoma and genitourinary cancers. Methods: We retrospectively reviewed records of all cancer patients exposed to infliximab after immune checkpoint inhibitor (ICI) treatment from 2004 to 2021 at the MD Anderson Cancer Center. Survival was assessed utilizing the Kaplan-Meier method. Univariate and multivariate logistic regression was utilized to evaluate predictors of infliximab response, OS, and PFS. Results: We identified 185 cancer patients (93 melanoma and 37 genitourinary cancers) treated with ICI and who received infliximab to treat irAEs. Within 3 months of treatment initiation, 71% of the patients responded to infliximab, 27% had no response, and 2% had unknown response. Among different irAEs, colitis was associated with increased response to infliximab at 3 months, irrespective of the type of malignancy. We evaluated best tumor response before and after infliximab in the entire cohort and again in the melanoma and genitourinary (GU); the findings were similar in the melanoma cohort and the entire cohort, where best tumor response before and after infliximab was not significantly different. In the melanoma cohort, acute kidney injury (AKI) was associated with increased risk of death, p = 0.0109, and having response to infliximab was associated with decreased risk of death, p = 0.0383. Interestingly in GU cancer patients, myositis was associated with increased risk of death, p = 0.0041, and having a response to infliximab was marginally associated with decreased risk of death, p = 0.0992. As regards PFS, in a multivariate Cox regression model, having a history of cardiovascular disease remained significantly associated with shorter PFS in the melanoma cohort. For patients with GU cancers, response to infliximab was associated with longer PFS. Conclusions: Our study is among the largest retrospective analyses of infliximab use for irAE management. Patients with colitis were the best responders to infliximab. AKI before initiation of infliximab in the melanoma subcohort and myositis in GU subcohort are associated with higher risk of death. Our results indicate no association between infliximab and cancer progression with the exception of genitourinary cancers.

Immune checkpoint inhibitor-related myocarditis: current understanding and potential diagnostic and therapeutic strategies

INTRODUCTION

Myocarditis associated with immune checkpoint inhibitors presents with an often-severe clinical phenotype with arrhythmias and concurrent myositis. This condition tends to occur early after treatment onset and is associated with a high fatality rate. Diagnosis may be challenging, and treatment algorithms are still evolving.

AREAS COVERED

This review will provide an overview of immune checkpoint inhibitor mechanism of action and how it relates to myocarditis pathophysiology, diagnostic algorithms and potential pitfalls, and emerging treatment approaches published until May 2023. We will focus on the state of the field and potential new directions in research and patient care. We will also provide consensus-based diagnostic and therapeutic algorithms endorsed by major societies.

EXPERT OPINION

The field needs more evidence-based approaches to risk stratification so that therapy can be tailored toward less cardiotoxic alternatives in high-risk patients. For diagnostic and therapeutic approaches, data from animal models are unlikely to provide conclusive evidence given the complexity of the human immune system. We strongly invite practitioners in the field to contribute every case to the ongoing multicenter registries.

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

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

Selective immune suppression using interleukin-6 receptor inhibitors for management of immune-related adverse events

BACKGROUND

Management of immune-related adverse events (irAEs) is important as they cause treatment interruption or discontinuation, more often seen with combination immune checkpoint inhibitor (ICI) therapy. Here, we retrospectively evaluated the safety and effectiveness of anti-interleukin-6 receptor (anti-IL-6R) as therapy for irAEs.

METHODS

We performed a retrospective multicenter study evaluating patients diagnosed with de novo irAEs or flare of pre-existing autoimmune disease following ICI and were treated with anti-IL-6R. Our objectives were to assess the improvement of irAEs as well as the overall tumor response rate (ORR) before and after anti-IL-6R treatment.

RESULTS

We identified a total of 92 patients who received therapeutic anti-IL-6R antibodies (tocilizumab or sarilumab). Median age was 61 years, 63% were men, 69% received anti-programmed cell death protein-1 (PD-1) antibodies alone, and 26% patients were treated with the combination of anti-cytotoxic T lymphocyte antigen-4 and anti-PD-1 antibodies. Cancer types were primarily melanoma (46%), genitourinary cancer (35%), and lung cancer (8%). Indications for using anti-IL-6R antibodies included inflammatory arthritis (73%), hepatitis/cholangitis (7%), myositis/myocarditis/myasthenia gravis (5%), polymyalgia rheumatica (4%), and one patient each with autoimmune scleroderma, nephritis, colitis, pneumonitis and central nervous system vasculitis. Notably, 88% of patients had received corticosteroids, and 36% received other disease-modifying antirheumatic drugs (DMARDs) as first-line therapies, but without adequate improvement. After initiation of anti-IL-6R (as first-line or post-corticosteroids and DMARDs), 73% of patients showed resolution or change to ≤grade 1 of irAEs after a median of 2.0 months from initiation of anti-IL-6R therapy. Six patients (7%) stopped anti-IL-6R due to adverse events. Of 70 evaluable patients by RECIST (Response Evaluation Criteria in Solid Tumors) V.1.1 criteria; the ORR was 66% prior versus 66% after anti-IL-6R (95% CI, 54% to 77%), with 8% higher complete response rate. Of 34 evaluable patients with melanoma, the ORR was 56% prior and increased to 68% after anti-IL-6R (p=0.04).

CONCLUSION

Targeting IL-6R could be an effective approach to treat several irAE types without hindering antitumor immunity. This study supports ongoing clinical trials evaluating the safety and efficacy of tocilizumab (anti-IL-6R antibody) in combination with ICIs (NCT04940299, NCT03999749).

