Acute rhabdomyolysis with severe polymyositis following ipilimumab-nivolumab treatment in a cancer patient with elevated anti-striated muscle antibody

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.

Rheumatologic immune checkpoint inhibitor-related adverse events

PURPOSE OF REVIEW

Immune check point inhibitors (ICIs) are a unique class of cancer treatments that harness the body's innate antitumor response. Although these medications have transformed oncology care, they also lead to generalized immune activation that can result in toxicities across a spectrum of organ systems called immune-related adverse events. This article reviews the most common rheumatologic immune-related adverse events and their management.

RECENT FINDINGS

Inflammatory arthritis, polymyalgia rheumatic, sicca symptoms, systemic sclerosis, myositis, and vasculitis have all been reported as ICI adverse events. Treatment includes nonsteroidal anti-inflammatory drugs, glucocorticoids, traditional DMARDs, and biologics.

SUMMARY

Rheumatologists have an important role in the management of patients with rheumatologic immune-related adverse events. Working with our oncology colleagues, we can help manage rheumatologic immune-related adverse events while optimally preserving ICI's antitumor effects.

Peripheral nervous system adverse events associated with immune checkpoint inhibitors

BACKGROUND

Immune checkpoint inhibitors (ICIs) represent an effective cancer immunotherapy yet are associated with immune-related adverse events (irAEs). The aim of this study was to characterize irAEs involving the peripheral nervous system (PNS-irAEs) in a real-world cohort of ICI-treated patients.

METHODS

Cancer patients treated with ICIs between January 2014 and March 2022 were included. Patients with PNS-irAEs were identified and divided into two groups: (1) cranial/peripheral neuropathies and (2) myasthenia gravis (MG) and/or myositis. Clinical characteristics and outcomes, measured with the modified Rankin Scale (mRS), were compared among the two groups.

RESULTS

Among 920 ICI-treated patients, 20 patients (2.17%) developed a PNS-irAEs. The median latency from ICI exposure was 8.8 weeks and the median time from onset to clinical nadir was 3.5 weeks. Eleven patients developed a neuropathy: polyneuropathy (n = 4), cranial neuropathy (n = 3), small-fiber neuropathy (n = 3), brachial plexopathy (n = 1). Nine patients presented MG and/or myositis: concomitant MG and myositis (n = 6), isolated myositis (n = 2), exacerbation of MG (n = 1). Immunosuppressive treatment and/or ICI withdrawal determined a significant clinical improvement, expressed by a mRS reduction, in the neuropathy group (p = 0.004), but not in the MG/myositis group (p = 0.11). Overall, death due to irAEs occurred in four patients (20%), all with MG/myositis. Compared to patients with neuropathies, those with MG/myositis had a shorter latency onset (p = 0.036), developed more frequently concomitant non-neurologic irAEs (p = 0.028) and showed a higher mortality rate (p = 0.026).

CONCLUSIONS

In our large cohort of ICI-treated patients, 2.17% developed PNS-irAEs. Compared to ir-neuropathies, ir-MG/myositis tend to occur earlier from ICI exposure and present a worse response to treatment and a higher mortality.

Autoantibody profiles in patients with immune checkpoint inhibitor-induced neurological immune related adverse events

Background

Neurological immune-related adverse events (irAE-n) are severe and potentially fatal toxicities of immune checkpoint inhibitors (ICI). To date, the clinical significance of neuronal autoantibodies in irAE-n is poorly understood. Here, we characterize neuronal autoantibody profiles in patients with irAE-n and compare these with ICI-treated cancer patients without irAE-n.

Methods

In this cohort study (DRKS00012668), we consecutively collected clinical data and serum samples of 29 cancer patients with irAE-n (n = 2 pre-ICI, n = 29 post-ICI) and 44 cancer control patients without irAE-n (n = 44 pre- and post-ICI). Using indirect immunofluorescence and immunoblot assays, serum samples were tested for a large panel of neuromuscular and brain-reactive autoantibodies.

Results

IrAE-n patients and controls received ICI treatment targeting programmed death protein (PD-)1 (61% and 62%), programmed death ligand (PD-L)1 (18% and 33%) or PD-1 and cytotoxic T-lymphocyte-associated protein (CTLA-)4 (21% and 5%). Most common malignancies were melanoma (both 55%) and lung cancer (11% and 14%). IrAE-n affected the peripheral nervous system (59%), the central nervous system (21%), or both (21%). Prevalence of neuromuscular autoantibodies was 63% in irAE-n patients, which was higher compared to ICI-treated cancer patients without irAE-n (7%, p <.0001). Brain-reactive autoantibodies targeting surface (anti-GABA_BR, -NMDAR, -myelin), intracellular (anti-GFAP, -Zic4, -septin complex), or unknown antigens were detected in 13 irAE-n patients (45%). In contrast, only 9 of 44 controls (20%) presented brain-reactive autoantibodies before ICI administration. However, seven controls developed de novo brain-reactive autoantibodies after ICI initiation, therefore, prevalence of brain-reactive autoantibodies was comparable between ICI-treated patients with and without irAE-n (p = .36). While there was no clear association between specific brain-reactive autoantibodies and clinical presentation, presence of at least one of six selected neuromuscular autoantibodies (anti-titin, anti-skeletal muscle, anti-heart muscle, anti-LRP4, anti-RyR, anti-AchR) had a sensitivity of 80% (95% CI 0.52-0.96) and a specificity of 88% (95% CI 0.76-0.95) for the diagnosis of myositis, myocarditis, or myasthenia gravis.

Conclusion

Neuromuscular autoantibodies may serve as a feasible marker to diagnose and potentially predict life-threatening ICI-induced neuromuscular disease. However, brain-reactive autoantibodies are common in both ICI-treated patients with and without irAE-n, hence, their pathogenic significance remains unclear.

