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

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.

Dermatomyositis unleashed by immune checkpoint inhibitors. Three additional cases and a review of the literature

OBJECTIVES

Immune checkpoint inhibitors (ICI) have revolutionized the treatment of several locally advanced and metastatic tumors. They enhance the effector function of the immune system, consequently leading to different immune-related adverse events. The aim of the present study was to describe three cases of dermatomyositis (DM) triggered by ICI diagnosed at our institution and to perform a review of the literature.

METHODS

We performed a retrospective clinical, laboratory, and pathological evaluation of three cases of DM triggered by ICI belonging to a cohort of 187 DM patients from the Clinic Hospital Muscle Research Group of Barcelona from January 2009 to July 2022. Moreover, we undertook a narrative review of the literature from January 1990 to June 2022.

RESULTS

Cases from our institution were triggered by avelumab, an anti-PD-1 ligand (PD-L1), nivolumab, and pembrolizumab, both anti-programmed death-1 (PD-1). One of these patients had locally advanced melanoma, and two had urothelial carcinoma. The severity and response to treatment were heterogeneous among the different cases. All were positive at high titers for anti-TIF1γ autoantibodies; in one of them, serum before the onset of ICI was available, and anti-TIF1γ autoantibodies were already present. RNA expression of IFNB1, IFNG and genes stimulated by these cytokines were markedly elevated in these patients.

CONCLUSIONS

In conclusion, data from our patients and the narrative review suggest that early positivity to anti-TIF1γ unleashed by ICI may play a role in the development of full-blown DM, at least in some cases.

Transcriptomic profiling reveals distinct subsets of immune checkpoint inhibitor induced myositis

OBJECTIVES

Inflammatory myopathy or myositis is a heterogeneous family of immune-mediated diseases including dermatomyositis (DM), antisynthetase syndrome (AS), immune-mediated necrotising myopathy (IMNM) and inclusion body myositis (IBM). Immune checkpoint inhibitors (ICIs) can also cause myositis (ICI-myositis). This study was designed to define gene expression patterns in muscle biopsies from patients with ICI-myositis.

METHODS

Bulk RNA sequencing was performed on 200 muscle biopsies (35 ICI-myositis, 44 DM, 18 AS, 54 IMNM, 16 IBM and 33 normal muscle biopsies) and single nuclei RNA sequencing was performed on 22 muscle biopsies (seven ICI-myositis, four DM, three AS, six IMNM and two IBM).

RESULTS

Unsupervised clustering defined three distinct transcriptomic subsets of ICI-myositis: ICI-DM, ICI-MYO1 and ICI-MYO2. ICI-DM included patients with DM and anti-TIF1γ autoantibodies who, like DM patients, overexpressed type 1 interferon-inducible genes. ICI-MYO1 patients had highly inflammatory muscle biopsies and included all patients that developed coexisting myocarditis. ICI-MYO2 was composed of patients with predominant necrotising pathology and low levels of muscle inflammation. The type 2 interferon pathway was activated both in ICI-DM and ICI-MYO1. Unlike the other types of myositis, all three subsets of ICI-myositis patients overexpressed genes involved in the IL6 pathway.

CONCLUSIONS

We identified three distinct types of ICI-myositis based on transcriptomic analyses. The IL6 pathway was overexpressed in all groups, the type I interferon pathway activation was specific for ICI-DM, the type 2 IFN pathway was overexpressed in both ICI-DM and ICI-MYO1 and only ICI-MYO1 patients developed myocarditis.

Paraneoplastic Necrotizing Myopathy Associated With Metastatic Colon Cancer: A Case Report

Necrotizing myopathy (NM) as a paraneoplastic process in malignancies is a rare phenomenon. An association of inflammatory myositis with malignancy and chemotherapies has been reported in several case reports. Here, we present an unusual case of paraneoplastic NM associated with metastatic colon cancer.

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.

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

BACKGROUND

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

PATIENTS AND METHODS

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

RESULTS

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

CONCLUSIONS

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

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.

[Rheumatological side effects of checkpoint inhibitors and their treatment]

The spectrum of tumors for which checkpoint inhibitor (CI) treatment is used is constantly expanding. The European Medicines Agency has currently approved nine CIs: one anti-cytotoxic T lymphocyte-associated antigen 4 (CTLA-4) CI, one anti-lymphocyte activation gene 3 (LAG-3) CI, four anti-programmed cell death protein 1 (PD-1) CIs and three anti-programmed death ligand 1 (PD-L1) CIs. By blocking immune checkpoints the physiological downregulation of T cell activity against autologous tissue is prevented. This results in an immunologically unregulated activation of T cells directed against malignant cells. Healthy tissue also expresses antigens and thereby continuously activates autologous T cells. Thus, the blockade of immune checkpoints can lead to T cell activity against healthy tissue (immune-related adverse events, irAE). The irAEs can occur in any organ system and approximately 10% of all patients under CI treatment develop rheumatological irAEs, mostly arthralgia and myalgia. The classification criteria of rheumatological diseases do not need to be met to initiate treatment and the primary goal of treatment of irAEs is to enable continuation of CI treatment. Rheumatological irAEs should be recognized and treated quickly. In the treatment of musculoskeletal irAEs, three stages can be defined. In the first stage, nonsteroidal anti-inflammatory drugs or intra-articular as well as systemic glucocorticoids are used. In the second stage, conventional synthetic and in the third stage, biologic disease-modifying antirheumatic drugs are used. The most severe musculoskeletal irAE is myositis with cardiac and/or respiratory involvement and/or myasthenia gravis. In addition to high-dose glucocorticoids, intravenous immunoglobulins or plasma exchange are used in treatment.