Neurological outcomes in immune checkpoint inhibitor-related neurotoxicity

While the spectrum of neurological immune checkpoint inhibitor-related adverse events is expanding, patients' outcomes are not well documented. This study aimed to assess outcomes of neurological immune-related adverse events and to identify prognostic factors. All patients experiencing grade ≥2 neurological immune-related adverse events identified at two clinical networks (French Reference Center for Paraneoplastic Neurological Syndromes, Lyon; and OncoNeuroTox, Paris) over five years were included. Modified Rankin scores were assessed at onset, 6, 12, 18 months, and last visit. A multi-state Markov model was used to estimate the transition rates between minor disability (mRS <3), severe disability (mRS 3-5), and death (mRS 6), over the study period. The state-to-state transition rates were estimated using maximum likelihood and variables were introduced into the different transitions to study their effects. A total of 147 patients were included out of 205 patients with a suspicion of neurological immune-related adverse events. The median age was 65 years (range 20-87) and 87/147 patients (59.2%) were male. Neurological immune-related adverse events involved the peripheral nervous system in 87/147 patients (59.2%), the central nervous system in 51/147 (34.7%), and both systems in 9/147 (6.1%). Paraneoplastic-like syndromes were observed in 30/147 patients (20.4%). Cancers included lung cancers (36.1%), melanoma (30.6%), urological cancers (15.6%), and others (17.8%). Patients were treated with programmed cell death protein (ligan) 1 (PD(L)1) inhibitors (70.1%), CTLA4 inhibitors (3.4%) or both (25.9%). Severe disability was reported in 108/144 patients (75.0%) at onset and in 33/146 patients (22.6%) at last visit (median follow-up duration: 12 months, range 0.5-50); 48/147 (32.7%) patients died, from cancer progression (17/48, 35.4%), neurological toxicity (15/48, 31.2%), other causes (10/48, 20.8%) or unknown causes (6/48, 12.5%). The rate of transition from severe to minor disability independently increased with melanoma [compared to lung cancer, hazard ratio = 3.26, 95%CI (1.27; 8.41)] and myositis/neuromuscular junction disorders [hazard ratio = 8.26, 95%CI (2.90; 23.58)], and decreased with older age [hazard ratio = 0.68, 95%CI (0.47; 0.99)] and paraneoplastic-like syndromes [hazard ratio = 0.29, 95%CI (0.09; 0.98)]. In patients with neurological immune-related adverse events, myositis/neuromuscular junction disorders and melanoma increase the transition rate from severe to minor disability, while older age and paraneoplastic-like syndromes result in poorer neurological outcomes; future studies are needed to optimize the management of such patients.

Advances in treatments of patients with classical and emergent neurological toxicities of anticancer agents

The neurotoxicity associated to the anticancer treatments has received a growing body of interest in the recent years. The development of innovating therapies over the last 20years has led to the emergence of new toxicities. Their diagnosis and management can be challenging in the clinical practice and further research is warranted to improve the understanding of their pathogenic mechanisms. Conventional treatments as radiation therapy and chemotherapy are associated to well-known and under exploration emerging central nervous system (CNS) and peripheral nervous system (PNS) toxicities. The identification of the risk factors and a better understanding of their pathogeny through a "bench to bedside and back again" approach, are the first steps towards the development of toxicity mitigation strategies. New imaging techniques and biological explorations are invaluable for their diagnosis. Immunotherapies have changed the cancer treatment paradigm from tumor cell centered to immune modulation towards an efficient anticancer immune response. The use of the immune checkpoints inhibitors (ICI) and chimeric antigen receptor (CAR-T cells) lead to an increase in the incidence of immune-mediated toxicities and new challenges in the neurological patient's management. The neurological ICI-related adverse events (n-irAE) are rare but potentially severe and may present with both CNS and PNS involvement. The most frequent and well characterized, from a clinical and biological standpoint, are the PNS phenotypes: myositis and polyradiculoneuropathy, but the knowledge on CNS phenotypes and their treatments is expanding. The n-irAE management requires a good balance between dampening the autoimmune toxicity without impairing the anticancer immunity. The adoptive cell therapies as CAR-T cells, a promising anticancer strategy, trigger cellular activation and massive production of proinflammatory cytokines inducing frequent and sometime severe toxicity known as cytokine release syndrome and immune effector cell-associated neurologic syndrome. Their management requires a close partnership between oncologist-hematologists, neurologists, and intensivists. The oncological patient's management requires a multidisciplinary clinical team (oncologist, neurologist and paramedical) as well as a research team leading towards a better understanding and a better management of the neurological toxicities.

Neurological adverse events of immune checkpoint inhibitors: An update of clinical presentations, diagnosis, and management

The use of immune checkpoint inhibitors (ICIs) has represented a major advance in cancer treatment. By enhancing endogenous immune responses to destroy cancer cells, ICIs can cause immune-related adverse events (irAEs), with possible involvement of any organ system. IrAEs are frequent, particularly those involving the skin or the endocrine system, and usually completely reversible after temporary immunosuppression, while neurological irAEs (n-irAEs) are relatively rare, often severe, and they carry a considerable risk of mortality and long-term disability. They usually affect the peripheral nervous system, mainly manifesting as myositis, polyradiculoneuropathy, or cranial neuropathy, and, less frequently, involve the central nervous system, causing encephalitis, meningitis, or myelitis. Although somehow reminiscent of the disorders that neurologists are familiar to deal with in their daily practice, n-irAEs are characterized by distinctive features from their idiopathic counterparts; for instance, myositis may have a predominant oculo-bulbar involvement reminiscent of myasthenia gravis and frequently associates with myocarditis; peripheral neuropathy, although often resembling Guillain-Barré syndrome, usually responds to corticosteroids. Remarkably, several associations between the neurological phenotype and the type of ICIs or the type of cancer have emerged in the last few years, and the growing administration of ICIs in patients with neuroendocrine cancers has led to an increased number of reports of paraneoplastic neurological syndromes (triggered or worsened by ICIs). This review aims to update current knowledge regarding the clinical presentation of n-irAEs. We also discuss the essential parts of the diagnostic approach, and we provide general recommendations for the management of these disorders.

Case report: A case of complete clinical response in a patient experiencing high microsatellite instability unresectable colon cancer being treated with a PD-L1 inhibitor after interstitial pneumonia

Immune checkpoint inhibitors (ICI) have dramatically transformed the treatment landscape for metastatic colorectal cancer (mCRC) with deficient DNA mismatch repair (dMMR) or high microsatellite instability (MSI-H). Envafolimab, a novel programmed death-1 ligand 1 (PD-L1) inhibitor, has been reported to be efficient and safe for the management of advanced MSI-H/dMMR solid tumors. Here, we report the case of a 35-year-old female patient with MSI-H/dMMR mCRC who was treated with envafolimab following mFOLFOX6 (oxaliplatin, leucovorin, and fluorouracil) plus bevacizumab. While suffering from interstitial pneumonia after chemotherapy, the patient achieved a complete clinical response with the use of envafolimab without additional adverse events. Thus, PD-L1 inhibitors may be potential candidates for treating patients with MSI-H/dMMR mCRC.

