Difficult-to-treat rheumatoid arthritis (D2T RA): clinical issues at early stages of disease

Difficult-to-treat rheumatoid arthritis: what have we learned and what do we still need to learn?

Difficult-to-treat RA (D2T RA) is an area of high unmet need. The prevalence reported in the first D2T RA cohort studies ranged from 5.5% to 27.5%. Key to the definition is a conviction by the patient and/or rheumatologist that disease management has become problematic and failure of at least two biological or targeted synthetic DMARDs. D2T RA is a multifactorial disease state which was reflected in data from D2T RA cohort studies: these pointed towards high prevalence of comorbidities and/or lower socioeconomic status in D2T RA subgroups, while others had persistent symptoms without these factors being present. A holistic approach is necessary to identify the root problems underlying D2T RA in individual patients. In this review, biological and non-biological drivers that should be considered to be optimized will be discussed in view of what we have learned from patient data emerging from the first D2T RA cohort studies.

Timely escalation to second-line therapies after failure of methotrexate in patients with early rheumatoid arthritis does not reduce the risk of becoming difficult-to-treat

BACKGROUND

To investigate the frequency of difficult-to-treat (D2T) rheumatoid arthritis (RA) in patients early escalated to biologic/targeted synthetic disease modifying anti-rheumatic drugs (b/tsDMARDs) after failure of treat-to-target with methotrexate (MTX).

METHODS

From a prospective cohort of early RA, all patients with their first access in the years 2005-2018, and eventually starting a b/tsDMARD before the end of 2022, were included and followed-up until April 2024. Study outcomes included drug survival on each consecutive b/tsDMARDs, development of D2T (according to the EULAR definition and subsequent modifications), and its predictors.

RESULTS

Of a total cohort of 722 early RA patients treated with initial MTX and followed-up for at least 3 years from diagnosis, 155 (21.5%) had started a b/tsDMARD after a median of 19 months. In more than 70% of the cases, RA was uncontrolled despite optimal doses of MTX of ≥ 15 mg/day. The retention rates of the first and the second b/tsDMARD were approximatively 70% after 1 year but dropped to 40% after 5 years. After a median (IQR) follow up of 72.6 (34.5-134.2) months, 45 patients (29%) fulfilled the EULAR D2T criteria. At multivariable analysis, higher number of swollen joints and worse pain scores were confirmed as predictors of D2T. Furthermore, in this early RA cohort, shorter disease duration at the start of treatment with b/tsDMARDs, together with negativity for autoantibodies, were also independent predictors of D2T.

CONCLUSIONS

Early implementation of treatment after failure of treat-to-target with MTX may not prevent the development of D2T in RA. Patients showing early refractoriness to conventional drugs and those lacking autoantibodies are at higher risk of multiple treatment failures.

Emerging Role and Mechanism of Mesenchymal Stem Cells-Derived Extracellular Vesicles in Rheumatic Disease

Mesenchymal stem cells (MSCs) are pluripotent stem cells derived from mesoderm. Through cell-to-cell contact or paracrine effects, they carry out biological tasks like immunomodulatory, anti-inflammatory, regeneration, and repair. Extracellular vesicles (EVs) are the primary mechanism for the paracrine regulation of MSCs. They deliver proteins, nucleic acids, lipids, and other active compounds to various tissues and organs, thus facilitating intercellular communication. Rheumatic diseases may be treated using MSCs and MSC-derived EVs (MSC-EVs) due to their immunomodulatory capabilities, according to mounting data. Since MSC-EVs have low immunogenicity, high stability, and similar biological effects as to MSCs themselves, they are advantageous over cell therapy for potential therapeutic applications in rheumatoid arthritis, systemic erythematosus lupus, systemic sclerosis, Sjogren's syndrome, and other rheumatoid diseases. This review integrates recent advances in the characteristics, functions, and potential molecular mechanisms of MSC-EVs in rheumatic diseases and provides a new understanding of the pathogenesis of rheumatic diseases and MSC-EV-based treatment strategies.