Immune checkpoint inhibitor-induced myocarditis with myasthenia gravis overlap syndrome: A case report and literature review

RATIONALE

The therapeutic value of immune checkpoint inhibitors (ICIs) in a variety of tumors has been found and recognized, and although ICIs have improved the prognosis of many patients with advanced tumors, these drugs sometimes cause immune-related adverse events (irAEs).

PATIENT CONCERNS

We report a 67-year-old woman with advanced rectal endocrine tumor. Ten days after receiving two cycles of treatment with camrelizumab combined with http://www.baidu.com/link?url=shAWG4LYTwwBcZAEb6pLb6DkDndJR2tUgOfFiWAkOf0hS-_sj2jjSLBwYaxSiHY3r6yPj31Lp2DCP-7q3w7ho5HIV46V4fbIShFyUY7Cbka sorafenib, the patient suddenly suffered from chest tightness, shortness of breath and progressive aggravation of limb weakness, the high-sensitivity cardiac troponin T (hs-cTnT) was elevated to 3015pg/mL and N-terminal pro-B-type natriuretic peptide (NT-proBNP) up to 5671pg/mL, and creatine kinase (CK) was 1419U/L.

DIAGNOSIS AND INTERVENTIONS

The patient was diagnosed as immune checkpoint inhibitor-induced myocarditis with myasthenia gravis overlap syndrome. The patient was transferred to the intensive care unit (ICU) in time and given oxygen inhalation, glucocorticoids, immunoglobulin and anticholinesterase drugs, and other related treatments.

OUTCOMES

After 2 weeks, the symptoms of myasthenia gravis (MG) were relieved, and the level of myocardial injury markers decreased significantly, but it was still at a high level. The patient's family refused further treatment, and the patient died soon after.

LESSONS

In this paper, Through the report and follow-up analysis of this case, this paper recognizes that the early correct understanding and evaluation of this fulminant and fatal irAEs and the reasonable treatment of patients are very important for the prognosis of patients.

A Successful Case of Hepatocellular Carcinoma Treated with Atezolizumab Plus Bevacizumab with Multisystem Immune-related Adverse Events

A 63-year-old man with hepatitis C was treated with atezolizumab plus bevacizumab for unresectable diffuse hepatocellular carcinoma (HCC). After four cycles of atezolizumab plus bevacizumab, the diffuse HCC markedly shrank; however, he complained of general fatigue, loss of appetite, and slight loss of muscle strength in the lower legs. He was diagnosed with isolated adrenocorticotropic hormone deficiency (IAD), hypothyroidism, and myopathy, suggesting multisystem immune-related adverse events (irAEs). After administration of hydrocortisone, the clinical symptoms rapidly disappeared. Patients with multisystem irAEs can have favorable outcomes; thus, to continue immune-checkpoint inhibitors therapy, a correct diagnosis and management of multisystem irAEs are important.

Myocarditis and myositis/myasthenia gravis overlap syndrome induced by immune checkpoint inhibitor followed by esophageal hiatal hernia: A case report and review of the literature

Immunotherapy with programmed death 1 (PD-1) inhibitor has shown activity as first- or second-line treatment for various metastatic human malignancies. Immune-related adverse events (irAEs) are now well-described, and most organ sites are potentially influenced, but the prevalence of myocarditis and myositis/myasthenia gravis (MG) overlap syndrome following esophageal hiatal hernia induced by immunotherapy is rarely reported. Here, we describe a 71-year-old woman with a progressed unresectable extrahepatic cholangiocarcinoma and biliary obstruction. She had no prior history of muscle weakness and neuromuscular disease with a normal body mass index. She was treated with sintilimab as a rescue regimen of immunotherapy. After the first cycle of treatment, she experienced a grade 4 myopathy including simultaneous myositis, myalgia, and myocarditis due to multiple injuries in her cardiac, skeletal, and ocular muscles. She had elevated levels of creatine kinase (CK), cardiac troponin I, and myoglobin (MYO), but MG and myositis-specific and myositis-related antibodies were negative. Immunotherapy was discontinued and pulse high-dose methylprednisolone with a slow tapering and intravenous immunoglobulin (IVIG) was initiated. Two weeks later, the patient’s clinical presentation improved significantly. A subsequent cardiac magnetic resonance (MR) examination revealed an old myocardial injury that may be a result of immune-related cardiac toxicity. In the third month following the PD-1 inhibitor therapy, she restarted systemic chemotherapy in combination with an anti-angiogenic agent but without immunotherapy. Half a year later, she complained of repeated abdominal distension and radiographic examinations and endoscopy showed a clinically confirmed diagnosis of sliding hiatal hernia of the esophagus and gastroesophageal reflux disease. Due to mild symptoms associated with gastroesophageal reflux, she was suggested close monitoring with acid secretion blockade rather than immediate surgical intervention. The severity for patients with myositis and myocarditis accompanied without MG is similar to those with MG. Considering the use of PD-1 inhibitors is increasing in cancer patients, physicians should therefore pay more attention to immunotherapy-induced myocarditis with myositis/MG overlap syndrome. Since we hypothesize diaphragmatic hiatal hernia as a potential consequence of immunotherapy-induced myositis, reports on hiatal hernias subsequent to immunotherapy-induced myositis are needed.