The role of immune checkpoints in cardiovascular disease

Immune checkpoint inhibitors (ICI) are monoclonal antibodies which bind to immune checkpoints (IC) and their ligands to prevent inhibition of T-cell activation by tumor cells. Currently, multiple ICI are approved targeting Cytotoxic T-lymphocyte antigen 4 (CTLA-4), Programmed Death Protein 1 (PD-1) and its ligand PD-L1, and Lymphocyte-activation gene 3 (LAG-3). This therapy has provided potent anti-tumor effects and improved prognosis for many cancer patients. However, due to systemic effects, patients can develop immune related adverse events (irAE), including possible life threatening cardiovascular irAE, like atherosclerosis, myocarditis and cardiomyopathy. Inhibition of vascular IC is associated with increased atherosclerotic burden and plaque instability. IC protect against atherosclerosis by inhibiting T-cell activity and cytokine production, promoting regulatory T-cell differentiation and inducing T-cell exhaustion. In addition, PD-L1 on endothelial cells might promote plaque stability by reducing apoptosis and increasing expression of tight junction molecules. In the heart, IC downregulate the immune response to protect against cardiac injury by reducing T-cell activity and migration. Here, inhibition of IC could induce life-threatening T-cell-mediated-myocarditis. One proposed purpose behind lymphocyte infiltration is reaction to cardiac antigens, caused by decreased self-tolerance, and thereby increased autoimmunity because of IC inhibition. In addition, there are several reports of ICI-mediated cardiomyopathy with immunoglobulin G expression on cardiomyocytes, indicating an autoimmune response. IC are mostly known due to their cardiotoxicity. However, t his review compiles current knowledge on mechanisms behind IC function in cardiovascular disease with the aim of providing an overview of possible therapeutic targets in prevention or treatment of cardiovascular irAEs.

Nivolumab-induced Myositis and Myocarditis with Positive Anti-titin Antibody and Anti-voltage-gated Potassium Channel Kv1.4 Antibody

Immune checkpoint inhibitors (ICIs) are complicated by immune-related adverse events (irAEs), such as myositis, myocarditis, and myasthenia gravis (MG). Anti-titin antibody and anti-voltage-gated potassium channel Kv1.4 antibody are anti-striated antibodies that are frequently detected in MG patients with myositis and/or myocarditis. However, the clinical relationship between positive anti-striated antibodies and irAEs of ICIs remains unknown. We herein report a case of nivolumab-induced myositis and myocarditis with positive anti-titin antibody and anti-voltage-gated potassium channel Kv1.4 antibody in a patient with non-small-cell lung cancer. We also review reported cases of positive anti-striated antibodies related to irAEs of ICIs.

Immune-Related Uncommon Adverse Events in Patients with Cancer Treated with Immunotherapy

Immunotherapy has dramatically changed the therapeutic landscape of oncology, and has become standard of care in multiple cancer types in front or late lines of therapy, with some longstanding responses and outstanding results. Notwithstanding, its use has brought a totally unique spectrum of adverse events, characterized by a myriad of diverse manifestations affecting nearly every organ and system of the body, including the endocrine, nervous, cardiac, respiratory and gastrointestinal systems. Uncommon adverse events, defined as those occurring in less than 1% of patients, comprise an even more heterogeneous group of diseases that are being seen more recurrently as the use of immune check-point inhibitors increases and indications spread in different tumor types and stages. Here, we comprehensively review some uncommon, but exceedingly important, immune-related adverse events, with special emphasis in the clinical approach and diagnostic workup, aiming to reunite the evidence published previously, allowing an increase in awareness and knowledge from all specialists implicated in the diagnosis, treatment, and care of cancer patients treated with immunotherapy.

Neurologic Toxicity of Immune Checkpoint Inhibitors: A Review of Literature

Immune checkpoint inhibitors have entailed a change of paradigm in the management of multiple malignant diseases and are acquiring a key role in an increasing number of clinical sceneries. However, since their mechanism of action is not limited to the tumor microenvironment, their systemic activity may lead to a wide spectrum of immune-related side effects. Although neurological adverse events are much less frequent than gastrointestinal, hepatic, or lung toxicity, with an incidence of <5%, their potential severity and consequent interruptions to cancer treatment make them of particular importance. Despite them mainly implying peripheral neuropathies, immunotherapy has also been associated with an increased risk of encephalitis and paraneoplastic disorders affecting the central nervous system, often appearing in a clinical context where the appropriate diagnosis and early management of neuropsychiatric symptoms can be challenging. Although the pathogenesis of these complications is not fully understood yet, the blockade of tumoral inhibitory signals, and therefore the elicitation of cytotoxic T-cell-mediated response, seems to play a decisive role. The aim of this review was to summarize the current knowledge about the pathogenic mechanisms, clinical manifestations, and therapeutic recommendations regarding the main forms of neurotoxicity related to checkpoint inhibitors.

CNS and PNS manifestation in immune checkpoint inhibitors: A systematic review

INTRODUCTION

Immunomodulatory therapies, including the use of immune checkpoint inhibitors (ICIs), have made a profound impact on treatment of advanced cancers in recent decades. Neurologic immune-related adverse events (irAEs) related to use of these agents are rare but potentially fatal sequelae. This systematic reviewed aimed to describe onset, clinical features, treatment, and outcome of neurological irAEs following ICI usage.

METHODS

A systematic literature search was conducted to identify all case reports (n = 168) and case series (n = 29) describing neurological irAEs (n = 255 patients). Patient demographics, clinical features, and clinical courses were extracted and used to assess statistical relationships between reported variables.

