American Academy of Allergy, Asthma and Immunology Annual Meeting

American Academy of Allergy, Asthma and Immunology Annual Meeting

Issue: April 2016
Perspective from James R. Baker Jr., MD
March 05, 2016
3 min read

LEAP-On: Early peanut introduction continued to reduce allergy risk after 1-year avoidance

Issue: April 2016
Perspective from James R. Baker Jr., MD
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LOS ANGELES — Early introduction of peanut maintained a reduction in the prevalence of peanut allergy despite 12 months of peanut avoidance, according to findings from the LEAP-On study simultaneously published in the New England Journal of Medicine and presented in a press conference at the American Academy of Allergy, Asthma and Immunology Annual Meeting.

In the original LEAP study, early introduction of peanuts significantly reduced the risk for the development of peanut allergy among children at high risk for this allergy and moderated immune responses to peanuts.

George du Toit, FRCPCH

George Du Toit

“The question then was: What if these infants who had been eating peanuts stopped eating peanuts?” George Du Toit, MD, study researcher from Evelina London Children’s Hospital and the Portland Hospital of London, said during a press conference. “There were some signals from eggs studies, in which, even after a short window of avoidance – around 4 weeks – many patients had lost that state of unresponsiveness that had protected them.”

To determine whether patients who had consumed peanut would remain protected against peanut allergy after an interruption of peanut consumption for 12 months, the researchers enrolled 550 of the eligible patients – regardless of previous inclusion in ‘peanut-consumption’ or ‘peanut-avoidance’ cohorts – from the primary trial to actively avoid peanut protein for 12 months.

According to study results, the rate of adherence to avoidance in the follow-up study was high: 90.4% in the ‘avoidance’ cohort vs. 69.3% in the ‘consumption’ cohort. At 72 months, peanut allergy was significantly more prevalent among patients in the ‘avoidance’ cohort than among those in the ‘consumption’ cohort (18.6% vs. 4.8%; P<0.001).

While three cases of allergy developed in each cohort, after 12 months of avoidance there was no significant increase in the prevalence of allergy among participants in the consumption group (3.6% at 60 months and 4.8% at 72 months; P= 0.25).

“The findings suggest that children who have regularly consumed peanut-containing foods from infancy to age 5 as a peanut allergy prevention strategy can safely switch to consuming peanut as desired as part of a normal diet,” Daniel Rotrosen, MD, director of NIAID’s Division of Allergy, Immunology and Transplantation, said in a press release. “We expect that many will continue to enjoy peanut-containing foods consumed regularly, and others will maintain their non-allergic status with moderate intervals of diminished or no peanut consumption.”

Additionally, the study demonstrated that fewer patients in the ‘consumption’ cohort had high levels of Ara h2–specific IgE and peanut-specific IgE, while patients in the ‘consumption’ cohort sustained a higher level of peanut-specific IgG4 and a higher peanut-specific IgG4:IgE ratio.

“Further studies are needed to determine the longer term effects of intermittent ad lib peanut consumption following introduction early in life,” Gideon Lack, MD, from King's College London, said in a press release. “Parents of infants and young children with eczema or egg allergy should consult with an allergist, pediatrician or their general practitioner prior to feeding them peanut products.”– by Bob Stott


Du Toit G, et al. N Eng J Med. 2016; doi:10.1056/NEJMoa1514209.

Disclosure: Du Toit reports no relevant financial disclosures. The LEAP study was funded by the National Institute of Allergy and Infectious Diseases, and the Food Allergy Research and Education. Please see the full study for a list of all other authors’ relevant financial disclosures.