The Clinical Impact of the Basophil Activation Test to Diagnose Food Allergy

Study Purpose

The BAT Impact study is a prospective multicentre study in the UK using a biomarker-led study design to compare the incidence of adverse events (defined as allergic reactions during oral food challenges) in a randomized-controlled trial. Patients will either follow the standard-of-care (i.e. an oral food challenge in case of equivocal SPT/sIgE) or follow a basophil activation test (BAT)/mast cell activation test (MAT)-based strategy, i.e. patients with a positive BAT or MAT are dispensed of an oral food challenge (OFC) and patients with a negative BAT/MAT undergo an OFC.

Recruitment Criteria

Accepts Healthy Volunteers Healthy volunteers are participants who do not have a disease or condition, or related conditions or symptoms	No
Study Type An interventional clinical study is where participants are assigned to receive one or more interventions (or no intervention) so that researchers can evaluate the effects of the interventions on biomedical or health-related outcomes. An observational clinical study is where participants identified as belonging to study groups are assessed for biomedical or health outcomes. Searching Both is inclusive of interventional and observational studies.	Interventional
Eligible Ages	6 Months - 15 Years
Gender	All

More Inclusion & Exclusion Criteria

Inclusion Criteria:

- Children and young people aged 6 months to 15 years.

- Suspected allergy to one of the study foods (peanut, cow's milk, egg, cashew, sesame) - defined as: - history of clinical reaction or.

- evidence of IgE sensitisation (SPT>0mm and/or specific IgE>=0.10 KU/L) to the respective food or.

- reassessment for possible resolution of allergy to the specific food following previous diagnosis of food allergy.

- Need for an oral food challengeOFC to the study food.

- Oral food challengeOFC to reach amount of food protein in a typical portion size for child's age.

- Consent from adults with parental responsibility and assent from children and young people in an age appropriate form.

Exclusion Criteria:

- Clinically significant chronic illness other than atopic diseases; - Previous history of severe life-threatening reaction to the suspected food with documented decrease in oxygen saturation (<90%), hypotension (≥20% reduction in systolic blood pressure) and/or admission to intensive care; - Unwillingness to comply with study procedures, namely to undergo a diagnostic food challenge; - Contra-indication for diagnostic food challenge, namely: - Uncontrolled atopic diseases (e.g. eczema, asthma, rhinitis); - Chronic medical conditions that pose significant risk in the event of anaphylaxis or treatment of anaphylaxis (e.g. cardiac disease, severe lung disease, pregnancy, mastocytosis); - Inability to discontinue medications that might interfere with assessment or safety (e.g. antihistamines, β-agonists, β-blockers, NSAIDs, ACE inhibitor, antacids); - Recent (within 7-14 days) treatment with systemic steroids or prolonged high-dose systemic steroids or immunosuppressants; - Undergoing treatment with omalizumab, food or inhalant allergen immunotherapy or other systemic immunomodulatory treatment; - Inability to stop anti-histamines prior to SPT or OFC.

Trial Details

Trial ID: This trial id was obtained from ClinicalTrials.gov, a service of the U.S. National Institutes of Health, providing information on publicly and privately supported clinical studies of human participants with locations in all 50 States and in 196 countries.	NCT05309772
Phase Phase 1: Studies that emphasize safety and how the drug is metabolized and excreted in humans. Phase 2: Studies that gather preliminary data on effectiveness (whether the drug works in people who have a certain disease or condition) and additional safety data. Phase 3: Studies that gather more information about safety and effectiveness by studying different populations and different dosages and by using the drug in combination with other drugs. Phase 4: Studies occurring after FDA has approved a drug for marketing, efficacy, or optimal use.	N/A
Lead Sponsor The sponsor is the organization or person who oversees the clinical study and is responsible for analyzing the study data.	King's College London
Principal Investigator The person who is responsible for the scientific and technical direction of the entire clinical study.	Alexandra Santos, MD, PhD
Principal Investigator Affiliation	King's College London
Agency Class Category of organization(s) involved as sponsor (and collaborator) supporting the trial.	Other
Overall Status	Recruiting
Countries	United Kingdom
Conditions The disease, disorder, syndrome, illness, or injury that is being studied.	Food Allergy, Food Allergy in Infants, Food Allergy in Children, Food Allergen Sensitisation, Milk Allergy, Egg Allergy, Nut Allergy

Additional Details

Children aged 6 months to 15 years requiring an oral food challenge to one of the study foods (milk, egg, peanut, sesame or cashew nut) will be invited to participate in the study. Eleven centres across the UK will be recruiting participants and perforning clinical procedures, such as skin prick testing and oral food challenges (OFC), as per standard clinical care. Participants will be randomised 4:5 to either have the standard-of-care, i.e. oral food challenge to the suspected food, or take BAT (MAT if BAT inconclusive) into account to decide whether or not OFC will be required: if BAT/MAT is positive, food allergy will be confirmed without doing OFC; if BAT/MAT is negative, participants in the biomarker arm will undergo OFC. The primary outcome is the proportion of positive OFC in the biomarker arm compared with the standard-of-care arm. Secondary outcomes are: number of OFC, quality of life, anxiety and costs associated with the diagnostic work-up.

Arms & Interventions

Arms

Experimental: Biomarker arm

All participants will have blood taken to test for BAT/MAT. Participants with a positive BAT/MAT will dispense from oral food challenge (OFC). Participants with negative or inconclusive BAT/MAT will undergo OFC.

Active Comparator: Standard-of-care arm

All participants in the standard-of-care arm will have blood taken to test for BAT/MAT. Regardless of the result of BAT/MAT, all participants in this arm will undergo an oral food challenge, as per the current standard-of-care.

Interventions

Diagnostic Test: - Basophil activation test (BAT)

Basophils and mast cells are the key drivers of food allergic reactions and anaphylaxis to foods. The study team have developed new tests that measure the reaction of mast cells and basophils by flow cytometry following stimulation with allergen, the BAT and the MAT: • BAT uses fresh whole blood from patients added to allergen and antibodies in a test tube. The tube containing the allergic cells are then analysed one by one to estimate how many and how much express activation markers on their surface, CD63 and CD203c. MAT uses a human mast cell line (LAD2 cells) which are human mast cells grown in the laboratory to which patients' plasma is added in order to mimic the patients' own mast cells. Sensitised LAD2 cells are then stimulated with allergen or controls and analysed by flow cytometry to assess the expression of the activation marker CD63 on the cell surface, similar to what happens in the BAT. Results of MAT will be considered only in cases of non-responding basophils.

Diagnostic Test: - Oral food challenge (OFC)

Consumption of the food suspected of causing an allergic reaction in a medically supervised environment, starting with small amounts and progressively increasing the dose at regular intervals up to a cumulative dose corresponding to an age-appropriate portion of the food.

Contact a Trial Team

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