Rheumatic and Musculoskeletal Immune-Related Adverse Events Due to Immune Checkpoint Inhibitors: A Systematic Review of the Literature

Immune checkpoint inhibitors and neurotoxicity: a focus on diagnosis and management for a multidisciplinary approach

INTRODUCTION

Although immune checkpoint inhibitors (ICIs) have revolutionized cancer treatment, the consequential over activation of the immune system is often complicated by adverse events that can affect several organs and systems, including the nervous system. The precise pathophysiology underlying neurological irAEs (n-irAEs) is not completely known. Around 3.8% of patients receiving anti-CTLA-4 agents, 6.1% of patients receiving anti-PD-1/PD-L1, and 12% of patients receiving combination therapies have n-irAEs. Most n-irAEs are low-grade, while severe toxicities have rarely been reported. in this article, we performed an updated literature search on immuno-related neurotoxicity on main medical research database, from February 2017 to December 2023.

AREAS COVERED

We have also compared the latest national and international guidelines on n-irAEs management with each other in order to better define patient management.

EXPERT OPINION

A multidisciplinary approach appears necessary in the management of oncological patients during immunotherapy. Therefore, in order to better manage these toxicities, we believe that it is essential to collaborate with neurologists specialized in the diagnosis and treatment of n-irAEs, and that a global neurological assessment, both central and peripheral, is necessary before starting immunotherapy, with regular reassessment during treatment.

A systematic review and meta-analysis of observational studies and uncontrolled trials reporting on the use of checkpoint blockers in patients with cancer and pre-existing autoimmune disease

BACKGROUND

Cancer patients with autoimmune disease have been excluded from randomized trials of immune checkpoint blockers (ICBs). We conducted a systematic review of observational studies and uncontrolled trials including cancer patients with pre-existing autoimmune disease who received ICBs.

METHODS

We searched 5 electronic databases through November 2023. Study selection, data collection, and quality assessment were performed independently by 2 investigators. We performed a meta-analysis to pool incidence of immune-related adverse events (irAEs), including de novo events and flares of existing autoimmune disease, hospitalizations due to irAEs, as well as deaths.

RESULTS

A total of 95 studies were included (23,897 patients with cancer and preexisting autoimmune disease). The most common cancer evaluated was lung cancer (30.7 %) followed by skin cancer (15.7 %). Patients with autoimmune disease were more likely to report irAEs compared to patients without autoimmune disease (relative risk 1.3, 95 % CI 1.0 to 1.6). The pooled occurrence rate of any irAEs (flares or de novo) was 61 % (95 % CI 54 % to 68 %); that of flares was 36 % (95 % CI 30 % to 43 %), and that of de novo irAEs was 23 % (95 % CI 16 % to 30 %). Flares were mild (grade <3) in half of cases and more commonly reported in patients with psoriasis/psoriatic arthritis (39 %), inflammatory bowel disease (37 %), and rheumatoid arthritis (36 %). 32 % of the patients with irAEs required hospitalization and treatment of irAEs included corticosteroids in 72 % of the cases. The irAEs mortality rate was 0.07 %. There were no statistically significant differences in cancer response to ICBs between patients with and without autoimmune disease.

CONCLUSIONS

Although more patients with pre-existing autoimmune disease had irAEs, these were mild and managed with corticosteroids in most cases, with no impact on cancer response. These results suggest that ICBs can be used in these patients, but careful monitoring is required, as over a third of the patients will experience a flare of their autoimmune disease and/or require hospitalization. These findings provide a crucial foundation for oncologists to refine their monitoring and management strategies, ensuring that the benefits of ICB therapy are maximized while minimizing its risks.

Case report: Inflammatory sternoclavicular joint arthritis induced by an immune checkpoint inhibitor with remarkable responsiveness to infliximab

This report describes the case of a 48-year-old woman who presented with sternoclavicular joint arthritis after administration of an immune checkpoint inhibitor (ICI), durvalumab, for small cell lung carcinoma. The onset of arthritis transpired 18 months after the commencement of the ICI therapeutic regimen and demonstrated resilience to glucocorticoid treatment. After excluding infectious aetiologies and metastatic involvement, the patient was diagnosed with ICI-induced arthritis (ICI-IA). Considering the articular implications akin to the SAPHO syndrome, the patient was treated with infliximab, resulting in complete resolution. This finding implies that biological DMARDs can serve as effective interventions for ICI-induced sternoclavicular joint arthritis. Given the heterogeneous nature of its pathogenesis, the selection of therapeutic agents may require customization based on the distinct clinical presentation of each individual case.

Patient reported outcomes and patient experiences of immune checkpoint modulators for advanced or recurrent melanoma: a mixed methods study

PURPOSE

Little is known about late and long-term patient-reported outcomes (PROs) of immune checkpoint modulators (ICMs) outside clinical trials. We conducted a cross-sectional, mixed-methods study to describe long-term PROs among advanced melanoma patients who began standard of care treatment with ICMs at least 1 year previously.

METHODS

All participants completed the Functional Assessment of Cancer Therapy-Immune Checkpoint Modulator (FACT-ICM), assessing 46 immune-related side effects on a 5-point Likert scale, and a subset completed individual interviews. Descriptive statistics were computed for quantitative data and applied thematic analysis was used to examine qualitative data.

RESULTS

Participants (N = 80) had a mean age of 67 years, and the majority were male (66%), non-Hispanic White (96%), and college graduates (61%). Single-agent nivolumab was the most common first (47%) and current/recent ICM (64%). On the FACT-ICM, 98% of participants reported at least one side effect, and 78% reported moderate or severe side effects. The most common moderate or severe side effects were aching joints (43%) and fatigue (38%). In interviews (n = 20), we identified five themes regarding patients' longer-term experiences after ICMs: lasting fatigue or decline in functioning, minimal side effects, manageable thyroid and pituitary dysfunction, skin conditions can be difficult to manage, and treating the cancer is worth the side effects.

CONCLUSIONS

Nearly all patients reported side effects of ICMs at least 1 year after starting treatment. Our findings suggest that ICM side effect screening and management-especially for aching joints and fatigue-are indicated during long-term care of people living with advanced melanoma.

Baseline predictors of disease severity in immune checkpoint inhibitor-induced inflammatory arthritis

OBJECTIVES

The objective of this study was to determine baseline risk factors for requiring immunosuppression and having persistent arthritis in patients with immune checkpoint inhibitor-induced inflammatory arthritis (ICI-inflammatory arthritis).

METHODS

Participants were adults with rheumatologist diagnosed ICI-inflammatory arthritis. The primary outcome was requirement of conventional synthetic (cs) or biologic (b) DMARDs; other outcomes were persistence of inflammatory arthritis >6 months after ICI cessation and requirement of CSs. Logistic regression models evaluated associations between clinical features and primary and secondary outcomes, with adjustment for potential confounders, as appropriate.

