Studying Outcomes after Steroid-Sparing Immunosuppressive Agent vs. Steroid-Only Treatment for Immune-Related Adverse Events in Non-Small-Cell Lung Cancer (NSCLC) and Melanoma: A Retrospective Case-Control Study.

BACKGROUND: The effects of steroid-sparing immunosuppressive agents (SSIAs), used for the treatment of immune-related adverse events (irAEs), on immune checkpoint inhibitor (ICI) antitumor activity is not well known. We compared tumor outcomes of patients who received corticosteroid monotherapy (CS) versus a corticosteroid plus SSIA (CS-SSIA) for irAE treatment, using statistical methods to address immortal time bias. METHODS: We conducted a retrospective case-control study on patients ≥ 18 years with melanoma or non-small-cell lung cancer (NSCLC) treated with ≥1 ICI at a quaternary care center between 1 January 2016 and 11 January 2021. Patients were divided into two cohorts: CS or CS-SSIA. We used propensity score nearest-neighbor matching to match on tumor type, stage, and prior lines of therapy. Primary outcomes were progression-free survival (PFS) and overall survival (OS). Secondary outcomes included the time from the start of the irAE treatment to the irAE resolution. Hazard ratios (HRs) for PFS and OS were calculated using the Cox proportional hazard regression method with both (1) the time to the steroid and SSIA as time-varying covariates and (2) a binary exposure classification not accounting for the time to the treatment. RESULTS: A total of 167 patients were included after matching (132 in the CS cohort and 35 in the CS-SSIA cohort). Sixty-six percent of all the patients had melanoma. The most common irAEs requiring treatment were gastroenterocolitis and hepatitis. In an adjusted analysis not accounting for immortal time bias, there were no significant differences in PFS (HR 0.75, 95% CI [0.46-1.23]) or OS (HR 0.82, 95% CI [0.46-1.47]). In analyses using a time-varying treatment indicator, there was a trend toward improved PFS in patients treated with SSIAs (HR 0.54, CI 0.26-1.10). There was no difference in OS (HR 1.11, CI 0.55-2.23). Patients with melanoma who specifically received infliximab had improved PFS compared to patients with CS only, after adjusting for immortal time bias (HR 0.32, CI 0.24-0.43). CONCLUSIONS: The use of SSIAs with CS did not have worse outcomes than CS monotherapy. In melanoma, our findings showed improved PFS for the use of infliximab versus steroid monotherapy for irAEs. Large, prospective, randomized controlled trials are needed to confirm these findings and guide the optimal treatment of irAEs.

Current and future advances in practice: aromatase inhibitor-induced arthralgia.

Aromatase inhibitors (AIs) have shown great success as adjuvant therapy for post-menopausal women with hormone receptor-positive breast cancers. AI-induced arthralgia (AIA) is a frequent AI toxicity contributing to non-adherence and discontinuation. This review aims to understand current knowledge of AIA. The mean incidence of AIA was 39.1% and the mean discontinuation of AI therapy due to AIA was 9.3%. Most of the AIAs were non-inflammatory. A shorter time since the last menstrual period and pre-existing joint pain were risk factors. Vitamin D3 supplementation may be a preventative measure and treatment with duloxetine, acupuncture and/or exercise is supported by large randomized controlled trials. There was consistent improvement in AIAs with switching to an alternate AI, and this could additionally allow continuation of cancer treatment with AI. Further research is needed to identify predictive biomarkers, better characterize AIA subcategories and study more reliable therapeutic options.

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.

Immunotherapy Toxicity Management in Clinical Practice: Building the Clinical Infrastructure for Immune-related Adverse Event Evaluation and Care.

Cancer immunotherapy is revolutionary for survival but has complications due to immunogenicity with unpredictable and potentially long-lasting autoimmune side effects known as immune-related adverse events (irAEs). Currently, treatment beyond corticosteroids can be complicated by the diversity of providers who are needed across a variety of clinical settings to manage irAEs. We outline the role of critical players in the management of irAEs, discuss the current limitations that exist, and propose various methodologies that can be adapted across clinical settings to tackle these needs. We aim to better understand who can be affected by irAEs and tailor diagnostics and therapeutics appropriately.

Immune Checkpoint Inhibitors and Lupus Erythematosus.

