Scientific Study

Background: Peanut allergy is severe and rarely resolves. Objective: To test the efficacy and safety of a new oral immunotherapy (OIT) protocol for peanut allergy. Method Twenty-two peanut-allergic children underwent oral challenge. OIT was administered by gradual updosing with 2-weekly increments (8-38 weeks) to 800 mg of protein (5 peanuts/day) followed by 30-week maintenance. Oral challenge was repeated after 6 and 30 weeks maintenance. Results Twenty-two children (median 11 years) had positive challenges (threshold 1-110 mg). Nineteen of 22 (86%) tolerated updosing and maintenance at 800 mg protein/day. One of 22 dropped out; 2/22 tolerated updosing and maintenance at 200-400 mg protein. Reactions; mostly mild; occurred in 86% during immunotherapy; adrenaline was not required. Eight of 8 with pre-immunotherapy peanut IgE<27.3 kU/L required no dose adjustment compared with 5/13 with pre-immunotherapy peanut IgE27.3 kU/L. Twelve of 22 (54%) required a transient dose reduction because of reactions possibly related to extrinsic factors: tiredness; infection and exercise. After 6 weeks; 12/22 (54%) had no reaction to a 2.6 g protein challenge. After 30 weeks; 14/22 (64%) tolerated 6.6 g protein. The median tolerated peanut dose increased 1000-fold following immunotherapy; from 6 to 6459 mg of protein. Conclusions and Clinical Relevance: We used a novel protocol using gradual updosing; and higher maintenance dose resulting in a better outcome compared with rush protocols. There was a 1000-fold increase in the amount of peanut tolerated with a good safety profile. No serious adverse events occurred. Most subjects tolerated five peanuts and all were protected against amounts likely during accidental ingestion. New information is provided on 'extrinsic factors'; updosing method and factors associated with success (trial registration http://ClinicalTrials.gov- ID number NCT01259804).