Follow up of LEAP Participants and Their Families

Follow up of Learning Early About Peanut Allergy (LEAP) Participants and Their Families: LEAP Trio (ITN070AD)

This prospective, cross-sectional study was designed to improve understanding of how early-life introduction of peanuts may promote the maintenance of tolerance in adolescence and will serve as an additional safety evaluation of the original nutritional intervention.

Study Overview

• Status: Completed
• Conditions: Peanut Allergy

Detailed Description

Background: Food allergies and specifically peanut allergy (PA) are increasingly common conditions and are an important public health concern. Dietary avoidance of peanut in early life has been recommended in many countries. However, there is evidence that the prevalence of PA is decreased in countries where children are fed peanut beginning at an early age.

The LEAP (Learning Early About Peanut allergy) Study (Protocol ITN032AD, NCT00329784) demonstrated that the early consumption of peanut in high-risk infants successfully reduced the prevalence of peanut allergy at five years of age when compared to peanut avoidance. The LEAP-On Study (Protocol ITN049AD, NCT01366846) was a follow-on study to LEAP and demonstrated that children who consumed peanut in the LEAP study remained protected against developing peanut allergy after cessation of peanut consumption for a period of 12 months.

This LEAP Trio cohort study, a longer-term follow-up of the LEAP study participants, assessed whether the benefits of regular early-life peanut consumption are maintained over many years when peanut consumption is ad libitum (in the amount and frequency chosen by the individual participant).

The three cohorts in LEAP-Trio include:

• LEAP Participants (NCT00329784, NCT01366846)
• their Siblings and
• their Parents

The study began on July 5, 2018, with data collection continuing until August 31, 2022. This allowed for the enrollment of former LEAP participants aged 12 years.:

• The enrollment phase was 217 weeks (4 years, 2 months).

--The LEAP siblings and parents were enrolled concurrently with the LEAP participant.

• Study participation was defined as a single visit (Visit 144 months); however, more than one clinic appointment might have been required to complete all assessments and were required to be completed within 8 weeks of the in-person visit. Due to COVID-19, telephone visits were undertaken when participants were not able to or did not wish to come into the clinic or have a home visit. The visit window did not apply to the telephone visit. Participants who underwent a telephone visit were invited to subsequently undergo an in-person clinic visit or home visit.

Participant assessments included general medical, -dietary, -allergy (including but not limited to oral peanut food challenges for former LEAP participants and their siblings), and mechanistic assessments (involving the collection of biological specimens, a blood draw, skin prick testing, as examples, to explore hypotheses related to potential mechanisms of peanut allergy).

• Study Type: Observational
• Enrollment (Actual): 1868

Contacts and Locations

Study Locations

• United Kingdom
  • London, United Kingdom, SE1 7EH
    • Evelina London Children's Hospital

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 1 second and older (Child, Adult, Older Adult)
• Accepts Healthy Volunteers: No

• Sampling Method: Non-Probability Sample

Study Population

• Original Learning Early About Peanut (LEAP) allergy study participants (NCT00329784): at high risk for peanut allergy, given the presence of severe eczema, egg allergy, or both
• Siblings of LEAP participants
• Parents of LEAP participants

Description

Inclusion Criteria:

Inclusion Criteria - LEAP Participants:

• Participation in LEAP;
• At least 9.5 years of age
• Willingness to participate in at least one study data collection (i.e. questionnaire, skin pricking testing, or blood draw) procedure; and
• Assent by child and informed consent by parent or legal guardian.

Inclusion Criteria - LEAP Siblings:

• Sibling of LEAP participant;
• Willingness to participate in at least one study data collection (i.e. questionnaire, skin pricking testing, or blood draw); and
• Assent by child and informed consent by parent or legal guardian if child is younger than 16; siblings aged 16 and over will provide their own consent.

Inclusion Criteria - LEAP Parents:

• Biological parent of LEAP participant;
• Willingness to participate in at least one study data collection (i.e. questionnaire, skin pricking testing, or blood draw); and
• Informed consent (for participants only returning a Questionnaire, informed consent will be implied).

