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A study to evaluate the long-term safety and effectiveness of barzolvolimab in patients with chronic spontaneous urticaria

Verified siteRegistered drugNo placebo
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What is this trial about?

A plain-language summary of the goals, design and what participants do

This study focuses on Chronic Spontaneous Urticaria, a condition characterized by the sudden appearance of itchy skin welts or hives without an obvious cause. The purpose of the study is to evaluate the long-term effectiveness and safety of the drug barzolvolimab in people living with this condition. Barzolvolimab is administered via subcutaneous injection, which is a method of delivering medication into the fatty tissue just under the skin.

Participants in this study are individuals who have previously taken part in other clinical trials involving the medication. During this phase, participants may be placed in an observation group to monitor their condition over time, or they may receive retreatment with barzolvolimab. The study follows participants for up to 52 weeks to observe how well the disease is controlled and to monitor for any adverse events, which are unintended or harmful medical occurrences that may happen during the course of treatment.

The research process

The trial runs in 4 steps – from screening to follow-up. Each step says what happens and what the team monitors.

  1. Step 1

    Study participation

    The study involves monitoring the long-term effects of barzolvolimab for the treatment of chronic spontaneous urticaria, which is a condition characterized by hives and swelling that occur without an obvious cause.

    You will be placed into one of two groups: an observation group or a retreatment group.

  2. Step 2

    Observation group activities

    If placed in the observation group, no new doses of barzolvolimab are administered. instead, your condition is monitored to see how long the disease remains under control.

    The condition is assessed using the urticaria activity score, which is a method to measure the severity of hives over a 7-day period.

  3. Step 3

    Retreatment group activities

    If placed in the retreatment group, you will receive barzolvolimab via a subcutaneous injection, which is an injection given just under the skin.

    The dosage for barzolvolimab is 300 mg per injection.

  4. Step 4

    Monitoring and duration

    The main observation period lasts through week 52.

    During this time, the focus is on determining the time until the disease worsens, such as when the urticaria activity score reaches a level of 16 or higher over 7 days, or if the medication must be stopped due to lack of effectiveness or side effects.

    Side effects, or adverse events, are monitored throughout the study.

Who can join the trial?

7 criteria

  • You must be able to read, understand, and sign a written informed consent document, which is a form that explains all the details of the study before you agree to join.
  • You must have already finished 52 weeks of treatment and a 16-week follow-up, which is a period of observation after treatment ends, in one of the previous specific clinical studies (CDX0159-12 or CDX0159-13).
  • The Investigator, who is the main doctor leading the study, must decide that participating in this long-term extension (LTE) study is safe for you based on a balance of possible benefits and risks.
  • If you are a female of childbearing potential, meaning you are still able to become pregnant, you must agree to use highly effective contraception (methods to prevent pregnancy, such as hormonal pills, an IUD, or a hormonal implant) from the start of the study until 150 days after your last treatment.
  • Female participants who cannot become pregnant because of surgery, such as a hysterectomy (removal of the uterus) or salpingectomy (removal of the fallopian tubes), or those who have reached menopause (the time when periods stop permanently), are also eligible.
  • Male participants who have female partners capable of pregnancy must agree to use barrier methods (such as condoms) or must have had a vasectomy (a medical procedure for male sterilization) and agree not to donate sperm during the study and for 150 days after the last treatment.
  • You must be willing and able to follow all study rules, including keeping a daily symptom diary, which is a personal record used to write down how you feel every day.

Who cannot join the trial?