Management of Cancer-Associated Myositis

Purpose of the Review

Cancer-associated myositis (CAM) is defined as when cancer appears within 3 years of myositis onset. Dermatomyositis and seronegative immune–mediated necrotizing myopathy are the phenotypes mostly related to cancer. In general, treatment principles in myositis patients with and without CAM are similar. However, some aspects of myositis management are particular to CAM, including (a) the need for a multidisciplinary approach and a close relationship with the oncologist, (b) the presence of immunosuppressive and antineoplastic drug interactions, and (c) the role of the long-term immunosuppressive therapy as a risk factor for cancer relapse or development of a second neoplasm. In this review, we will also discuss immunotherapy in patients treated with checkpoint inhibitors as a treatment for their cancer.

Recent Findings

Studies on cancer risk in patients treated with long-term immunosuppressive drugs, in autoimmune diseases such as systemic lupus erythematosus or rheumatoid arthritis, and in solid organ transplant recipients have shed some light on this topic. Immunotherapy, which has been a great advance for the treatment of some types of malignancy, may be also of interest in CAM, given the special relationship between both disorders.

Summary

Management of CAM is a challenge. In this complex scenario, therapeutic decisions must consider both diseases simultaneously.

Supplementary Information

The online version contains supplementary material available at 10.1007/s40674-022-00197-2.

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.

PD-1 Alleviates Cisplatin-Induced Muscle Atrophy by Regulating Inflammation and Oxidative Stress

Skeletal muscle atrophy is an important characteristic of cachexia, which can be induced by chemotherapy and significantly contributes to functional muscle impairment. Inflammation and oxidative stress are believed to play important roles in the muscle atrophy observed in cachexia, but whether programmed cell death protein 1 (PD-1) is affected by this condition remains unclear. PD-1 is a membrane protein that is expressed on the surface of many immune cells and plays an important role in adaptive immune responses and autoimmunity. Thus, we investigated the role and underlying mechanism of PD-1 in cisplatin-induced muscle atrophy in mice. We found that PD-1 knockout dramatically contributed to skeletal muscle atrophy. Mechanistically, we found that E3 ubiquitin-protein ligases were significantly increased in PD-1 knockout mice after cisplatin treatment. In addition, we found that PD-1 knockout significantly exacerbated cisplatin-induced skeletal muscle inflammation and oxidative stress. Moreover, we found that there were significant increases in ferroptosis-related and autophagy-related genes in PD-1 knockout mice after cisplatin treatment. These data indicate that PD-1 plays an important role in cisplatin-induced skeletal muscle atrophy.

Severe Immune-Related Adverse Events: A Case Series of Patients Needing Hospital Admission in a Spanish Oncology Referral Center and Review of the Literature

Immune checkpoint inhibitors (ICI) have revolutionized the landscape of cancer treatment. Although several studies have shown that ICIs have a better safety profile than chemotherapy, some patients develop immune-related adverse events (irAEs), which require specialized and multidisciplinary management. Since ICI indications are rapidly increasing, it is crucial that clinicians involved in cancer care learn to identify irAEs and manage them properly. Here, we report a case series of 23 patients with severe irAEs requiring hospitalization over a period of 12 months and seize the opportunity to review and update different general features related to irAEs along with the management of the most frequent severe irAEs in our series.

[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.

Mechanisms underlying immune-related adverse events during checkpoint immunotherapy

Immune checkpoint (IC) proteins are some of the most important factors that tumor cells hijack to escape immune surveillance, and inhibiting ICs to enhance or relieve antitumor immunity has been proven efficient in tumor treatment. Immune checkpoint blockade (ICB) agents such as antibodies blocking programmed death (PD) 1, PD-1 ligand (PD-L) 1, and cytotoxic T lymphocyte-associated antigen (CTLA)-4 have been approved by the U.S. Food and Drug Administration (FDA) to treat several types of cancers. Although ICB agents have shown outstanding clinical success, and their application has continued to expand to additional tumor types in the past decade, immune-related adverse events (irAEs) have been observed in a wide range of patients who receive ICB treatment. Numerous studies have focused on the clinical manifestations and pathology of ICB-related irAEs, but the detailed mechanisms underlying irAEs remain largely unknown. Owing to the wide expression of IC molecules on distinct immune cell subpopulations and the fact that ICB agents generally affect IC-expressing cells, the influences of ICB agents on immune cells in irAEs need to be determined. Here, we discuss the expression and functions of IC proteins on distinct immune cells and the potential mechanism(s) related to ICB-targeted immune cell subsets in irAEs.