Exclusion Criteria:

• There are no exclusion criteria for LEAP Participants, LEAP Siblings, LEAP Parents

Study Plan

How is the study designed?

Design Details

• Observational Models: Cohort
• Time Perspectives: Cross-Sectional

Number of groups / cohorts

8

Cohorts and Interventions

Group / Cohort
LEAP Participants: Peanut Avoidance; Participants of the LEAP study who enrolled in the LEAP Trio study and were originally randomized to the Peanut Avoidance treatment arm upon entry into the LEAP study.
LEAP Participants: Peanut Consumption; Participants of the LEAP study who enrolled in the LEAP Trio study and were originally randomized to the Peanut Consumption treatment arm upon entry into the LEAP study.
Younger Siblings: Peanut Avoidance; Participants enrolled in the LEAP Trio study who are younger siblings of a LEAP Participant who was randomized to the Peanut Avoidance treatment arm upon entry into the LEAP study.
Younger Siblings: Peanut Consumption; Participants enrolled in the LEAP Trio study who are younger siblings of a LEAP Participant who was randomized to the Peanut Consumption treatment arm upon entry into the LEAP study.
Older Siblings: Peanut Avoidance; Participants enrolled in the LEAP Trio study who are older siblings of a LEAP Participant who was randomized to the Peanut Avoidance treatment arm upon entry into the LEAP study.
Older Siblings: Peanut Consumption; Participants enrolled in the LEAP Trio study who are older siblings of a LEAP Participant who was randomized to the Peanut Consumption treatment arm upon entry into the LEAP study.
Parents: Peanut Avoidance; Participants enrolled in the LEAP Trio study who are parents of a LEAP Participant who was randomized to the Peanut Avoidance treatment arm upon entry into the LEAP study.
Parents: Peanut Consumption; Participants enrolled in the LEAP Trio study who are parents of a LEAP Participant who was randomized to the Peanut Consumption treatment arm upon entry into the LEAP study.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Percentage of LEAP Participants With Peanut Allergy	Peanut allergy status at LEAP Trio Visit 144 was determined by peanut challenge where possible. Participants who met criteria for peanut oral allergy syndrome in the absence of primary peanut allergy were not considered peanut allergic. Individuals who reported consuming at least 2 g of peanut protein without reaction on at least one occasion in the last year were considered peanut tolerant. If oral challenge was not possible and participants did not meet the above criteria for tolerance, peanut allergy status was determined by an internally and externally validated novel peanut allergy prediction model using data for peanut wheal size (mm), peanut specific IgE (kU/L), Ara h1 (kU/L), Ara h2 (kU/L) and Ara h3 (kU/L)	Assessments were performed on consented LEAP Participants at the time of the LEAP Participant's Visit 144 (when the LEAP Study (NCT00329784) Participant was approximately 12 years old (age approximately 144 months)).
Percentage of Younger Siblings With Peanut Sensitization	Peanut sensitization in the siblings of the LEAP Participants was defined as meeting at least one of the following criteria: Specific-IgE ≥0.35 kU/L or Specific-IgE to individual peanut component Ara h2 ≥0.1 kU/L, or Skin prick test wheal to peanut ≥3mm	Assessments were performed on consented siblings at the time of the LEAP Participant's Visit 144 (when the LEAP Study (NCT00329784) Participant was approximately 12 years old (age approximately 144 months)).

