Oral Immunotherapy May Desensitize Children with Egg Allergy

Oral immunotherapy for children with an egg allergy can desensitize a high proportion of children who undergo treatment, according to the results of a new randomized control trial. These latest findings were recently published in the New England Journal of Medicine [2012;367(3):233-243].

According to the authors of the placebo-controlled study, an egg allergy in children can impact both health and quality of life for those affected and, other than dietary avoidance, there is currently no approved treatment for those faced with the allergy.

In this study, researchers assessed the impact of oral immunotherapy, a treatment used to attempt to produce a more sustained clinical effect than desensitization, in children age 5 to 11 years with an egg allergy using a double-blind, randomized, placebo-controlled study design.

The 55 children who participated in the study were randomized in an 8:3 ratio to receive either oral immunotherapy (n=40) or a placebo (n=15).

The study began with initial dose-escalation, build-up, and maintenance phases before an oral food challenge at 10-months where participants tried to consume 5 g of egg white powder. The food challenge was repeated again with 10 g of egg white powder at 22 months. At that point, those participants who passed the food challenge discontinued the oral immunotherapy and avoided consuming egg for a period of 4 to 6 weeks before participating in an additional food challenge at 24 months that consisted of 10 g of egg white powder followed by a whole cooked egg an hour later.

Participants who passed the final egg challenge at 24 months were advised to add egg to their diet and received follow-up either at a clinic or over the phone at 30-months and 36-months to assess any adverse events.

Researchers were assessing what they termed "sustained unresponsiveness" or the ability after 22 months of oral immunotherapy and subsequent avoidance of egg to consume the egg powder and whole egg at the 24-month food challenge without any clinically significant symptoms.

The sustained unresponsiveness after 22 months of oral immunotherapy with egg was the primary outcome of the study. Researchers also identified secondary outcomes that included desensitization and the safety of oral immunotherapy.

They defined desensitization as the ability to pass the oral food challenge at 10 months and at 22 months while receiving oral immunotherapy.

The study was designed as a double-blind study through the 10-month mark; however, after the initial oral food challenge, the placebo was stopped in the placebo group.

Researchers found that by using oral immunotherapy, they were able to desensitize a large portion of the study population. While no children in the placebo group were able to pass the oral food challenge after 10 months, 55% of those in the oral immunotherapy group passed the food challenge and were considered desensitized. This trend was more significant at the 22-month mark, when 75% of those in the oral immunotherapy group passed the food challenge and were identified as desensitized.

Researchers also found that 28% of the oral immunotherapy group were considered to have sustained unresponsiveness by 24 months (P=.03 when compared with placebo). No children in the placebo group were eligible to take the food challenge at 24 months because they were unable to pass the food challenge at 22 months.

Finally, researchers noted that small wheal diameters on the skin-prick test were associated with the ability to pass the oral food challenge at 24 months, as was an increase in egg-specific IgG4 antibody levels.

Researchers concluded by saying oral immunotherapy could be a promising therapy option, however, more research is needed before it should be recommended as a standard of care. They also acknowledged there may be other reasons for the results they observed including the possibility that participants in the study could have outgrown their egg allergy during the study or may lose their sustained unresponsiveness if ad libitum egg consumption was stopped.