RESULTS

Of reports describing neurological irAEs related to ICI use, the majority of cases were in men (66%) and patients above the age of fifty (85%). Disorders of the peripheral nervous system (PNS, 83%) were more common than central nervous system involvement. Neuromuscular disorders were the most common type of neurological irAE (e.g. myasthenia gravis, 36%), followed by peripheral neuropathies (16%), followed by all CNS disorders combined (15%). Most cases presented within the first 5 doses of ICI treatment. Most patients improved clinically, but 24% of cases were fatal. Mortality was highest in patients with neuromuscular irAEs, such as myasthenia gravis and myositis.

CONCLUSION

This systematic literature review describes the largest collection of neurological irAEs to date including both CNS and PNS manifestations of ICIs. The information described herein can be used to better inform monitoring and treatment of patients undergoing treatment with ICIs.

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.

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.

Marked Respiratory Failure in an Ambulant Patient with Immune-mediated Necrotizing Myopathy and Anti-Kv1.4 and Anti-titin Antibodies

We herein report a case of seronegative immune-mediated necrotizing myopathy (IMNM) concurrent with anti-Kv1.4 and anti-titin antibodies. A 72-year-old Japanese woman presented with a 29-year history of fluctuating high serum creatine kinase (CK) levels followed by intermittent ptosis and respiratory muscle weakness. This case highlights the fact that marked respiratory muscle weakness requiring intubation can be seen in an ambulant patient with IMNM. Marked respiratory muscle weakness, rhabdomyolysis-like acute elevation of CK levels, and anti-striational muscle antibodies may be a characteristic constellation of findings in a distinct subgroup of patients with inflammatory myopathy with myasthenia gravis or similar symptoms.

[Rheumatic immune adverse events related to immune checkpoint inhibitors-(IrAEs related to ICI)]

New anti-cancer therapeutics have been developed in the recent years and dramatically change prognosis and patient management. Either used alone or in combination, immune checkpoint inhibitors (ICI), such as anti-CTLA-4 and anti-PD1/PD-(L)1, act by removing T-cell inhibition to enhance their antitumor response. This change in therapeutic targets leads to a break in immune-tolerance and a unique toxicity profile resulting in immune complications. These side effects, called Immune-Related Adverse Events (IrAEs), can affect all organs, with a wide range of clinical and biological presentations and severity. Various rheumatic and musculoskeletal manifestations have been reported in the literature, ranging from mild arthralgia, polymyalgia rheumatica, to genuine serodefined rheumatoid arthritis and myositis. Tolerance studies suggest some correlations between IrAEs occurrence and tumor response. Assessment of patient musculoskeletal status prior to the start of the ICI is warranted. Management of rheumatic IrAEs does not usually request ICI discontinuation, exception for myositis or very severe forms where it should be discussed. Treatment relies on non-steroidal anti-inflammatory drugs (NSAIDs) or low dose glucocortioids (<20mg per day). Dose should be adjusted according to severity. The use of disease modifying anti-rheumatic drugs (DMARDs), either conventional and/or biological should be very cautious and result from a shared decision between oncologist and rheumatologist to best manage dysimmunitary complications without hampering the antitumor efficacy of ICI.

Inflammatory Myositis in Cancer Patients Receiving Immune Checkpoint Inhibitors

OBJECTIVE

To estimate the incidence of immune checkpoint inhibitor-related myositis (ICI-myositis) in cancer patients receiving ICIs, and to report associated clinical manifestations, patterns of care, and outcomes.

METHODS

We identified a retrospective cohort of patients receiving ICIs between 2016 and 2019 seen at the University of Texas MD Anderson Cancer Center. Cases of ICI-myositis were identified using International Classification of Disease codes and confirmed by reviewing medical records and pathology, as available.

RESULTS

A total of 9,088 patients received an ICI. Thirty-six patients (0.40%) were identified as having ICI-myositis: 17 patients (47%) with ICI-myositis alone and 19 (53%) with overlap manifestations (5 patients with myocarditis, 5 with myasthenia gravis, and 9 with both). The incidence of ICI-myositis was 0.31% in those receiving ICI monotherapy and 0.94% in those receiving combination ICI therapy (relative risk 3.1 [95% confidence interval 1.5-6.1]). Twenty-five patients (69%) received ≥1 treatment in addition to glucocorticoids: plasmapheresis in 17 patients (47%), intravenous immunoglobulin in 12 (33%), and biologics in 11 (31%). Patients with overlap conditions had worse outcomes than those with myositis alone, and 79% of them developed respiratory failure. Eight patients died as a result of ICI-myositis, and all had overlap syndrome with myasthenia gravis or myocarditis (P < 0.05); 75% of these patients had a concomitant infection.

CONCLUSION

ICI-myositis is a rare but severe adverse event. More than half of the patients presented with overlap manifestations and had deleterious outcomes, including respiratory failure and death. None of the patients with ICI-myositis alone died as a result of adverse events. Optimal treatment strategies have yet to be determined.

Nivolumab-associated myositis myocarditis and myasthenia and anti-striated muscle antibodies

An 82-year-old man was treated with neo-adjuvant nivolumab (programmed cell death protein 1 or PD-1 inhibitor) for local recurrence of melanoma developed myositis, myocarditis and a myasthenic-like syndrome with a fatal outcome. The occurrence of these three conditions may constitute a new immune checkpoint-induced syndrome. The relevance of the clinical features and the immunology is discussed. This case highlights the special role of anti-striated muscle antibodies as a predictor of mortality.

Diagnosis and management of immune-related adverse effects of immune checkpoint therapy in the emergency department

Rapid advances in cancer immunotherapy using immune checkpoint inhibitors have led to significantly improved survival. Rapid identification of the toxicity syndromes associated with these therapeutic agents is very important for emergency physicians because the population of patients diagnosed with cancer is increasing and cancer therapies including immune checkpoint inhibitors have become the first-line treatment for more and more types of cancer. The emergency medicine literature lags behind rapid advances in oncology, and oncology guidelines for rapid recognition and management of these emerging toxicity syndromes are not familiar to emergency physicians. In this review article, we discuss the clinical presentation and management of immune-related adverse effects during the critical first hours of emergency care. We also suggest a workflow for the recognition and treatment of emergencies arising from serious immune-related adverse effects, including but not limited to colitis, adrenal crisis, myocarditis, pneumonitis, myasthenic crisis, diabetic ketoacidosis, bullous pemphigus, and hemophagocytic lymphohistiocytosis. Rapid advances in cancer therapy are bringing new diagnostic and therapeutic challenges to emergency providers, and therefore it is crucial to raise awareness and provide guidelines for the management of new treatment-related toxicities.

