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A Phase 1 Study of GTX-B001 in Healthy Subjects and Patients 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)

Status
Recruiting
Phases
Phase 1
Study type
Interventional
Source
ClinicalTrials.gov
Registry ID
NCT07181369
Acronym
CHILL-MC
Enrollment
72
Registered
2025-09-18
Start date
2025-10-06
Completion date
2027-08-01
Last updated
2026-09-09

For informational purposes only — not medical advice. Sourced from public registries and may not reflect the latest updates. Terms

Conditions

Chronic Inducible Urticaria, Cold Urticaria, Healthy Subjects, Symptomatic Dermographism

Keywords

Urticaria, Skin diseases, Mast cells, Bispecific antibody, GTX-B001, Infusion, Single Ascending Dose, Healthy subjects, Safety, Pharmacokinetics, Pharmacodynamics, Cold urticaria, Intravenous, symptomatic dermographism

Brief summary

This is a first-in-human study aimed at determining the safety of a single dose of GTX-B001 in healthy participants and in people with chronic inducible urticaria.

Detailed description

GTX-B001 is a humanized bispecific antibody than binds with one arm to a protein called c-Kit and with the second arm to a protein called CD203c, both expressed on mast cells. This study is a randomized, double-bind, placebo-controlled phase 1 study evaluating the safety, pharmacokinetics and pharmacodynamics of a single dose of GTX-B001 in healthy participants (Part A) and in patients with chronic inducible urticaria (cold urticaria and symptomatic dermographism) who remain symptomatic despite treatment with antihistamines (Part B). In part B, the preliminary efficacy of GTX-B001 on the signs and symptoms of chronic inducible urticaria will also be evaluated. 48 healthy participants are estimated to be enrolled in part A in five ascending cohorts, while 24 patients with chronic inducible urticaria are estimated to be enrolled in Part B in two ascending cohorts. Potential participants will be screened for up to 4 weeks prior to enrollment. GTX-B001 will be administered intravenously on Day 1 to randomized participants who will be followed for 12 weeks post-treatment. Participants will be required to attend a total of 9 visits including the screening visit.

Interventions

DRUGGTX-B001

Single infusion of one of up to five dosages of GTX-B001

DRUGNormal Saline

Single infusion of normal saline

Sponsors

Granular Therapeutics Limited
Lead SponsorINDUSTRY

Study design

Allocation
RANDOMIZED
Intervention model
SEQUENTIAL
Primary purpose
TREATMENT
Masking
QUADRUPLE (Subject, Caregiver, Investigator, Outcomes Assessor)

Intervention model description

Single Ascending Dose

Eligibility

Sex/Gender
ALL
Age
18 Years to 75 Years
Healthy volunteers
Yes

Inclusion 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).

Design outcomes

Primary

MeasureTime frameDescription
Safety as assessed by the incidence and severity of adverse events (Parts A and B)Day 1 to Day 85Safety and tolerability of a single intravenous infusion of GTX-B001 as assessed by the percentage of subjects at each dose level with Grade 2 or higher adverse events as assessed by the Common Terminology Criteria for Adverse Events (CTCAE).

Secondary

MeasureTime frameDescription
GTX-B001 pharmacokinetics (Parts A and B)Day 1 to Day 85Serum concentrations of GTX-B001 at specified visits

Countries

Germany

Outcome results

None listed

Source: ClinicalTrials.gov · Data processed: Sep 10, 2026