Rheumatic Manifestations and Diseases From Immune Checkpoint Inhibitors in Cancer Immunotherapy

Immune checkpoint inhibitors (ICIs), which can enhance antitumor immunity and inhibit cancer growth, have revolutionized the treatment of multiple cancers and dramatically decreased mortality. However, treatment with ICIs is directly associated with immune-related adverse events (irAEs) because of inflammation in off-target organs and autoimmunity resulting from non-specific immune activation. These irAEs can cause rheumatic diseases and manifestations such as inflammatory arthritis, polymyalgia rheumatica, myositis, vasculitis, Sicca and Sjogen's syndrome, and systemic lupus erythematosus. Early diagnosis and treatment of these adverse events will improve outcomes and quality of life for cancer patients. The treatment of rheumatic diseases induced by ICIs requires multidisciplinary cooperation among physicians. Furthermore, the underlying mechanisms are not fully understood and it is difficult to predict and evaluate these side effects precisely. In this review, we summarize available studies and findings about rheumatic irAEs, focusing mainly on the clinical manifestations, epidemiology, possible mechanisms, and guiding principles for treating these irAEs.

Differential diagnosis of necrotizing myopathy

PURPOSE OF REVIEW

Necrotizing myopathy is a broad term. It includes patients with the recently described immune-mediated necrotizing myopathies (IMNM) who have specific antibodies, such as anti-hydroxy-3-methylglutaryl-CoA reductase or anti-signal recognition particle, seronegative phenotypes that can be associated with cancer, and other types of myositis and connective tissue diseases involving necrotic muscle fibers as a characteristic pathologic feature. Necrotizing myopathies that are not immune-mediated, such as those caused by drugs, dystrophies, infections, or even hypothyroidism are also included. The purpose of this review is to address the differential diagnosis of these disorders.

RECENT FINDINGS

New IMNM have been described over the last few years, some of them related with checkpoint inhibitors, drugs that are being increasingly used in cancer treatment. Necrotizing myopathy has also been reported in association with specific phenotypes and autoantibodies (e.g. anti-Mi2 dermatomyositis, antisynthetase syndrome, and myositis associated with antimitochondrial antibodies). Rarer cases associated with graft-versus-host disease and severe acute respiratory syndrome coronavirus 2 infection are also emerging.

SUMMARY

Differentiation between patients with IMNM and those without the superimposed autoimmune phenomena helps clinicians determine the best individualized approach to use and the appropriate immunosuppressive therapy, whenever needed.

Tocilizumab for the treatment of immune-related adverse events: a systematic literature review and a multicentre case series

OBJECTIVE

Research is moving towards a more personalized management of immune-related adverse events (irAEs) due to immune checkpoint inhibitors (ICI). Our objective was to evaluate the efficacy and safety of tocilizumab in the treatment of these clinical manifestations.

METHODS

A systematic literature review was performed to retrieve data about the use of tocilizumab in the treatment of irAEs. Additionally, data from cancer patients referred to our Immune-related Adverse Event Clinic and treated with tocilizumab were collected.

RESULTS

Our literature review identified 20 articles and 11 meeting abstracts. Data about 91 cancer patients who received tocilizumab for the treatment of irAEs were collected. In 85% of cases, this therapy was associated with clinical benefit and no case of disease progression was reported. ICI therapy was continued following irAE onset and biologic therapy initiation in only three patients. Five patients developed irAEs upon ICI initiation and were subsequently treated with tocilizumab at our Centre. At a median follow-up of eight months, tocilizumab was safely continued along with ICI in three out of five patients, and an adequate control of irAE was obtained in all cases. No significant adverse reactions to tocilizumab were reported. Only one patient experienced a disease progression 18 months after ICI discontinuation.

CONCLUSION

Both our systematic literature review and case series highlight the efficacy and safety of tocilizumab in the treatment of irAEs. Furthermore, they both support the possibility of a combined approach with tocilizumab and ICI, to guarantee an effective irAEs management without losing the oncologic response.

Skeletal muscle immunohistochemistry of acquired and hereditary myopathies

PURPOSE OF REVIEW

The continued development in the field of immunohistochemistry (IHC) has improved the ability to diagnose muscle diseases. Many hereditary diseases are diagnosed by the absence or abnormal localization of proteins. Detection of secondary pathological protein expression is also used in diagnostics, and to study disease processes. We relate and discuss recent reports, where IHC has been an important tool in the investigation of muscle diseases.

