Barzolvolimab

July 21, 2026: Celldex (NASDAQ: CLDX) reported topline results from a randomized, double-blind, placebo-controlled Phase 2 study of subcutaneous barzolvolimab in moderate-to-severe prurigo nodularis (PN). The trial missed its primary endpoint (proportion of patients with ≥4-point improvement in Worst Itch Numeric Rating Scale [WI-NRS] at Week 12) and key secondary endpoints, including IGA-CPNG-S 0/1; results did not differentiate from placebo at either dose level, and no improvement was seen with longer treatment to Week 24. Despite rapid, profound systemic mast cell depletion (significant serum tryptase reduction, enhanced by a 450 mg loading dose), clinical benefit was not observed versus placebo. Celldex is discontinuing the Phase 2 PN study; barzolvolimab was well tolerated with a safety profile consistent with prior studies using a 450 mg loading dose followed by 150 mg or 300 mg Q4W.

Upcoming catalysts: Phase 3 chronic spontaneous urticaria (CSU) topline data expected Sept/Oct 2026; Phase 3 symptomatic dermographism (SD) and cold urticaria (ColdU) enrollment on track; Phase 2 atopic dermatitis (AD) topline data expected late 2026. Celldex planned a webcast/conference call July 21, 2026 at 4:30 p.m. ET.