Immune checkpoint inhibitors (ICIs) are the standard of care for a growing number of malignancies. Unfortunately, they are associated with a broad range of unique toxicities that mimic the presentations of primary autoimmune conditions. These adverse events are termed immune-related adverse events (irAEs), of which ICI-lupus erythematosus (ICI-LE) constitutes a small percentage. Our review aims to describe the available literature on ICI-LE and ICI treatment for patients with pre-existing lupus. Most diagnoses of ICI-LE had findings of only cutaneous lupus; four diagnoses of ICI-LE had systemic lupus manifestations. Over 90% (27 of 29) of cases received anti-PD-1/PDL-1 monotherapy, 1 received combination therapy, and 1 received only anti-CTLA-4 treatment. About three-fourths (22 of 29 or 76%) of patients with ICI-lupus were managed with topical steroids, 13 (45%) received hydroxychloroquine, and 10 (34%) required oral corticosteroids. In our case series, none of the patients with pre-existing lupus receiving ICI therapy for cancer had a flare of their lupus, but few had de novo irAE manifestations, all of which were characterized as low-grade. The review of the literature yielded seven ICI-LE flares from a total of 27 patients with pre-existing lupus who received ICI. Most flares were manageable without need for ICI cessation.

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.

JAK inhibitors and black box warnings: what is the future for JAK inhibitors?

INTRODUCTION: Janus kinase inhibitors (JAKi) have dramatically improved the treatment of various autoimmune and myeloproliferative disorders. Recently, concern has arisen regarding their safety in patients with rheumatoid arthritis. AREAS COVERED: Here, we provide a comprehensive summary of the major current and emerging JAKi and their indications, address recent studies on comparative safety, and provide insight into their future and use. We emphasize that the application of the research findings on a case-by-case basis should consider a patient's age, comorbidities, disease for which JAKi is being considered, disease activity, the JAKi target(s), alternate treatment options available for the patient, and the planned duration of JAKi. EXPERT OPINION: Rheumatologists are used to prescribing therapies in which a risk-to-benefit assessment is required as well as to screening and monitoring the safety of medications. Thus, rheumatologists are already practiced in applying specific criteria to effectively screen and monitor patients who are candidates for JAKi therapy. Ongoing research will help to clarify any mechanisms underlying differential safety signals between JAK and other therapies, what the balance between risk and efficacy is, who the susceptible subpopulations are, and whether safety signals are shared between different JAKis and across indications.

Managing Cardiovascular and Cancer Risk Associated with JAK Inhibitors.

Janus kinase inhibitors (JAKi) have enormous appeal as immune-modulating therapies across many chronic inflammatory diseases, but recently this promise has been overshadowed by questions regarding associated cardiovascular and cancer risk emerging from the ORAL Surveillance phase 3b/4 post-marketing requirement randomized controlled trial. In that study of patients with rheumatoid arthritis with existing cardiovascular risk, tofacitinib, the first JAKi registered for chronic inflammatory disease, failed to meet non-inferiority thresholds when compared with tumor necrosis factor inhibitors for both incident major adverse cardiovascular events and incident cancer. While this result was unexpected by many, subsequently published observational data have also supported this finding. Notably, however, such a risk has largely not yet been demonstrated in patients outside the specific clinical situation examined in the trial, even in the face of many studies examining this. Nevertheless, this signal has practically re-aligned approaches to both tofacitinib and other JAKi to varying extents, in other patient populations and contexts: within rheumatoid arthritis, but also in psoriatic arthritis, axial spondyloarthritis, inflammatory bowel disease, atopic dermatitis, and beyond. Application to individual patients can be more challenging but remains important to harness the substantive potential of JAKi to the maximum extent safely possible. This review not only explores the evolution of the regulatory response to the signal, its informing data, biological plausibility, and its impact on guidelines, but also the many factors that clinicians must consider in navigating cardiovascular and cancer risk for their patients considering JAKi as immune-modulating therapy.

Checkpoint Inhibitor-Associated Scleroderma and Scleroderma Mimics.

