Use of Magnetic Resonance Imaging to Identify Immune Checkpoint Inhibitor-Induced Inflammatory Arthritis

Immune Checkpoint Inhibitor-induced Inflammatory Arthritis: Current Approaches to Management

The introduction of immune checkpoint inhibitors (ICIs) has changed the landscape of the treatment of cancer. Several immune-related adverse events (irAEs) have now been described such as ICI-inflammatory arthritis (IA), sicca syndrome, polymyalgia rheumatica, myositis, and vasculitis as a consequence of immune activation. The onset of the ICI-IA can vary from after the first infusion of ICIs to a delayed presentation a year or more after ICI initiation. Ultimately, baseline patient and tumor characteristics, the types of immunotherapies used, pre-existing autoimmune diseases, and/or other irAEs, as well as patient preferences will all shape the discussions around ICI-IA management.

Imaging in Rheumatic Immune-related Adverse Events

Since their introduction, immune checkpoint inhibitors have revolutionized cancer treatment by harnessing the body's own immune system as a defense against tumor growth. The downside of activating the immune system is the development of immune-related adverse events (irAEs), which mimic autoimmune disease of various organ systems. The musculoskeletal system is an uncommon, but substantial one for patients and can lead to long-term pain and disability that affects their quality of life. This review summarizes recent literature on imaging forms utilized for diagnosis and assessing treatment response in rheumatic irAEs.

Mild Synovitis Impairs Chondrogenic Joint Environment

The impact of mild synovitis on the chondrogenic environment in the joint pertaining to cartilage repair is often neglected. In this study, 21 synovial samples were collected from foot surgeries for histology and isolation of fibroblast-like synoviocytes (FLSs). Of the 21 samples, 13 were normal and eight were mild synovitis, according to their synovitis scores. In mild synovitis, CD3+ lymphocytes were increased in the sublining layer. When chondrocytes were cultured and treated with the conditioned medium produced by FLSs, their glycosaminoglycan production was negatively correlated with the synovitis scores of the synovium, from which FLSs were isolated. In conclusion, mild synovitis in common joint conditions compromises the process of chondrogenesis, via inhibiting chondrocyte matrix production by FLSs. The results suggest that the concomitant synovitis, even being mild, could significantly alter the joint environment for chondrogenesis and impair the outcome of cartilage repair.

Rheumatic Immune-Related Adverse Events due to Immune Checkpoint Inhibitors—A 2023 Update

With the aging of the population, malignancies are becoming common complications in patients with rheumatoid arthritis (RA), particularly in elderly patients. Such malignancies often interfere with RA treatment. Among several therapeutic agents, immune checkpoint inhibitors (ICIs) which antagonize immunological brakes on T lymphocytes have emerged as a promising treatment option for a variety of malignancies. In parallel, evidence has accumulated that ICIs are associated with numerous immune-related adverse events (irAEs), such as hypophysitis, myocarditis, pneumonitis, and colitis. Moreover, ICIs not only exacerbate pre-existing autoimmune diseases, but also cause de novo rheumatic disease–like symptoms, such as arthritis, myositis, and vasculitis, which are currently termed rheumatic irAEs. Rheumatic irAEs differ from classical rheumatic diseases in multiple aspects, and treatment should be individualized based on the severity. Close collaboration with oncologists is critical for preventing irreversible organ damage. This review summarizes the current evidence regarding the mechanisms and management of rheumatic irAEs with focus on arthritis, myositis, and vasculitis. Based on these findings, potential therapeutic strategies against rheumatic irAEs are discussed.

Checkpoint Inhibitor Immune-Related Adverse Events: A Multimodality Pictorial Review

Cancer immunotherapies are drugs that modulate the body's own immune system as an anticancer strategy. Checkpoint inhibitor immunotherapies interfere with cell surface binding proteins that function to promote self-recognition and tolerance, ultimately leading to upregulation of the immune response. Given the striking success of these agents in early trials in melanoma and lung cancer, they have now been studied in many types of cancer and have become a pillar of anticancer therapy for many tumor types. However, abundant upregulation results in a new class of side effects, known as immune-related adverse events (IRAEs). It is critical for the practicing radiologist to be able to recognize these events to best contribute to care for patients on checkpoint inhibitor immunotherapy. Here, we provide a comprehensive system-based review of immune-related adverse events and associated imaging findings. Further, we detail the best imaging modalities for each as well as describe problem solving modalities. Given that IRAEs can be subclinical before becoming clinically apparent, radiologists may be the first provider to recognize them, providing an opportunity for early treatment. Awareness of IRAEs and how to best image them will prepare radiologists to make a meaningful contribution to patient care as part of the clinical team.

MRI techniques for immunotherapy monitoring

MRI is a widely available clinical tool for cancer diagnosis and treatment monitoring. MRI provides excellent soft tissue imaging, using a wide range of contrast mechanisms, and can non-invasively detect tissue metabolites. These approaches can be used to distinguish cancer from normal tissues, to stratify tumor aggressiveness, and to identify changes within both the tumor and its microenvironment in response to therapy. In this review, the role of MRI in immunotherapy monitoring will be discussed and how it could be utilized in the future to address some of the unique clinical questions that arise from immunotherapy. For example, MRI could play a role in identifying pseudoprogression, mixed response, T cell infiltration, cell tracking, and some of the characteristic immune-related adverse events associated with these agents. The factors to be considered when developing MRI imaging biomarkers for immunotherapy will be reviewed. Finally, the advantages and limitations of each approach will be discussed, as well as the challenges for future clinical translation into routine clinical care. Given the increasing use of immunotherapy in a wide range of cancers and the ability of MRI to detect the microstructural and functional changes associated with successful response to immunotherapy, the technique has great potential for more widespread and routine use in the future for these applications.

