Aimmune Therapeutics' AR101 helped peanut allergy sufferers to tolerate peanuts, showed pivotal trial data published in the New England Journal of Medicine and presented at the American College of Allergy, Asthma & Immunology meeting in Seattle.

In the 551-patient phase III desensitization trial, Aimmune randomized patients to daily treatment with either AR101, which is an orally administered defatted peanut flour, or to placebo. At the start of this trial, patients were able to tolerate on average less than half a peanut. After 1 year in the trial, 67% of treated patients could tolerate the equivalent of four peanuts. Only 4% of the patients in the placebo arm could tolerate this much peanut protein at the end of the trial.

AR101 does not cure peanut allergy, but instead enables patients to build up a tolerance to accidental exposure. Allergy sufferers probably need to keep taking the drug in order to see sustained desensitization.

In an accompanying editorial, Michael Perkin, an allergist at St George's, University of London, noted that the market for a peanut allergen immunotherapy could be in the billions. But “desensitization was not easy on the patients,” he wrote. Nearly 12% of the treated participants withdrew from the study because of severe adverse events, compared with 2% in the placebo group. 14% of the treated patients needed epinephrine during the course of the trial, versus 7% in the placebo group. “This is not something to start at home,” he wrote.

Some research groups have previously desensitized patients by giving them controlled doses of “peanut flour costing peanuts”, he added. An approval for AR101 “may result in the peanut being deemed an unlicensed medicinal product.”

Aimmune is expected to file the drug for approval by the end 2018. The company is partnered with Regeneron and Sanofi to explore whether combination use of AR101 and the IL-4 receptor antibody dupilumab can improve outcomes.

DBV Technologies is also developing a peanut allergen immunotherapy, using a patch to deliver peanut protein through the skin. The company filed for regulatory approval for their drug Viaskin Peanut in 2018, after narrowly missing their primary end point in a pivotal trial.

Approvals for these products could pave the way for the development of products to desensitize patients with other food allergies (see Nature Reviews Drug Discovery 15, 149–150; 2016).