GTX-B001 in healthy people and adults with chronic inducible urticaria
A Phase 1, Randomized, Double-Blind, Placebo-Controlled, Single Ascending Dose Tolerability, Pharmacokinetic, Pharmacodynamic, and Preliminary Efficacy Trial of GTX-B001 in Healthy Volunteers (Part A) and Patients With Chronic Inducible Urticaria (Part B)
This will test a single intravenous dose of GTX-B001, a bispecific antibody, in healthy volunteers and in adults with chronic inducible urticaria (cold urticaria or symptomatic dermographism) who still have symptoms despite antihistamines.
Quick facts
| Phase | Phase 1 |
|---|---|
| Study type | Interventional |
| Enrollment | 72 (estimated) |
| Ages | 18 Years to 75 Years |
| Sex | All |
| Sponsor | Granular Therapeutics Limited Industry-sponsored |
| Drugs / interventions | infliximab, adalimumab, omalizumab, dupilumab, ligelizumab, methotrexate, cyclophosphamide |
| Locations | 2 sites (Berlin and 1 other locations) |
| Trial ID | NCT07181369 on ClinicalTrials.gov |
What this trial studies
GTX-B001 is a humanized bispecific antibody designed to bind c-Kit and CD203c on mast cells to limit their activation. This randomized, double-blind, placebo-controlled, first-in-human Phase 1 study administers a single IV dose and follows participants for 12 weeks to characterize safety, pharmacokinetics, and pharmacodynamics. Part A will enroll about 48 healthy adults across five ascending dose cohorts, while Part B will enroll about 24 symptomatic patients across two ascending cohorts to also explore preliminary efficacy. Patients in Part B must have positive provocation tests (TempTest for cold urticaria or FricTest for symptomatic dermographism) and inadequate control on second‑generation H1 antihistamines.
Who should consider this trial
Good fit: Ideal candidates are adults (18–55 for healthy volunteers; 18–75 for patients) with confirmed cold urticaria or symptomatic dermographism who remain symptomatic despite second‑generation H1 antihistamines.
Not a fit: People with other types of urticaria, well-controlled symptoms on current therapy, serious uncontrolled medical conditions, or who cannot attend in-person visits are unlikely to benefit or be eligible.
Why it matters
Potential benefit: If successful, GTX-B001 could offer a new targeted treatment that reduces mast-cell–driven hives and itching in people with chronic inducible urticaria.
How similar studies have performed: Mast-cell–directed and anti-IgE therapies have helped some urticaria patients, but this c-Kit/CD203c bispecific antibody is a novel first-in-human approach and has not yet been tested in people.
Eligibility criteria
Show full inclusion / exclusion criteria
Key inclusion Criteria (Part A): * The subject is between 18 and 55 years of age (both inclusive) at the date of screening. * The subject is in good general health based on the medical history, physical examination and the results of vital signs, electrocardiogram and clinical laboratory, as judged by the investigator. Key inclusion Criteria (Part B): * The subject is between 18 and 75 years of age (both inclusive) at the date of screening * A history of signs and/or symptoms of ColdU or SD experienced ≥ 3 months prior to screening. * For ColdU patients, a positive provocation test during screening and baseline, using the TempTest® device. * For SD patients, a positive provocation test with at least 3 pins during screening and baseline, using the FricTest® device. * Inadequate control of ColdU or SD by second generation H1-antihistamine (sgAH) as defined as the presence of itch and hives following a trigger (e.g. cold or scratching, respectively) within the last 6 weeks prior to screening in spite of use of a sgAH. * A Urticaria Control Test (UCT) score of \< 12 at screening. Key exclusion Criteria (Parts A \& B): * Presence of any clinically significant illness, such as cardiovascular, neurologic, pulmonary, hepatic, renal, metabolic, gastrointestinal, urologic, immunologic, or endocrine disease or disorder that would interfere with the patient's safety or the interpretation of trial results in the judgment of the investigator. * Treatment with an investigational drug or intervention for any condition within three months of screening, or concurrent participation in another clinical trial in which an investigational drug is administered. * Treatment with immunomodulating therapy (e.g., intravenous or intramuscular immunoglobulins, systemic corticosteroids, cyclosporine, methotrexate, dapsone, cyclophosphamide, tacrolimus, mycophenolate mofetil, hydroxychloroquine, infliximab, adalimumab, etanercept, etc.) within 4 weeks (or 5 half-lives, whichever is longer) prior to screening. * Use of any monoclonal antibody or therapeutic protein within 4 weeks (or 5 half-lives, whichever is longer) prior to screening. * History of anaphylaxis, autoimmune disorders requiring more than topical medication, or asthma requiring regular use of inhaled medication within the past 5 years, unless, in the opinion of the Investigator, the condition is not considered clinically significant and is unlikely to affect subject safety or study outcomes. Additionally for Part B: * Disease with symptoms of urticaria or angioedema other than Chronic Urticaria (CU), for example urticaria vasculitis, erythema multiforme, mastocytosis, or drug-induced urticaria. Patients with concomitant Chronic Spontaneous Urticaria (CSU) or other forms of Chronic Inducible Urticaria (CIndU) are eligible provided that symptoms at screening are consistent with ColdU or SD and that ColdU or SD is the dominant form of CU. * Any other skin disease associated with chronic itching that might influence in the investigators' opinion of the study evaluations and results, e.g., atopic dermatitis, bullous pemphigoid, dermatitis herpetiformis, or psoriasis. * Receipt of any biologic therapy for urticaria control (e.g. omalizumab, dupilumab, ligelizumab, etc.) within three months of screening (whether on-label or off-label).
Where this trial is running
Berlin and 1 other locations
- Charité Research Organization gmbh — Berlin, Germany (Recruiting)
- Fraunhofer Institute For Translational Medicine And Pharmacology — Berlin, Germany (Not_yet_recruiting)
How to participate
- Review the eligibility criteria above with your treating physician.
- Visit the official trial page on ClinicalTrials.gov for the most current contact information and recruitment status.
- Contact the listed study coordinator or principal investigator to request pre-screening. Pre-screening is free and never obligates you to enroll.