Rare forms of inflammatory myopathies - part I, generalized forms

INTRODUCTION

The idiopathic inflammatory myopathies traditionally comprise dermatomyositis, polymyositis, immune-mediated necrotizing myopathy, anti-synthetase syndrome, and inclusion body myositis. In this review, we aimed to cover the less common forms of generalized myositis.

AREAS COVERED

We identified rare forms of widespread myositis on the basis of list provided by the homepage of the Neuromuscular disease center of Washington University, USA and on the basis of the authors' knowledge. We searched PubMed® and EMBASE® for relevant articles on these forms with the aim of providing as much as possible information on their clinical manifestations as well as guidance on their work-up and treatment.

EXPERT OPINION

There is substantial heterogeneity among the various rare forms of generalized myositis in terms of their frequency and characterization. Some forms are reasonably well defined, while others may not represent truly well-defined diseases, but rather variants of other myopathies. The landscape of rare forms appears to have evolved over time, with some forms now being better characterized, while others, such as SARS-Cov-2- and immune checkpoint inhibitor-related myositis have come to the fore only in recent years. Knowledge about rare forms of myositis can aid in their recognition and treatment.

The role of bDMARDs in idiopathic inflammatory myopathies: A systematic literature review

Idiopathic inflammatory myopathies (IIM) are a group of different conditions typically affecting striate muscle, lung, joints, skin and gastrointestinal tract. Treatment typically relies on glucocorticoids and synthetic immunosuppressants, but the occurrence of refractory, difficult to treat, manifestations, may require more aggressive treatment, borrowed from other autoimmune diseases, including biologic disease modifying drugs (bDMARDs). In this regard, we conducted a systemic literature review in order to depict the current evidence about the use of bDMARDs in IIM. A total of 78 papers, published during the last 21 years, were retrieved. The majority of patients was treated with TNF-α inhibitors, whose effectiveness was assessed particularly in recalcitrant striate muscle, skin and joints involvement. Rituximab, whose evidence is supported by a large number of real-life studies and trials, seems to be an excellent option in case of ILD and anti-synthetase syndrome, while Tocilizumab, despite not meeting primary and secondary endpoints in a recently published clinical trial, proved its effectiveness in rapidly progressing ILD. Similarly, Abatacept, studied in a phase IIb clinical trial with conflicting evidence, was reported to be effective in some case reports of refractory dermatomyositis. Less data exist for anti-IL1 and anti-IL23 agents, which were employed particularly for inclusion body myositis and severe skin disease, respectively. This study provides an organ-focused assessment of bDMARDs in IIM, which display encouraging results in the treatment of refractory subsets of disease.

Immune checkpoint inhibitor-induced myocarditis and myositis in liver cancer patients: A case report and literature review

With the development of immunotherapy, immune checkpoint inhibitors (ICIs) are widely used in clinical oncology and have achieved good results. ICIs could induce immune-related adverse events (irAEs) in cancer treatment, which warrant sufficient attention. Among them, immune myositis can manifest severe symptoms affecting the whole body, and immune myocarditis occurs with a low incidence but high fatality rate. Here we report a case of grade 3/4 adverse reactions in a patient with partial hepatectomy for malignancy after using ICIs and describe the clinical presentation, laboratory results, treatment, and prognosis. It emphasizes that clinicians should focus on being alert to irAEs in liver cancer patients who have received ICI therapy. The case we present is a 56-year-old male diagnosed with hepatocellular carcinoma. Right hepatic lobectomy was performed in April 2019. Postoperative follow-up showed that transcatheter arterial chemoembolization (TACE) combined with sorafenib (400 mg twice daily) failed to stop the recurrence of the tumor. In December 2020, the patient started to use Camrelizumab injections (200mg/injection every 21 days as a cycle). After 3 cycles, the patient had decreased muscle strength in both lower extremities with chest tightness, dyspnea, and expectoration (whitish sputum). The diagnosis was ICIs injection-induced immune myocarditis and myositis accompanied. The patient's condition improved considerably by steroid pulse therapy timely. The case emphasizes that clinicians should focus on being alert to irAEs in liver cancer patients who have received ICI therapy.

Exploring the role of immune checkpoint inhibitors in the etiology of myasthenia gravis and Lambert-Eaton myasthenic syndrome: A systematic review

Background

While immune checkpoint inhibitors (ICIs) have been revolutionary in the treatment of cancer, their administration has been associated with a variety of immune-related adverse events (irAEs), including myasthenia gravis (MG), and Lambert-Eaton myasthenic syndrome (LEMS).

Objective

To provide a comprehensive synthesis of the evidence supporting an etiological role for ICIs in MG and LEMS in patients with no prior history of autoimmune disease.

Hypothesis

ICIs may trigger MG and LEMS in patients with no prior susceptibility to autoimmune disease.

Methods

Relevant primary research on Medline was interrogated using a series of search algorithms. Search terms were constructed based on the PICOS tool endorsed by the Cochrane Collaboration, which describes population, intervention, comparison, outcomes, and study design. Papers were screened according to inclusion and exclusion criteria. Additional papers were retrieved from the reference lists of screened papers. Each paper included in the qualitative synthesis was assigned an integrated metric of evidence (IME) value, ranging from 0 to 7, based on study design, quality of data, likelihood of a causal link between the immune checkpoint inhibitor(s) and MG/LEMS, confidence of MG/LEMS diagnosis, and the number of patients treated with an ICI prior to MG/LEMS diagnosis.

Results

Ninety-four papers describing at least one patient treated with ICI(s) prior to the onset of MG and/or LEMS were documented. Overall evidence for a causal link between ICI administration and MG/LEMS was low, with a median IME value of 2.88 (range 2.05-6.61).

Conclusions

There is a paucity of evidence in support of an etiological relationship between ICIs and MG/LEMS, due largely to the lack of mechanistic studies and/or prospective clinical trials with relevant study endpoints. The current literature is dominated by case reports and retrospective cohort studies, which inherently yield only low-level evidence, supporting the need for further work in this area. A role of ICIs in the etiology of MG/LEMS remains plausible, arguing for continued vigilance for irAEs in patients treated with these drugs. We argue that there is a need for future mechanistic, high quality, large-scale studies specifically investigating the possible etiological role of ICIs in MG/LEMS.

