Most Patients Still Eating Daily Peanut in Follow-up of Immunotherapy Trials

Researchers are encouraged by a set of peanut allergy immunotherapy data released Sunday at the 2019 American Academy of Allergy, Asthma & Immunology (AAAAI) Annual Meeting, but they said that more discoveries are needed to understand which treatment might be best suited for patients.

Fifty-five past participants in either oral immunotherapy (OIT) or sublingual immunotherapy (SLIT) peanut trials from 2010 until 2017 at University of North Carolina (UNC) Chapel Hill were enrolled in a longitudinal observational study. They had been desensitized to between 300 mg (representing 1 peanut kernel) and 5000 mg of peanut. Desensitization increases the amount of peanut it takes to cause an allergic reaction, decreasing the likelihood of a severe reaction caused by accidental ingestion.

After completing their immunotherapy trial, participants were encouraged to introduce foods containing peanuts into their diets with a goal of about 300 mg of peanut each day. As part of their long-term follow-up, participants were asked to report how much they ate, how often they ate it, and how they felt afterward. Researchers reviewed peanut food equivalent ingestion and associated reactions.

Most continued regularly eating peanuts daily for up to 8 years after completing immunotherapy. Among those still eating peanuts (74%), the median amount of daily consumption was 600 mg. Patients who stopped eating peanut cited reactions and taste aversion as reasons for discontinuing.

Ten individuals reported allergic reactions to the daily peanut foods. The majority of reactions were mild (such as gastrointestinal symptoms and urticaria) and treated with antihistamines; 3 reactions required epinephrine and 2 needed emergency response services.

Of the 10 who reported reactions, 7 were from patients who were using OIT as opposed to SLIT. Researchers said there was no correlation between the amount of peanut ingested and the likelihood of a reaction.

One person developed eosinophilic esophagitis; there were no reactions from accidental ingestions for any of the participants.

The study was led by Edwin Kim, MD, FAAAAI, who presented the findings at the AAAAI meeting in San Francisco, California, on Sunday.

“People just want to know that they are protected,” said Kim, assistant professor of medicine and pediatrics at the UNC School of Medicine and director of the UNC Food Allergy Initiative, in a statement. “They don’t necessarily want to eat large amounts of their allergen, they just want a level of reassurance that if a restaurant cook makes a mistake or a food label is wrong, they won't have a severe allergic reaction.”

He noted that although the more significant reactions were infrequent, patients who are allergic to peanut but trying to stay desensitized should only do so under the care of an allergist.

“One of the big questions out there now is, ‘what does life after immunotherapy look like?’” said Kim. “That's what we were trying to answer with this research, and it appears that eating these small amounts of peanut is safe, can improve quality of life, and may help to maintain desensitization.”

“It is exciting that we are even talking about potentially reintroducing peanut into the diets of allergic children. However, there is still a lot we don’t know about peanut immunotherapy,” said Kim. “Different types of immunotherapy, age, and numerous other factors need to be studied to help us understand what treatment plan is best for our patients.”

Reference

Cook Q, Yang L, Hamad A, et al. Dosing and safety of peanut food equivalents after immunotherapy trials. Presented at: American Academy of Allergy, Asthma & Immunology 2019 Annual Meeting; February 22-25, 2019; San Francisco, CA. Abstract 740.