Significantly longer time seen to first flare that required rescue therapy, and significant benefit seen in all secondary end points
MONDAY, June 8, 2026 (HealthDay News) — For patients with active immunoglobulin (Ig)G4-related disease, obexelimab, a bifunctional monoclonal antibody that inhibits B-cell activity, yields a significantly lower risk for disease flare, according to a study published online June 2 in the New England Journal of Medicine to coincide with the European Alliance of Associations for Rheumatology 2026 Congress, held from June 3 to 6 in London.
Emanuel Della‑Torre, M.D., Ph.D., from IRCCS San Raffaele Scientific Institute in Milan, and colleagues conducted a phase 3, randomized, placebo-controlled trial involving patients with active IgG4-related disease receiving obexelimab (250 mg) or placebo once weekly for 52 weeks (97 patients in each group). Glucocorticoids were tapered in a standardized schedule to discontinuation at week 8 for patients in both groups.
The researchers observed a significantly longer time to first flare that required rescue therapy with obexelimab than placebo (hazard ratio, 0.44), with flares reported in 26.8 and 54.6 percent of patients in the obexelimab and placebo groups, respectively. With respect to all secondary end points, including complete remission and cumulative dose of glucocorticoid rescue therapy, obexelimab showed significant benefit over placebo (37.1 versus 19.6 percent and 329.5 versus 929.8 mg, respectively). Adverse events included arthralgias (19.6 versus 11.3 percent in the obexelimab and placebo groups, respectively), hypersensitivity (16.5 versus 11.3 percent, respectively), and diarrhea (11.3 versus 6.2 percent, respectively).
“The phase 3 INDIGO data indicate obexelimab could offer a novel, highly active, self-administered therapy for people living with IgG4-related disease, one that has the potential to avoid the safety concerns associated with chronic steroid use and long-term B cell depletion,” Della-Torre said in a statement.
Several authors disclosed ties to biopharmaceutical companies, including Zenas BioPharma, which is developing obexelimab and funded the study.
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