RESULTS

One hundred and twenty-six patients with ICI-inflammatory arthritis were included; 53 patients (42%) required a csDMARD/bDMARD. In the univariate logistic regression analysis, higher clinical disease activity index (CDAI), tenosynovitis, longer symptom duration before first rheumatology visit and longer ICI duration were significantly associated with a higher likelihood of requiring DMARDs; in addition, there was a trend towards those treated with prior chemotherapy being less likely to need DMARDs. After adjustment, tenosynovitis, longer symptom duration and higher CDAI remained associated with requiring DMARDs, while those with prior chemotherapy were significantly less likely to require DMARDs. Combination anti-CTLA-4 (cytotoxic T-lymphocyte-associated protein-4)/PD-1 (Programmed cell death protein-1) therapy and CS use at baseline were associated with a higher risk of persistent inflammatory arthritis.

CONCLUSION

Higher levels of disease activity, tenosynovitis and longer symptom duration prior to rheumatology referral were associated with requiring DMARDs for ICI-inflammatory arthritis, while those treated previously with chemotherapy were less likely to require additional immunosuppression. The presence of risk factors for severe disease at baseline may indicate a role for higher initial CS dose, earlier rheumatology referral, and adoption of immunosuppression beyond CSs to improve outcomes.

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.

Mimickers of Immune Checkpoint Inhibitor-induced Inflammatory Arthritis

The differential diagnosis of inflammatory arthritis as an immune-related adverse event can be challenging as patients with cancer can present with musculoskeletal symptoms that can mimic arthritis because of localized or generalized joint pain. In addition, immune checkpoint inhibitors can exacerbate joint conditions such as crystal-induced arthritis or osteoarthritis, or induce systemic disease that can affect the joints such as sarcoidosis. This distinction is important as the treatment of these conditions can be different from that of immune-related inflammatory arthritis.

Clinical Phenotypes, Serological Biomarkers, and Synovial Features Defining Seropositive and Seronegative Rheumatoid Arthritis: A Literature Review

Rheumatoid arthritis (RA) is a chronic autoimmune disorder which can lead to long-term joint damage and significantly reduced quality of life if not promptly diagnosed and adequately treated. Despite significant advances in treatment, about 40% of patients with RA do not respond to individual pharmacological agents and up to 20% do not respond to any of the available medications. To address this large unmet clinical need, several recent studies have focussed on an in-depth histological and molecular characterisation of the synovial tissue to drive the application of precision medicine to RA. Currently, RA patients are clinically divided into "seropositive" or "seronegative" RA, depending on the presence of routinely checked antibodies. Recent work has suggested that over the last two decades, long-term outcomes have improved significantly in seropositive RA but not in seronegative RA. Here, we present up-to-date differences in epidemiology, clinical features, and serological biomarkers in seronegative versus seropositive RA and discuss how histological and molecular synovial signatures, revealed by recent large synovial biopsy-based clinical trials, may be exploited to refine the classification of RA patients, especially in the seronegative group.

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

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

Antinuclear antibodies may predict the development of immune-related adverse events in asymptomatic patients treated with immune checkpoint inhibitors: results from a single-center cohort

We aim at investigating the association between subclinical autoimmunity and immune-related adverse events (irAEs) in a cohort of patients treated by immune checkpoint inhibitors for solid metastatic cancer. In the context of an oncology/rheumatology outpatient clinic, we evaluated patients treated with anti-PD-1 or anti-PD-L1. Before treatment, each patient underwent a physical evaluation and a blood sample to identify the presence of a set of autoantibodies. Indeed, all the patients were followed during treatment to identify irAEs and to assess the association with autoantibodies. Fifty-one patients (M/F 16/35; median age 70 years, IQR 16.5) were evaluated; 34.8% of patients showed ANA positivity, 6.5% ENA positivity (anti-SSA), 4.3% Ratest positivity, and 2.1% (one patient) ACPA positivity. During a median period of 21 months (IQR 38.75), 39.2% of patients developed irAEs. Musculo-skeletal manifestations, in particular arthritis, were the most frequent. We found a significant association between the positivity for ANA and the development of irAES (p = 0.03, RR 2.01, 95% CI 1.03-3.92). Furthermore, the progression-free survival was significantly longer in patients developing irAEs compared to those who are not experiencing these events (p = 0.007). This study underlines the potential role of ANA positivity as a predictive biomarker for the development of irAEs.

Programmed Death Ligand 1-Expressing Macrophages and Their Protective Role in the Joint During Arthritis

OBJECTIVE

Arthritis associated with immune checkpoint inhibitor therapies highlights the importance of immune checkpoint expression for joint homeostasis. We investigated the role of programmed death ligand (PD-L) 1 in the synovium using a collagen-induced arthritis (CIA) mouse model.

METHODS

We blocked PD-L1 using blocking antibodies during CIA and assessed the arthritis severity by clinical and histologic scoring. PD-L1 expression and the origin of synovial macrophages were investigated using flow cytometry and parabiosis. We used Cre-Lox mice to ascertain the protective role of PD-L1-expressing macrophages in arthritis. The immune profile of human and murine synovial PD-L1+ macrophages was determined by reverse transcriptase-polymerase chain reaction, flow cytometry, and single-cell RNA sequencing.

RESULTS

Anti-PD-L1 antibody treatment during CIA worsened arthritis with increased immune cell infiltration compared with isotype control, supporting the regulatory role of PD-L1 in the joint. The main cells expressing PD-L1 in the synovium were macrophages. Using parabiosis, we showed that synovial PD-L1+ macrophages were both locally proliferating and partially replaced by the circulation. PD-L1+ macrophages had increased levels of MER proto-oncogene tyrosine kinase (MerTK) and interleukin (IL)-10 expression during acute CIA. Genetic depletion of PD-L1 on macrophages in LyzcrePD-L1fl/fl mice resulted in worsened CIA compared with controls. We found that human PD-L1+ macrophages in the synovium of healthy individuals and patients with rheumatoid arthritis express MerTK and IL-10.

CONCLUSION

PD-L1+ macrophages with efferocytotic and anti-inflammatory characteristics protect the synovium from severe arthritis in the CIA mouse model. Tissue-protective, PD-L1-expressing macrophages are also present in the human synovium at homeostasis and during rheumatoid arthritis.

PET/Computed Tomography Transformation of Oncology: Immunotherapy Assessment

Immunotherapy approaches have changed the treatment landscape in a variety of malignancies with a high anti-tumor response. Immunotherapy may be associated with novel response and progression patterns that pose a substantial challenge to the conventional criteria for assessing treatment response, including response evaluation criteria in solid tumors (RECIST) 1.1. In addition to the morphologic details provided by computed tomography (CT) and MRI, hybrid molecular imaging emerges as a comprehensive imaging modality with the capacity to interrogate pathophysiological mechanisms like glucose metabolism. This review highlights the current status of 2-deoxy-2-[18F]fluoro-D-glucose positron emission tomography/computed tomography (18F-FDG PET/CT) in prognostication, response monitoring, and identifying immune-related adverse events. Furthermore, it investigates the potential role of novel immuno-PET tracers that could complement the utilization of 18F-FDG PET/CT by imaging the specific pathways involved in immunotherapeutic strategies.

Rapid identification of inflammatory arthritis and associated adverse events following immune checkpoint therapy: a machine learning approach

Introduction

Immune checkpoint inhibitor-induced inflammatory arthritis (ICI-IA) poses a major clinical challenge to ICI therapy for cancer, with 13% of cases halting ICI therapy and ICI-IA being difficult to identify for timely referral to a rheumatologist. The objective of this study was to rapidly identify ICI-IA patients in clinical data and assess associated immune-related adverse events (irAEs) and risk factors.

