Zenas BioPharma to Present Obexelimab Phase 3 Data Showing 56% Flare Risk Reduction in IgG4-RD
Zenas BioPharma will present Phase 3 INDIGO trial data on obexelimab June 4, showing a 56% IgG4-RD flare risk reduction (HR 0.443; p=0.0005) over 52 weeks versus placebo. It also met all four key secondary endpoints (p≤0.0049) and showed lower grade≥3 adverse events (11.3% vs 23.7%) with no treatment-related deaths.
1. Robust Efficacy Outcomes
Phase 3 INDIGO trial evaluating obexelimab in IgG4-RD met its primary endpoint with a 56% reduction in flare risk (HR 0.443; 95% CI 0.277–0.711; p=0.0005) over 52 weeks versus placebo, and achieved statistical significance on all four key secondary endpoints, including time to flare (p=0.0001), flare count (p=0.0008), complete remission rates (p=0.0049) and cumulative glucocorticoid use (p=0.0042).
2. Favorable Safety Profile
Obexelimab displayed a favorable safety profile, with treatment-emergent adverse events in 97.9% vs 95.9% in placebo, lower rates of grade ≥3 events (11.3% vs 23.7%), fewer serious adverse events (10.3% vs 18.6%), reduced infection incidence (53.6% vs 62.9%), and no treatment-related deaths versus one in placebo.
3. EULAR 2026 Presentation Details
Zenas BioPharma will present these results at the EULAR 2026 Congress on June 4 at 2:45 PM GMT in London, with Emanuel Della Torre, M.D., Ph.D., delivering the oral presentation titled 'Obexelimab, a B Cell Inhibitor, in IgG4-Related Disease: Results From the Phase 3 INDIGO Trial'.
4. Pipeline Development
Following the randomized period, patients continue in a three-year open-label extension to bolster long-term data, and Zenas expects to report Phase 2 Systemic Lupus Erythematosus topline results, including biomarkers, in the fourth quarter of 2026.