Effect of Avoidance on Peanut Allergy After Early Peanut Consumption
Du Toit G, Sayre PH, Roberts G et al; Immune Tolerance Network LEAP-On Study Team
N Engl J Med. 2016;374:1435-1443
LEAP Study Follow-up
The Learning Early about Peanut Allergy (LEAP) trial demonstrated that introduction of peanut into the diet of infants at high risk for allergy before the age of 1 year significantly (by 81%) reduced the prevalence of peanut allergy at age 5 years. The current study is a 12-month follow-up of the same cohort, which assessed whether rates of peanut allergy remained low when families were no longer encouraged to include peanut in their child's diet.
The follow-up study was conducted in the United Kingdom. LEAP, which originally enrolled 640 infants, stratified infants into two groups of 314 infants on the basis of skin-prick testing results ("no response" vs a 1- to 4-mm wheal). Infants were then randomly assigned to peanut avoidance vs consumption, and outcomes at age 5 years were evaluated. Slightly more than 88% of the LEAP infants were involved in the follow-up trial.
In the 12 months after the end of the LEAP trial, 79% of the peanut avoidance group and 46% of the peanut consumption group had completely avoided peanut consumption. For the primary outcome, at 72 months, 18.6% of the children originally assigned to the avoidance group had a peanut allergy vs only 4.8% of those originally assigned to the consumption group. When outcomes were examined on a per-protocol basis, the findings were very similar, with 19.2% of the avoidance group having a peanut allergy vs only 2.1% of the consumption group.
The investigators concluded that among children at high risk for allergy who were exposed to peanuts during early life, a 1-year period of avoidance was not associated with an increase in peanut allergy.
This study received a great deal of lay press, as did its predecessor. This study and others like it are critically important to child health, given the meteoric rise in peanut sensitivity in developed countries.
As the father of a peanut-allergic child, I have had a personal interest in following the progression of the research in this area, and it is heartening to see that we are quickly nearing the point where we can apply preventive therapy to begin to reduce the striking rise in peanut allergy in the developed world. I suspect that we will see further longitudinal follow-up of this cohort to help us determine just how stable the protection offered by early exposure might be.
Because of the rapidly changing thought about early introduction of peanut, the LEAP study team and others issued a brief, yet very helpful, document to provide interim guidance to clinicians and parents on how to apply these findings. This document provides a summary of the selection criteria for the LEAP trial (in other words, the patient population to consider for treatment), and offers examples of the peanut-containing foods used in the trial. The authors caution against applying this approach to all infants (because the LEAP study focused on only high-risk infants), and they suggest involving an allergist or immunologist as a resource for confirming eligibility before commencing home introduction of peanut.
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Cite this: Peanuts and Preventing Allergy: Does It Last? - Medscape - May 09, 2016.