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.

Altered serum metabolome as an indicator of paraneoplasia or concomitant cancer in patients with rheumatic disease

OBJECTIVES

A timely diagnosis is imperative for curing cancer. However, in patients with rheumatic musculoskeletal diseases (RMDs) or paraneoplastic syndromes, misleading symptoms frequently delay cancer diagnosis. As metabolic remodelling characterises both cancer and RMD, we analysed if a metabolic signature can indicate paraneoplasia (PN) or reveal concomitant cancer in patients with RMD.

METHODS

Metabolic alterations in the sera of rheumatoid arthritis (RA) patients with (n=56) or without (n=52) a history of invasive cancer were quantified by nuclear magnetic resonance analysis. Metabolites indicative of cancer were determined by multivariable regression analyses. Two independent RA and spondyloarthritis (SpA) cohorts with or without a history of invasive cancer were used for blinded validation. Samples from patients with active cancer or cancer treatment, pulmonary and lymphoid type cancers, paraneoplastic syndromes, non-invasive (NI) precancerous lesions and non-melanoma skin cancer and systemic lupus erythematosus and samples prior to the development of malignancy were used to test the model performance.

RESULTS

Based on the concentrations of acetate, creatine, glycine, formate and the lipid ratio L1/L6, a diagnostic model yielded a high sensitivity and specificity for cancer diagnosis with AUC=0.995 in the model cohort, AUC=0.940 in the blinded RA validation cohort and AUC=0.928 in the mixed RA/SpA cohort. It was equally capable of identifying cancer in patients with PN. The model was insensitive to common demographic or clinical confounders or the presence of NI malignancy like non-melanoma skin cancer.

CONCLUSIONS

This new set of metabolic markers reliably predicts the presence of cancer in arthritis or PN patients with high sensitivity and specificity and has the potential to facilitate a rapid and correct diagnosis of malignancy.

[The subanalysis of Rheuma-VOR demonstrates a considerable need for rheumatological care]

BACKGROUND

Early diagnosis and treatment of inflammatory rheumatic diseases can prevent consequential damage such as permanently limited mobility and joint or organ damage. Simultaneously, there is an increasing deficit in medical care owing to the lack of rheumatological capacity. Rural regions are particularly affected.

OBJECTIVES

The available unconfirmed diagnoses of the study Rheuma-VOR were analysed regarding another definitive inflammatory rheumatic disease.

MATERIALS AND METHODS

The returned questionnaires of the rheumatologists participating in Rheuma-VOR were screened for definitive inflammatory rheumatic diseases other than the required diagnosis of rheumatoid arthritis, psoriatic arthritis or spondyloarthritis.

RESULTS

Of 910 unconfirmed diagnoses, in 245 patients another definitive diagnosis could be confirmed. A total of 29.8% of the diagnoses corresponded to degenerative joint changes or chronic pain syndrome, whereas 26.1% involved different forms of inflammatory arthritis. The majority of diagnoses (40.5%) were collagenosis or vasculitis, DISCUSSION: The available data show that a rheumatological presentation was indicated for the majority of patients. Owing to the increasing deficits in medical care a prior selection of the patients is crucial to make optimal use of restricted rheumatological capacities.

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.