Methods

We conducted a retrospective study of the electronic health records (EHRs) of 89 patients who developed ICI-IA out of 2451 cancer patients who received ICI therapy at Northwestern University between March 2011 to January 2021. Logistic regression and random forest machine learning models were trained on all EHR diagnoses, labs, medications, and procedures to identify ICI-IA patients and EHR codes indicating ICI-IA. Multivariate logistic regression was then used to test associations between ICI-IA and cancer type, ICI regimen, and comorbid irAEs.

Results

Logistic regression and random forest models identified ICI-IA patients with accuracies of 0.79 and 0.80, respectively. Key EHR features from the random forest model included ICI-IA relevant features (joint pain, steroid prescription, rheumatoid factor tests) and features suggesting comorbid irAEs (thyroid function tests, pruritus, triamcinolone prescription). Compared to 871 adjudicated ICI patients who did not develop arthritis, ICI-IA patients had higher odds of developing cutaneous (odds ratio [OR]=2.66; 95% Confidence Interval [CI] 1.63-4.35), endocrine (OR=2.09; 95% CI 1.15-3.80), or gastrointestinal (OR=2.88; 95% CI 1.76-4.72) irAEs adjusting for demographics, cancer type, and ICI regimen. Melanoma (OR=1.99; 95% CI 1.08-3.65) and renal cell carcinoma (OR=2.03; 95% CI 1.06-3.84) patients were more likely to develop ICI-IA compared to lung cancer patients. Patients on nivolumab+ipilimumab were more likely to develop ICI-IA compared to patients on pembrolizumab (OR=1.86; 95% CI 1.01-3.43).

Discussion

Our machine learning models rapidly identified patients with ICI-IA in EHR data and elucidated clinical features indicative of comorbid irAEs. Patients with ICI-IA were significantly more likely to also develop cutaneous, endocrine, and gastrointestinal irAEs during their clinical course compared to ICI therapy patients without ICI-IA.

Immune Checkpoint Inhibitors and Scleroderma: Data from the European Pharmacovigilance Database

BACKGROUND

Immune checkpoint inhibitors (ICIs) can be commonly associated with the occurrence of immune-related adverse drug reactions (irADRs), which can involve any tissue and organ. ICI-induced skin toxicities are common irADRs and they can be a consequence of a rheumatologic ADR, such as in the case of scleroderma. A recent literature review reported that scleroderma and scleroderma mimics represent a group of disorders with significant morbidity that have been described during ICIs' use.

OBJECTIVE AND METHODS

Considering the clinical significance of scleroderma cases, the present study aimed to analyze the occurrence of these events in patients receiving ICIs by describing data from individual case safety reports (ICSRs) retrieved from the European spontaneous reporting system, EudraVigilance (EV).

RESULTS

Until February 2023, 70 ICSRs with at least one ICI as the suspected drug and at least one preferred term (PT) related to scleroderma cases were retrieved from the EV. Pembrolizumab was reported as suspected in 41 ICSRs, nivolumab in 25 ICSRs, ipilimumab in 8 ICSRs and atezolizumab in 3 ICSRs. Patients who experienced scleroderma cases were adults, and no differences were found in terms of sex distribution. Scleroderma cases were mainly classified as serious, while the outcome was mainly reported as favorable. The most reported PTs were scleroderma and morphea.

CONCLUSIONS

Considering the seriousness of ICI-induced scleroderma cases and the recent marketing authorization of some ICIs, we believe that further high-quality clinical studies should be conducted on this topic to better estimate the impact of these events in patients with cancer.

Risk factors for immune-related adverse effects during CPI therapy in patients with head and neck malignancies - a single center study

Introduction

Checkpoint inhibitors, such as PD1 inhibitors, represent an important pillar in the therapy of advanced malignancies of the head and neck region. The most relevant complications are immune-related adverse effects (irAEs), which represent an immense burden for patients. Currently, no sufficient stratification measures are available to identify patients at increased risk of irAEs. The aim of this retrospective study was to examine whether demographic, histopathological, clinical, or laboratory values at the start of CPI therapy represent a risk factor for the later occurrence of autoimmune complications.

Material and methods

Data from 35 patients between 2018 and 2021 who received therapy with nivolumab or pembrolizumab for head and neck malignancy were analyzed and assessed for any associations with the subsequent occurrence of irAEs.

Results

IrAE developed in 37% of patients, with pneumonitis being the most common form (14%). Pneumonitis was found in patients with an average significantly lower T-stage of primary tumors. An increase in basophilic leukocytes was found in patients with dermatitis later in the course. When thyroiditis developed later, the patients had a higher CPS score and lower monocyte levels.

Discussion

Even though individual laboratory values at the beginning of therapy might show a statistical association with the later occurrence of irAEs, neither demographic, histopathological, nor laboratory chemistry values seem to be able to generate a sound and reliable risk profile for this type of complication. Therefore, patients need to be educated and sensitized to irAEs, and regular screening for irAEs should be carried out.

Achilles' Heel of currently approved immune checkpoint inhibitors: immune related adverse events

Immunotherapy has revolutionized the cancer treatment landscape by opening up novel avenues for intervention. As the use of immune checkpoint inhibitors (ICIs) has exponentially increased, so have immune-related adverse events (irAEs). The mechanism of irAEs may involve the direct damage caused by monoclonal antibodies and a sequence of immune responses triggered by T cell activation. Common side effects include dermatologic toxicity, endocrine toxicity, gastrointestinal toxicity, and hepatic toxicity. While relatively rare, neurotoxicity, cardiotoxicity, and pulmonary toxicity can be fatal. These toxicities pose a clinical dilemma regarding treatment discontinuation since they can result in severe complications and necessitate frequent hospitalization. Vigilant monitoring of irAEs is vital in clinical practice, and the principal therapeutic strategy entails the administration of oral or intravenous glucocorticoids (GSCs). It may be necessary to temporarily or permanently discontinue the use of ICIs in severe cases. Given that irAEs can impact multiple organs and require diverse treatment approaches, the involvement of a multidisciplinary team of experts is imperative. This review aims to comprehensively examine the pathogenesis, clinical manifestations, incidence, and treatment options for various irAEs.

Ocular Surface Side Effects of Novel Anticancer Drugs

Surgery, anticancer drugs (chemotherapy, hormonal medicines, and targeted treatments), and/or radiation are common treatment strategies for neoplastic diseases. Anticancer drugs eliminate malignant cells through the inhibition of specific pathways that contribute to the formation and development of cancer. Given the ability of such pharmacological medications to combat cancerous cells, their role in the management of neoplastic diseases has become essential. However, these drugs may also lead to undesirable systemic and ocular adverse effects due to cyto/neuro-toxicity and inflammatory reactions. Ocular surface side effects are recognized to significantly impact patient's quality of life and quality of vision. Blepharoconjunctivitis is known to be a common side effect caused by oxaliplatin, cyclophosphamide, cytarabine, and docetaxel, while anastrozole, methotrexate, and 5-fluorouracil can all determine dry eye disease. However, the potential processes involved in the development of these alterations are yet not fully understood, especially for novel drugs currently available for cancer treatment. This review aims at analyzing the potential ocular surface and adnexal side effects of novel anticancer medications, trying to provide a better understanding of the underlying pharmacological processes and useful insights on the choice of proper management.