Cost-effectiveness of nivolumab in advanced melanoma: a drug review

Introduction: The immune checkpoint inhibitors, including nivolumab, and targeted agents have dramatically improved the outcome for patients with unresectable advanced melanoma. Areas covered: This is a narrative review of the published evidence on nivolumab in metastatic melanoma. Expert opinion: In ipilimumab pre-treated patients (CheckMate 037), nivolumab was associated with a higher response rate and a longer duration of response when compared to chemotherapy. In previously untreated patients, nivolumab improves survival when compared to chemotherapy (CheckMate 066) or to ipilimumab (CheckMate 067). The combination of nivolumab and ipilimumab also improves survival when compared to ipilimumab (CheckMate 067). CheckMate 067 was not designed to compare the nivolumab-ipilimumab combination to nivolumab alone. A modified regimen using a lower dose of ipilimumab in combination with standard dose nivolumab is better tolerated than nivolumab in combination with standard dose ipilimumab (CheckMate 511). In patients with previously untreated metastatic melanoma, the anti-PD-1 monoclonal antibodies nivolumab and pembrolizumab improve survival when compared to ipilimumab. Nivolumab is equally active in BRAF mutated and BRAF wild type melanoma. The optimal sequence of checkpoint inhibitors and BRAF/MEK inhibitors in BRAF mutated patients has not been established.

Immune checkpoint inhibitor-associated myopathy: a clinicoseropathologically distinct myopathy

Immune checkpoint inhibitors have revolutionized the landscape of cancer treatment. Alongside their many advantages, they elicit immune-related adverse events, including myopathy, which potentially result in substantial morbidity if not recognized and treated promptly. Current knowledge of immune checkpoint inhibitor-associated myopathy is limited. We conducted a 5-year retrospective study of patients with immune checkpoint inhibitor-associated myopathy. Clinical features, survival and ancillary test findings were analysed and compared with those of immune-mediated necrotizing myopathy patients without immune checkpoint inhibitor exposure seen during the same time period. We identified 24 patients with immune checkpoint inhibitor-associated myopathy (median age 69 years; range 28-86) and 38 patients with immune-mediated necrotizing myopathy. Ocular involvement occurred in 9/24 patients with immune checkpoint inhibitor exposure, without electrodiagnostic evidence of neuromuscular transmission defect, and in none of the immune-mediated necrotizing myopathy patients (P < 0.001). Myocarditis occurred in eight immune checkpoint inhibitor-associated myopathy patients and in none of the immune-mediated necrotizing myopathy patients (P < 0.001). Median creatine kinase was 686 IU/l in the immune checkpoint inhibitor cohort (seven with normal creatine kinase) compared to 6456 IU/l in immune-mediated necrotizing myopathy cohort (P < 0.001). Lymphopenia was observed in 18 and 7 patients with and without immune checkpoint inhibitor exposure, respectively (P < 0.001). Myopathological findings were similar between patients with and without immune checkpoint inhibitor exposure, consisting of necrotic fibres with no or subtle inflammation. Necrotic fibres however arranged in clusters in 10/11 immune checkpoint inhibitor-associated myopathy patients but in none of the immune checkpoint inhibitor-naïve patients (P < 0.001). Despite the lower creatine kinase levels in immune checkpoint inhibitor-exposed patients, the number of necrotic fibres was similar in both groups. Immune checkpoint inhibitor-associated myopathy patients had a higher frequency of mitochondrial abnormalities and less number of regenerating fibres than immune-mediated necrotizing myopathy patients (P < 0.001). Anti-hydroxy-3-methylglutaryl-CoA reductase or signal recognition particle antibodies were absent in patients with immune checkpoint inhibitor exposure but positive in two-thirds of immune checkpoint inhibitor-naïve patients. Most patients with immune checkpoint inhibitor-associated myopathy responded favourably to immunomodulatory treatments, but four died from myopathy-related complications and one from myocarditis. Intubated patients had significantly shorter survival compared to non-intubated patients (median survival of 22 days; P = 0.004). In summary, immune checkpoint inhibitor-associated myopathy is a distinct, treatable immune-mediated myopathy with common ocular involvement, frequent lymphopenia and necrotizing histopathology, which contrary to immune-mediated necrotizing myopathy, is featured by clusters of necrotic fibres and not accompanied by anti-hydroxy-3-methylglutaryl-CoA reductase or signal recognition particle antibodies. Normal or mildly elevated creatine kinase level does not exclude the diagnosis.

Immune-related myositis resulting from combination therapy of ipilimumab and nivolumab in patient with metastatic renal cell carcinoma

Immune-related myositis is one of the rare immune-related adverse events whose underlying precise mechanisms are not fully understood. Here, we describe a case of immune-related myositis that developed after four cycles of combination therapy with nivolumab plus ipilimumab for the treatment of metastatic renal cell carcinoma. Negative results of autoimmune antibodies, including anti-acetylcholine receptor and anti-muscle-specific kinase antibodies suggested a T-cell-mediated mechanism. After recovery with steroid therapy, the patient resumed nivolumab monotherapy and survived without any evidence of disease progression or refractory of myositis. Differential diagnosis between T-cell-mediated and B-cell-mediated immune-related myositis and its impact on optimal management are discussed.

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.

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.

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.

