March 1, 2021 -- Allergy drops administered under the tongue are safe and effective as treatment for peanut allergy, even in children as young as 1, according to new research.

In a double-blind, placebo-controlled trial of 36 children ages 1 to 4 years old who were allergic to peanuts, those who were randomly assigned to receive peanut immunotherapy drops showed significant desensitization to peanuts at the end of the 3-year trial compared with children who received placebo.

In addition, there was a "strong potential" that the treatment lasted 3 months after the trial ended for the toddlers who received the active treatment, according to the researchers.

The findings were presented in a at the 2021 American Academy of Allergy, Asthma & Immunology virtual annual meeting. Allergy drops and other orally-given immunotherapies are used as treatments for allergies in children, but usually not in children as young as toddlers.

"We have learned from some studies … that strongly suggest that the immune systems in younger patients may be more amenable to change, and there may be some justification for early intervention," study lead author Edwin H. Kim, MD, director of the UNC Food Allergy Initiative at the University of North Carolina School of Medicine in Chapel Hill, said in an interview with Medscape.

"Based on both of those ideas, we wanted to take our … approach, which we have shown to have a pretty good efficacy in older children, and bring it down to this younger group and see if it still could have the same efficacy and also maintain what seems to be a very good safety signal," he said.

Last year, the FDA Palforzia, a peanut allergen powder, for the treatment of peanut allergy in children 4 and older. “It is a great option, but I think what we have learned over time is that this approach is not for everybody," Kim said.

Palforzia is a powder made from peanuts that is mixed in food like yogurt or pudding that the child then eats daily, according to a rigorous schedule. But Palforzia treatment presents some difficulties. It must be mixed with food, like pudding or apple sauce. Then, the child must eat it, which can be a challenge with some children.

" It tastes and smells like peanut which can cause aversion. Kids have to refrain from exercise or strenuous activity for at least 30 minutes before and after dosing and have to be observed for up to 2 hours postdose for symptoms," Kim said.

"It's a great drug, but the treatment could be overly difficult for certain families to be able to do, and in some cases the side effects may be more than certain patients are able or willing to handle, so there is a real urgent need for alternative approaches," Kim said. "Sublingual immunotherapy is several drops under the tongue, held for 2 minutes, swallowed and done."

In the new study, Kim and his colleagues tested the feasibility, efficacy, and safety of sublingual immunotherapy with allergy drops for children age 4 years and younger with peanut allergy.

Both groups were similar with regard to gender, race, and ethnicity, and all children were previously allergic with positive blood and skin tests and a positive reaction during the baseline food challenge.

The researchers randomly assigned the children to receive allergy drops or to receive placebo drops for 3 years. Fifty children began the study and 36 completed it.

At the end of the 3-year study period, the children’s allergies were tested with up to 4,333 mg of peanut protein.

Children were tested again 3 months after ending the therapy to see if they were still had allergic reactions to peanut protein.

Fourteen of the children receiving allergy drops, and none of the children receiving placebo, passed the food challenge at the end of the trial. Twelve of the children receiving allergy drops and two of the children receiving placebo passed the challenge 3 months later.

Additionally, children who received allergy drops saw improvement in a allergy skin prick test.

The most common side effect reported was mouth irritation or itchiness. Most side effects resolved on their own, although some patients used an antihistamine. Getting children as young as 1 to hold the dose under their tongue was a challenge in some instances, but it eventually worked out, Kim said.

"It took a lot of work from the parents as well as from our research coordinators in trying to train these young kids to, first of all, allow us to put the peanut medication in the mouth and then to try as best as possible to keep it in their mouth for up to 2 minutes, but the families involved in our study were very dedicated and so we were able to get through that," he said.

Study Merits Larger Numbers

"Overall, these findings suggest the promise of peanut sublingual immunotherapy, which should be studied in larger numbers of preschool children,"

Leonard B. Bacharier, MD, director of the Center for Pediatric Asthma, Monroe Carell Jr Children's Hospital at Vanderbilt University in Nashville, said.

Bacharier was not part of the study.

Jonathan A. Bernstein, MD, professor of medicine, at the University of Cincinnati, agreed.

"It's a well-designed study, it's small, but it's promising," Bernstein, who was not involved with the study, told Medscape.

"They did show that most of the patients who got the sublingual therapy were able to get to the target dose and develop tolerance, so I think it's promising. We know that this stuff works. This is just more data from a well-controlled study in a younger population," he said.