Uncovering the flip side of immune checkpoint inhibitors: a comprehensive review of immune-related adverse events and predictive biomarkers

Immune checkpoint inhibitors (ICIs) have generated considerable excitement as a novel class of immunotherapeutic agents due to their remarkable efficacy in treating various types of cancer. However, the widespread use of ICIs has brought about a number of safety concerns, especially the development of immune-related adverse events (irAEs). These serious complications could result in treatment discontinuation and even life-threatening consequences, making it critical to identify high-risk groups and predictive markers of irAEs before initiating therapy. To this end, the current article examines several potential predictive markers of irAEs in important organs affected by ICIs. While retrospective studies have yielded some promising results, limitations such as small sample sizes, variable patient populations, and specific cancer types and ICIs studied make it difficult to generalize the findings. Therefore, prospective cohort studies and real-world investigations are needed to validate the potential of different biomarkers in predicting irAEs risk. Overall, identifying predictive markers of irAEs is a crucial step towards improving patient safety and enhancing the management of irAEs. With ongoing research efforts, it is hoped that more accurate and reliable biomarkers will be identified and incorporated into clinical practice to guide treatment decisions and prevent the development of irAEs in susceptible patients.

Evaluation of a self-questionnaire to screen for neurological complications associated with immunological checkpoint inhibitors: Are we missing something?

INTRODUCTION

Immunological checkpoint inhibitors (ICI) have led to a therapeutic revolution in the management of many cancers and indications are increasing. Neurological complications seem to have a profile quite distinct from that of toxicities related to chemotherapy, although it is possible that some manifestations remain under-reported or misdiagnosed.

OBJECTIVES

(i) To evaluate the value of a self-questionnaire in screening for neurological ICI-related complications. (ii) To investigate whether, apart from the subacute complications described in the literature, neurological complications of more insidious onset might occur.

METHOD

Patients followed in dermatology department for skin cancers treated with ICI, completed every infusion a neurological screening auto-questionnaire. Patients were selected for a neurological expertise based on the questionnaire's data.

RESULTS

In total, 149 patients completed≥1 questionnaire, with a median delay of 174 days from the start of treatment. A total of 229 questionnaires were completed between July 2019 and December 2019. 38 patients were identified for a neurological consultation. None of these patients had a neurological event attributable to ICI. During the follow-up, only one patient had a neurological event related to ICI, which was not revealed by the questionnaire.

DISCUSSION

Neurological signs in ICI-treated-skin-cancer context are more often due to tumoral progression. Neurological complications of ICI remain rare and unpredictable. The systematic neurological questionnaire has not been shown to be useful in this context. These results highlight the need to educate patients about possible subacute signs that should lead to contact the treating physicians and the need for a close cooperation between dermatologists/oncologists and neurologists.

Safety and effectiveness of combination versus monotherapy with immune checkpoint inhibitors in patients with preexisting autoimmune diseases

Patients with preexisting autoimmune disease (pAID) are generally excluded from clinical trials for immune checkpoint inhibitors (ICIs) for cancer due to concern of flaring pAID. In this multi-center, retrospective observational study, we compared safety of ICI combination (two ICI agents) versus monotherapy in cancer patients with pAIDs. The primary outcome was time to AEs (immune-related adverse events (irAEs) and/or pAID flares), with progression-free survival (PFS) and overall survival as secondary outcomes. Sixty-four of 133 patients (48%) received ICI combination and 69 (52%) monotherapy. Most had melanoma (32%) and lung cancer (31%). Most common pAIDs were rheumatic (28%) and dermatologic (23%). Over a median follow-up of 15 months (95%CI, 11-18 mo), the cumulative incidence of any-grade irAEs was higher for combination compared to monotherapy (subdistribution hazard ratio (sHR) 2.27, 95%CI 1.35-3.82). No statistically significant difference was observed in high-grade irAEs (sHR 2.31 (0.95-5.66), P = .054) or the cumulative incidence of pAID flares. There was no statistically significant difference for melanoma PFS between combination versus monotherapy (23.2 vs. 17.1mo, P = .53). The combination group was more likely to discontinue or hold ICI, but > 50% of the combination group was still able to continue ICI therapy. No treatment-related deaths occurred. In our cohort with pAIDs, patients had a tolerable toxicity profile with ICI combination therapy. Our results support the use of ICI combination if deemed necessary for cancer therapy in patients with pAIDs, since the ICI toxicities were comparable to monotherapy, able to be effectively managed and mostly did not require ICI interruption.

Bibliometric analysis of rheumatic immune related adverse events associated with immune checkpoint inhibitors

Background

Immune checkpoint inhibitors (ICIs) has emerged as a popular cancer treatment approach. However, non-specific activation of T cells by ICIs can lead to immune-related adverse events (irAEs), including specific rheumatic manifestations. The study aimed to explore the current trend of ICIs associated rheumatic irAEs and summarize the knowledge structure through bibliometric methods.

Methods

The Web of Science Core Collection database (WoSCC) was selected for retrieving literature on ICIs associated rheumatic irAEs. To evaluate contributions from different countries/regions, institutions, journals, and authors, bibliometric analysis software, including VOSviewer and CiteSpace, as well as bibliometric online platforms, were utilized to construct and visualize bibliometric networks. Through the systematic review of this knowledge domain, future research directions were determined.

Results

In This study, a total of 803 publications on ICIs-associated rheumatic irAEs were included for analysis. The distribution of these publications revealed two distinct growth phases: a stable phase between 2007 to 2015 followed by rapid growth from 2016 to 2020. The United States emerged as the top contributor in terms of publications, citations, and h-index, with the majority of leading institutions and funding agencies located there. Apart from government funding, pharmaceutical companies such as Bristol Myers Squibb and Merck Company also play a significant role in drug development and research. Analysis of keywords and citation bursts indicated that the initial burst was related to "monoclonal antibody," "anti-CLTA4 antibody," and "melanoma". This was followed by a rise in interest related to "sarcoidosis," "safety," "inflammatory arthritis," and "preexisting autoimmune."

Conclusion

This study summarized the global research trends concerning ICIs associated rheumatic irAEs. The findings can provide valuable insights into the current understanding of rheumatic irAEs, highlight the research trend and developments in the field. Future efforts should focus on developing classification criteria and guidelines, conducting prospective studies, investigating the mechanisms involved, and identifying biomarkers for prediction and monitoring of these events.

Arthralgia adverse events due to immune-checkpoint inhibitors for lung cancer patients: a systematic review and meta-analysis

Background

Immune agents targeting Programmed cell death-1 (PD-1) are a new type of cancer treatment drugs. By inhibiting the interaction between PD-1 and PD-L1, the ability of the immune system to attack tumor cells is enhanced. These immune preparations have shown significant efficacy in the treatment of various malignant tumors. However, like other drugs, immune preparations targeting PD-1 may also cause side effects, including arthralgia. Therefore, we conduct a meta-analysis to assess whether immune-checkpoint inhibitors targeting programmed cell death-1 in lung cancer patients will lead to arthralgia adverse events.