Immune checkpoint inhibitors (ICI) are the standard of care for various malignancies and have been associated with a wide spectrum of complications that are phenotypically akin to primary autoimmune diseases. While the literature on these toxicities is growing, there is a paucity of data regarding ICI-associated scleroderma which can carry significant morbidity and limit the ability to continue effective ICI therapy. Our review aimed to analyze the current literature on ICI-associated systemic scleroderma (ICI-SSc) and key scleroderma mimics. Cases of ICI-SSc had notable differences from primary SSc, such as fewer vascular features and less seropositivity (such as scleroderma-specific antibodies and antinuclear antibodies). We found that patients with a diagnosis of SSc prior to the start of ICI can also experience flares of pre-existing disease after ICI treatment used for their cancer. Regarding scleroderma mimics, several cases of ICI-eosinophilic fasciitis have also been described with variable clinical presentations and courses. We found no cases of scleroderma mimics: ICI-scleromyxedema or ICI-scleroedema. There is a critical need for multi-institutional efforts to collaborate on developing a patient database and conducting robust, prospective research on ICI-scleroderma. This will ultimately facilitate more effective clinical evaluations and management for ICI-scleroderma.

Anticitrullinated peptide antibody epitope expansion and the HLA DRB1 'shared epitope' are less common in seropositive checkpoint inhibitor-induced inflammatory arthritis than in longstanding rheumatoid arthritis.

BACKGROUND: Immune checkpoint inhibitors (ICI) can potentially cause ICI-inflammatory arthritis (ICI-IA), which often resembles rheumatoid arthritis (RA). In this study, we examined the degree of anticitrullinated peptide antibodies (ACPA) epitope expansion in CCP+ICI-IA and patients with RA. METHODS: We used clinical data and serum from ICI-IA and patients with RA with early disease as well as longstanding disease. A custom, bead-based antigen array was used to identify IgG ACPA reactivities to 18 putative RA-associated citrullinated proteins. Hierarchical clustering software was used to create a heatmap to identify ACPA levels. Additionally, HLA DRB1 typing was performed on ICI-IA patients as well as controls of patients treated with ICI that did not develop ICI-IA (ICI controls). RESULTS: Compared to patients with CCP+RA, patients with CCP+ICI-IA were older (p<0.001), less likely to have positive rheumatoid factor (p<0.001) and had a shorter duration of symptoms (p<0.001). There were less ACPA levels and a lower number of distinct ACPA epitopes in the serum of patients with ICI-IA compared with longstanding patients with RA (p<0.001). Among those tested for HLA DRB1, there were no differences in the frequency of the shared epitope between those with ICI-IA and ICI controls. CONCLUSION: Patients with ICI-IA had lower ACPA titres and targeted fewer ACPA epitopes than longstanding patients with RA, and there were no significant differences in the presence of the shared epitope between those that developed ICI-IA and ICI controls. It remains to be determined if ICI-IA represents an accelerated model of RA pathogenesis with ICI triggering a transition from preclinical to clinical disease.

Abnormalities on baseline chest imaging are risk factors for immune checkpoint inhibitor associated pneumonitis.

BACKGROUND: Chronic lung disease is a proposed risk factor for immune checkpoint inhibitor pneumonitis (ICI-pneumonitis); however, data is sparse regarding the impact of pre-existing lung disease and baseline chest imaging abnormalities on the risk of developing ICI-pneumonitis. METHODS: We conducted a retrospective cohort study of patients with ICI treatment for cancer from 2015 to 2019. ICI-pneumonitis was determined by the treating physician with corroboration via an independent physician review and exclusion of alternative etiologies. Controls were patients treated with ICI without a diagnosis of ICI-pneumonitis. Fisher's exact tests, Student's t-tests, and logistic regression were used for statistical analysis. RESULTS: We analyzed 45 cases of ICI-pneumonitis and 135 controls. Patients with abnormal baseline chest CT imaging (emphysema; bronchiectasis; reticular, ground glass and/or consolidative opacities) had increased risk for ICI-pneumonitis (OR 3.41, 95%CI: 1.68-6.87, p = 0.001). Patients with gastroesophageal reflux disease (GERD) (OR 3.83, 95%CI: 1.90-7.70, p = < 0.0001) also had increased risk for ICI-pneumonitis. On multivariable logistic regression, patients with abnormal baseline chest imaging and/or GERD remained at increased risk for ICI-pneumonitis. Eighteen percent of all patients (32/180) had abnormal baseline chest CT consistent with chronic lung disease without a documented diagnosis. CONCLUSION: Patients with baseline chest CT abnormalities and GERD were at increased risk for developing ICI-pneumonitis. The large proportion of patients with baseline radiographic abnormalities without a clinical diagnosis of chronic lung disease highlights the importance of multidisciplinary evaluation prior to ICI initiation.