RECENT FINDINGS

In idiopathic inflammatory myopathies, IHC has extended its role to diagnose subgroups. This is most evident concerning immune-mediated necrotizing myopathy and antisynthetase syndrome. The availability of new antibodies has increased the sensitivity of a muscle biopsy to diagnose several hereditary myopathies. The introduction of protein restoration therapies in muscular dystrophies also comes with the need to detect and measure protein levels. For the study of disease processes at the protein level, in both acquired and hereditary myopathies IHC, often combined with gene studies, PCR-based methods, western blotting and electron microscopy, continues to bring forth interesting results.

SUMMARY

IHC is an integrated tool in muscle pathology, where recent studies contribute to improved diagnostic skills and increased insights into disease processes.

Characterization and management of neurological adverse events during immune-checkpoint inhibitors treatment: an Italian multicentric experience

BACKGROUND

Neurological immune-related adverse events (nirAEs) are rare toxicities of immune-checkpoint inhibitors (ICI). With the increase of ICI oncological indications, their incidence is growing. Their recognition and management remain nevertheless challenging.

METHODS

A national, web-based database was built to collect cases of neurological symptoms in patients receiving ICI and not attributable to other causes after an adequate workup.

RESULTS

We identified 27 patients who developed nirAEs (20 males, median age 69 years). Patients received anti-PD1/PDL1 (78%), anti-CTLA4 (4%), or both (19%). Most common cancers were melanoma (30%) and non-small cell lung cancer (26%). Peripheral nervous system was mostly affected (78%). Median time to onset was 43.5 days and was shorter for peripheral versus central nervous system toxicities (36 versus 144.5 days, p = 0.045). Common manifestations were myositis (33%), inflammatory polyradiculoneuropathies (33%), and myasthenia gravis (19%), alone or in combination, but the spectrum of diagnoses was broad. Most patients received first-line glucocorticoids (85%) or IVIg (15%). Seven patients (26%) needed second-line treatments. At last follow-up, four (15%) patients were deceased (encephalitis, 1; myositis/myasthenia with concomitant myocarditis, 2; acute polyradiculoneuropathy, 1), while seven (26%) had a complete remission, eight (30%) partial improvement, and six (22%) stable/progressing symptoms. ICI treatment was discontinued in most patients (78%).

CONCLUSIONS

Neurological irAEs are rare but potentially fatal. They primarily affect neuromuscular structures but encompass a broad range of presentations. A prompt recognition is mandatory to timely withheld immunotherapy and administrate glucocorticoids. In corticoresistant or severely affected patients, second-line treatments with IVIg or plasmapheresis may result in additional benefit.

The Inconsistent and Inadequate Reporting Of Immune-Related Adverse Events in PD-1/PD-L1 Inhibitors: A Systematic Review of Randomized Controlled Clinical Trials

Background

Immune‐related adverse events (irAEs) are of great interest and importance in clinical practice, and many deficiencies and controversies have been noted in the reporting of irAEs. Herein, we aimed to evaluate the current status of irAE reporting in randomized controlled clinical trials (RCTs) of PD‐1/PD‐L1 inhibitors and to attempt to explain and solve the current pitfalls associated with this reporting.

Materials and Methods

We conducted a systematic review across multiple databases, including PubMed, Web of Science, Embase, and the Cochrane Library. The RCTs that compared PD‐1/PD‐L1 inhibitors with standard treatments were included. The Harms extension of the Consolidated Standards of Reporting Trials (CONSORT) was used to evaluate the completeness of irAE reporting.

Results

A total of 44 articles and 23,759 patients were included in the analysis. The terminology of the irAEs changed over time (p = .01) and was different among immune checkpoint inhibitors (ICIs) (p = .005). Twenty‐two of the studies provided a definition of irAE, but only four of them concretely addressed this definition. The incidence of any grade of irAEs ranged from 16.9% to 96%, whereas grade 3–4 irAE ranged from 2% to 23%. The RCTs with combined therapy exhibited a higher incidence of grade 3–4 irAEs (p = .012). Thirty‐two studies reported irAEs in the control arms, whereas seven studies reported irAEs only in the experimental arms. Respiratory, endocrine, and gastrointestinal disorders were the most commonly reported irAEs. IrAEs were generally neglected in the introduction or conclusion sections in all of the study reviews and were never subjected to subgroup analyses. Moreover, withdrawals due to severe irAEs, as well as clarifications of the irAE collection methods, were also poorly reported. RCTs using combination therapies in the experimental arms were associated with a higher reporting quality (p = .032). However, the completeness of the reporting did not improve over the last 5 years (p = .076).

Conclusion

The reporting of irAEs was inadequate, and there are still inconsistencies and controversies in the reporting of irAEs. In the future, authors should be encouraged to adhere to the Harms extension of the CONSORT statement.