Psoriatic arthritis induced by anti-PD1 and treated with apremilast: a case report and review of the literature

Immune checkpoint inhibitors targeting programmed cell death protein 1 pathways are generally well tolerated, but immune-related adverse events have been observed in more than 80% of all patients. Rheumatic and musculoskeletal immune related adverse events have to date not been widely recognized or well characterized. Psoriasic arthritis is a rare entity and it makes management of patients difficult due to the limited therapeutic possibilities and the strong impact on the quality of life. The majority of cases were treated with glucocorticoids, in some cases not enough. We present the case of a patient with psoriasic arthritis and report cases described in literature of patients treated with apremilast, a small oral molecule that inhibits of phosphodiestherase 4.

EULAR points to consider for the diagnosis and management of rheumatic immune-related adverse events due to cancer immunotherapy with checkpoint inhibitors

Background

Rheumatic and musculoskeletal immune-related adverse events (irAEs) are observed in about 10% of patients with cancer receiving checkpoint inhibitors (CPIs). Given the recent emergence of these events and the lack of guidance for rheumatologists addressing them, a European League Against Rheumatism task force was convened to harmonise expert opinion regarding their identification and management.

Methods

First, the group formulated research questions for a systematic literature review. Then, based on literature and using a consensus procedure, 4 overarching principles and 10 points to consider were developed.

Results

The overarching principles defined the role of rheumatologists in the management of irAEs, highlighting the shared decision-making process between patients, oncologists and rheumatologists. The points to consider inform rheumatologists on the wide spectrum of musculoskeletal irAEs, not fulfilling usual classification criteria of rheumatic diseases, and their differential diagnoses. Early referral and facilitated access to rheumatologist are recommended, to document the target organ inflammation. Regarding therapeutic, three treatment escalations were defined: (1) local/systemic glucocorticoids if symptoms are not controlled by symptomatic treatment, then tapered to the lowest efficient dose, (2) conventional synthetic disease-modifying antirheumatic drugs, in case of inadequate response to glucocorticoids or for steroid sparing and (3) biological disease-modifying antirheumatic drugs, for severe or refractory irAEs. A warning has been made on severe myositis, a life-threatening situation, requiring high dose of glucocorticoids and close monitoring. For patients with pre-existing rheumatic disease, baseline immunosuppressive regimen should be kept at the lowest efficient dose before starting immunotherapies.

Conclusion

These statements provide guidance on diagnosis and management of rheumatic irAEs and aim to support future international collaborations.

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.

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.

Management of rheumatic complications of ICI therapy: a rheumatology viewpoint

Since immune checkpoint inhibitors became the standard of care for an increasing number of indications, more patients have been exposed to these drugs and physicians are more challenged with the management of a unique spectrum of immune-related adverse events (irAEs) associated with immune checkpoint inhibitors. Those irAEs of autoimmune or autoinflammatory origin, or both, can involve any organ or tissue, but most commonly affect the dermatological, gastrointestinal and endocrine systems. Rheumatic/systemic irAEs seem to be less frequent (although underreporting in clinical trials is probable), but information on their management is highly relevant given that they can persist longer than other irAEs. Their management consists of anti-inflammatory treatment including glucocorticoids, synthetic and biologic immunomodulatory/immunosuppressive drugs, symptomatic therapies as well as holding or, rarely, discontinuation of immune checkpoint inhibitors. Here, we summarize the management of rheumatic/systemic irAEs based on data from clinical trials but mainly from published case reports and series, contextualize them and propose perspectives for their treatment.

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.

Fatal myositis and spontaneous haematoma induced by combined immune checkpoint inhibitor treatment in a patient with pancreatic adenocarcinoma

BACKGROUND

Immune checkpoint inhibitors (ICIs) have achieved unprecedented success in cancer treatment over the past decade. The application of ICIs hasled to the discovery of various types of immune-related adverse events (irAEs). Here, we report a case of fatal myositis and spontaneous haematoma following concurrent treatment of nivolumab and ipilimumab for pancreatic adenocarcinoma.

CASE PRESENTATION

A 71-year-old gentleman with pancreatic adenocarcinoma underwent the Whipple procedure in September 2014. The patient received 8 cycles of adjuvant chemotherapy with gemcitabineand achieved a complete responsein April 2015. Treatment with the PD-1 inhibitor nivolumab was started due to suspected tumour recurrence in November 2015. In August 2016, the CTLA-4 inhibitor ipilimumab was added to nivolumab for 2 cycles. Eight weeks after the last dose, the patient developed severe myositis complicated with spontaneous haematomain skeletalmuscle. Pathology of the skeletal muscle autopsy revealed lymphocytic infiltration. Intense immunosuppressive therapy, including high-dose corticosteroids and methotrexate, resulted in clinical success in the treatment of myositis. However, the patient died of cancer recurrence.

CONCLUSION

Myositis due to immunotherapy can be a fatal adverse event of ICIs, which requires close monitoring and cautious management.

Neurologic Immune-Related Adverse Events Associated with Immune Checkpoint Inhibition

PURPOSE OF REVIEW

This review highlights the spectrum of neurologic adverse events seen with use of immune checkpoint inhibitors (ICIs), their potential mechanisms, the treatments undertaken, and the clinical outcomes.

RECENT FINDINGS

The advent of ICIs has revolutionized cancer therapy. Neurologic adverse events (NAEs) are rare but clinically significant complication of ICIs. They can involve both the central and peripheral nervous system. Examples include myositis, neuropathy, encephalopathy, and myasthenia gravis. Treatment consists of holding the ICI, administration of corticosteroids, and other immunomodulatory agents as needed. The outcomes are generally favorable; however, rarely severe events can lead to significant morbidity and even mortality. Identifying and treating the range of neurologic adverse events that may potentially arise with ICIs is very important as the oncologic indications for their use continues to expand.