Neurological Complications of Conventional and Novel Anticancer Treatments

Various neurological complications, affecting both the central and peripheral nervous system, can frequently be experienced by cancer survivors after exposure to conventional chemotherapy, but also to modern immunotherapy. In this review, we provide an overview of the most well-known adverse events related to chemotherapy, with a focus on chemotherapy induced peripheral neurotoxicity, but we also address some emerging novel clinical entities related to cancer treatment, including chemotherapy-related cognitive impairment and immune-mediated adverse events. Unfortunately, efficacious curative or preventive treatment for all these neurological complications is still lacking. We provide a description of the possible mechanisms involved to drive future drug discovery in this field, both for symptomatic treatment and neuroprotection.

Treatment of rheumatic adverse events of cancer immunotherapy

Immune checkpoint inhibitors (ICIs), used to treat many advanced cancers, activate the immune system to elicit an antitumor response. ICIs can also cause immune-related adverse events (irAEs) when nontumor tissues are affected by excess inflammation and autoimmunity. Rheumatic irAEs include inflammatory arthritis, myositis, sicca syndrome, polymyalgia rheumatica, and several other rare phenotypes. Treating rheumatic irAEs requires balancing the desire to decrease off-target inflammation while not negatively impacting the antitumor immune response. In this review, treatment recommendations for rheumatic irAEs have been discussed. Pathogenesis of rheumatic irAEs has been briefly reviewed. Knowledge about the effects of corticosteroids and steroid-sparing agents on tumor responses has been detailed to give context for treatment decisions. Recommendations ultimately depend not only on the clinical presentation and severity of the irAE but also on the goals of cancer treatment. Finally, how to safely use ICI therapy in patients with preexisting autoimmune diseases is considered.

Environmental Risks for Inflammatory Myopathies

This is an up-to-date review on external environmental factors for adult-onset idiopathic inflammatory myopathies (IIMs). Environmental factors with suggestive evidence including ultraviolet radiation, smoking, infectious agents (viruses in particular), pollutants, medications (ie, statin) and vitamin D deficiency are discussed. We also discuss the potential implications of environmental factors in IIM development, identify current challenges, and provide insight into future investigations.

Expert Clinical Management of Severe Immune-Related Adverse Events: Results from a Multicenter Survey on Hot Topics for Management

There are differences in recommendations for the management of immune-related adverse events (irAEs) associated with immune checkpoint inhibitors (ICIs). To assess the real-world management of irAEs, three surveys regarding ICI-induced hepatitis (IIH), renal irAEs, and myositis were developed and sent to experts in each area. Fifty-six surveys were completed (17 IIH, 20 renal irAEs, and 19 myositis). All experts agreed on performing imaging in every suspected case of severe IIH. Sixty-five percent agreed on performing a liver biopsy in patients not responding to corticosteroids. The most common indication for corticosteroid use (59%) was for severe IIH not improving after discontinuation of ICIs. Additionally, 60% of the experts agreed on performing a biopsy for stage 2/3 acute kidney injury (AKI), and 70% recommended imaging for any stage of AKI. Thirty-five percent favored corticosteroids in AKI patients with creatinine levels 2–3-fold above baseline. For myositis, 58% would recommend a muscle biopsy in a patient with weakness and creatine kinase levels of 5000 U/L; 47% would also opt for an endomyocardial biopsy when the troponin levels are increased. Fifty-eight percent recommended oral corticosteroids for myositis, and 37% recommended additional therapy, mainly immunoglobulins. These results show substantial differences in expert practice patterns for the management of severe liver, kidney, and muscular irAEs.

Immune Checkpoint Inhibitor-Associated Myositis: A Distinct Form of Inflammatory Myopathy

ABSTRACT

Research on the relationship between inflammatory myopathy and malignancy has grown considerably within the last century. Now, the burgeoning field of inflammatory myopathy has yet another player in the mix: immune checkpoint inhibitor-associated myositis (ICI myositis). Immune checkpoint inhibitor-associated myositis is indicated by clinical diagnosis of inflammatory myopathy after initiation of immune checkpoint inhibitor for cancer management. Current literature reflects low prevalence but high mortality associated with ICI myositis, especially when involving myasthenia gravis and myocarditis. Immune checkpoint inhibitor-associated myositis tends to have muscle pain along with weakness, infrequent presentation with dermatitis, or interstitial lung disease and is typically seronegative with scattered, endomysial inflammatory infiltrates on biopsy. The differential diagnosis of ICI myositis includes myasthenia gravis and other neurological immune-related adverse events. Therapeutic approach involves high doses of corticosteroids with a choice of steroid-sparing immunomodulating agent(s) that is primarily driven by expert opinion due to lack of robust research to support one agent over another. There is wide variation in the inclusion criteria for ICI myositis used in previous studies. We review previously used inclusion criteria and suggest an expertise-based classification criterion to provide a standardized definition and allow comparability between studies. There is a critical need for prospective translational and clinical studies that elucidate the pathophysiology of ICI myositis in order to improve evaluation and management of these patients.

The effects of glucocorticoids and immunosuppressants on cancer outcomes in checkpoint inhibitor therapy

The emergence of checkpoint inhibitors has created a paradigm shift for the treatment of various malignancies. However, although these therapies are associated with improved survival rates, they also carry the risk of immune-related adverse events (irAEs). Moderate to severe irAEs are typically treated with glucocorticoids, sometimes with the addition of immunosuppressants as steroid-sparing therapy. However, it is unclear how glucocorticoids and immunosuppressants may impact cancer survival and the efficacy of immune checkpoint therapy on cancer. In this narrative review, we discuss the effects of glucocorticoids and immunosuppressants including methotrexate, hydroxychloroquine, azathioprine, mycophenolate mofetil, tumor-necrosis factor (TNF)-inhibitors, interleukin-6 inhibitors, interleukin-1 inhibitors, abatacept, rituximab, and Janus kinase inhibitors (JAKi) on cancer-specific outcomes in the setting of immune checkpoint inhibitor use.

[Clinical features of immune checkpoint inhibitor-related myositis in patients with urological cancer]

OBJECTIVE

Immune checkpoint inhibitors (ICI) have significantly improved the treatment efficacy of a variety of malignant tumors. However, patients may experience a series of special side effects during treatments with ICI. Immune-related myositis after ICI treatment is characterized by autoimmune rheumatic and musculoskeletal damage, which is relatively rare. To analyze the clinical characteristics and outcomes of ICI-associated myositis in urological tumors, we summarized the clinical manifestations, electrophysiological and pathological characteristics, treatments and outcomes in 8 patients.