The immunomodulatory of interleukin-33 in rheumatoid arthritis: A systematic review

Rheumatoid arthritis (RA) is a systemic chronic autoimmune disease that primarily affects the joints and surrounding soft tissues, characterized by chronic inflammation and proliferation of the synovium. Various immune cells are involved in the pathophysiology of RA. The complex interplay of factors such as chronic inflammation, genetic susceptibility, dysregulation of serum antibody levels, among others, contribute to the complexity of the disease mechanism, disease activity, and treatment of RA. Recently, the cytokine storm leading to increased disease activity in RA has gained significant attention. Interleukin-33 (IL-33), a member of the IL-1 family, plays a crucial role in inflammation and immune regulation. ST2 (suppression of tumorigenicity 2 receptor), the receptor for IL-33, is widely expressed on the surface of various immune cells. When IL-33 binds to its receptor ST2, it activates downstream signaling pathways to exert immunoregulatory effects. In RA, IL-33 regulates the progression of the disease by modulating immune cells such as circulating monocytes, tissue-resident macrophages, synovial fibroblasts, mast cells, dendritic cells, neutrophils, T cells, B cells, endothelial cells, and others. We have summarized and analyzed these findings to elucidate the pathways through which IL-33 regulates RA. Furthermore, IL-33 has been detected in the synovium, serum, and synovial fluid of RA patients. Due to inconsistent research results, we conducted a meta-analysis on the association between serum IL-33, synovial fluid IL-33, and the risk of developing RA in patients. The pooled SMD was 1.29 (95% CI: 1.15-1.44), indicating that IL-33 promotes the onset and pathophysiological progression of RA. Therefore, IL-33 may serve as a biomarker for predicting the risk of developing RA and treatment outcomes. As existing drugs for RA still cannot address drug resistance in some patients, new therapeutic approaches are needed to alleviate the significant burden on RA patients and healthcare systems. In light of this, we analyzed the potential of targeting the IL-33/ST2-related signaling pathway to modulate immune cells associated with RA and alleviate inflammation. We also reviewed IL-33 and RA susceptibility-related single nucleotide polymorphisms, suggesting potential involvement of IL-33 and macrophage-related drug-resistant genes in RA resistance therapy. Our review elucidates the role of IL-33 in the pathophysiology of RA, offering new insights for the treatment of RA.

Five-year follow-up of patients with difficult-to-treat rheumatoid arthritis

OBJECTIVES

To elucidate the long-term outcomes of patients with difficult-to-treat rheumatoid arthritis (D2T RA).

METHODS

We collected data on the clinical course of patients who had been identified as D2T RA in 2018 until 2023. We stratified the patients according to outcomes at the last visit: resolved D2T RA, persistent D2T RA, and mortality. We compared their clinical characteristics and investigated the predictive factors for the resolution of D2T RA or mortality. Furthermore, we investigated the impact of the causes of D2T RA identified in 2018, multidrug resistance, comorbidities, and socioeconomic factors on outcomes in 2023.

RESULTS

Of 173 patients identified as D2T RA in 2018, 150 were included in the analysis. Among them, D2T RA was resolved in 67 (45%), 75 (50%) remained as D2T RA, and 8 (5%) died. Patients with resolved D2T RA were significantly younger at the latest visit (p= 0.02), had a higher proportion of treatment changes during five years (p= 0.002), and had a higher proportion of interleukin-6 receptor inhibitors use in 2023 (p= 0.04) than those in patients with persistent D2T RA or those who died. D2T RA resolved in 38% of patients with multidrug resistance, mainly with treatment changes. Rheumatic disease comorbidity index and glucocorticoid dose escalation were independent risk factors for mortality (odds ratio [OR], 3.50; p= 0.02 and OR, 31.9; p= 0.002, respectively).

CONCLUSION

Further modifications in RA treatment are useful for resolving D2T RA. Multiple comorbidities and glucocorticoid use are associated with mortality.

Patterns of comorbidities differentially affect long-term functional evolution and disease activity in patients with 'difficult to treat' rheumatoid arthritis

BACKGROUND

Characterisation of the long-term outcome of patients with 'difficult to treat' (D2T) rheumatoid arthritis and factors contributing to its evolution are unknown. Herein, we explored the heterogeneity and contributing factors of D2T long-term outcome.

METHODS

Patients included from a prospective single centre cohort study. The EULAR definition of D2T was applied. Longitudinal clustering of functional status (modified Health Assessment Questionnaire (mHAQ)) and disease activity (Disease Activity Score-28 (DAS28)) were assessed using latent-class trajectory analysis. Multiple linear mixed models were used to examine the impact of comorbidities and their clusters on the long-term outcome.