Comparative safety and effectiveness of TNF inhibitors, IL6 inhibitors and methotrexate for the treatment of immune checkpoint inhibitor-associated arthritis.

OBJECTIVES: To compare the safety and effectiveness of biologic and conventional disease-modifying antirheumatic drugs (DMARDs) for immune checkpoint inhibitor-associated inflammatory arthritis (ICI-IA). METHODS: The retrospective multicentre observational study included patients with a diagnosis of ICI-IA treated with a tumour necrosis factor inhibitor (TNFi), interleukin-6 receptor inhibitor (IL6Ri) and/or methotrexate (MTX); patients with pre-existing autoimmune disease were excluded. The primary outcome was time to cancer progression from ICI initiation; the secondary outcome was time to arthritis control from DMARD initiation. Cox proportional hazard models were used to compare medication groups, adjusting for confounders. RESULTS: 147 patients were included (mean age 60.3 (SD 11.9) years, 66 (45%) women). ICI-IA treatment was TNFi in 33 (22%), IL6Ri 42 (29%) and MTX 72 (49%). After adjustment for time from ICI initiation to DMARD initiation, time to cancer progression was significantly shorter for TNFi compared with MTX (HR 3.27 (95% CI 1.21 to 8.84, p=0.019)) while the result for IL6Ri was HR 2.37 (95% CI 0.94 to 5.98, p=0.055). Time to arthritis control was faster for TNFi compared with MTX (HR 1.91 (95% CI 1.06 to 3.45, p=0.032)) while the result for IL6Ri was HR 1.66 (95% CI 0.93 to 2.97, p=0.089). A subset analysis in patients with melanoma gave similar results for both cancer progression and arthritis control. CONCLUSION: The treatment of ICI-IA with a biologic DMARD is associated with more rapid arthritis control than with MTX, but may be associated with a shorter time to cancer progression.

Role-Specific Curricular Needs for Identification and Management of Immune-Related Adverse Events.

Immune checkpoint inhibitors (ICIs) activate the immune system against cancer and have become standard of care for many cancers. With increased ICI use, their toxicities known as immune-related adverse events (irAEs) are becoming more common, but it is unclear how prepared relevant clinicians feel to diagnose and treat irAEs. The objective of this study was to assess irAE knowledge, confidence, and experience among generalists and oncology clinicians to guide future curricular interventions related to irAEs. A 25-item survey with questions assessing knowledge, experience level, confidence, and resource utilization regarding irAE diagnosis and management was sent to University of Chicago-affiliated (UChicago) internal medicine residents and hospitalists (inpatient irAE management) along with UChicago oncology fellows, attendings, nurse practitioners (NPs), and physician assistants (PAs) (inpatient and outpatient) as well as Chicago community oncologists (outpatient) in June 2022. Overall response rate was 37% (171/467). Knowledge scores averaged below 70% for all clinicians. "No idea" responses were most common with knowledge questions on steroid-sparing agent use and ICI use for patients with preexisting autoimmune disease. IrAE experience correlated with higher knowledge for oncology attendings (p = 0.015) and hematology/oncology NPs/PAs (p = 0.031). IrAE experience correlated with higher confidence for residents (p = 0.026), oncology fellows (p = 0.047), and hematology/oncology NPs/PAs (p = 0.042). Most commonly utilized resources were colleagues and UpToDate, and most clinicians were very likely to use online resources in the future. Knowledge and confidence gaps exist, and they were somewhat mitigated by experience. Future irAE curricula can fill these needs through online role-specific resources: irAE identification for generalists versus irAE identification and management for oncologists.

Association Between Rheumatic Autoantibodies and Immune-Related Adverse Events.