METHODS

The clinical data of the 8 patients with immune-related myositis after ICI treatment for urological tumors treated in the Department of Urology, Peking University First Hospital from March 2018 to March 2022 were retrospectively analyzed for demographic characteristics, drug regimen, clinical symptoms, laboratory indices, electromyography examination, pathological manifestations and outcomes.

RESULTS

The eight patients included 2 females and 6 males with a median age of 68 years, all treated with ICI for urological neoplasms, including 2 upper tract urothelial carcinoma (UTUC), 3 renal cell carcinoma (RCC), and 3 bladder cancer (BCa). The median time between the first ICI treatment and the detection of immune-related myositis was 39.5 days, and the median duration of treatment was 2 sessions. The main symptoms were muscle pain and weakness, 5 cases with ptosis, 3 cases with secondary rhabdomyolysis, 5 cases with myocarditis, 1 case with myasthenia gravis, and 1 case with enterocolitis. Among them, patients with immune-related myocarditis had a shorter interval from the first anti-programmed cell death protein-1 (PD-1) therapy to the onset of immune-related myositis (P=0.042) compared with patients without myocarditis. The 8 patients had significant elevation of transaminases and muscle enzyme profile indexes, and 5 patients showed positive auto-antibodies. 3 patients had perfected muscle biopsies and showed typical skeletal muscle inflammatory myopathy-like pathological changes with CD3⁺, CD4⁺, CD8⁺, CD20⁺ lymphocytes and CD68⁺ macrophage infiltration. After the diagnosis of immune-related myositis, all the 8 patients immediately discontinued ICI therapy and improved after intravenous administration of methylprednisolone alone or in combination with gamma-globulin.

CONCLUSION

Immune-related myositis after ICI treatment is an immune-related adverse reactions (irAEs) with unique clinical and pathological features, commonly combined with cardiovascular adverse reactions. Immediate discontinuation of ICI and initiation of glucocorticoid therapy may improve the patient's condition in a timely manner.

Clinical Patterns and Follow-Up of Inflammatory Arthritis and Other Immune-Related Adverse Events Induced by Checkpoint Inhibitors. A Multicenter Study

Objectives

To describe different clinical patterns of rheumatic immune-related adverse events (irAEs) induced by immune checkpoint inhibitors (ICI) and their rheumatic and oncologic outcomes.

Methods

We classified clinical syndromes according to five different categories: non-inflammatory arthralgias (NIA), rheumatoid arthritis (RA)-like, psoriatic arthritis (PsA)-like, polymyalgia rheumatica (PMR)-like, and a miscellaneous group of patients with other syndromes. We conducted a baseline visit and then follow-up in order to determine their clinical pattern, treatment response, and outcome.

Results

We included 73 patients (64% male) with a mean age of 66.1 ± 11.6 years. Main underlying diagnosis was lung carcinoma in 29 (39%) patients, melanoma in 20 (27%), and renal-urothelial cancer in 11 (15%). Main ICI included Pembrolizumab in 24 (32%), Nivolumab 17 (23%), and Atezolizumab 7 (9 %). Seventeen out of seventy-three patients had an underlying rheumatic disease before ICI treatment. Fourteen patients developed other irAEs before or simultaneously with rheumatic syndromes. Main rheumatic irAEs included: RA-like in 31 (42.4%), NIA in 19 (26.0%), PMR-like in 10 (13.7%), and PsA-like in 5 (6.8%), among others. Median time from ICI to irAEs was 5 months (IQR 3–9). Those patients who received combined therapy, had a trend for an earlier presentation than those who received monotherapy (4.3 months IQR 1.85–17 vs. 6 months IQR 3–9.25, p = NS). Mean follow-up time was 14.0 ± 10.8 (SD, months). At the last visit, 47 % were taking glucocorticoids and 11% DMARD therapy. At the last visit, 13 (17.8%) patients remained with persistent arthritis, 19 (26%) had intermittent flares, and 39 (53.4%) had a self-limited pattern. Only in 15.1% of patients ICI therapy was discontinued.

Conclusions

We described different patterns according to treatment and irAEs. Combined ICI therapy had an earlier onset of symptoms. Patients who presented as RA-like, had a higher risk of persistent arthritis. After a mean follow-up of more than 1 year, one-fifth of the patients remained with persistent arthritis and 11% required DMARD therapy.

Plasma Exchange for Severe Immune-Related Adverse Events from Checkpoint Inhibitors: An Early Window of Opportunity?

Immune checkpoint inhibitors (ICIs) have revolutionized the treatment of several advanced malignancies leading to durable remission in a subset of patients. Their rapidly expanding use has led to an increased frequency of immune-related adverse events (irAEs). The pathogenesis of irAEs is poorly understood but may involve aberrant activation of T cells leading to inflammatory cytokine release or production of pathogenic antibodies leading to organ damage. Severe irAEs can be extremely debilitating and, in some cases, life threatening. IrAEs may not always be corticosteroid responsive or may require excessively high, often toxic, corticosteroid doses. Therapeutic plasma exchange (PLEX) is a treatment modality that has shown promising results for the management of certain severe irAEs, including irAEs that are not mentioned in current treatment guidelines. PLEX may attenuate ongoing irAEs and prevent delayed irAEs by accelerating clearance of the ICI, or by acutely removing pathogenic antibodies, cytokines, and chemokines. Here, we summarize examples from the literature in which PLEX was successfully used for the treatment of irAEs. We posit that timing may be a critical factor and that earlier utilization of PLEX for life-threatening irAEs may result in more favorable outcomes. In individuals at high risk for irAEs, the availability of PLEX as a potential therapeutic mitigation strategy may encourage life-saving ICI use or rechallenge. Future research will be critical to better define which indications are most amenable to PLEX, particularly to establish the optimal place in the sequence of irAE therapies and to assess the ramifications of ICI removal on cancer outcomes.

Mechanism and Management of Checkpoint Inhibitor-Related Toxicities in Genitourinary Cancers

The use of immune checkpoint inhibitors (ICIs) is rapidly increasing as more combinations and clinical indications are approved in the field of genitourinary malignancies. Most immunotherapeutic agents being approved are for the treatment of renal cell carcinoma and bladder cancer, which mainly involve PD-1/PD-L1 and CTLA-4 pathways. There is an ongoing need for recognizing and treating immunotherapy-related autoimmune adverse effects (irAEs). This review aims to critically appraise the recent literature on the mechanism, common patterns, and treatment recommendations of irAEs in genitourinary malignancies. We review the epidemiology of these adverse effects as well as general treatment strategies. The underlying mechanisms will also be discussed. Diagnostic considerations including differential diagnosis are also included in this review.

