A "peanut patch" showed promising results in a late-phase clinical trial in toddlers with peanut allergies, according to a new study.

Researchers from the French biopharmaceutical firm DBV Technologies and institutions around the world conducted randomized double-blind trial of the Viaskin Peanut patch in children ages 1 through 3 years old who had been diagnosed with a peanut allergy, they reported Wednesday in The New England Journal of Medicine.

The trial involved 362 toddlers from eight countries; 244 were randomly assigned to receive the Viaskin patch -- which features 250 micrograms of peanut protein, the equivalent of about 1/1000th of one peanut -- and 118 got a placebo patch. They wore the patches between their shoulder blades daily for a year before undergoing screening for peanut challenges.

After 12 months, two-thirds of the children who used the Viaskin patch and one-third of the placebo group had met the trial's primary endpoint. Children with a less sensitive allergy could safely tolerate peanut protein equivalent to consuming three or four peanuts, and children who were more sensitive could tolerate the equivalent of consuming one peanut.

The researchers also noted "a shift towards less severe food challenge reactions" in the Viaskin group, DBV said in a news release.

Nearly all of the young study participants had adverse events, with the most common being application-site reactions such as redness, itching and swelling. Serious events were reported in 21 children who used the Viaskin patch and three in the placebo group.

Over the course of the study, a dangerous allergic reaction known as anaphylaxis was reported in 7.8% of the Viaskin recipients and 3.4% of children who got the placebo. Only four of the reactions were deemed to be related to treatment. Eight participants dropped out of the trial because of adverse events.

The researchers note that their study has several limitations, including that children with a history of severe allergic reactions were excluded for safety reasons and that there was a lack of racial diversity among the participants.

An estimated 2.5% of US children may have peanut allergies, and only about 20% will eventually outgrow them. An oral treatment called Palforzia is approved for 4- to 17-year-olds with peanut allergies, but there are no available options for younger kids.

"Parents and caregivers are eagerly awaiting FDA-approved treatment options for this age group," DBV CEO Daniel Tassé said in the news release.

The study's lead author, Dr. Matthew Greenhawt of Children's Hospital Colorado, said in the news release that the findings are a "meaningful advancement."

"I see peanut-allergic patients in my clinical practice daily. I speak with parents who are experiencing increased anxiety and a decreased quality of life due to fear of life-threatening reactions," he said. "The Viaskin Peanut patch has the potential to give new hope to toddlers and their families who currently have no approved treatment options and must instead rely on avoidance, which can severely impact quality of life."

In an editorial published alongside the study, Dr. Alkis Togias of the Division of Allergy, Immunology and Transplantation at the National Institute of Allergy and Infectious Diseases noted that "Peanut allergy can be very substantially reduced if peanut is introduced into the diet as early as 4 to 6 months of age." Health care providers around the world now advise such introduction, but there are questions about dosage, age, frequency and duration, he said.

"Toddlers are of particular interest since their immune systems have plasticity that can theoretically allow for higher efficacy and longer-lasting benefits from allergen immunotherapy after therapy is discontinued," wrote Togias, who was not involved in the new research.

Compared with oral therapy, he said, skin patches may have less of a protective effect but a better safety profile.

Still, he said, the Viaskin trial findings "are very good news for toddlers and their families as the next step toward a future with more treatments for food allergies."