Oral immunotherapy safe, effective for children with high-threshold peanut allergy
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Fixed-dose OIT appeared safe and effective for younger children with high-threshold peanut allergy, according to a single-center, cross-sectional prospective study published in Annals of Allergy, Asthma & Immunology.
Soad Haj Yahia, MD, clinical immunologist and allergist in the angioedema and allergy unit at the center for autoimmune diseases at Sheba Medical Center in Tel Hashomer, Israel, and colleagues evaluated data of 104 children aged 1 to 18 years (89% aged younger than 6 years; 56% boys) with a diagnosis of peanut allergy proven by an oral food challenge between January 2019 and January 2021.
The 76 children (73%) who had a single highest eliciting dose of peanut protein of 100 mg or less causing an allergic reaction were categorized with a low-threshold peanut allergy (LTPA). The 28 children (27%) with a single highest eliciting dose higher than 100 mg were classified with a high-threshold peanut allergy (HTPA).
Overall, children with HTPA tended to have smaller peanut skin prick test results (9.2 mm vs. 11.6 mm), lower sIgE levels (6.4 vs. 26.7) and lower Ara h2 sIgE levels (5.1 vs. 22.3; P = .03 for all) compared with the children with LTPA. They also were younger (average age, 41 months vs. 57 months; P = .053).
Of the children with HTPA, nine with a single highest eliciting dose of 300 mg or greater — defined as a very HTPA — received a fixed daily dose of 300 mg of peanut protein for 40 weeks. The other 19 HTPA children, who had a single highest eliciting dose between 100 and 300 mg, received a daily dose of 100 mg of peanut protein for 20 weeks, followed by a 300 mg OFC. Those who passed continued with a 300 mg daily dose for 20 weeks.
After 40 weeks, all the children with HTPA underwent another OFC of up to 2 g of peanut protein. Children who passed then received 2 g of peanut protein three times a week as a maintenance dose. Six months later, participants had one more OFC, with up to 15 g of peanut protein or peanut doses that were age appropriate.
Eight of the nine children with very HTPA completed the 40-week treatment period, passed the 2 g exit challenge and completed the 6-month maintenance protocol. All eight also passed the 6-month follow-up challenge and are now consuming their maintenance dose and age-appropriate doses of foods that include 4 g to 15 g of peanut protein.
Fifteen of the remaining 19 children with HTPA passed the 2 g exit challenge and began the maintenance protocol. They then passed the 6-month follow-up challenge and are now consuming age-appropriate doses of foods with 3 g to 10 g of peanut proteins without issue.
Overall, 23 of 28 patients (82%) completed the protocol successfully, began the maintenance dose and successfully incorporated foods that include peanut into their regular diet along with the maintenance dose, the researchers wrote.
There was a single anaphylactic reaction at home, which resolved promptly with epinephrine, two mild allergic reactions treated with antihistamines and no gastrointestinal complaints.
Although the researchers said these safety results need confirmation in larger, blinded studies, they added that these findings support the protocol’s adoption among relatively young patients with higher-threshold peanut allergies.
Perspective
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This interesting study offers new information about children with HTPA, a group that has been excluded from most clinical trials. It is not surprising that the HTPA group was younger with a lower peanut IgE.
The authors evaluated the use of a fixed-dose regimen for OIT. Typically, OIT protocols include a buildup period over several months, which requires frequent office visits and is often associated with a higher rate of reactions compared with the maintenance phase.
In this protocol, the authors used the initial food challenge to start home dosing using a fixed dose. There was no need for frequent buildup visits. This is an interesting concept that could be appealing to many families.
The safety information that is provided suggests that overall, this regimen was well tolerated. However, two participants were discontinued due to allergic reactions at home to a dose previously tolerated in clinic and due to an anaphylactic reaction at home.
The authors did not provide detailed information about frequency of dosing symptoms, but they did note that there were no gastrointestinal complaints, which is much different than typical OIT studies where 10% to 20% may drop out due to gastrointestinal symptoms.
Finally, it is always important to consider the goals of the family. The HTPA group is still at risk for peanut reactions, but they do have a lower risk for reacting to cross-contamination compared with the LTPA group. Families should understand the there is risk with the treatment itself.
In this study, it was surprising that all the children introduced dietary peanut. In my experience, many children with peanut allergy do not want to eat it. So again, it is important to discuss goals with the family when considering risks and benefits of any potential treatment.
These authors provided interesting data about a group of children with HTPA. Additional larger studies are needed to better understand the safety and efficacy of this approach.
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