Implications for Practice

PD‐1/PD‐L1 inhibitors profoundly changed the landscape of cancer treatment, and thousands of randomized controlled clinical trials (RCTs) were active or completed over the past decade. However, different from chemotherapy or targeted therapy, the profile of immune‐related adverse effects (irAE) was unique. An understanding of irAEs is developed mainly from clinical trials; however, inconsistencies and controversies between trials were noted. This study primarily reviewed the evolution of irAE terminology and definitions and evaluated the reporting quality of each RCT. It was found that RCTs using combined immunotherapy were associated with higher quality of irAE reporting. This article identifies the controversies and deficiencies in current irAE reporting and provides possible explanations and suggestions for these inadequacies.

Reporting of immune‐related adverse events (irAEs) has not yet been standardized. This review evaluates the current state of irAE reporting in clinical trials, focusing on shortcomings associated with this reporting and possible solutions.

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.

Evolving Roles of Muscle-Resident Fibro-Adipogenic Progenitors in Health, Regeneration, Neuromuscular Disorders, and Aging

Normal skeletal muscle functions are affected following trauma, chronic diseases, inherited neuromuscular disorders, aging, and cachexia, hampering the daily activities and quality of life of the affected patients. The maladaptive accumulation of fibrous intramuscular connective tissue and fat are hallmarks of multiple pathologies where chronic damage and inflammation are not resolved, leading to progressive muscle replacement and tissue degeneration. Muscle-resident fibro-adipogenic progenitors are adaptable stromal cells with multilineage potential. They are required for muscle homeostasis, neuromuscular integrity, and tissue regeneration. Fibro-adipogenic progenitors actively regulate and shape the extracellular matrix and exert immunomodulatory functions via cross-talk with multiple other residents and non-resident muscle cells. Remarkably, cumulative evidence shows that a significant proportion of activated fibroblasts, adipocytes, and bone-cartilage cells, found after muscle trauma and disease, descend from these enigmatic interstitial progenitors. Despite the profound impact of muscle disease on human health, the fibrous, fatty, and ectopic bone tissues' origins are poorly understood. Here, we review the current knowledge of fibro-adipogenic progenitor function on muscle homeostatic integrity, regeneration, repair, and aging. We also discuss how scar-forming pathologies and disorders lead to dysregulations in their behavior and plasticity and how these stromal cells can control the onset and severity of muscle loss in disease. We finally explore the rationale of improving muscle regeneration by understanding and modulating fibro-adipogenic progenitors' fate and behavior.

Treatment strategies and safety of rechallenge in the setting of immune checkpoint inhibitors-related myositis: A national multicenter study

OBJECTIVES

The occurrence of immune-related myositis (irM) is increasing, yet there are no therapeutic guidelines. We sought to analyze the current therapeutic strategies of irM and evaluate the outcomes of immune checkpoint inhibitors (ICI) rechallenge.

METHODS

We conducted a nationwide retrospective study between April 2018 and March 2020 including irM without myocardial involvement. Depending on the presence of cutaneous signs or unusual histopathological features, patients were classified into two groups: typical or atypical irM. Therapeutic strategies were analyzed in both groups. The modalities and outcomes of ICI rechallenge were reviewed.

RESULTS

Among the 20 patients, 16 presented typical irM. Regardless of severity, most typical irM were treated with steroid monotherapy (n = 14/16) and all had a complete response within ≤ 3 weeks. The efficacy of oral steroids for non-severe typical irM (n = 10) was the same with low-dose (≤ 0.5 mg/kg/day) or high-dose (1 mg/kg/day). Severe typical irM were successfully treated with intravenous methylprednisolone. Atypical irM (n = 4) had a less favorable evolution, including one irM-related death, and required heavy immunosuppression. ICI were safely reintroduced in 9 patients presenting a moderate (n = 6) or a severe (n = 3) irM.

CONCLUSION

Our data highlight that steroid monotherapy is an effective treatment for typical irM, either with prednisone or with intravenous methylprednisone pulses depending on the severity. The identification of unusual features is important in determining the initial therapeutic strategy. The outcomes of rechallenged patients are in favor of a safe reintroduction of ICI following symptom resolution and CK normalization in moderate and severe forms of irM.

Neurological complications of chimeric antigen receptor T cells and immune-checkpoint inhibitors: ongoing challenges in daily practice

PURPOSE OF REVIEW

The aim of this review is to summarize the most recent advances in the management of neurological toxicities associated with immune-checkpoint inhibitors (ICIs) and chimeric antigen receptor (CAR)-T cells.

RECENT FINDINGS

The advent of cancer immunotherapies has dramatically improved the prognosis of several refractory and advanced neoplasms. Owing to their mechanism of action, cancer immunotherapies have been associated with a variety of immune-related adverse events (irAE). Neurological irAE are uncommon compared with other irAE, but they are associated with significant morbidity and mortality. Despite the efforts to draft common protocols and guidelines, the management of neurological irAE remains challenging. Our ability to predict the development of neurotoxicity is still limited, hampering to elaborate prevention strategies. Treatment heavily relies on the administration of high-dose corticosteroids that, however, have the potential to impair oncological efficacy. The experimentation of novel strategies to avoid resorting to corticosteroids is hindered by the lack of an adequate understanding of the pathogenetic mechanisms driving the development of irAE.