16 criteria

  • You have other active skin conditions that cause itching (pruritus), such as atopic dermatitis (a common skin inflammatory condition), psoriasis (a condition causing red, scaly patches), bullous pemphigoid (a skin blistering disease), dermatitis herpetiformis (an itchy, blistering skin rash), prurigo nodularis (a condition where itchy bumps form on the skin), or chronic pruritus of unknown origin (long-term itching with no known cause).
  • You have a history of malignancy (cancer) within the last 5 years, unless it was a fully treated carcinoma in-situ of the cervix (early-stage cancer that has not spread) or a fully treated and resolved non-metastatic squamous or basal cell carcinoma of the skin (common types of skin cancer that have not spread to other parts of the body).
  • You had a medical procedure requiring general anesthesia (medicine that puts you to sleep) or epidural anesthesia (medicine injected near the spine to numb a part of the body) within 8 weeks before starting the study, or you have a minor procedure like dental work planned within 14 days.
  • You have already used other investigational products (medicines being tested in studies) or other anti-KIT therapies (medicines that target a specific protein called KIT) other than barzolvolimab.
  • You did not follow the rules for keeping a diary (a daily record of symptoms) well enough during previous specific studies to ensure your safety.
  • You are currently in detention (being held in custody) due to a court order or regulatory action.
  • You are a staff member of the sponsor (the company running the study), a contract research organization (a company hired to help run the study), or the site staff (the people working at the clinic where the study happens), or you are a family member of these employees.
  • You do not have a recorded UAS7 score (a specific measurement of hives severity over seven days) from the required timeframe in previous studies.
  • You have any other sudden or long-term medical or psychiatric (mental health) conditions or laboratory abnormalities (unusual results from blood or urine tests) that could make the study unsafe for you or make it hard to understand the study results.
  • You have used prohibited non-biologic systemic agents (medicines that work throughout the whole body rather than being targeted) within the last 30 days or 5 half-lives (the time it takes for the amount of medicine in your body to reduce by half).
  • You have used immunomodulating biologic therapy (medicines that change how your immune system works) within the last 3 months.
  • For women in the retreatment group, you are pregnant or nursing (breastfeeding), or you have a positive pregnancy test.
  • You have severe or uncontrolled long-term illnesses, such as chronic hepatic disease (long-term liver problems), renal disease (long-term kidney problems), or diabetes mellitus (a condition affecting blood sugar).
  • You have moderate-to-severe pulmonary (lung) or cardiovascular (heart and blood vessel) diseases.
  • You have a known active infection of hepatitis B, hepatitis C, or HIV.
  • You have an active infection that requires systemic antibiotics (medicine to fight bacteria), antivirals (medicine to fight viruses), antifungals (medicine to fight fungi), or other medicines to fight parasites.
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Investigated drugs

  • Barzolvolimab

    is a medication being tested to see how well it works and how safe it is for people living with chronic spontaneous urticaria (a long-term skin condition involving hives). It is given as an injection under the skin.

  • Epinephrine

    is a medication used as part of the background care for participants. It is used to treat severe allergic reactions and is given as an injection under the skin.

What is already known about the treatment

  • Epinephrine

    This medication is an injection given under the skin using a pre-filled pen. It is a well-known treatment used widely in medicine to quickly reverse life-threatening allergic reactions. It works by stimulating specific receptors in the body to tighten airways and increase blood pressure during an emergency. It is classified as an alpha and beta-adrenergic agonist.

  • Barzolvolimab

    This medication is administered as an injection under the skin using a pre-filled syringe. It is currently being studied in clinical trials to evaluate its long-term effectiveness and safety for treating chronic skin hives. The drug works at a molecular level by targeting and blocking specific proteins in the immune system that cause inflammation. It is classified as a monoclonal antibody.

Investigated diseases

Chronic Spontaneous Urticaria - This condition is characterized by the repeated appearance of itchy, raised red or skin-colored bumps on the skin. These bumps, known as wheals, can occur without any obvious external trigger. The condition may also involve swelling beneath the skin surface, which is called angioedema. The symptoms often appear and disappear suddenly, sometimes lasting for only a few hours or several days. In many cases, the episodes recur frequently over a long period of time.
Trial detailsLast updated 7 Oct 2026
Age18+ yearsPhasePhase IIITrial ID2025-522878-36-00Protocol codeCDX0159-17Estimated enrolment1 370 patientsSponsorCelldex Therapeutics Inc.

sourced from the EU Clinical Trials Register and site verification

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