Rising Hope for Oral Peanut Allergy Treatment

Sublingual immunotherapy (SLIT) appears to desensitize therapy peanut allergy, with better results the longer therapy continues, according to a new study.

Researchers at National Jewish Health (Denver, CO, USA) conducted a randomized trial to investigate safety, efficacy, and immunologic effects of peanut SLIT. Following a baseline oral food challenge (OFC) of up to 2 grams of peanut powder, 40 subjects—aged 12 to 37 years—were randomized to daily peanut or placebo SLIT. A five gram OFC was performed after 44 weeks, followed by unblinding. Placebo-treated subjects then crossed over to higher dose peanut SLIT protocol. Both groups were then compared with baseline OFCs, with subjects with a successfully consumed dose (SCD) of 5 grams or at least 10-fold more peanut powder than the baseline OFC threshold considered as responders.

The results showed that after 44 weeks of SLIT, 70% of the subjects receiving peanut SLIT were responders, compared with 15% in those receiving placebo. In peanut SLIT responders, median SCD increased from 3.5 to 496 mg. After 68 weeks of SLIT, median SCD significantly increased to 996 mg. The median SCD at the Week 44 Crossover OFC was also significantly higher than baseline, with 44% of the 16 crossover subjects being responders, with median SCD increasing from 21 to 496 mg. The study was published in the January 2013 issue of the Journal of Allergy and Clinical Immunology.

“These data suggest continued long-term therapy with peanut SLIT might confer reduced reactivity to peanut after further desensitization, allowing for protection against accidental ingestions, which are reactions to less than 100 mg of peanut protein in general,” concluded lead author David Fleischer, MD, and colleagues. “While encouraging, the effect of sublingual immunotherapy at 44 weeks appeared to be modest desensitization that didn't reach the threshold of five grams without symptoms, which might not provide clinically relevant protection.”

Peanut allergy is a type 1 hypersensitivity reaction to dietary substances from peanuts that causes an overreaction of the immune system, which in a small percentage of people may lead to severe physical symptoms; it is estimated to affect 0.4%–0.6% of the population. The most severe allergies in general can result in anaphylaxis, an emergency requiring immediate attention and treatment with epinephrine. Peanut allergies are usually treated with an exclusion diet and vigilant avoidance of foods that may contain whole peanuts or peanut particles and/or oils.

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