Celldex’s Barzolvolimab Faces Upcoming Phase III CSU Data as AD Milestone Approaches

Celldex Therapeutics (CLDX) is preparing for a critical milestone as it prepares to disclose Phase III clinical results for barzolvolimab, a novel monoclonal antibody targeting the KIT receptor, in chronic spontaneous urticaria (CSU) by September or October 2025 or later in 2026. The drug’s efficacy in addressing severe CSU—including angioedema—has drawn attention, with Phase II data showing a 40-point improvement in symptom-free rates at week 12 compared to placebo, a delta more than double that of existing therapies. The company’s Phase III program, involving nearly 2,000 patients across two studies, is designed to assess barzolvolimab’s efficacy in a large, statistically powered cohort, with a focus on the omalizumab-refractory subgroup—a segment representing about 20% of the first-line severe CSU market. The trial is powered at 90% to detect a 10-point difference in the UAS7 score, a measure of urticaria activity, ensuring robust validation of the drug’s potential in this underserved population.