Methods

We conducted a comprehensive search across multiple databases, including PubMed, Medline (Ovid), Web of Science, Cochrane, Embase, Scopus, CKNI, Wang fang, VIP database, Sino Med, and Clinical Trails, to identify relevant studies. The search encompassed articles published up until June 20th, 2023. The primary outcome is adverse events about arthralgia and secondary outcomes are any other related with arthralgia. Data extraction was carried out by two independent individuals, and the Cochrane Risk of Bias tool version 2.0 was employed to assess the included studies. The systematic review and meta-analysis were conducted using RevMan 5.3 software.

Results

12 studies are included in the meta-analysis. All included studies were determined to have a low risk of random sequence generation bias. The meta-analysis result showed that arthralgia RR = 1.11, 95% CI [0.88, 1.40], I2 = 56%, back pain RR = 1.86, 95% CI [1.07, 3.26], I2 = 84%, myalgia RR = 0.49, 95% CI [0.27, 0.88], I2 = 86% and muscular pain RR = 1.97, 95% CI [1.40, 2.77], I2 = 23%.

Conclusion

The use of targeted inhibitors may lead to an increased incidence of back pain, while potentially reducing the occurrence of myalgia. On the other hand, immune-checkpoint inhibitors targeting programmed cell death-1 in lung cancer patients may not cause arthralgia and muscular pain.

Sex and anti-inflammatory treatment affect outcome of melanoma and non-small cell lung cancer patients with rheumatic immune-related adverse events

BACKGROUND

Rheumatic immune-related adverse events (R-irAEs) occur in 5-15% of patients receiving immune checkpoint inhibitors (ICI) and, unlike other irAEs, tend to be chronic. Herein, we investigate the factors influencing cancer and R-irAEs outcomes with particular focus on adverse effects of anti-inflammatory treatment.

METHODS

In this prospective, multicenter, long-term, observational study, R-irAEs were comprehensively analyzed in patients with malignant melanoma (MM, n=50) and non-small cell lung cancer (NSCLC, n=41) receiving ICI therapy who were enrolled in the study between August 1, 2018, and December 11, 2022.

RESULTS

After a median follow-up of 33 months, progressive disease or death occurred in 66.0% and 30.0% of MM and 63.4% and 39.0% of patients with NSCLC. Male sex (progression-free survival (PFS): p=0.013, and overall survival (OS): p=0.009), flare of a pre-existing condition (vs de novo R-irAE, PFS: p=0.010) and in trend maximum glucocorticoid (GC) doses >10 mg and particularly ≥1 mg/kg prednisolone equivalent (sex-adjusted PFS: p=0.056, OS: p=0.051) were associated with worse cancer outcomes. Patients receiving disease-modifying antirheumatic drugs (DMARDs) showed significantly longer PFS (n=14, p=0.011) and OS (n=20, p=0.018). Effects of these variables on PFS and/or OS persisted in adjusted Cox regression models. Additionally, GC treatment negatively correlated with the time from diagnosis of malignancy and the latency from ICI start until R-irAE onset (all p<0.05). R-irAE features and outcomes were independent of other baseline patient characteristics in both studied cancer entities.

CONCLUSION

Male sex, flare of pre-existing rheumatologic conditions and extensive GC treatment appeared to be linked with unfavorable cancer outcomes, while DMARD use had a favorable impact. These findings challenge the current dogma of restrictive DMARD use for R-irAE and thus may pave the way to better strategies and randomized controlled trials for the growing number of patients with R-irAE.

Gastrointestinal mucosal toxicities from immune checkpoint inhibitors: Current understanding and future directions

Immune checkpoint inhibitor (ICI) therapy has revolutionized the field of oncology over the past decade, leading to durable remissions in some patients but also producing a wide spectrum of treatment-limiting inflammatory toxicities that are referred to as immune-related adverse events (irAEs). Although irAEs can involve any organ system in the body, they most commonly affect the barrier tissues, including the gastrointestinal tract with colitis and enterocolitis affecting a significant fraction of patients on ICIs. We are beginning to understand the mechanisms that drive ICI colitis, with early experiments indicating a role for CD8+ resident memory T cells (TRMs) in the gut, which become activated and differentiate into cytotoxic cells in response to ICI therapy. The risk factors that define who will develop ICI colitis are not understood and substantial efforts are underway to identify potential biomarkers for risk of this and other toxicities. Optimal management of ICI colitis is also an area of active investigation. Current standard treatments are based largely on small, retrospective analyses, and while drugs like systemic glucocorticoids or the TNFα inhibitor infliximab do appear to be highly active in ICI colitis, the impact of these therapies on antitumor responses is poorly understood. As discussed in this review, future work will have to define the immune mechanisms driving ICI colitis in more detail and in comparison to antitumor responses in order to identify candidate pathways that can be targeted to improve ICI colitis without interfering in antitumor immunity. Studying these interventions will require randomized, controlled trials with both tumor and colitis endpoints, a goal that will necessitate collaboration across institutions and funding agencies. We are at a point where such collaborative trials are feasible, and have the potential to greatly improve the care of patients with ICI colitis as well as other irAEs.

Unexpected Adverse Events of Immune Checkpoint Inhibitors

The introduction of immune checkpoint inhibitors (ICIs) has revolutionized cancer treatment standards and significantly enhanced patient prognoses. However, the utilization of these groundbreaking therapies has led to the observation and reporting of various types of adverse events, commonly known as immune-related adverse events (irAEs). In the following article, we present four patients who encountered uncommon toxicities induced by ICIs. The first patient was a 59-year-old female diagnosed with stage 4 lung adenocarcinoma. She received immunotherapy (pembrolizumab) together with chemotherapy and subsequently developed autonomic neuropathy (AN). The next two patients also received chemo-immunotherapy (pembrolizumab) and were both 63-year-old males with stage 4 lung adenocarcinoma. One of the two experienced palmoplantar keratoderma, while the other presented with Reiter's syndrome (urethritis, conjunctivitis and arthritis). The 4th patient, an 80-year-old male with stage 4 squamous cell carcinoma of the lung, received chemo-immunotherapy (pembrolizumab) and developed myasthenia gravis.

Seronegative Rheumatoid Arthritis Secondary to Immune Checkpoint Inhibitor in a Renal Cell Carcinoma Patient Encountered in a Rural Community-Based Rheumatology Clinic: A Case Report

Immune checkpoint inhibitors (ICIs) are a widely used class of cancer immunotherapy. Those drugs have improved the treatment of cancer since its introduction in the 2000s. Nivolumab is an ICI that can be used for previously untreated renal cell carcinoma. Immune-related adverse events (irAEs) are a type of adverse event of immunotherapy that is associated with an overreactive immune system. We report a case of a 69-year-old Caucasian man with stage IV renal cell carcinoma who presented to a rural community-based rheumatology clinic referred by his oncologist, after starting to develop morning stiffness for at least three hours, joint swelling, warmth, and erythema five months after starting immunotherapy with nivolumab. The patient was diagnosed with seronegative rheumatoid arthritis secondary to ICIs and required a higher dose of prednisone (up to 40 mg per day) with methotrexate to achieve remission. With the widespread availability of ICIs, rheumatologic irAEs can be encountered in a rural community-based practice. Practicing physicians taking care of cancer patients need to be aware of the adverse effect of ICIs.