Autoimmune rhabdomyolysis and a multiorgan display of PD-1 inhibitor induced immune related adverse events during treatment of metastatic melanoma

Background

Programmed death-1 (PD-1) inhibitors are among the immunotherapies that have revolutionized our approach to treating several cancers. These novel agents act by blocking PD-1 receptor/PD-1 ligand interactions that would otherwise allow tumor cells to evade host immune destruction by inhibiting response of cytotoxic T-lymphocytes. They are overall well tolerated, though they have been associated with a constellation of immune mediated adverse events (irAEs).

Case presentation

We present a case of rare nivolumab mediated adverse events in a patient with nodular recurrence of melanoma. The patient presented with rhabdomyolysis and shortly thereafter developed a constellation of immune-mediated organ derangements. This case further demonstrates the utility and effectiveness of steroid therapy in the setting of irAEs despite our patient’s eventual poor clinical outcome. While PD-1 inhibitors have revolutionized the treatment of several cancers, they require vigilance by the clinician for early detection and treatment of uncommon but potentially fatal irAEs.

Conclusions

PD-1 inhibitors are now widely used in a multitude of cancer types including melanoma, advanced non-small cell lung cancer, metastatic renal cell carcinoma, and Hodgkin lymphoma amongst others. While these agents are often well tolerated, they are associated with a unique profile of immune-related toxicities that can cause significant morbidity and mortality. Education of both patients and healthcare providers is essential for diagnosis and treatment of these adverse events early in their course. This case highlights the uncommon but potentially serious PD-1-associated toxicity of myopathy and rhabdomyolysis along with other organ involvement and is directly applicable to use of these agents in patients with advanced cancers.

[A case of anti-titin antibody positive nivolumab-related necrotizing myopathy with myasthenia gravis]

A 53-year-old man suffering from squamous cell lung cancer presented with bilateral ptosis and bulbar palsy a month after initial treatment with the immune checkpoint inhibitor nivolumab. The symptoms showed worsening from midday, suggesting myasthenia gravis (MG), although anti-AChR antibody was negative. Although no muscle weakness was detected, the CK level was elevated to 5,255 IU/l, and MRI of the thigh revealed inflammation of the bilateral rectus femoris muscle. A muscle biopsy showed signs of necrotizing myopathy with expression of sarcolemmal HLA class I and accumulation of macrophages, CD4, CD8, and CD20-positive lymphocytes. Positivity for anti-titin antibody, one of the anti-striated muscle antibodies, was evident. The patient was diagnosed as having nivolumab-related necrotizing myopathy with myasthenia gravis, an immune-related adverse event (irAE). Treatment with prednisolone rapidly ameliorated the symptoms, and the serum CK level normalized. There have been several reports of nivolumab-related myositis with MG. On the basis of the muscle pathology and antibody data, we were able to clarify that necrotizing myopathy was related to the pathogenesis of this case.

Rhabdomyolysis-induced acute kidney injury in a patient with undifferentiated connective tissue disease: A case report and literature review rhabdomyolysis-induced AKI in a patient with UCTD

RATIONALE

Acute kidney injury (AKI) accounts for 8% to 16% of hospital admissions and can quadruple hospital mortality, placing a serious burden on the health economy. Acute kidney injury (AKI) is mainly caused by dehydration, shock, infection, sepsis, heart disease, or as a side-effect of nephrotoxic drugs. About 10% to 60% of patients with rhabdomyolysis develop AKI, and 10% of AKI is attributable to rhabdomyolysis. However, rhabdomyolysis-induced AKI secondary to undifferentiated connective tissue disease (UCTD) has rarely been reported before.

PATIENT CONCERNS

We report the case of a 50-year-old male of UCTD presented with dark brown urine, swelling and edema of the upper limbs, and decreased urine output.

DIAGNOSIS

The patient was diagnosed with rhabdomyolysis-induced AKI secondary to UCTD.

INTERVENTIONS

The patient was successfully treated with intravenous methylprednisolone with other supportive treatment.

OUTCOMES

After 3 days of initiating treatment of medicinal charcoal tablets, sodium bicarbonate and intravenous fluids upon admission, the patient's serum creatinine changed mildly from 145.0 μmol/L to 156.0 μmol/L, but the urinary output increased from 1000 mL/24 h to 2400 mL/24 h, with his creatine kinase (CK) and myoglobin rose from 474 IU/L to 962 IU/L and from 641.5ng/mL to 1599 ng/mL, respectively. We then tried to empirically initiate UCTD therapy by giving corticosteroids. After the administration of the 40 mg of methylprednisolone daily, the serum creatinine level dropped to 97 μmol/L the second day, CK decreased to 85 IU/L within 1 week and myoglobin decreased to 65.05 ng/mL within 10 days. When maintenance dose of 4 mg daily was given, the patient showed no abnormalities in creatinine or CK levels.

LESSONS

There have been few reports on the association between rhabdomyolysis-induced AKI and UCTD and its mechanism remains unclear. Clinicians should be aware of UCTD as a possible cause to rhabdomyolysis-induced AKI.

Pembrolizumab-induced Ocular Myasthenia Gravis with Anti-titin Antibody and Necrotizing Myopathy

A 73-year-old man developed diplopia after the administration of pembrolizumab for lung adenocarcinoma. He had ptosis and external ophthalmoplegia without general muscle weakness. Serum CK levels were elevated. Although autoantibodies to acetylcholine receptor and muscle-specific kinase, the edrophonium test, and the repetitive nerve stimulation test were all negative, anti-titin autoantibody was positive, leading to the diagnosis of myasthenia gravis (MG). Muscle pathology showed necrotizing myopathy with tubular aggregates. Unlike previously reported cases of pembrolizumab-associated MG, the present case showed ocular MG. This is the first case of pembrolizumab-associated MG with anti-titin antibody, as well as the first case with tubular aggregates.