SUMMARY

In this review, we will discuss the most recent advances on the diagnosis and management of neurological irAE associated with ICIs and CAR-T cells, focusing on the issues that remain most challenging in clinical practice.

Giant cell myositis associated with concurrent myasthenia gravis: a case-based review of the literature

The term “giant cell myositis” has been used to refer to muscle diseases characterized histologically by multinucleated giant cells. Myasthenia gravis is an autoimmune neuromuscular junction disorder. The rare concurrence of giant cell myositis with myasthenia gravis has been reported; however, the clinical and histological features have varied widely. Here, we present such a case and a review of the literature. An 82-year-old woman admitted for subacute, progressive, proximal muscle weakness developed acute-onset dysphagia, dysphonia, and respiratory distress 5 days after admission. Laboratory findings were positive for acetylcholine receptor binding antibodies and striational muscle antibodies against titin. Muscle biopsy demonstrated widespread muscle fiber necrosis with multinucleated giant cells, consistent with giant cell myositis. She died despite treatment with pulse methylprednisolone and plasma exchange. A literature review of the PubMed and Scopus databases from 1944 to 2020 identified 15 additional cases of these co-existing diagnoses. We found that giant cell myositis with myasthenia gravis primarily affects female patients, is typically diagnosed in the 6–7th decades, and is characterized by the presence of thymoma. Muscle histology predominantly shows giant cell infiltrate without granulomas. The onset of myasthenia gravis symptoms may precede, follow, or coincide with symptoms of myositis. Treatment with thymectomy, anticholinesterase inhibitors, or immunosuppressive therapy may lead to favorable clinical outcomes.

Expert Perspective: Immune Checkpoint Inhibitors and Rheumatologic Complications

Rheumatologists increasingly receive consults for patients treated with immune checkpoint inhibitors (ICIs) for cancer. ICIs can cause inflammatory syndromes known as immune-related adverse events (IRAEs). Several rheumatic IRAEs have been reported, including inflammatory arthritis, polymyalgia rheumatica, and myositis. For patients who present with musculoskeletal symptoms while receiving ICI therapy, it is important to have an algorithm for evaluation. The differential diagnosis includes a range of musculoskeletal syndromes, such as crystalline arthritis, mechanical issues, and osteoarthritis, in addition to IRAEs. After diagnosing a rheumatic IRAE, rheumatologists must work with the patient and the oncologist to form a treatment plan. Treatment of IRAEs is guided by severity. Evidence for management is limited to observational studies. Inflammatory arthritis and polymyalgia rheumatica are treated with nonsteroidal antiinflammatory drugs in mild cases, glucocorticoids for moderate-to-severe cases, and sometimes require other disease-modifying antirheumatic drugs. Myositis due to ICIs can be accompanied by myocarditis or myasthenia gravis. Glucocorticoids and withholding the ICI are usually required to treat myositis; some patients with severe myositis require intravenous immunoglobulin or plasmapheresis. Further research is needed to optimize treatment of IRAEs that does not compromise the antitumor effect of ICIs.

Efficacy of immunosuppressive therapy in myocarditis: A 30-year systematic review and meta analysis

AIMS

Myocarditis is an inflammation of the heart muscle, due to infectious, toxic or autoimmune causes. Literature reported controversial results in relation to the effect of immunosuppression (IS)/immunomodulation (IM). We aimed at assessing the effect of IS/IM by meta analysis.

METHODS AND RESULTS

Using the P.R.I.S.M.A. approach, two researchers searched for relevant studies on PubMed, Embase, and the Central Registry of Controlled Trials of the Cochrane Library. Proposed MeSH terms were: "immunotherapy OR immune therapy OR immune modeling OR Immunosuppressive Agents" AND "combination OR combined with OR plus" AND "myocarditis OR cardiomyopathies OR inflammatory cardiomyopathy". The language was restricted to English. Reference lists of included articles and those relevant to the topic were hand searched for the identification of additional, potentially relevant articles. The cutoff date was from 1987 until 30th Nov 2019. Reported survival or mortality events or change of left ventricular ejection fraction (LVEF) after IS/IT were primary outcomes of the study; in addition, improvement of New York Heart Association class, follow-up biopsy (Bx) findings, viral genome clearance on Bx and recurrence of myocarditis were recorded if reported. Statistical analysis was conducted using Review Manager 5.3; 5452 studies were screened, of these 73 were assessed for eligibility, including 8 randomized control studies, 26 retrospective studies, 2 prospective studies and 1 case control study, 34 case reports and 2 case series. In prospective studies, the difference in mortality between the IS and control groups tended to be lower in the combined IS groups (12.5% vs. 18.2%) (95% CI of odds ratio 0.7(0.3, 1.64)) and the pooled difference of the increase of LVEF between the IS and control groups tended to be higher in the combined IS groups (95% CI 7.26 (-2.29, 16.81)). In retrospective studies, the difference of survival between the IS and control group was significantly in favor of IS (95%CI Hazard ratio 0.82(0.69, 0.96)).

