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I was excited to see the LEAP Trio study published. It is a follow-up of the LEAP and LEAP-On studies, which demonstrated that early introduction and incorporation of age-appropriate peanut-containing foods decrease the risk of developing a peanut allergy in childhood. LEAP Trio's results are important not just for babies but also, in my opinion, for those with food allergies. More on that in a bit.
Let's recap the study.
The Research Question
Dr. Gideon Lack, the primary investigator of the LEAP and LEAP-On trials, and his team published the LEAP Trio study yesterday in NEJM Evidence. The study investigates whether early introduction of peanut into babies at risk of peanut allergy and incorporating peanut into their diets from infancy through age five-years can prevent peanut allergy through adolescence.
The Outcome
The LEAP Trio demonstrates that early incorporation of peanut into babies at risk of peanut allergy results in significantly fewer adolescents having peanut allergies compared to their peanut-avoidance peers.
Why This Matters
In Babies Without Food Allergies
Long-term data is incredibly valuable, especially in pediatric research. This long-term study shows that the early introduction and incorporation of peanut-containing foods prevents peanut allergies in high-risk children, both in early childhood and as they grow up into adolescence.
The LEAP Trio study should reassure doctors and patients alike that getting peanut into a baby’s diet sooner rather than later will help that baby avoid peanut allergies in early childhood years but also into adolescence. If the LEAP approach is applied to babies, it can save families a lot of heartache and distress as a peanut allergy is less likely to occur.
What if a child already has a food allergy?
When thinking about food allergies, I think of them as a gradient. Yes, a food-allergic person already has an epigenetic predisposition to have a food allergy, but that person's tolerance of an allergen can vary both within that individual and compared to others with the same allergy.
For example, some food-allergic children can tolerate relatively large amounts of their allergens where as some food-allergic children react to even microgram amounts. Also, an allergic individual's threshold to react can change with illness, other allergen burdens, medications, etc. So food allergy is, in a way, somewhat of a spectrum.
Note that it remains difficult to characterize an individual's threshold to react and the severity that a reaction could reach. It's critical to talk with your child's allergist about their food allergy reaction plan and, if the food allergy is IgE-mediated, then to give epinephrine as soon as anaphylaxis is recognized.
So why might LEAP Trio matter in children who already have food allergies?
It's because the study demonstrates that interventions in babies that are continued through early childhood can impact health into adolescence. It underscores the importance of early childhood in modifying the immune system. I have been a big believer in this critical window for some time now, and it continues to be supported by evidence.
While LEAP Trio did not study early childhood OIT, I believe the study's findings support the concept that early interventions in immune system-modification can be long-lasting. This is why so many patients who start OIT young have long-lasting effects - we've essentially reprogrammed the immune system before its allergic programming has really set in.
Side note: Is early childhood OIT a cure for food allergy?
We can never say OIT is a cure because a cure is treatment that
is applied to condition,
resolves the condition, and then
the condition does not recur even upon removal of the treatment.
In OIT, the goal is to have the person safely eat the food, so we don't want to ever remove the food from the diet. On the flip side, some studies do sustained unresponsiveness challenges in which:
an OIT study participant will reach maintenance OIT dosing,
be on that dose for a specific amount of time,
have a negative ingestion challenge, then
begin strictly avoiding the food for a specific period of time, then
have another challenge after that period of avoidance:
if the challenge is positive (the child reacts), then sustained unresponsiveness has NOT been achieved; the child is often advised to resume maintenance OIT.
if the challenge is negative (no reaction), then sustained unresponsiveness has been achieved; recommendations at this point are typically to keep the food in the diet to help prevent the loss of tolerance.
In research, studying sustained unresponsiveness has its merits. In practice, however, I do not typically embark on such approaches as the patient and family have worked hard to reach maintenance and then to have a negative ingestion challenge, ultimately getting their child to a much safer place than when we started - and I don't want to jeopardize that safety by trying to determine sustained unresponsiveness when the recommendation will be the same - keep the food in the diet.
It's great to have the long-term data of LEAP Trio.
We as allergists have seen for years now that early incorporation of commonly allergenic foods into the diets of babies helps grow tolerance to these foods, i.e. helps prevent food allergies. Whatever we as allergists can do to preserve a family’s lifestyle of never knowing what it’s like to have a child with food allergies, we need to do because living an allergy-free life is a blessing you never quite appreciate until it’s gone. This study demonstrates that early incorporation of peanut can result in an adolescence free of peanut allergy, which is a priceless blessing.