Bone-modifying agents for non-small-cell lung cancer patients with bone metastases during the era of immune checkpoint inhibitors: A narrative review

During the course of lung cancer progression, bone metastases occur in about 40% of patients. Common complications associated with bone metastases in lung cancer patients include musculoskeletal pain, pathologic fractures, spinal cord compression, and hypercalcemia. We discuss the efficacy of bone-modifying agents (BMAs) in reducing skeletal-related events (SREs) and improving cancer-related outcomes, particularly in patients with stage IV non-small-cell lung cancer with bone metastases. In addition, the combined effects of BMAs with radiotherapy or immunotherapy in reducing SREs in patients with lung cancer and bone metastases are explored.

Mortality and immune-related adverse events after immune checkpoint inhibitor initiation for cancer among patients with pre-existing rheumatoid arthritis: a retrospective, comparative, cohort study

Background

Patients with pre-existing rheumatoid arthritis initiating immune checkpoint inhibitors for cancer might be at risk of increased mortality, rheumatoid arthritis flares, and other immune-related adverse events (AEs). We aimed to determine whether pre-existing rheumatoid arthritis was associated with higher mortality and immune-related AE risk in patients treated with immune checkpoint inhibitors.

Methods

This retrospective, comparative cohort study was conducted at the Mass General Brigham Integrated Health Care System and the Dana-Farber Cancer Institute in Boston (MA, USA). We searched data repositories to identify all individuals who initiated immune checkpoint inhibitors from April 1, 2011, to April 21, 2021. Patients with pre-existing rheumatoid arthritis had to meet the 2010 American College of Rheumatology-European Alliance of Associations for Rheumatology (ACR-EULAR) criteria. For each pre-existing rheumatoid arthritis case, we matched up to three non-rheumatoid arthritis comparators at the index date of immune checkpoint inhibitor initiation by sex (recorded as male or female), calendar year, immune checkpoint inhibitor target, and cancer type and stage. The coprimary outcomes were time from index date to death and time to the first immune-related AE, measured using an adjusted Cox proportional hazards model. Deaths were identified by medical record and obituary review. Rheumatoid arthritis flares and immune-related AE presence, type, and severity were determined by medical record review.

Findings

We identified 11 901 patients who initiated immune checkpoint inhibitors for cancer treatment between April 1, 2011, and April 21, 2021; of those, 101 met the 2010 ACR-EULAR criteria for rheumatoid arthritis. We successfully matched 87 patients with pre-existing rheumatoid arthritis to 203 non-rheumatoid arthritis comparators. The median age was 71·2 years (IQR 63·2-77·1). 178 (61%) of 290 participants were female, 112 (39%) were male and 268 (92%) participants were White. PD-1 was the most common immune checkpoint inhibitor target (80 [92%] of 87 patients with rheumatoid arthritis vs 188 [93%] of 203 comparators). Lung cancer was the most common cancer type (43 [49%] vs 114 [56%]), followed by melanoma (21 [24%] vs 50 [25%]). 60 (69%) patients with rheumatoid arthritis versus 127 (63%) comparators died (adjusted hazard ratio [HR] of 1·16 [95% CI 0·86-1·57]; p=0·34). 53 (61%) patients with rheumatoid arthritis versus 99 (49%) comparators had any all-grade immune-related AE (adjusted HR 1·72 [95% CI 1·20-2·47]; p=0·0032). There were two (1%) grade 5 immune-related AEs (deaths) due to myocarditis, both in the comparator group. Rheumatoid arthritis flares occurred in 42 (48%) patients with rheumatoid arthritis, and inflammatory arthritis occurred in 14 (7%) comparators (p<0·0001). Those with rheumatoid arthritis were less likely to have rash or dermatitis (five [6%] vs 28 [14%]; p=0·048), endocrinopathy (two [2%] vs 22 [11%]; p=0·0078), colitis or enteritis (six [7%] vs 28 [14%] comparators; p=0·094), and hepatitis (three [3%] vs 19 [9%]; p=0·043).

Interpretation

Patients with pre-existing rheumatoid arthritis initiating immune checkpoint inhibitors had similar risk of mortality and severe immune-related AEs as matched comparators. Although patients with pre-existing rheumatoid arthritis were more likely to have immune-related AEs, this finding was mostly due to mild rheumatoid arthritis flares. These results suggest that this patient population can safely receive immune checkpoint inhibitors for cancer treatment.

Funding

None.

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.

Rheumatic Diseases Development in Patients Treated by Anti-PD1 Immune Checkpoint Inhibitors: A Single-Centre Descriptive Study

The introduction of the so-called immune checkpoint inhibitors (ICIs) substantially changed the history of cancer therapy. On the other hand, they can induce the development of rheumatic immune-related adverse events (Rh-irAEs). In the scenario of a joint oncology/rheumatology outpatient clinic, we conducted a single-centre descriptive study to define from a laboratory, clinical and therapeutic point of view, rheumatic conditions developed during anti-PD1 treatment. The study included 32 patients (M/F 16/16, median age 69, IQR 16.5). According to the international classification criteria, eight patients could be classified as affected by Rheumatoid Arthritis, one by Psoriatic Arthritis, six by Polymyalgia Rheumatica, five by systemic connective tissue diseases (two systemic lupus erythematosus, two Sjögren’s syndrome, one undifferentiated connective tissue disease). The remaining patients were diagnosed as having undifferentiated arthritis or inflammatory arthralgia. The median interval between ICIs starting and the onset of symptoms was 14 weeks (IQR 19.75). Moving to treatment, the longitudinal observation revealed that all RA, PsA and CTD patients required the introduction of treatment with DMARDs. In conclusion, the growing use of ICIs in a real-life setting confirmed the possible development of different rheumatological conditions, further emphasising the need for shared oncology/rheumatology management.

Immune Checkpoint Inhibitor Related Rheumatological Complications: Cooperation between Rheumatologists and Oncologists

In cancer, immune checkpoint inhibitors (ICIs) improve patient survival but may lead to severe immune-related adverse events (irAEs). Rheumatic irAEs are a distinct entity that are much more common in a real-life than in clinical trial reports due to their unspecific symptoms and them being a rare cause of hospitalization. This review focuses on an interdisciplinary approach to the management of rheumatic irAEs, including cooperation between oncologists, rheumatologists, and immunologists. We discuss the immunological background of rheumatic irAEs, as well as their unique clinical characteristics, differentiation from other irAEs, and treatment strategies. Importantly, steroids are not the basis of therapy, and nonsteroidal anti-inflammatory drugs should be administered in the front line with other antirheumatic agents. We also address whether patients with pre-existing rheumatic autoimmune diseases can receive ICIs and how antirheumatic agents can interfere with ICIs. Interestingly, there is a preclinical rationale for combining ICIs with immunosuppressants, particularly tumor necrosis factor α and interleukin 6 inhibitors. Regardless of the data, the mainstay in managing irAEs is interdisciplinary cooperation between oncologists and other medical specialties.

Common toxicities associated with immune checkpoint inhibitors and targeted therapy in the treatment of melanoma: A systematic scoping review

INTRODUCTION

This systematic scoping review compares the toxicities experienced by patients receiving immune checkpoint inhibitors (ICIs) or targeted therapy (TT) for stage III (resected and unresectable) and stage IV melanoma.