BACKGROUND: Side effects of immune checkpoint inhibitors (ICIs), called immune-related adverse events (irAEs), closely resemble primary autoimmune or rheumatic diseases. We aimed to understand the clinical utility of rheumatic autoantibodies (rhAbs) for diagnosing irAEs. PATIENTS AND METHODS: Patients without pre-existing autoimmune disease (pAID) who had cancer treated with ICI(s) treatment from 1/1/2011 to 12/21/2020 and a rhAb checked were retrospectively identified. Logistic regression assessed associations between autoantibodies and irAEs, cancer outcome, and survival. Specificity, sensitivity, and positive/negative predictive values (PPV, NPV) were estimated for key rhAbs and ICI-arthritis. Kaplan-Meier analyzed objective response rate (ORR) and overall survival (OS). RESULTS: A total of 2662 patients were treated with≥1 ICIs. One hundred and thirty-five without pAID had ≥ 1 rhAb tested. Of which 70/135(52%) were female; median age at cancer diagnosis was 62 years with most common cancers: melanoma (23%) or non-small cell lung cancer (21%), 96/135 (75%) were anti-PD1/PDL1 treated. Eighty had a rhAb ordered before ICI, 96 after ICI, and 12 before and after. Eighty-two (61%) experienced an irAE, 33 (24%) with rheumatic-irAE. Pre-ICI RF showed significant association with rheumatic-irAEs (OR = 25, 95% CI, 1.52-410.86, P = .024). Pre- and post-ICI RF yielded high specificity for ICI-arthritis (93% and 78%), as did pre- and post-ICI CCP (100% and 91%). Pre-ICI RF carried 93% NPV and pre-ICI CCP had 89% PPV for ICI-arthritis. No variables were significantly correlated with ORR. Any-type irAE, rheumatic-irAE and ICI-arthritis were all associated with better OS (P = .000, P = .028, P = .019). CONCLUSIONS: Pre-ICI RF was associated with higher odds of rheumatic-irAEs. IrAEs had better OS; therefore, clinical contextualization for rhAbs is critical to prevent unnecessary withholding of lifesaving ICI for fear of irAEs.

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.

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

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

Activated osteoarthritis following immune checkpoint inhibitor treatment: an observational study.

Immune checkpoint inhibitors (ICIs) have revolutionized cancer therapy but can result in toxicities, known as immune-related adverse events (irAEs), due to a hyperactivated immune system. ICI-related inflammatory arthritis has been described in literature, but herewith we introduce and characterize post-ICI-activated osteoarthritis (ICI-aOA). We conducted a multicenter, retrospective, observational study of patients with cancer treated with ICIs and diagnosed with ICI-aOA by a rheumatologist. ICI-aOA was defined by (1) an increase in non-inflammatory joint pain after ICI initiation, (2) in joints characteristically affected by osteoarthritis, and (3) lack of inflammation on exam. Cases were graded using the Common Terminology Criteria for Adverse Events (CTCAE) V.6.0 rubric for arthralgia. Response Evaluation Criteria in Solid Tumors V.1.1 (v.4.03) guidelines determined tumor response. Results were analyzed using χ2 tests of association and multivariate logistic regression. Thirty-six patients had ICI-aOA with a mean age at time of rheumatology presentation of 66 years (51-81 years). Most patients had metastatic melanoma (10/36, 28%) and had received a PD-1/PD-L1 inhibitor monotherapy (31/36, 86%) with 5/36 (14%) combination therapy. Large joint involvement (hip/knee) was noted in 53% (19/36), small joints of hand 25% (9/36), and spine 14% (5/36). Two-thirds (24/36) suffered multiple joint involvement. Three of 36 (8%) had CTCAE grade 3, 14 (39%) grade 2 and 19 (53%) grade 1 manifestations. Symptom onset ranged from 6 days to 33.8 months with a median of 5.2 months after ICI initiation; five patients suffered from ICI-aOA after ICI cessation (0.6, 3.5, 4.4, 7.3, and 15.4 months after ICI cessation). The most common form of therapy was intra-articular corticosteroid injections only (15/36, 42%) followed by non-steroidal anti-inflammatory drugs only (7/36, 20%). Twenty patients (56%) experienced other irAEs, with rheumatic and dermatological being the most common. All three patients with high-grade ICI-aOA also had another irAE diagnosis at some point after ICI initiation. ICI-aOA should be recognized as an adverse event of ICI immunotherapy. Early referral to a rheumatologist can facilitate the distinction between ICI induced inflammatory arthritis from post-ICI mechanical arthropathy, the latter of which can be managed with local therapy that will not compromise ICI efficacy.

Successful treatment of squamous cell carcinoma arising from a presumed ovarian mature cystic teratoma with pembrolizumab.

•Metastatic SCC arising from the ovary is rare, and the optimal treatment is unknown.•Pembrolizumab successfully treated a patient with metastatic SCC.•Patients on pembrolizumab should be monitored for immune-related adverse events.