RESULTS

251 out of 1264 patients (19.9%) were identified as D2T. Younger age, fibromyalgia, osteoarthritis, DAS28-erythrocyte sedimentation rate (ESR) at first biological or targeted synthetic disease-modifying antirheumatic drug (b/ts-DMARD) initiation and failure to reduce DAS28-ESR scores within the first 6 months of b/ts-DMARD therapy were significant predictors of patients becoming D2T. Long-term follow-up (total of 5872 person-years) revealed four groups of functional status evolution: 18.2% had stable, mildly compromised mHAQ (mean 0.41), 39.9% had gradual improvement (1.21-0.87) and two groups had either slow deterioration or stable significant functional impairment (HAQ>1). Similarly, four distinct groups of disease activity evolution were identified. Among the different clusters of comorbidities assessed, presence of 'mental-health and pain-related illnesses' or 'metabolic diseases' had significant contribution to mHAQ worsening (p<0.0001 for both) and DAS28 evolution (p<0.0001 and p=0.018, respectively).

CONCLUSION

D2T patients represent a heterogeneous group in terms of long-term disease course. Mental-health/pain-related illnesses as well as metabolic diseases contribute to long-term adverse outcomes and should be targeted in order to optimise the prognosis of this subset of rheumatoid arthritis.

A Review of Difficult-to-Treat Rheumatoid Arthritis: Definition, Clinical Presentation, and Management

PURPOSE OF REVIEW

A subset of patients with rheumatoid arthritis (RA) who fail multiple biologic therapies are deemed to have "difficult-to-treat" (D2T) RA. In 2021, a European Alliance of Associations for Rheumatology (EULAR) task force proposed a clinical definition of D2T RA. Here we review RA phenotypes and clinical assessment of RA, propose a different definition of D2T RA, discuss possible D2T RA risk factors, and summarize existing literature on the management of D2T RA.

RECENT FINDINGS

High disease activity at the time of diagnosis or prior to treatment with a biologic is associated with the development of D2T RA. Prolonged time from diagnosis to beginning treatment has been consistently associated with the development of D2T RA. Other clinical factors such as burden of disease, extraarticular disease, obesity, smoking, pain, fatigue, and psychological conditions have inconsistent associations with D2T RA according to current literature. D2T RA is a relatively new concept that represents an area of great need for research regarding the characterization of those with the disease as well as how best to treat the disease. With this gained knowledge, rheumatologists will be able to better identify patients at the time of diagnosis that are likely to develop D2T RA to help guide management.

Inappropriate treatment response to DMARDs: A pathway to difficult-to-treat rheumatoid arthritis

In recent years, difficult-to-treat rheumatoid arthritis (D2T RA) has attracted significant attention from rheumatologists due to its poor treatment response and the persistent symptoms or signs experienced by patients. The therapeutic demands of patients with D2T RA are not properly met due to unclear pathogenic causes and a lack of high-quality data for current treatment options, creating considerable management difficulties with this patient population. This review describes the clinical challenges associated with disease-modifying antirheumatic drugs (DMARDs) and explores contributing factors associated with inappropriate response to DMARDs that may lead to D2T RA and related immunological dysregulation. It is now understood that D2T RA is a highly heterogeneous pathological status that involves multiple factors. These factors include but are not limited to genetics, environment, immunogenicity, comorbidities, adverse drug reactions, inappropriate drug application, poor adherence, and socioeconomic status. Besides, these factors may manifest in the selection and utilization of specific DMARDs, either individually or in combination, thereby contributing to inadequate treatment response. Finding these variables may offer hints for enhancing DMARD therapy plans and bettering the condition of D2T RA patients.

Difficult-to-treat inflammatory bowel disease: results from an international consensus meeting

Many patients with inflammatory bowel disease (IBD) have persistent symptoms and disease activity despite the best available medical or surgical treatments. These patients are commonly referred to as having difficult-to-treat IBD and need additional therapeutic strategies. However, the absence of standard definitions has impeded clinical research efforts and comparisons of data. Under the guidance of the endpoints cluster of the International Organization for the Study of Inflammatory Bowel Disease, we held a consensus meeting to propose a common operative definition for difficult-to-treat IBD. 16 participants from 12 countries voted on 20 statements covering various elements of difficult-to-treat IBD, such as failure of medical and surgical treatments, disease phenotypes, and specific complaints from patients. "Agreement" was defined as at least 75% consensus. The group agreed that difficult-to-treat IBD is defined by the failure of biologics and advanced small molecules with at least two different mechanisms of action, or postoperative recurrence of Crohn's disease after two surgical resections in adults, or one in children. In addition, chronic antibiotic-refractory pouchitis, complex perianal disease, and comorbid psychosocial complications that impair disease management also qualified as difficult-to-treat IBD. Adoption of these criteria could serve to standardise reporting, guide enrolment in clinical trials, and help identify candidates for enhanced treatment strategies.