METHODS

OVID Medline, Embase, and PsycInfo were searched to identify Phase III trials reporting toxicities of FDA-approved ICIs and TT for advanced melanoma. AEs that were reported by ≥ 10% of patients in the evaluated trials were included.

RESULTS

Toxicity profiles of 11208 patients from 24 studies were reviewed. The rate of AEs was lower with ICIs compared to TT. However, ICIs were associated with higher rates of long-term or permanent AEs compared to TT, where toxicities generally were shortterm and reversible with treatment discontinuation.

CONCLUSION

The toxicity profiles of ICIs and TT vary substantially. Whilst the rate of AEs was lower with ICIs than during TT, it was also associated with higher rates of potentially chronic AEs.

Rheumatological adverse events secondary to immune checkpoint inhibitors

The first experiences with a group of drugs called immune checkpoint inhibitors for the treatment of cancer were described in 2010. They are currently used in many tumours, with successful survival outcomes but a new profile of adverse events. This new spectrum of immune-mediated toxicities includes an exaggerated inflammatory response of T lymphocyte and the development of autoimmune diseases or similar pathologies. Of these, of particular note are the rheumatological toxicities. This review aims to alert internists and rheumatologists to their recognition and clinical management.

Identification of outcome domains in immune checkpoint inhibitor-induced inflammatory arthritis and polymyalgia rheumatica: A scoping review by the OMERACT irAE working group

INTRODUCTION

Immune checkpoint inhibitors (ICI), increasingly used cancer therapeutics, can cause off-target inflammatory effects called immune-related adverse events (irAEs), including ICI-induced inflammatory arthritis (ICI-induced IA) and polymyalgia rheumatica (ICI-induced PMR). There are no validated classification criteria or outcome measures for these conditions, and adaptation of treatment recommendations from corresponding rheumatic diseases may not be appropriate. We summarized clinical descriptors of ICI-induced IA and ICI-induced PMR and aggregated domains used for these conditions in order to inform the development of a core set of outcome domains.

METHODS

As the initial step of the core domain set generation process, we systemically searched Medline (Pubmed), EMBASE, Cochrane, and CINHL through March 2021 to identify all studies that provide both clinical descriptions and domains relevant to ICI-induced IA and ICI-induced PMR. Domains were mapped to core areas, such as pathophysiological manifestations, life impact, resource use, and longevity/survival, as suggested by the OMERACT 2.1 Filter.

RESULTS

We identified 69 publications, over a third of which utilized non-specific diagnoses of "arthritis," "arthralgia," and/or "PMR". Other publications provided the number, the distribution and/or names of specific joints affected, while others labeled the irAE as the corresponding rheumatic disease, such as rheumatoid arthritis or spondyloarthritis. Most distinct domains mapped to the pathophysiology/manifestations core area (24 domains), such as signs/symptoms (13 domains), labs (6 domains), and imaging (5 domains), with harm domains of adverse effects from irAE treatment and fear of irAE treatment decreasing ICI efficacy. Forty-three publications also referenced irAE treatment and 35 subsequent response, as well as 32 tumor response.

CONCLUSION

There is considerable heterogeneity in the domains used to clinically characterize ICI-induced IA and ICI-induced PMR. There were several domains mapped to the pathophysiologic manifestations core area, although several publications highlighted domains evenly distributed among the other core areas of life impact, longevity/survival and resource use.

Implication of the Gut Microbiome and Microbial-Derived Metabolites in Immune-Related Adverse Events: Emergence of Novel Biomarkers for Cancer Immunotherapy

Immune checkpoint inhibitors (ICIs) have changed how we think about tumor management. Combinations of anti-programmed death ligand-1 (PD-L1) immunotherapy have become the standard of care in many advanced-stage cancers, including as a first-line therapy. Aside from improved anti-tumor immunity, the mechanism of action of immune checkpoint inhibitors (ICIs) exposes a new toxicity profile known as immune-related adverse effects (irAEs). This novel toxicity can damage any organ, but the skin, digestive and endocrine systems are the most frequently afflicted. Most ICI-attributed toxicity symptoms are mild, but some are severe and necessitate multidisciplinary side effect management. Obtaining knowledge on the various forms of immune-related toxicities and swiftly changing treatment techniques to lower the probability of experiencing severe irAEs has become a priority in oncological care. In recent years, there has been a growing understanding of an intriguing link between the gut microbiome and ICI outcomes. Multiple studies have demonstrated a connection between microbial metagenomic and metatranscriptomic patterns and ICI efficacy in malignant melanoma, lung and colorectal cancer. The immunomodulatory effect of the gut microbiome can have a real effect on the biological background of irAEs as well. Furthermore, specific microbial signatures and metabolites might be associated with the onset and severity of toxicity symptoms. By identifying these biological factors, novel biomarkers can be used in clinical practice to predict and manage potential irAEs. This comprehensive review aims to summarize the clinical aspects and biological background of ICI-related irAEs and their potential association with the gut microbiome and metabolome. We aim to explore the current state of knowledge on the most important and reliable irAE-related biomarkers of microbial origin and discuss the intriguing connection between ICI efficacy and toxicity.

Immune-related adverse events in checkpoint blockade: Observations from human tissue and therapeutic considerations

Checkpoint inhibitors (CPIs) are monoclonal antibodies which, by disrupting interactions of immune checkpoint molecules with their ligands, block regulatory immune signals otherwise exploited by cancers. Despite revolutionary clinical benefits, CPI use is associated with an array of immune-related adverse events (irAEs) that mirror spontaneous autoreactivity. Severe irAEs necessitate pausing or stopping of CPI therapy and use of corticosteroids and/or other immunomodulatory interventions. Despite increasingly widespread CPI use, irAE pathobiology remains poorly understood; its elucidation may point to targeted mitigation strategies and uncover predictive biomarkers for irAE onset in patients, whilst casting new light on mechanisms of spontaneous immune-mediated disease. This review focuses on common CPI-induced irAEs of the gut, skin and synovial joints, and how these compare to immune-mediated diseases such as ulcerative colitis, vitiligo and inflammatory arthritis. We review current understanding of the immunological changes reported following CPI therapy at the level of peripheral blood and tissue. Many studies highlight dysregulation of cytokines in irAE-affected tissue, particularly IFNγ and TNF. IrAE-affected tissues are also predominantly infiltrated by T-cells, with low B-cell infiltration. Whilst there is variability between studies, patients treated with anti-programmed cell death-1 (PD-1)/PDL-1 therapies seem to exhibit CD8+ T-cell dominance, with CD4+ T-cells dominating in those treated with anti-cytotoxic T-lymphocyte-associated protein 4 (CTLA-4) monotherapy. Interestingly, CD8+CXCR3+ T-cells have been reported to be elevated in gastrointestinal, dermatological and musculoskeletal -irAE affected tissues. These findings may highlight potential opportunities for therapeutic development or re-deployment of existing therapies to prevent and/or improve the outcome of irAEs.

[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.

