Oral immunotherapy for treatment of egg allergy in children

Abstract

Background: For egg allergy, dietary avoidance is the only currently approved treatment. We evaluated oral immunotherapy using egg-white powder for the treatment of children with egg allergy.

Methods: In this double-blind, randomized, placebo-controlled study, 55 children, 5 to 11 years of age, with egg allergy received oral immunotherapy (40 children) or placebo (15). Initial dose-escalation, build-up, and maintenance phases were followed by an oral food challenge with egg-white powder at 10 months and at 22 months. Children who successfully passed the challenge at 22 months discontinued oral immunotherapy and avoided all egg consumption for 4 to 6 weeks. At 24 months, these children underwent an oral food challenge with egg-white powder and a cooked egg to test for sustained unresponsiveness. Children who passed this challenge at 24 months were placed on a diet with ad libitum egg consumption and were evaluated for continuation of sustained unresponsiveness at 30 months and 36 months.

Results: After 10 months of therapy, none of the children who received placebo and 55% of those who received oral immunotherapy passed the oral food challenge and were considered to be desensitized; after 22 months, 75% of children in the oral-immunotherapy group were desensitized. In the oral-immunotherapy group, 28% (11 of 40 children) passed the oral food challenge at 24 months and were considered to have sustained unresponsiveness. At 30 months and 36 months, all children who had passed the oral food challenge at 24 months were consuming egg. Of the immune markers measured, small wheal diameters on skin-prick testing and increases in egg-specific IgG4 antibody levels were associated with passing the oral food challenge at 24 months.

Conclusions: These results show that oral immunotherapy can desensitize a high proportion of children with egg allergy and induce sustained unresponsiveness in a clinically significant subset. (Funded by the National Institutes of Health; ClinicalTrials.gov number, NCT00461097.).

Figure 1. Study Enrollment, Randomization, and Outcomes

Eligibility criteria included both a convincing clinical history of egg allergy and elevated levels of egg-specific IgE antibody. No oral food challenge (OFC) was performed at baseline. The 55 children who met the screening requirements were randomly assigned to receive placebo or oral immunotherapy (OIT) with egg. After the challenge at 10 months, the study was unblinded, and all children who had received placebo were followed longitudinally without further dosing. Children in the placebo group were not eligible for the challenge at 22 months unless the level of egg-specific IgE antibody was less than 2 kU per liter. All children in the OIT group continued to receive OIT after the challenge at 10 months, until the challenge at 22 months. Of the 30 children who passed the challenge at 22 months, 29 stopped receiving OIT for 4 to 6 weeks and then underwent a challenge to assess sustained unresponsiveness at 24 months. All 11 children who passed the challenge at 24 months were placed on an ad libitum egg diet, with subsequent evaluation at 30 months (11 children) and 36 months (10 children).