Immune Checkpoint Inhibitor-Related Myositis Overlapping With Myocarditis: An Institutional Case Series and a Systematic Review of Literature

Background: Immune checkpoint inhibitor (ICI)-related myositis with myocarditis is a rare but potentially fatal immune-related adverse event. However, its clinical features, response to immunosuppressive treatment, and prognosis remain poorly understood. Here, we describe the clinical course of patients with ICI-related myositis overlapping with myocarditis treated at our institution and a systematic review focusing on the response to immunosuppressive therapy.

Methods: We identified patients who developed ICI-induced myositis with myocarditis and were treated at our hospital using a retrospective chart review of electronic medical records. For the systematic review, studies reporting ICI-induced myositis with myocarditis were identified using the Cochrane Library and PubMed databases.

Results: Of the 625 patients treated with ICIs, four developed myositis with concurrent myocarditis. All the patients received immunosuppressive therapy. We assessed the activity of myocarditis and myositis based on temporal changes in troponin and creatine kinase (CK) levels. In all patients, peak troponin values appeared later than the peak CK values (median, 17 days). The median time from the start of ICI therapy to the peak of troponin and CK levels was 42.5 and 28 days, respectively. In all patients, CK levels decreased rapidly and steadily after the initiation of immunosuppressants. However, troponin levels were unstable and increased. In all patients, CK levels normalized within one month (range, 12–27 days), but troponin levels took several months to normalize (range, 84–161 days). Fourteen cases of ICI-related myositis with myocarditis were included in the systematic review. Of the 14 cases, 12 (86%) had their CK level decreased after the initial steroid treatment, but the troponin level increased and was higher than that before the start of treatment. In addition, the peak troponin values appeared later than the peak CK values (a median of 6.5 days). Eight (89%) of 9 long-term follow-up patients had troponin levels above the normal range even after CK normalization.

Conclusion: In most cases of ICI-related myositis with myocarditis, troponin levels increased after the initial steroid treatment despite decreased CK levels, and exceeded pre-steroid levels. In addition, troponin remained elevated for several months after CK normalized.

Autoantibodies in Patients With Immune-Related Adverse Events From Checkpoint Inhibitors: A Systematic Literature Review

BACKGROUND

Immune-related adverse events (irAEs) from immune checkpoint inhibitors (ICIs) are sometimes associated with autoantibodies, but we do not know how frequently or whether these autoantibodies are present before ICI initiation. Our aim was to determine the positivity rate of autoantibodies in patients with organ-specific ICI-associated irAEs and determine their value as pretreatment biomarkers.

METHODS

We searched for all English, peer-reviewed publications from MEDLINE, Embase, and Cochrane Library through February 20, 2020, and included any publication describing patients with irAEs and reporting results of any autoantibody investigation. Three reviewers independently extracted data, and 1 reviewer verified all data for accuracy and quality of reporting.

RESULTS

We identified 515 publications. Most reports described endocrine, rheumatic, gastrointestinal/hepatic, and myositis/myasthenia/myocarditis irAEs. Autoantibodies were present in close to 50% of patients with ICI-associated endocrinopathies. Anti-BP180 was found in more than 50% of patients with skin irAEs. Antibodies were also common in patients with the triad of myositis/myasthenia/myocarditis including striational antibodies (49%), acetylcholine receptor antibodies (40%), and myositis-associated antibodies (27%). Only 11% of patients with arthritis had either rheumatoid factor or cyclic citrullinated peptide antibodies, and only 30% of patients with sicca had Sjögren antibodies. Autoantibodies were also relatively uncommon in patients with hepatitis (antinuclear antibody, 18%) and colitis (perinuclear antineutrophil cytoplasmic antibody, 19%). Some cohort studies analyzing pre-ICI seropositivity suggest there may be a role for autoantibodies as biomarkers of irAEs.

CONCLUSIONS

Reported autoantibody positivity is high in irAEs involving the endocrine organs, skin, and muscle, but lower in irAEs affecting other organ systems. Autoantibody investigations in pre-ICI treatment patients have yielded mixed results regarding their utility as a biomarker of irAEs.

Predictors of Rheumatic Immune-Related Adverse Events and De Novo Inflammatory Arthritis After Immune Checkpoint Inhibitor Treatment for Cancer

OBJECTIVE

To identify predictors of rheumatic immune-related adverse events (irAEs) following immune checkpoint inhibitor (ICI) treatment for cancer.

METHODS

We performed a case-control study to predict the occurrence of rheumatic irAEs in cancer patients who initiated ICI treatment at Mass General Brigham and the Dana-Farber Cancer Institute between 2011 and 2020. We screened for the presence of rheumatic irAEs by reviewing the medical records of patients evaluated by rheumatologists or those prescribed nonglucocorticoid immunomodulatory drugs after the time of ICI initiation (baseline). Review of medical records confirmed the presence of rheumatic irAEs and the indications necessitating immunomodulatory drug treatment. Controls were defined as patients who did not experience rheumatic irAEs, did not have preexisting rheumatic disease, did not have a clinical evaluation by a rheumatologist after ICI treatment, did not receive an immunomodulatory drug after ICI, did not receive systemic glucocorticoids after ICI, and survived at least 6 months after the initial ICI treatment. We used logistic regression to estimate the odds ratios (ORs) (with 95% confidence intervals [95% CIs]) for the risk of a rheumatic irAE in the presence of various baseline predictors.

RESULTS

A total of 8,028 ICI recipients were identified (mean age 65.5 years, 43.1% female, 31.8% with lung cancer). After ICI initiation, 404 patients (5.0%) were evaluated by rheumatologists, and 475 patients (5.9%) received an immunomodulatory drug to treat any irAEs. There were 226 confirmed rheumatic irAE cases (2.8%) and 118 de novo inflammatory arthritis cases (1.5%). Rheumatic diseases (either preexisting rheumatic diseases or rheumatic irAEs) were a common indication for immunomodulatory drug use (27.9%). Baseline predictors of rheumatic irAEs included melanoma (multivariable OR 4.06 [95% CI 2.54-6.51]) and genitourinary (GU) cancer (OR 2.22 [95% CI 1.39-3.54]), both relative to patients with lung cancer; combination ICI treatment (OR 2.35 [95% CI 1.48-3.74]), relative to patients receiving programmed death 1 inhibitor monotherapy; autoimmune disease (OR 2.04 [95% CI 1.45-2.85]) and recent glucocorticoid use (OR 2.13 [95% CI 1.51-2.98]), relative to patients not receiving a glucocorticoid, compared to the 2,312 controls without rheumatic irAEs. Predictors of de novo inflammatory arthritis were similar to those of rheumatic irAEs.