Neuromuscular Weakness Syndromes from Immune Checkpoint Inhibitors: A Case Series and Literature Review

Immune checkpoint inhibitors (CPIs) (anti-cytotoxic T-lymphocyte antigen-4, anti-programmed death 1, and anti-programmed death-ligand 1) have transformed the landscape of cancer therapy. However, their increasing use has unleashed immune-related adverse events in various organs, among which neurologic ones, while rare, are increasingly being recognized and remain incompletely characterized. Herein, we report five patients with nonmelanoma cancers who developed weakness after receiving CPIs. The etiology was attributed to radiculoneuritis (one patient), myositis (one patient), Miller Fisher/myasthenia gravis (MG) (one patient), neuropathy/myositis/MG (one patient), and myositis/MG (one patient). Weakness developed after a median of two doses (range: 1–3) and 4 weeks (range: 3–10) from initiation of therapy. Two patients had severe manifestations without improvement while the other three experienced partial improvement despite discontinuation of the CPI (s) and initiation of immunosuppressive therapy. A review of literature identified 62 similar cases. This report highlights the challenges in the diagnosis and management of neurologic adverse events related to the use of CPIs. It also addresses the crucial need for early recognition, proper workup, and better biomarkers to help improve the outcomes of these adverse events.

Checkpoint inhibitor-associated autoimmunity

Checkpoint inhibitors (CI) have revolutionized the management of many cancers but can result in immune-related adverse events (IRAE). In this chapter, we review the clinical manifestations and management of the most common IRAE, plus less common IRAE, such as inflammatory arthritis, of particular interest to rheumatologists. We review the mechanism of action of CI, predictors of IRAE, and the impact of IRAE on cancer outcomes. The study of IRAE is in its infancy; there are very few prospective studies and virtually no treatment trials. Where possible, we have drawn estimates of IRAE incidence from meta-analyses of randomized controlled trials. Clinical descriptions are derived from case series and case reports. Readers are encouraged to refer to consensus guidelines for IRAE management published by the American Society of Clinical Oncology and the Society for Immunotherapy of Cancer.

Autoimmune myositis and myasthenia gravis resulting from a combination therapy with nivolumab and ipilimumab for metastatic melanoma

Checkpoint inhibitors are a novel option in the management of metastatic melanomas and many other malignancies. They are used to promote the activation of cytotoxic T-lymphocytes by inhibiting deactivation signals, enabling the immune response to the tumor. Numerous Immune-related adverse effects caused by checkpoint inhibitors have been reported in the literature. They are diverse in nature, and many are life threatening. We report a case of autoimmune myositis and myasthenia gravis following treatment with a combination of ipilimumab and nivolumab for metastatic melanoma.

Inflammatory myopathy associated with PD-1 inhibitors

OBJECTIVE

To characterize the inflammatory myopathy associated with programmed cell death 1 inhibitors (PD-1 myopathy).

METHODS

We studied 19 Japanese patients with PD-1 myopathy (13 men and 6 women, mean age 70 years), who were referred to Keio University. As control groups, we used 68 patients with anti-signal recognition particle antibodies, 51 patients with anti-aminoacyl transfer RNA synthetase antibodies and 460 healthy subjects.

RESULTS

In regard to muscle-disease severity, 10 patients showed a mild form of disease and 9 patients showed a severe form. Non-small cell lung cancer was the most common underlying cancer. PD-1 inhibitor consisted of 11 nivolumab and 8 pembrolizumab. PD-1 myopathy occurred 29 days on average after the first administration of PD-1 inhibitor. The initial manifestation of muscle weakness was ptosis in 10 patients, 15 patients had ptosis, 13 diplopia, 8 facial muscle weakness, 10 bulbar symptoms, 13 limb weakness, 14 neck weakness, 4 cardiac involvement, 6 respiratory involvement and 16 myalgia. Ocular, facial, cardiac and respiratory involvement and myalgia were more frequently observed than controls. Serum creatine kinase was increased to 5247 IU/L on average. Autoantibodies related to inflammatory myopathy were negative, while anti-striational antibodies were found in 13 (68%) patients. HLA-C*12:02 alleles were more frequently detected than healthy controls. Muscle pathology was characterized by multifocal necrotic myofibers with endomysial inflammation and expression of MHC class I. Immunosuppressive therapy with corticosteroids was generally effective for muscle weakness.

CONCLUSIONS

Based on our clinical, histological and immunological findings, PD-1 myopathy is a discrete subset of inflammatory myopathy.

Neuromuscular adverse events associated with anti-PD-1 monoclonal antibodies: Systematic review

Neuromuscular adverse events following cancer treatment with anti-programmed cell death protein 1 (PD-1) monoclonal antibodies are relatively rare, yet potentially fatal. We performed a systematic review to characterize the clinical presentation, diagnostic workup, and management of neuromuscular disorders (NMDs) in patients treated with nivolumab or pembrolizumab monotherapy or concurrent with other immunologic agents, such as ipilimumab. Sixty-one publications on 85 patients (mean age 66.9 years [range 34-86]; male/female 2.6:1; 59% metastatic melanoma) were identified from selected indexing databases until June 2018. Forty-eight patients had received nivolumab and 39 pembrolizumab. The mean number of PD-1 inhibitor treatment cycles prior to onset of symptoms was 3.6 (range 1-28). Symptoms included oculomotor (47%), respiratory (43%), bulbar (35%), and proximal weakness (35%), as well as muscle pain (28%). Diagnoses were categorized as myasthenia gravis (27%), neuropathy (23%), myopathy (34%), or a combination of these (16%). After a critical review of the data, however, evidence did not support the stated NMD diagnosis in 13% of cases, while up to 25% of patients had signs of additional NMDs. Cardiac complications occurred in more than 30% of patients diagnosed with myasthenia gravis or myositis. Mortality was high in these patients, despite adequate treatment strategies including corticosteroid, IV immunoglobulins, and plasma exchange. The clinical presentation of NMDs associated with PD-1 inhibitors is often atypical, with considerable overlap between myasthenia gravis and myopathy, and cardiac/respiratory complications are common.

