Experts who were not involved in the trial said the outcomes exceeded their expectations, calling the results “potentially lifesaving.” But they also cautioned that the treatment does not cure peanut allergies and should not be attempted at home. They emphasized that children who complete the regimen need to continue to eat a peanut-free diet and may need to keep up maintenance therapy with minute doses of peanut, possibly for the rest of their lives.

“This is not the cure, but it is a good first step,” said Dr. James R. Baker Jr., chief medical officer of Food Allergy Research & Education (FARE), a nonprofit advocacy group that focuses on food allergies, noting the results were better than he expected. Until now, he said, “We’ve had nothing, nothing to give these poor kids that can keep them from having these reactions and put them in a much more positive outlook on life. It’s just a wonderful thing to have.

“The fact that the kids were eating the equivalent of a peanut a day pretty much tells you that if they accidentally eat a peanut, they won’t have a life-threatening reaction,” Dr. Baker said.

Michael Perkin, a clinical epidemiologist and pediatric allergy consultant at St. George’s, University of London who wrote an accompanying editorial about the study, said the regimen was “not a walk in the park” and requires tremendous discipline. Children are required to rest for two hours after receiving their daily dose but cannot fall asleep because of the risk of a reaction.

Dr. Perkin said that the long-term side effects of consuming allergens when one has a severe allergy are still unknown. But he described the results as “beyond exciting.”

“It isn’t a cure like an antibiotic that makes a bug go away and it’s not there anymore,” he said. But “psychologically it makes a massive difference if you can keep your kid from living in fear. These kids can eat enough peanut that parents no longer will have to worry about their teenage daughter kissing someone who’s eaten peanut butter. You cannot estimate what a psychological relief that is.”

For children like Carter Grodi, a junior in high school in Ocala, Fla., who completed the treatment a year ago and continues to ingest a small amount of peanut every day to maintain his low-level tolerance, the treatment was transformative, making it easier to go out with friends and make plans to go away for college.