EULAR 2026 Highlights – Rheumatoid Arthritis (therapeutic and non-therapeutic)

CD19 CAR T-Cell Therapy in ACPA-Positive, Treatment-Refractory, Active Rheumatoid Arthritis – Data from the Phase 1 of the Prospective, Interventional COMPARE Trial

Abstract format and assignment number: Oral presentation OP008 

Presenting author: F. Albach (Germany)

This first phase of the prospective phase I/II study evaluated CD19-directed CAR T-cell therapy (mivocabtagene autoleucel) in six patients with severe, treatment-refractory, ACPA-positive RA. Treatment was well tolerated, induced profound B-cell depletion and marked reductions in autoantibody levels. Median DAS28-CRP reduction was 41% (range 23-66), and half of the patients achieved DAS28-CRP remission while remaining off immunosuppressive therapy (median follow-up was 24 weeks).

Real-world electronic health record data platform with machine learning to emulate randomized controlled trials in rheumatoid arthritis evaluating treatments after methotrexate failure

Abstract format and assignment number: Poster POS0255

Presenting author: D. Cheng (USA)

This study emulated a randomized-controlled trial using real-world U.S. Veterans Affairs electronic health record data and a validated machine learning model to infer RA disease activity from routine clinical data. Among 3,472 patients with inadequate response to methotrexate, initiation of etanercept plus methotrexate was associated with a modestly lower prevalence of moderate-to-high disease activity at 24 and 48 weeks compared with triple therapy, consistent with the original trial. Emulation of RCTs using real-world data is a promising concept that could enable valuable analyses without the complexity of conducting conventional clinical trials.

Safety in Continuing and Restarting Biologics in Rheumatoid Arthritis Patients with New-Onset Cancer – A Retrospective Multi-Center Study from the National Database of Rheumatic Diseases in Japan

Abstract format and assignment number: Oral presentation OP089

Presenting author: Y. Siripongvutikorn (Japan)

This retrospective study of 220 patients with RA and newly diagnosed cancer while receiving biologic therapy found that continuation or resumption of biologics was not associated with worse 5-year overall survival, whereas older age, metastatic (stage 4) cancer, glucocorticoid use ≥5 mg/day, and inability to resume biologic therapy were associated with higher mortality. While this needs prospective validations, approaches to effective save therapy of rheumatic diseases in cancer patients are highly needed.

Therapeutic Decisions, Not Mechanisms of Action, Drive Progression to Difficult-to-Treat RA: Insights From a 20-Year Real-World UCLouvain Brussels Cohort

Abstract format and assignment number: Poster POS0358

Presenting author: C. Van Mullem (Belgium)

In this retrospective cohort of 675 patients with RA, approximately 19% developed difficult-to-treat (D2T) RA during long-term follow-up. Progression to D2T-RA was associated with greater disease severity, worse functional status and prior glucocorticoid use, whereas the choice of first-line biologic or targeted synthetic DMARD (TNFi vs. non-TNFi) did not significantly influence the risk of developing D2T-RA. In this study, disease characteristics rather than initial treatment mechanism were the primary drivers of progression to D2T-RA.

Enrichment of T peripheral helper cells in both organized and diffuse immune infiltrates in RA-ILD lung explants

Abstract format and assignment number: Oral presentation OP0273

Presenting author: A. Seng (USA)

This is a translational study of formalin-fixed paraffin-embedded explanted lung tissues from patients with RA-ILD (n=11), non-RA CTD-ILD (n=8) or IPF (n=8). Immunofluorescence staining showed that T peripheral helper (Tph) cells were enriched in the lungs of patients with RA-ILD compared with other fibrotic lung diseases and were present in both organized and diffuse immune infiltrates. Tph cell abundance did not correlate with B-cell infiltration and persisted despite recent rituximab treatment, suggesting that Tph cells may contribute to RA-ILD pathogenesis through mechanisms beyond B-cell help and represent a potential therapeutic target.

Rheumatoid arthritis modulates immune cell trajectories across pregnancy

Abstract format and assignment number: Oral presentation OP0275

Presenting author: B. Goulden (UK)

This prospective study analyzed 279 peripheral blood samples from 106 women (67 with RA, 39 healthy controls) collected before, during, and after pregnancy using 31-marker spectral flow cytometry. Pregnancy induced broad immune adaptations in both groups, but women with RA exhibited relatively higher proportions of memory, senescent/exhausted, and T follicular helper (TFH) CD4⁺ T cells throughout pregnancy. This shows characteristics of pregnancy-associated immune regulation in RA and potential mechanisms underlying pregnancy-induced remission and postpartum disease flare.

Venous thromboembolism with Janus kinase inhibitors and other immunomodulatory drugs: a Swedish comparative safety study among patients with rheumatoid arthritis

Abstract format and assignment number: Oral presentation OP085

Presenting author: M. Raffray (Sweden)

This nationwide Swedish register study included 26,116 treatment initiations (2017–2024) and compared the risk of venous thromboembolism (VTE) across targeted therapies for RA. JAK inhibitors were associated with a significantly higher risk of VTE than TNF inhibitors (adjusted HR 1.89), a finding that persisted in more recent treatment initiations (2021–2024). A possible increased VTE risk was also observed with IL-6 inhibitors, warranting further investigation.

Genetic Risk Variants Reveal Cytokine-Responsive Modules Driving Pathogenic Programs in Rheumatoid Arthritis Synovial Fibroblasts

Abstract format and assignment number: Oral presentation OP0279

Presenting author: E. Ezen (Switzerland)

This translational genomics study integrated RA GWAS data, chromatin interactions, eQTL analyses, and single-cell RNA sequencing to identify 150 candidate RA risk genes in synovial fibroblasts. The authors found that synovial fibroblast-specific genetic risk is enriched in TGF-β-responsive gene programs, particularly in pathogenic sublining fibroblast populations, suggesting that dysregulated TGF-β signaling is a key mechanism through which genetic susceptibility contributes to RA.

Risk factors for interstitial lung disease in patients with rheumatoid arthritis: results from the international ANCHOR-RA study

Abstract format and assignment number: Oral presentation OP084

Presenting author: J. Sparks (USA)

The international ANCHOR-RA study prospectively screened 1,169 patients with RA at increased risk for ILD using high-resolution CT and found that 9.1% had previously undiagnosed RA-associated ILD. Factors associated with ILD included older age, male sex, greater smoking exposure, higher RA disease activity, lower DLCO, lower oxygen saturation, lung crackles, and the MUC5B risk variant, supporting their role as predictors for future RA-ILD risk models.

Rosnilimab, a Selective and Potent Depleter of Pathogenic T Cells, Demonstrates Efficacy, Safety and Translational Proof of Mechanism in RENOIR, a Phase 2B Trial in Moderate-to-Severe Rheumatoid Arthritis

Abstract format and assignment number: Oral presentation OP0202

Presenting author: J. Graft (USA)

The phase 2b RENOIR trial randomized 424 patients with active seropositive RA to the anti-PD-1 antibody rosnilimab, a T-cell-depleting agent, or placebo. Rosnilimab significantly improved DAS28-CRP, ACR20 responses, inflammatory markers, and patient-reported outcomes versus placebo at 12 weeks, with benefits maintained after treatment discontinuation in many patients. The drug was well tolerated.