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Average Weekly Peanut Protein Consumption of LEAP Participants, Younger Siblings, Older Siblings and Parents	At LEAP Trio Visit 144, participants were asked to provide responses to questions about their peanut protein consumption. Responses obtained at LEAP Trio Visit 144 were based on the recollection of peanut consumption during the 4 weeks prior to the LEAP Trio study Visit 144.	Assessments were performed on consented LEAP Participants and family members at the time of the LEAP Participant's Visit 144 (when the LEAP Study (NCT00329784) Participant was approximately 12 years old (age approximately 144 months)).
Peanut Skin Prick Test Wheal Size for LEAP Participants, Younger Siblings, Older Siblings and Parents	Skin prick tests were performed to assess participants for potential peanut allergy, select food allergens, and select aeroallergens	Assessments were performed on consented LEAP Participants and family members at the time of the LEAP Participant's Visit 144 (when the LEAP Study (NCT00329784) Participant was approximately 12 years old (age approximately 144 months)).
Peanut Specific-IgE Measurements for the LEAP Participants, Younger Siblings, Older Siblings, and Parents	Participants had blood draws to assess specific-IgE measurements to peanut, select food allergens and select aeroallergens	Assessments were performed on consented LEAP Participants and family members at the time of the LEAP Participant's Visit 144 (when the LEAP Study (NCT00329784) Participant was approximately 12 years old (age approximately 144 months)).
SCORAD Score for the Eczema Severity in LEAP Participants, Younger Siblings and Older Siblings	Eczema severity was assessed using a modified Scoring Atopic Dermatitis (SCORAD) assessment. The range of the SCORAD is 0-103. A score of 0 indicates no eczema, scores between 0 and 15 indicate mild eczema, scores between 15 and 40 indicate moderate eczema, and scores greater than 40 indicate severe eczema.	Assessments were performed on consented LEAP Participants and family members at the time of the LEAP Participant's Visit 144 (when the LEAP Study (NCT00329784) Participant was approximately 12 years old (age approximately 144 months)).
Percentage of LEAP Participants, Younger Siblings, Older Siblings, and Parents With Eczema	Participants were classified as having eczema using standard methodology. Participants were assessed for eczema using a modified Scoring Atopic Dermatitis System (SCORAD) and using participant report of a history of eczema. The range of the SCORAD is 0-103. A score of 0 indicates no eczema, scores between 0 and 15 indicate mild eczema, scores between 15 and 40 indicate moderate eczema, and scores greater than 40 indicate severe eczema.	Assessments were performed on consented LEAP Participants and family members at the time of the LEAP Participant's Visit 144 (when the LEAP Study (NCT00329784) Participant was approximately 12 years old (age approximately 144 months)).
Percentage of LEAP Participants, Younger Siblings, Older Siblings, and Parents With Asthma	Participants were classified as having asthma if they meet at least one of the following definitions: Participant report of cough, wheeze, or shortness of breath that was responsive to therapy with bronchodilators on two or more occasions in the previous 24 months; or required one visit to a physician in the previous 24 months; or occurred during the night, during early morning, or upon exercising in the intervals between exacerbations at any time in the previous 12 months.; Participant report of an asthma diagnosis with current use of asthma medications (short-acting beta-agonist or controller); Participant report of transient wheeze on exposure to a suspected allergen with confirmatory allergy tests	Assessments were performed on consented LEAP Participants and family members at the time of the LEAP Participant's Visit 144 (when the LEAP Study (NCT00329784) Participant was approximately 12 years old (age approximately 144 months)).
Percentage of LEAP Participants, Younger Siblings, Older Siblings, and Parents With Perennial Rhinitis	Participants were considered to have perennial rhinitis if they demonstrated a sensitization to the aeroallergen and clinical history of rhinoconjunctivitis symptoms experienced when exposed to the relevant allergen. Sensitization to the relevant allergen was defined as: Allergen specific IgE ≥ 0.35 kU/L, or; Skin prick test wheal size to allergen ≥ 3 mm.	Assessments were performed on consented LEAP Participants and family members at the time of the LEAP Participant's Visit 144 (when the LEAP Study (NCT00329784) Participant was approximately 12 years old (age approximately 144 months)).
Percentage of LEAP Participants, Younger Siblings, Older Siblings and Parents With Seasonal Rhinitis	Participants were considered to have seasonal rhinitis if they demonstrated a sensitization to a seasonal aeroallergen and clinical history of rhinoconjunctivitis symptoms experienced when exposed to the allergen during the relevant season. Sensitization to the relevant allergen was defined as: Allergen specific IgE ≥ 0.35 kU/L, or; Skin prick test wheal size to allergen ≥ 3 mm	Assessments were performed on consented LEAP Participants and family members at the time of the LEAP Participant's Visit 144 (when the LEAP Study (NCT00329784) Participant was approximately 12 years old (age approximately 144 months)).
Percentage of LEAP Younger Siblings, Older Siblings and Parents With Peanut Allergy	Peanut allergy status at LEAP Trio Visit 144 was determined by peanut challenge where possible. Participants who met criteria for peanut oral allergy syndrome in the absence of primary peanut allergy were not considered peanut allergic. Individuals who reported consuming at least 2 g of peanut protein without reaction on at least one occasion in the last year were considered peanut tolerant. If oral challenge was not possible and participants did not meet the above criteria for tolerance, peanut allergy status was determined by an internally and externally validated novel peanut allergy prediction model using data for peanut wheal size (mm), peanut specific IgE (kU/L), Ara h1 (kU/L), Ara h2 (kU/L) and Ara h3 (kU/L)	Assessments were performed on consented family members at the time of the LEAP Participant's Visit 144 (when the LEAP Study (NCT00329784) Participant was approximately 12 years old (age approximately 144 months)).
Percentage of LEAP Participants, Younger Siblings and Older Siblings With at Least One Peanut-related Adverse Event	Peanut-related adverse events were reported from reactions experienced during or within 30 days after the LEAP Trio Visit 144 peanut oral food challenge (peanut OFC)	Within 30 days after peanut OFC performed on consented LEAP Participants and family members at the time of the LEAP Participant's Visit 144 (when the LEAP Study (NCT00329784) Participant was approximately 12 years old (age approximately 144 months)).

