Barzolvolimab Responses Persist After Treatment in Selected Chronic Urticaria Patients
Key Takeaways
- In a post hoc phase 2 analysis, 69% of 48 evaluable patients with chronic spontaneous urticaria (CSU) who achieved well-controlled disease after 52 weeks of barzolvolimab maintained that status at week 76, approximately 7 months after their last dose.
- At week 76, 50% of the evaluable subgroup had a complete response (weekly Urticaria Activity Score [UAS7] of 0). Among 24 patients who remained well controlled throughout follow-up, 20 (83%) reported no dermatology-related quality-of-life impact.
- The findings concern patients who had already responded to treatment and completed the treatment period; they do not establish off-treatment durability in all patients starting barzolvolimab.
Nearly 7 in 10 evaluable patients with antihistamine-refractory chronic spontaneous urticaria (CSU) who achieved well-controlled disease after a year of barzolvolimab maintained control 24 weeks later, according to a post hoc analysis of a phase 2 trial presented at the 2026 Fall Clinical Dermatology Conference.
Researchers evaluated off-treatment outcomes from a randomized, double-blind, placebo-controlled dose-finding study (NCT05368285). Barzolvolimab is a monoclonal antibody that inhibits KIT activation by stem cell factor, a pathway involved in mast cell survival.
The analysis focused on patients assigned to barzolvolimab 150 mg every 4 weeks or 300 mg every 8 weeks who completed 52 weeks of treatment and achieved a weekly Urticaria Activity Score (UAS7) of 6 or lower at week 52. Of 55 patients meeting those criteria, 48 had UAS7 data at week 76. Their last treatment dose was administered at week 48.
Disease Control and Quality of Life After Discontinuation
At week 76, 69% of the 48 evaluable patients remained well controlled (UAS7 ≤6), and 50% had a complete response (UAS7 = 0). Among 24 patients who maintained control throughout follow-up, 20 (83%) had a Dermatology Life Quality Index score of 0 or 1 at week 76.
Drug concentrations declined below the poster-defined therapeutic range by week 64, while circulating tryptase levels rose toward the healthy-reference range by week 76. The investigators interpreted persistent symptom control despite these changes as a possible signal of disease modification, which this analysis cannot establish.
“Barzolvolimab represents a promising treatment for CSU with sustained off-treatment efficacy especially in patients who achieve well-controlled disease,” the investigators concluded.