Checkpoint Inhibitors

BACKGROUND

Treatment with checkpoint inhibitors such as anti-programmed death-1 (anti-PD-1), anti-PD-ligand 1 (anti-PD-L1), and anti-cytotoxic T-lymphocyte antigen-4 (anti-CTLA-4) antibodies can prolong the survival of cancer patients, but it also induces autoimmune side effects in 86-96% of patients by activating the immune system. In 17-59% of patients, these are severe or even life-threatening.

METHODS

This review is based on pertinent articles retrieved by a search in PubMed and on an evaluation of a side-effect registry.

RESULTS

Checkpoint-inhibitor-induced autoimmune side effects manifest themselves in all organ systems, most commonly as skin lesions (46-62%), autoimmune colitis (22-48%), autoimmune hepatitis (7-33%), and endocrinopathies (thyroiditis, hypophysitis, adrenalitis, diabetes mellitus; 12-34%). Rarer side effects include pneumonitis (3-8%), nephritis (1-7%), cardiac side effects including cardiomyositis (5%), and neurological side effects (1-5%). Severe (sometimes lethal) side effects arise in 17-21%, 20-28%, and 59% of patients undergoing anti-PD-1 and anti- CTLA-4 antibody treatment and the approved combination therapy, respectively. With proper monitoring, however, these side effects can be recognized early and, usually, treated with success. Endocrine side effects generally require long-term hormone substitution. Patients who have stopped taking checkpoint inhibitors because of side effects do not show a poorer response of their melanoma or shorter survival in comparison to patients who continue to take checkpoint inhibitors.

CONCLUSION

The complex management of checkpoint-inhibitor-induced side effects should be coordinated in experienced centers. The creation of an interdisciplinary "tox team" with designated experts for organ-specific side effects has proven useful. Prospective registry studies based on structured documentation of side effects in routine clinical practice are currently lacking and urgently needed.

Immune Checkpoint Inhibitor-Induced Myositis: a Case Report and Literature Review

PURPOSE OF THE REVIEW

We clarify clinical characteristics of patients with immune checkpoint inhibitor (ICI)-induced myositis.

RECENT FINDINGS

In 13 of 15 cases with ICI-induced myositis, the type of malignancy was melanoma. Eight, 4, and 3 patients received anti-PD-1 alone, anti-CTLA4 alone, and a combination of those, respectively. The mean period to the onset of ICI-induced myositis from the initiation of ICI was 4 weeks. Myocarditis was a complication in five patients. Seven of the patients died. The causes of death were myocarditis in three patients, respiratory muscle paralysis in two patients, and cancer progression in two patients. In patients without myocarditis or respiratory muscle paralysis, the prognosis for myositis was favorable with normalization of the CK levels occurring upon the cessation of ICI and the administration of immunosuppressive agents. Myocarditis and respiratory muscle paralysis are the major causes of death as immune-related adverse events in patients with ICI-induced myositis.

Success of rechallenging dabrafenib and trametinib combination therapy after trametinib-induced rhabdomyolysis: a case report

The mitogen-activated protein kinase pathway regulates cell growth and differentiation and is activated by BRAF mutations. BRAF mutations are present in about 40-50% of cutaneous melanomas. More than 90% of BRAF mutations are the V600E type. BRAF inhibitor (dabrafenib or vemurafenib) and MEK inhibitor (trametinib or cobimetinib) combination therapies are effective for BRAF-mutant advanced melanomas. A variety of side effects have been observed with combination therapy including pyrexia, fatigue, nausea, and vomiting. Rhabdomyolysis is one of the most severe adverse events, but it is very rare. Only two cases of rhabdomyolysis have been reported in clinical trials. A 41-year-old Japanese woman with cutaneous melanoma was started on a combination of dabrafenib and trametinib therapy after failure of immune checkpoint therapy. One month later, she complained of myalgia and fatigue and was shifted to our hospital. She was diagnosed with trametinib-induced rhabdomyolysis and showed improvement only with a high volume of fluid infusion. We stopped combination therapy, but there were no useful treatment options for her. After resuming dabrafenib, followed by trametinib, she did not have any problems. This is the first case of a patient with metastatic cutaneous melanoma who could recommence combination therapy after trametinib-associated rhabdomyolysis. We assume that not all patients experience recurrence of rhabdomyolysis in trametinib-induced rhabdomyolysis. As few cases have been reported, more information is needed. We have to evaluate safety carefully if rechallenging combination therapy.

Management of immune-related adverse events resulting from immune checkpoint blockade

INTRODUCTION

Immune checkpoint inhibitors (ICI) are now a standard of care in the treatment of many cancers leading to durable responses in patients with metastatic disease. These agents are generally well tolerated but may lead to the occurrence of immune-related adverse events (irAEs). As any organ may be affected, clinicians should be aware of the broad range of clinical manifestations and symptoms and keep in mind that toxicities may occur late, at any point along a patient's treatment course. Although the most common irAEs are rarely severe, some of them may be associated with great morbidity and even become life-threatening. The rate of occurrence, type and severity of irAEs may vary with the type of ICI; thus, grade 3 and 4 irAEs are reported in more than 55% of patients treated with the combination of ipilimumab 3 mg/kg and nivolumab 1 mg/kg. Area covered: This review presents the management of irAEs resulting from checkpoint blockade, with a focus on rare irAEs. Expert commentary: With the development of immuno-oncology and the expanding role of ICI, physicians have learnt to diagnose and treat most of the irAEs that can occur. This review provides an overview of current guidelines, previously published studies and our multidisciplinary team based practices.