Imaging Findings in Patients with Immune Checkpoint Inhibitor-Induced Arthritis

Immune checkpoint inhibitor (ICI)-induced arthritis is an increasingly recognized adverse event in patients with oncologic disease during immunotherapy. Four patterns are well described, including rheumatoid arthritis (RA)-like, polymyalgia rheumatica (PMR)-like, psoriatic arthritis (PsA)-like, and oligo-monoarthritis, among others. Despite better clinical recognition of these syndromes, information about the main imaging findings is limited. Methods: We conducted a retrospective observational study including all adult patients referred to the Rheumatology Department of a single-center due to ICI-induced arthritis who underwent imaging studies [ultrasound (US), magnetic resonance imaging (MRI), and ¹⁸F-FDG PET/CT)] between January 2017 and January 2022. Results: Nineteen patients with ICI-induced arthritis with at least one diagnostic imaging assessment were identified (15 US, 4 MRI, 2 ¹⁸F-FDG PET/CT). Most patients were male (84.2%), with a median age at inclusion of 73 years. The main underlying diagnoses for ICI treatment were melanoma in five cases. The distribution of ICI-induced arthritis was as follows: PMR-like (5, 26.2%), RA-like (4, 21.1%), PsA-like (4, 21.1%), and others (6, 31.6%). All RA-like patients had US findings indistinguishable from conventional RA patients. In addition, 3/5 (60%) of PMR-like patients had significant involvement of the hands and wrists. Abnormal findings on MRI or PET-CT were reported by clinical symptoms. No erosions or myofascitis were seen. Conclusions: ICI-induced arthritis patients present inflammatory patterns on imaging studies similar to conventional inflammatory arthropathies, and therefore these syndromes should be followed carefully and treated according to these findings.

Monitoring and Management of the Patient with Immune Checkpoint Inhibitor-Induced Inflammatory Arthritis: Current Perspectives

In this review, we draw from observational studies, treatment guidelines and our own clinical experience to describe approaches to monitoring and management of immune checkpoint inhibitor (ICI)-induced inflammatory arthritis, including polymyalgia rheumatica. This condition occurs in about 4% of ICI-treated cancer patients and can persist for a year or longer. Mild arthritis can generally be managed with non-steroidal anti-inflammatory drugs, intraarticular steroids injections and/or low dose corticosteroids. Higher grade arthritis should be brought under control with corticosteroids, but early introduction of a steroid-sparing agent is recommended to minimize steroid toxicity. In order to assess the effectiveness of any arthritis treatment, tender and swollen joint counts and patient reported measures of physical function, such as the health assessment questionnaire, should be obtained at each visit. Referral to a rheumatologist is recommended for patients with high grade arthritis to help guide the use of disease-modifying antirheumatic drugs.

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.

Low-Intensity Pulsed Ultrasound Suppresses Synovial Macrophage Infiltration and Inflammation in Injured Knees in Rats

This study was designed to investigate how low-intensity pulsed ultrasound (LIPUS) suppresses traumatic joint inflammation and thereafter affects the progression of posttraumatic osteoarthritis. Intra-articular fracture (IAF) was created in the right knee of rats. LIPUS was applied to the knees with IAFs for 20 min/d for 2 wk-LIPUS(+) group. The study controls included rats that underwent sham surgery but no LIPUS treatment (control group) or underwent IAF surgery without LIPUS treatment-LIPUS(-) group. By histology, at 4 wk, leukocyte infiltration in the synovium was reduced in the LIPUS(+) group. Furthermore, LIPUS treatment reduced CD68⁺ macrophages in the synovium and limited their distribution mostly in the subintimal synovium. Measured with enzyme-linked immunosorbent assay, interleukin-1β (IL-1β) in the joint fluid of the LIPUS(+) group was reduced to about one-third that in the LIPUS(-) group. By reducing synovial macrophages and lowering IL-1β in the joint fluid, LIPUS is potentially therapeutic for posttraumatic osteoarthritis.

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.

Nebenwirkungen immunonkologischer Therapien

Immunonkologische Therapien und insbesondere die Immuncheckpoint-Inhibitoren (ICPi) als Hauptvertreter dieser neuen Substanzklasse kommen bei zunehmender Anzahl von soliden und teils auch hämatologischen Tumorentitäten und Indikationen zum Einsatz. Die relativ hohen (Langzeit-)Tumoransprechraten auch in fortgeschrittenen und therapierefraktären Stadien haben die therapeutischen Möglichkeiten der Onkologie geradezu revolutioniert. Gleichzeitig bringt der zunehmende Einsatz von ICPi auch neue Herausforderungen: Immunonkologische Therapien verursachen ein breites Spektrum an autoimmunen Nebenwirkungen, sogenannten „immune-related adverse events“ (irAEs), die teilweise klassischen Autoimmunopathien ähneln und jedes Organsystem betreffen können. Die große Mehrheit der ICPi-behandelten Patienten erlebt ein irAE an mindestens einem Organsystem und davon weisen ca. 5–20% ein rheumatisches irAEs auf. Diese sind interessanterweise mit einem besseren Tumoransprechraten bei ICPi-Therapie assoziiert und können entweder die Erstmanifestation einer klassischen entzündlich-rheumatischen Erkrankung oder auch nur eine transiente Nebenwirkung mit spezifischen Charakteristika sein. Zweifelsohne wird das interdisziplinäre Management immunvermittelter Nebenwirkungen auch den Rheumatologen in den nächsten Jahren zunehmend beschäftigen. Der vorliegende Artikel fasst die Erkenntnisse zum klinischen Management von irAEs für den praktizierenden Rheumatologen zusammen.

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.

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.