EULAR 2026: New biologic halves flare risk in IgG4-related disease

Clinical Takeaway: Consider obexelimab as a promising steroid-sparing treatment option for active IgG4-related disease, reducing disease flares by more than 50% while increasing remission rates over 1 year.

IgG4-related disease is a chronic, relapsing inflammatory condition often managed with prolonged glucocorticoid therapy. Effective steroid-sparing options remain limited, making durable disease control a key unmet need.

Patients with active IgG4-related disease who received weekly subcutaneous obexelimab had significantly fewer disease flares and lower glucocorticoid exposure than those receiving placebo in the phase 3 INDIGO trial, presented at EULAR 2026 and published in the New England Journal of Medicine.

The global study randomized 194 adults with active IgG4-related disease to obexelimab 250 mg weekly or placebo for 52 weeks. All patients underwent a standardized glucocorticoid taper that ended by week 8. The primary endpoint was time to first disease flare requiring rescue therapy.

Obexelimab reduced the risk of flare by 56% versus placebo (hazard ratio, 0.44; 95% confidence interval, 0.28-0.71; P<0.001). Flares occurred in 26.8% of patients receiving obexelimab compared with 54.6% of those receiving placebo. Complete remission at week 52 was achieved in 37.1% versus 19.6%, respectively (P=0.005). The annualized flare rate was 0.34 per year with obexelimab versus 0.70 with placebo, and cumulative rescue glucocorticoid use was reduced by about 65% (330 mg vs 930 mg; P=0.004).

Adverse events were common in both groups, but serious adverse events occurred less frequently with obexelimab (10.3% vs 18.6%). The most common adverse events associated with obexelimab included arthralgia (19.6%), hypersensitivity (16.5%), and diarrhea (11.3%). No deaths occurred in the obexelimab group.

The findings suggest that obexelimab, a CD19/FcγRIIb-targeting biologic that inhibits rather than depletes B cells, may offer an effective new maintenance strategy for this chronic disease while reducing dependence on long-term corticosteroids.

“Having something that works this well, and may be safer than what is currently available, is a real step forward,” said co–first author Matthew Baker, MD.

Overall, these findings position obexelimab as a promising first-line or maintenance therapy candidate for IgG4-related disease, addressing both relapse prevention and steroid burden in this underserved population.

Source: Della-Torre E, et al; INDIGO Trial Investigators. (2026, June 2). N Engl J Med. Obexelimab for the Treatment of IgG4-Related Disease