CONCLUSION

We identified novel predictors of rheumatic irAE development in cancer patients, including baseline presence of melanoma, baseline presence of GU tract cancer, preexisting autoimmune disease, receiving or having received combination ICI treatment, and receiving or having received glucocorticoids. The proportion of cancer patients experiencing rheumatic irAEs may be even higher than was reported in the present study, since we used stringent criteria to identify cases of rheumatic irAEs. Our findings could be used to identify cancer patients at risk of developing rheumatic irAEs and de novo inflammatory arthritis and may help further elucidate the pathogenesis of rheumatic irAEs in patients with cancer who are receiving ICI treatment.

18 F-FDG PET/CT features of immune-related adverse events and pitfalls following immunotherapy

¹⁸F‐FDG PET/CT scanning is routinely performed to stage and evaluate the treatment response in many malignancies. Immunotherapy is a rapidly growing treatment option for many cancers, and both clinicians and imaging specialists need to be familiar with ¹⁸F‐FDG PET/CT imaging characteristics unique to patients on this type of treatment. In particular, many immune‐related adverse events (irAEs) can be detected on ¹⁸F‐FDG PET/CT and early accurate identification is critical to reduce treatment related morbidity and incorrect interpretation of malignant disease status. This pictorial essay reviews frequently encountered irAEs in clinical practice and their appearances on ¹⁸F‐FDG PET/CT along with a brief discussion on pseudoprogression and hyperprogression.

Neurologic Complications of Immune Checkpoint Inhibitors

The clinical use of cancer immunotherapy with immune checkpoint inhibitors has transformed the management of cancer and added another effective treatment option for different types of malignancies. The blockade of immune checkpoint pathways triggers an enhanced immune response leading to cancer regression but may also lead to autoimmune toxicities or immune-related adverse events, which may involve skin, endocrine, respiratory, gastrointestinal or neurologic manifestations. Clinically relevant neurologic complications involving the central and/or peripheral nervous system affect up to 1% of patients treated with immune checkpoint inhibitors and may be associated with significant morbidity and mortality. Common neurologic complications include aseptic meningitis and encephalitis, hypophysitis, myasthenia, myositis and neuropathies. Neurologic immune-related adverse events after immune checkpoint inhibition should be distinguished from cancer progression or other complications of cancer therapy (e.g. infections). The treatment of neurologic complications may include holding or withdrawing cancer immunotherapy, anti-inflammatory and immunosuppressive therapies with corticosteroids and steroid-sparing agents, immunomodulation with intravenous immune globulin or plasmapheresis and symptomatic treatment (e.g. antiepileptic medications, pain medications).

Incidence and Distinct Features of Immune Checkpoint Inhibitor-Related Myositis From Idiopathic Inflammatory Myositis: A Single-Center Experience With Systematic Literature Review and Meta-Analysis

Immune checkpoint inhibitor (ICI)-related myositis is a rare, potentially fatal condition that warrants further studies. Its incidence, clinical features, and prognosis remain poorly understood. To address these gaps, we conducted a systematic review and meta-analysis to evaluate the risk of myositis associated with ICI for solid tumors by analyzing phase III randomized controlled trials of anti-programmed death-1/ligand-1 (PD-1/PD-L1) and anti-cytotoxic T-lymphocyte antigen-4 (CTLA-4). To complement this analysis with clinical data, we evaluated published ICI case reports along with cases from our institutional registry. This registry comprised 422 patients treated with ICIs alone or in combination from September 2014 to June 2021. The analysis revealed an incidence of ICI-related myositis in 6,838 patients in 18 randomized controlled trials of 0.38% (odds ratio 1.96; 95% confidence interval 1.02–3.75) for patients receiving ICIs compared with controls. Detailed analysis of 88 cases from the literature search and our registry showed that myositis induced by PD-1 inhibitors was more frequent than that induced by anti-CTLA-4 agents, revealing a clinically diverse trend including myasthenia gravis and myocarditis. Importantly, having ptosis at the time of onset was significantly associated with the development of concomitant myocarditis (odds ratio 3.81; 95% CI 1.48–9.83), which is associated with poor prognosis. Regarding treatment, most patients received glucocorticoids, and some received immunosuppressants. Our study revealed the incidence of ICI-mediated myositis and the clinical features of myocarditis, highlighting the need for recognition and early intervention.

What Is in the Myopathy Literature?

ABSTRACT

This edition concentrates on inflammatory myopathies with reports of reclassification of polymyositis, cancer associations, evaluation of subclinical cardiac involvement, myositis-specific and -associated antibodies, and immune checkpoint inhibitor myositis. A number of reports address sporadic late-onset nemaline myopathy and point out its diagnostic difficulty and the importance of identifying an associated monoclonal gammopathy that is likely of clinical significance and may warrant aggressive immunotherapy. Finally, treatment of nondystrophic channelopathies is addressed.

Management of Immune-Related Adverse Events in Patients Treated With Immune Checkpoint Inhibitor Therapy: ASCO Guideline Update

PURPOSE

To increase awareness, outline strategies, and offer guidance on the recommended management of immune-related adverse events (irAEs) in patients treated with immune checkpoint inhibitor (ICPi) therapy.

METHODS

A multidisciplinary panel of medical oncology, dermatology, gastroenterology, rheumatology, pulmonology, endocrinology, neurology, hematology, emergency medicine, nursing, trialists, and advocacy experts was convened to update the guideline. Guideline development involved a systematic literature review and an informal consensus process. The systematic review focused on evidence published from 2017 through 2021.

RESULTS

A total of 175 studies met the eligibility criteria of the systematic review and were pertinent to the development of the recommendations. Because of the paucity of high-quality evidence, recommendations are based on expert consensus.

