EULAR 2026 Highlights – Other Connective Tissue Disease and Vasculitis

Mosaic loss of the Y chromosome differentiates Giant Cell Arteritis from Polymyalgia Rheumatica across the GCA-PMR spectrum

Abstract format and assignment number: Oral presentation, OP0120

Date: Wednesday, 3 June, 17:10-17:20

Presenting author: S. M. Petzinna (Germany)

This study evaluated mosaic loss of the Y chromosome (mLOY) as a biomarker across the giant cell arteritis–polymyalgia rheumatica (GCA–PMR) spectrum. Among 122 men (88 GCA, 12 isolated PMR, 22 GCA+PMR), mLOY burden was significantly lower in isolated PMR (3.3%) than in isolated GCA (17.5%) or GCA+PMR (18.1%; p=0.030). mLOY was not associated with GCA phenotype or inflammatory markers, suggesting its potential as a biomarker for phenotypic stratification rather than disease activity.

Methotrexate versus Tocilizumab for treatment of giant cell arteritis (METOGIA trial): a multicenter, randomized, controlled trial

Abstract format and assignment number: Oral presentation, OP0119

Date: Wednesday, 3 June, 17:00-17:10

Presenting author: M. Samson (France)

This open-label randomized trial compared methotrexate (MTX) and tocilizumab (TCZ) plus glucocorticoids in 218 patients with giant cell arteritis (GCA). At week 78, sustained remission without relapse or glucocorticoid taper deviation was achieved in 39% of MTX versus 51% of TCZ patients, failing to demonstrate MTX non-inferiority (difference 12%, 95% CI −2% to 26%). TCZ showed better relapse prevention at week 52 and a more favorable safety profile, with fewer serious adverse events and deaths (1 vs 6).

Response to Upadacitinib in new-onset versus relapsing giant cell arteritis: two-year outcomes from the SELECT-GCA Phase 3 Trial

Abstract format and assignment number: Oral presentation, OP0117

Date: Wednesday, 3 June, 16:40-16:50

Presenting author: A. B. Dua (USA)

This post hoc analysis of the SELECT-GCA phase 3 trial evaluated continuation of upadacitinib 15 mg/day (UPA15) versus switch to placebo in 103 patients with giant cell arteritis (GCA) who achieved remission at week 52. Continuous UPA15 reduced risk of disease flare by ≥90% and maintained remission in >70% of patients through week 104, with ≥59% achieving complete remission and minimal glucocorticoid exposure (median 0 mg). Patients switched to placebo had higher flare rates, particularly in relapsing GCA (89% vs 11% on UPA15), with greater relapse burden and glucocorticoid use. Safety remained consistent with known UPA15 profiles.

Identifying difficult-to-treat giant cell arteritis: results from a French large vessel vasculitis study group cohort

Abstract format and assignment number: Poster, POS0023

Date: Wednesday, 3 June, 15:54-16:00

Presenting author: O. Dhrif (Tunisia)

This cohort study proposed the first definition of difficult-to-treat giant cell arteritis (D2T-GCA) and identified associated risk factors. Among 546 patients, 53 (9.7%) met D2T criteria. Female sex (OR 2.91, 95% CI 1.31–6.49), large-vessel involvement (OR 4.91, 95% CI 2.43–9.92), and higher glucocorticoid dose at 6 months (OR 1.03 per mg/day, 95% CI 1.01–1.08) independently predicted D2T-GCA (AUC 0.765). A glucocorticoid dose ≥15 mg/day at 6 months strongly excluded future D2T disease (negative predictive value 96.9%).

Mepolizumab 100 vs 300 mg/4 weeks for Eosinophilic Granulomatosis with Polyangiitis (EGPA): a 24-month retrospective cohort study by the European EGPA study group

Abstract format and assignment number: Oral presentation, OP0233

Date: Thursday, 4 June, 09:25-09:35

Presenting author: A. Bettiol (Italy)

This multicentre study compared mepolizumab 100 mg versus 300 mg every 4 weeks in 587 patients with eosinophilic granulomatosis with polyangiitis (EGPA). Complete response rates were higher with 300 mg at 3 months (26.5% vs 12.1%), 6 months (37.5% vs 22.0%), and 12 months (50.0% vs 33.3%) (all p<0.001), with greater corticosteroid discontinuation. By 24 months, complete response rates were similar (51.8% vs 39.7%, p=NS). Adverse events were generally infrequent but tended to be more common with 300 mg.

A randomised study of Rituximab and Belimumab sequential therapy in PR3 ANCA-associated vasculitis

Abstract format and assignment number: Oral presentation, OP0232 

Date: Thursday, 4 June, 09:15-09:25

Presenting author: M. McClure (United Kingdom)

This multicentre, double-blind, placebo-controlled trial evaluated rituximab plus belimumab versus rituximab plus placebo in 34 patients with PR3-ANCA–associated vasculitis. PR3-ANCA negativity occurred more frequently with belimumab (29.4% vs 13.3%; HR 4.70, 95% CI 0.65–33.8; p=0.12), with lower ANCA levels at 52 weeks. Belimumab delayed B-cell reconstitution and reduced naïve B-cell counts. Time to remission was shorter with belimumab (42 vs 91 days; HR 2.29, p=0.031), while relapse rates were lower but not significant (35% vs 53%; HR 0.64, p=0.40). Safety was comparable between groups.

Apremilast suppresses monocyte-driven inflammation by targeting BACH1 in Behçet’s disease

Abstract format and assignment number: Oral presentation, OP0288

Date: Friday, 5 June, 09:25-09:35

Presenting author: Y. Liu (China)

This study investigated the mechanism of apremilast in Behçet’s disease (BD) using transcriptomic and in vitro analyses. In 15 responders, apremilast suppressed inflammatory and oxidative stress pathways and reduced circulating monocytes (39.1% to 27.4%, p<0.001). In monocytes, apremilast decreased tumor necrosis factor-α, interleukin (IL)-6, IL-1β, and reactive oxygen species while restoring superoxide dismutase activity (all p<0.05). Integrated analyses identified BACH1 as a key mediator, with BACH1 knockdown reproducing these anti-inflammatory effects.