CONCLUSIONS

A tailored IS may be considered in myocarditis, depending on the phase of the disease, and the type of underlying autoimmune or immune-mediated form.

Immune checkpoint inhibitor-induced inflammatory arthritis: identification and management

INTRODUCTION

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

AREAS COVERED

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

EXPERT OPINION

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

[Immune Checkpoint Inhibitors-induced Myasthenia Gravis: From Diagnosis to Treatment]

已经证实免疫检查点抑制剂（immune checkpoint inhibitor, ICI）使多种肿瘤的治疗有了翻天覆地的变化。尽管治疗的有效性让人欣慰，但是这些治疗也造成了多样化的免疫治疗相关的不良反应（immune-related adverse events, irAEs）。重症肌无力（myasthenia gravis, MG）就是一种罕见且危及生命的irAE，通常在ICI治疗后急性发病并迅速进展。早期诊断和积极的治疗非常重要。在此，我们对近几年的相关文献进行了复习和整理，针对ICI-MG诊断和治疗相关的常见问题提供参考意见。

Immune checkpoint inhibitor-induced musculoskeletal manifestations

Immune checkpoint inhibitors (ICI) associate with a wide range of immune-related adverse events (Ir-AE), including musculoskeletal manifestations. We aimed at identifying all studies reporting musculoskeletal Ir-AE. An electronic (Medline, Scopus and Web of Science) search was performed using two sets of key words. The first set consisted of: arthritis, musculoskeletal, polymyalgia rheumatica and myositis. The second set consisted of: anti-PD-1, anti-PD-L1, anti-CTLA-4, ipilimumab, tremelimumab, pembrolizumab, nivolumab, atezolizumab, avelumab and durvalumab. We identified 3 prospective studies, 17 retrospective studies and 4 case series reporting 363 patients in total. Combined data from all three prospective studies provide a prevalence rate of 6.13%. Most patients were males (59.68%) and the vast majority (73%) were on programmed death-1 (PD-1)/programmed death ligand-1 (PD-L1) inhibitors. Most studies report a median time of ≤ 12 weeks from first ICI administration to symptom onset. The main clinical phenotypes reported were: (a) inflammatory arthritis (57.57%), (b) myositis (14.04%) and (c) polymyalgia rheumatica (PMR) (12.12%). A total of 256 patients required steroids (70.52%) and 67 patients (18.45%) were treated with DMARDs. Positive auto-antibodies and family history of any autoimmune disease were present in 18.48% and 19.04% of cases, respectively. Only a few patients (19%) had to discontinue treatment due to musculoskeletal Ir-AE. Two prospective studies show that significantly more patients with musculoskeletal Ir-AE exhibit a favorable oncologic response compared to patients not exhibiting such manifestations whereas retrospective studies show that 77.22% of patients with musculoskeletal Ir-AE have a good tumor response. One out of 15 patients treated with ICI will develop musculoskeletal Ir-AE; in most cases the severity of these manifestations is mild/moderate and usually ICI may be continued. Rheumatologists should familiarize with this new clinical entity and develop relevant therapeutic algorithms.

Risk of scleroderma according to the type of immune checkpoint inhibitors

INTRODUCTION

Immune checkpoint inhibitors (ICIs) are associated with immune-related adverse events (irAEs). Among them, ICIs-induced systemic sclerosis (SSc) is poorly known.

METHODS

To better characterize this irAE, our comprehensive approach combined the description of ICIs-induced scleroderma cases, the systematic review of the literature and the analysis of VigiBase, the WHO pharmacovigilance database.

RESULTS

We identified two cases with underlying limited cutaneous SSc who presented a dramatic increase in the skin thickening following pembrolizumab, associated with scleroderma renal crisis in one case. In the literature, four cases of scleroderma and four cases of morphea have been reported with pembrolizumab or nivolumab. None following ipilimumab, atezolizumab or durvalumab were retrieved. Skin changes appeared or worsened more quickly with pembrolizumab than nivolumab, and had different patterns between both drugs. Patients with generalized skin changes required high-dose prednisone to improve skin thickening. Among the 2527 scleroderma cases identified in VigiBase, 35 were associated with ICIs. Nivolumab and pembrolizumab showed a disproportionality in scleroderma reporting. No disproportionality was found for ipilimumab, atezolizumab or durvalumab.

CONCLUSION

The risk of scleroderma or fibrosis extension in SSc patients should be considered when initiating anti-PD-1 agents. It suggests the role of PD-1/PD-L1 interaction in the pathophysiology of SSc.

Rheumatic Manifestations in Patients Treated with Immune Checkpoint Inhibitors

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