Collaborators and Investigators

• Sponsor: National Institute of Allergy and Infectious Diseases (NIAID)
• Collaborators: PPD; Immune Tolerance Network (ITN)
• Investigators: Study Chair: Gideon Lack, MD, Evelina Children's Hospital, Guy's and St. Thomas's NHS Foundation Trust

Publications and helpful links

General Publications

• Sever ML, Calatroni A, Roberts G, du Toit G, Bahnson HT, Radulovic S, Larson D, Byron M, Santos AF, Huffaker MF, Wheatley LM, Lack G. Developing a Prediction Model for Determination of Peanut Allergy Status in the Learning Early About Peanut Allergy (LEAP) Studies. J Allergy Clin Immunol Pract. 2023 Jul;11(7):2217-2227.e9. doi: 10.1016/j.jaip.2023.04.032. Epub 2023 May 3.

Helpful Links

• National Institute of Allergy and Infectious Diseases (NIAID)
• Division of Allergy, Immunology, and Transplantation (DAIT)
• Immune Tolerance Network (ITN)

Study record dates

Study Major Dates

• Study Start (Actual): July 5, 2018
• Primary Completion (Actual): August 31, 2022
• Study Completion (Actual): August 31, 2022

Study Registration Dates

• First Submitted: April 17, 2018
• First Submitted That Met QC Criteria: June 1, 2018
• First Posted (Actual): June 6, 2018

Study Record Updates

• Last Update Posted (Actual): March 29, 2024
• Last Update Submitted That Met QC Criteria: March 28, 2024
• Last Verified: March 1, 2024

More Information

Terms related to this study

• Keywords: prevention; food; allergy; peanut
• Additional Relevant MeSH Terms: Immune System Diseases; Food Hypersensitivity; Hypersensitivity, Immediate; Nut and Peanut Hypersensitivity; Hypersensitivity; Peanut Hypersensitivity
• Other Study ID Numbers: DAIT ITN070AD; LEAP Trio (Other Identifier: Immune Tolerance Network); NIAID CRMS ID#: 38498 (Other Identifier: DAIT NIAID)

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: YES
• IPD Plan Description: The plan is to share data upon completion of the study in: Immunology Database and Analysis Portal (ImmPort), a long-term archive of clinical and mechanistic data from DAIT-funded grants and contracts.
• IPD Sharing Time Frame: On average, within 24 months after database lock for the trial.
• IPD Sharing Access Criteria: Open access.

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No