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Testing barzolvolimab for chronic spontaneous urticaria

A Phase 3 Randomized, Double-Blind, Placebo-Controlled Study to Assess the Efficacy and Safety of Barzolvolimab in Patients With Chronic Spontaneous Urticaria Who Remain Symptomatic Despite H1 Antihistamine Treatment (EMBARQ-CSU2)

PHASE3 · Celldex Therapeutics · NCT06455202

This study is testing a new medication called barzolvolimab to see if it can help adults with chronic spontaneous urticaria who haven't found relief from standard allergy medications.

Quick facts

PhasePHASE3
Study typeInterventional
Enrollment915 (estimated)
Ages18 Years and up
SexAll
SponsorCelldex Therapeutics (industry)
Drugs / interventionsbarzolvolimab
Locations183 sites (Cullman, Alabama and 182 other locations)
Trial IDNCT06455202 on ClinicalTrials.gov

What this trial studies

This phase 3 study evaluates the efficacy, safety, and tolerability of barzolvolimab in adults suffering from chronic spontaneous urticaria (CSU) who have not found relief from non-sedating second generation H1-antihistamines. The study is designed as a global, multicenter, randomized, double-blind, placebo-controlled trial, involving approximately 915 participants. It includes a screening period, a 24-week placebo-controlled treatment phase, followed by a 28-week active treatment phase where all participants receive barzolvolimab, and concludes with a 16-week treatment-free period.

Who should consider this trial

Good fit: Ideal candidates are adults aged 18 and older with chronic spontaneous urticaria for at least 6 months, who have not achieved symptom control with second generation non-sedating H1-antihistamines.

Not a fit: Patients who have not been diagnosed with chronic spontaneous urticaria or those who have not tried second generation non-sedating H1-antihistamines may not benefit from this study.

Why it matters

Potential benefit: If successful, this treatment could provide significant relief for patients with chronic spontaneous urticaria who do not respond adequately to current antihistamine therapies.

How similar studies have performed: Previous studies have shown promise in treating chronic spontaneous urticaria with biologic therapies, suggesting that this approach may be effective.

Eligibility criteria

Show full inclusion / exclusion criteria 
Key Inclusion Criteria:

1. Males and females, \>/= 18 years of age.
2. Chronic spontaneous urticaria (CSU) \>/= 6 months prior to Screening (Visit 1).
3. CSU despite the use of a stable regimen of second generation non-sedating H1-antihistamine as defined by:

   1. The presence of hives for \>/= 6 weeks at any time prior to Visit 1 despite the use of non-sedating H1-antihistamines.
   2. Must be on a stable regimen of second generation non-sedating H1-antihistamine for \>/= 4 weeks prior to study treatment.
   3. UAS7 of \>/= 16 and ISS7 of \>/= 8 during the 7 days prior to study treatment.
4. Normal blood counts and liver function tests.
5. Both males and females of child-bearing potential must agree to use highly effective contraceptives during the study and for 150 days after treatment.
6. Willing and able to complete a daily symptom electronic diary and comply with study visits.
7. Participants with and without prior biologic experience are eligible.

Key Exclusion Criteria:

1. Women who are pregnant or nursing.
2. Chronic urticaria whose predominant manifestation is due to CIndU.
3. Other diseases associated with urticaria.
4. Active pruritic skin condition in addition to CSU.
5. Medical condition that would cause additional risk or interfere with study procedures.
6. Known HIV, hepatitis B or hepatitis C infection.
7. Vaccination of a live vaccine within 30 days prior to Screening (Visit 1) (subjects must agree to avoid live vaccinations during the study). Inactivated vaccines are allowed such as seasonal influenza injection or authorized COVID-19 vaccine.
8. History of anaphylaxis
9. Prior treatment with barzolvolimab

There are additional criteria that your study doctor will review with you to confirm you are eligible for the study.

Where this trial is running

Cullman, Alabama and 182 other locations

+133 more sites — see ClinicalTrials.gov for the full list.

Study contacts

How to participate

  1. Review the eligibility criteria above with your treating physician.
  2. Visit the official trial page on ClinicalTrials.gov for the most current contact information and recruitment status.
  3. Contact the listed study coordinator or principal investigator to request pre-screening. Pre-screening is free and never obligates you to enroll.

View on ClinicalTrials.gov →

Conditions: Chronic Spontaneous Urticaria, CDX-0159, barzolvolimab, chronic spontaneous urticaria, CSU, urticaria activity score, itch severity score, hives severity score

Last reviewed 2026-05-15 by the Find a Trial editorial team. Information on this page is for educational purposes and is not medical advice. Always consult qualified healthcare professionals about clinical trial participation.