RECOMMENDATIONS

Recommendations for specific organ system-based toxicity diagnosis and management are presented. While management varies according to the organ system affected, in general, ICPi therapy should be continued with close monitoring for grade 1 toxicities, except for some neurologic, hematologic, and cardiac toxicities. ICPi therapy may be suspended for most grade 2 toxicities, with consideration of resuming when symptoms revert ≤ grade 1. Corticosteroids may be administered. Grade 3 toxicities generally warrant suspension of ICPis and the initiation of high-dose corticosteroids. Corticosteroids should be tapered over the course of at least 4-6 weeks. Some refractory cases may require other immunosuppressive therapy. In general, permanent discontinuation of ICPis is recommended with grade 4 toxicities, except for endocrinopathies that have been controlled by hormone replacement. Additional information is available at www.asco.org/supportive-care-guidelines.

Polymyositis: does it really exist as a distinct clinical subset?

PURPOSE OF REVIEW

To summarize information on polymyositis; diagnosis, definitions, published data and opinions.

RECENT FINDINGS

Polymyositis originally referred to inflammatory muscle diseases presenting with muscle weakness and inflammatory cell infiltrates on muscle tissue visible by microscopy. Over time and with improved technology to immunophenotype infiltrating inflammatory cells and characterize muscle fibres, the meaning of polymyositis changed and became more specific. There is ongoing controversy over the term polymyositis, with proponents for a strict definition based on histopathological and immunohistochemical features on muscle biopsies whereas others advocate for a broader clinical and histopathological phenotype. Over the past decades, the discovery of several myositis-specific autoantibodies together with distinct histopathological features have enabled the identification of new subsets previously labelled as polymyositis notably the antisynthetase syndrome and the immune-mediated necrotizing myopathies thus reducing the number of patients classified as polymyositis.

SUMMARY

There are still a small number of patients among the idiopathic inflammatory myopathies that can be classified as polymyositis as discussed in this review but the entity is now considered relatively rare.

Neurological disorders associated with immune checkpoint inhibitors: an association with autoantibodies

Among diverse neurological immune-related adverse events (irAEs), autoimmune encephalitis, aseptic meningitis, Guillain-Barré syndrome (GBS), myasthenia gravis (MG), and myositis are particularly important. The clinical presentation may be different from that of patients with conditions unrelated to immune checkpoint inhibitors (ICIs). Many of the autoantibodies detected in patients' sera are committed to the pathogenesis, while the clinical significance of such autoantibodies in cases of neurological irAEs is different from the significance in cases of typical neuronal disorders. A broad range of clinical symptoms complicates the diagnosis of autoimmune encephalitis. The clinical features of aseptic meningitis induced by classical drugs are different from those of aseptic meningitis induced by ICIs. Although autoantibodies against synaptic receptors or neuronal cell surface proteins are not detected, anti-Ma2 antibodies, which are onconeural antibodies against intracellular proteins, are detected in patients with autoimmune encephalitis associated with ICIs. GBS induced by ICIs sometimes shows gradual progression and a relapse of symptoms, suggesting chronic inflammatory demyelinating polyneuropathy. Bulbar symptoms and myasthenic crisis are frequently observed in ICI-induced MG. Anti-acetylcholine receptor antibodies are found in only half of patients with MG occurring as an irAE. ICI-induced myositis is accompanied by ocular muscle symptoms, such as ptosis and diplopia, which can suggest MG. Patients receiving ICI treatment present clinical features and laboratory findings that represent a mixture of MG and myositis. Anti-striational antibodies may act as biomarkers in cases in which MG and myositis overlap. A correct understanding of neurological adverse events is required to achieve the best management of patients.

Immune Checkpoint Inhibitor-Induced Myocarditis with Myositis/Myasthenia Gravis Overlap Syndrome: A Systematic Review of Cases

BACKGROUND

The development of immune checkpoint inhibitors (ICIs) represents a paradigm shift in the treatment of cancers. Despite showing remarkable efficacy, these agents can be associated with life-threatening immune-related adverse events. In recent years, several cases of myocarditis with myositis and/or myasthenia gravis overlap syndrome (IM3OS) have been reported. However, given the rarity, the clinical features and outcomes of these cases remain poorly understood. We, therefore, attempted to systematically review and summarize all cases of IM3OS reported in the literature.

MATERIALS AND METHODS

Studies reporting IM3OS were identified in Embase and MEDLINE. Only case reports and case series published in journals or presented at conferences were included. We conducted a systematic review according to the PRISMA Harms guidelines.

RESULTS

A total of 60 cases were eligible. The patients' median age was 71 years, and the majority (67%) were males; melanoma was the most common indication for ICIs (38%). The most-reported symptoms were fatigue (80%) and muscle weakness (78%). The median number of doses to the development of IM3OS was one. The average creatine kinase level was 9,645 IU/L. Cardiac arrhythmias occurred in 67% of patients, and 18% had depressed ejection fraction. Initial treatment consisted of immunosuppression with high-dose steroids and supportive therapies. Sixty percent of the patients died in hospital because of acute complications.

CONCLUSION

IM3OS can be associated with significant mortality and morbidity. Prospective studies are needed to understand the optimal approach to diagnose and manage these patients and to develop biomarkers to predict the occurrence and severity of this rare but serious condition.

IMPLICATIONS FOR PRACTICE

Clinicians should suspect coexisting myositis and/or myasthenia gravis in all patients with immune checkpoint inhibitor-induced myocarditis, given their propensity to occur together. Early recognition and prompt treatment with the help of a multidisciplinary team might help improve the outcomes of this life-threatening condition.

Cardiotoxicity associated with immune checkpoint inhibitors and CAR T-cell therapy

INTRODUCTION

The expanding use of immunotherapy and the growing population of patients with cancer has led to an increase in the reporting of immune related adverse events (irAEs). The emergency clinician should be aware of these emerging toxicities, some of which can be fatal. In this review we discuss the cardiotoxic side effects of immune checkpoint inhibitors (ICIs) and chimeric antigen receptor T-cell (CAR T-cell) therapy.

DISCUSSION

Recognizing the possible presentations of cardiotoxic irAEs is of utmost important as the diagnosis of cardiotoxicity associated with ICI and CAR T-cell can be difficult to make in the emergency department. The emergency clinician will have to presume the diagnosis and treat it without final confirmation in most cases. For this reason, if the diagnosis is suspected, early involvement of the cardiologist and oncologist is important to help guide management. Most irAEs will be treated with glucocorticoids, but in the case of CAR T-cell cardiotoxicity, Tocilizumab should be used as first line.

CONCLUSION

Although cardiotoxicity is rare, it is often life-threatening. Treatment should be initiated as soon as the diagnosis is suspected, and early involvement of the cardiologist and oncologist is imperative for optimal treatment.