Imaging assessment of toxicity related to immune checkpoint inhibitors

In recent years, a wide range of cancer immunotherapies have been developed and have become increasingly important in cancer treatment across multiple oncologic diseases. In particular, immune checkpoint inhibitors (ICIs) offer promising options to improve patient outcomes. However, a major limitation of these treatments consists in the development of immune-related adverse events (irAEs) occurring in potentially any organ system and affecting up to 76% of the patients. The most frequent toxicities involve the skin, gastrointestinal tract, and endocrine system. Although mostly manageable, potentially life-threatening events, particularly due to neuro-, cardiac, and pulmonary toxicity, occur in up to 30% and 55% of the patients treated with ICI-monotherapy or -combination therapy, respectively. Imaging, in particular computed tomography (CT), magnetic resonance imaging (MRI), and 2-deoxy-2-[¹⁸F]fluoro-D-glucose positron emission tomography/computed tomography (¹⁸F-FDG-PET/CT), plays an important role in the detection and characterization of these irAEs. In some patients, irAEs can even be detected on imaging before the onset of clinical symptoms. In this context, it is particularly important to distinguish irAEs from true disease progression and specific immunotherapy related response patterns, such as pseudoprogression. In addition, there are irAEs which might be easily confused with other pathologies such as infection or metastasis. However, many imaging findings, such as in immune-related pneumonitis, are nonspecific. Thus, accurate diagnosis may be delayed underling the importance for adequate imaging features characterization in the appropriate clinical setting in order to provide timely and efficient patient management. ¹⁸F-FDG-PET/CT and radiomics have demonstrated to reliably detect these toxicities and potentially have predictive value for identifying patients at risk of developing irAEs. The purpose of this article is to provide a review of the main immunotherapy-related toxicities and discuss their characteristics on imaging.

Musculoskeletal immune-related adverse events in 927 patients treated with immune checkpoint inhibitors for solid cancer

OBJECTIVE

The prevalence of the musculoskeletal immune-related adverse events (irAEs) is probably underestimated, as most studies report only severe side effects. Our aim was to describe and characterize all musculoskeletal irAEs in a large cohort of patients treated with immune checkpoint inhibitors (ICI).

METHODS

We conducted a retrospective study among patients who received ICI from 07/27/2014 to 05/08/2020 at the medical oncology department of the Institut Paoli-Calmettes, Marseille, France. All medical files were systemically reviewed by a rheumatologist who collected clinical features, time of occurrence, treatment regimen, irAEs management, course and outcomes. We also assessed tumor response 3 months after introduction of ICI, according to severity and treatments used to manage musculoskeletal irAEs.

RESULTS

Among 927 patients treated with ICI for a solid tumor, 118 patients (12.7%) presented a musculoskeletal irAE. Their median age was 66.5, 61% were male, and they mainly had a lung (57.6%) or urological cancer (27.1%). The most frequently involved ICI was an anti PD-1. Arthralgias and myalgias were the most frequent musculoskeletal irAEs (9.8%) and inflammatory rheumatic features were reported in 36 patients (3.9%) with elevated acute phase reactants and negative immunological markers. The median time of onset was 2 months (IC 95% 1.8; 2.7). Tumor response at 3 months did not differ according to musculoskeletal irAE severity, type of manifestation (arthralgias/myalgias versus inflammatory rheumatic features), pain patterns (mechanical versus inflammatory) or irAE treatments.

CONCLUSION

Musculoskeletal irAEs in this large cohort of patients treated with ICI were frequent (12.7%), mostly mild and well tolerated.

Immunopathogenesis of Immune Checkpoint Inhibitor Induced Myocarditis: Insights from Experimental Models and Treatment Implications

Despite the extraordinary success of immune checkpoint inhibitors (ICIs) in cancer treatment, their use is associated with a high incidence of immune-related adverse events (IRAEs), resulting from therapy-related autoimmunity against various target organs. ICI-induced myocarditis is one of the most severe forms of IRAE, which is associated with risk of hemodynamic compromise and mortality. Despite increasing recognition and prompt treatment by clinicians, there remain significant gaps in knowledge regarding the pathophysiology, diagnosis and treatment of ICI-induced myocarditis. As the newly emerged disease entity is relatively rare, it is challenging for researchers to perform studies involving patients at scale. Alternatively, mouse models have been developed to facilitate research understanding of the pathogenesis of ICI-induced myocarditis and drug discovery. Transgenic mice with immune checkpoint genes knocked out allow induction of myocarditis in a highly reproducible manner. On the other hand, it has not been possible to induce ICI-induced myocarditis in wild type mice by injecting ICIs monotherapy alone. Additional interventions such as combinational ICI, tumor inoculation, cardiac sarcomere immunization, or cardiac irradiation are necessary to mimic the underlying pathophysiology in human cancer patients and to induce ICI-induced myocarditis successfully. This review focuses on the immunopathogenesis of ICI-induced myocarditis, drawing insights from human studies and animal models, and discusses the potential implications for treatment.

Side Effects of Cancer Immunotherapies: Dermatologic and Rheumatologic Toxicities

Dermatologic and rheumatologic toxicities are frequent adverse events during treatment with immune checkpoint inhibitors in oncology. Timely identification of these events and the referral to the oncologist or dermatologist are important in daily practice, such an organ damage involvements can be severe and sometimes life-threatening. The diagnosis and management of cutaneous toxicities, such as maculopapular rash and bullous dermatitis in particular, must be based on the body surface affected by skin lesions. Corticosteroids are basic treatment in moderate to severe cases. Rheumatologic toxicities are rarer and more heterogeneous, and they are often underestimated. They can occur in the absence of autoantibodies, and myositis can be life-threatening.

Emerging Trends in Radionuclide Imaging of Infection and Inflammation in Pediatrics: Focus on FDG PET/CT and Immune Reactivity

The most common indication for ¹⁸F-FDG PET/CT is tumor imaging, which may be performed for initial diagnosis, staging, therapeutic response monitoring, surveillance, or suspected recurrence. In the routine practice of pediatric nuclear medicine, most infectious, inflammatory, and autoimmune processes that are detected on ¹⁸F-FDG PET/CT imaging - except for imaging in fever or inflammation of unknown origin - are coincidental and not the main indication for image acquisition. However, interpreting these "coincidental" findings is of utmost importance to avoid erroneously attributing these findings to a neoplastic process. We review the recent literature on fever of unknown origin as well as inflammation of unknown origin in pediatrics and then focus on the ¹⁸F FDG PET/CT imaging findings seen in two specific entities with increased immune reactivity: hemophagocytic lymphohistiocytosis syndrome and the immune-related adverse events associated with checkpoint inhibitors. We will subsequently close with two sections highlighting related topics and relevant references for further reading.

A Review of Immune Checkpoint Blockade for the General Surgeon

The immune system is a complex and interconnected system that has evolved to protect its host from foreign pathogens. CD8+ T cells are a type of immune cell that can be directly lethal to tumor cells. However, their tumor killing capabilities can be inhibited by checkpoint molecules. During the last decade, the development of medications that block these checkpoint molecules has revolutionized treatment for some cancer types and indications for use continue to grow. As usage of immunotherapy increases, toxicities and adverse events unique to immunotherapy are becoming more prevalent. Here, we review the commonly targeted inhibitory molecules along with their food and drug administration-approved indications in various cancer therapeutic regimens, immunotherapy-related toxicities, and how this may impact surgical planning.

Treatment of rheumatic adverse events of cancer immunotherapy

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

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.

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.