A Phase 1 interventional study of GTX-B001 and Normal Saline in Healthy Subjects, Cold Urticaria and Symptomatic Dermographism, sponsored by Granular Therapeutics Limited. Recruiting at 5 sites in Germany. Open to participants aged 18 Years to 75 Years, including healthy volunteers. Per ClinicalTrials.gov, last updated 2026-10-30.
Sponsored by Granular Therapeutics Limited · Phase 1, Interventional, and Treatment
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.
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.
147 studies on the registry are indexed under Urticaria; 19 are open to participants now.
This study's planned enrollment of 72 is above the median of 51 across 104 interventional studies indexed under Urticaria.
Browse Urticaria studies →This is the only study on the registry with Granular Therapeutics Limited as lead sponsor.
Counted across the registry records on this site, refreshed daily.
Key inclusion Criteria (Part A):
Key inclusion Criteria (Part B):
Key exclusion Criteria (Parts A \& B):
Additionally for Part B:
Underlined terms in the criteria open these too. Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
A recording of the heart’s electrical activity, taken with stickers on the chest, arms and legs. It takes a few minutes and does not hurt.
Judged by the study doctor to matter for your health or for the study. It is a doctor’s decision, so ask the study team if you are unsure whether something counts.
A drug or device being studied in a clinical trial.
It may be new, or already approved and being studied for another use, dose or form. Criteria often leave out people who took part in another study of one within a recent period, commonly 30 days or five half-lives.
Anti-inflammatory medicines such as prednisone, prednisolone and dexamethasone — not the anabolic steroids used for muscle.
Studies differ in what they allow: check which steroid medicines, routes (tablets, injections, creams, inhalers, eye drops) and doses this study accepts.
A condition in which the immune system attacks the body’s own tissues, such as rheumatoid arthritis, lupus, psoriasis, type 1 diabetes or inflammatory bowel disease.
Immunotherapy studies often leave out active autoimmune disease, and some name exceptions, such as thyroid disease on replacement hormone. Check the exceptions this study lists.
ECG (electrocardiogram)
A recording of the heart’s electrical activity, taken with stickers on the chest, arms and legs. It takes a few minutes and does not hurt.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Clinically significant
Judged by the study doctor to matter for your health or for the study. It is a doctor’s decision, so ask the study team if you are unsure whether something counts.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Investigational drug or device
A drug or device being studied in a clinical trial.
It may be new, or already approved and being studied for another use, dose or form. Criteria often leave out people who took part in another study of one within a recent period, commonly 30 days or five half-lives.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Corticosteroids (steroids)
Anti-inflammatory medicines such as prednisone, prednisolone and dexamethasone — not the anabolic steroids used for muscle.
Studies differ in what they allow: check which steroid medicines, routes (tablets, injections, creams, inhalers, eye drops) and doses this study accepts.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Autoimmune disease
A condition in which the immune system attacks the body’s own tissues, such as rheumatoid arthritis, lupus, psoriasis, type 1 diabetes or inflammatory bowel disease.
Immunotherapy studies often leave out active autoimmune disease, and some name exceptions, such as thyroid disease on replacement hormone. Check the exceptions this study lists.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Healthy participants will receive a single dose of GTX-B001
Drug: GTX-B001
Healthy participants assigned to receive placebo will receive a single dose of normal saline
Drug: Normal Saline
Patients with cold urticaria or symptomatic dermographism will receive a single dose of GTX-B001
Drug: GTX-B001
Patients with cold urticaria or symptomatic dermographism assigned to receive placebo will receive a single dose of normal saline
Drug: Normal Saline
Single infusion of one of up to five dosages of GTX-B001
Also known as: ALY-301
Single infusion of normal saline
Safety as assessed by the incidence and severity of adverse events (Parts A and B)
Safety 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).
Time frame: Day 1 to Day 85
GTX-B001 pharmacokinetics (Parts A and B)
Serum concentrations of GTX-B001 at specified visits
Time frame: Day 1 to Day 85
GTX-B001 pharmacodynamics (Parts A and B)
Change from baseline in blood biomarkers such as serum tryptase
Time frame: Day 1 to Day 85
GTX-B001 pharmacodynamics in skin (Part B)
Change from baseline in mast cell density and mast cell activation markers upon cold or friction provocation, assessed from skin punch biopsy at baseline and three times post-treatment.
Time frame: Day 1 to Day 29
Evaluation of immunogenicity (Parts A and B)
Incidence of anti-drug antibodies
Time frame: Day 1 to Day 85
Disease control (Part B ColdU) - Critical Temperature Threshold (CTT)
Change from baseline and percentage of responders in Critical Temperature Threshold (CTT) over time as determined by provocation testing using the TempTest®. The CTT determines the highest temperature that induces symptoms.
Time frame: Day 1 to Day 85
Disease control (Part B SD) - Critical Friction Threshold (CFT)
Change from baseline and percentage of responders in Critical Friction Threshold (CFT) over time as determined by provocation testing using the FricTest®. The CFT determines the shortest pin length (or lowest pressure) that induces symptoms.
Time frame: Day 1 to Day 85
Disease control (Part B) - Urticaria Control Test (UCT)
Change from baseline and percentage of responders for the Urticaria Control Test (UCT). Total score ranges from 0 to 16. A score of 12 or higher indicates well-controlled chronic urticaria, while a score below 12 suggests poorly controlled disease.
Time frame: Day 1 to Day 85
Disease control (Part B ColdU) - Cold Urticaria Activity Score (Cold UAS)
Change from baseline in Cold Urticaria Activity Score (Cold UAS). The total score ranges from 0 to 6, the higher the score the higher the disease activity.
Time frame: Day 1 to Day 85
Disease control (Part B SD) - Symptomatic Dermographism Activity Score (SDAS)
Change from baseline in Symptomatic Dermographism Activity Score (SDAS)
Time frame: Day 1 to Day 85
Disease control (Part B ColdU) - Cold Urticaria Quality of Life Questionnaire (ColdU-QoL)
Change from baseline in Cold Urticaria Quality of Life Questionnaire (ColdU-QoL). The total score ranges from 0 to 100, the higher the score the higher the impairment.
Time frame: Day 1 to Day 85
Disease control (Part B SD) - Symptomatic Dermographism Quality of Life Questionnaire (SD-QoL)
Change from baseline in Symptomatic Dermographism Quality of Life Questionnaire (SD-QoL). The total score ranges from 0 to 100, the higher the score the higher the impairment.
Time frame: Day 1 to Day 85
Not enrolling at this site.
Plan to share: No
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From the registry record's own update history. This site started tracking changes on Sep 25, 2026; for anything earlier, see the record history on ClinicalTrials.gov ↗
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