Oral immunotherapy using egg-white powder represents a highly promising therapeutic intervention for children with egg allergy, according to findings from a randomized, placebo-controlled trial reported online in the July 19 issue of the New England Journal of Medicine.
After 10 months of immunotherapy, none of the 15 children with egg allergy who received placebo as part of the double-blind study passed an oral food challenge of 5 g of egg-white powder, whereas 22 (55%) of 40 children who received oral immunotherapy passed the oral food challenge and were considered to be desensitized. At 22 months, 30 (75%) of the 40 children who received oral immunotherapy passed an oral food challenge with 10 g of egg-white powder, Dr. A. Wesley Burks, chair of the department of pediatrics at the University of North Carolina and chief physician of N.C. Children’s Hospital, his colleagues reported on behalf of the Consortium of Food Allergy Research.
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The investigators state that the study findings could have important implications because egg avoidance (which is difficult and can adversely affect quality of life) is the only available treatment for egg allergy.
Of the 30 children who passed the oral food challenge at 22 months, 29 were rechallenged at 24 months with 10 g of egg-white powder, followed 1 hour later with one whole cooked egg (after having discontinued immunotherapy and egg consumption for 4-6 weeks); 11 (28%) passed the challenge and were considered to have "sustained unresponsiveness," the investigators reported (N. Engl. J. Med. 2012 July 19 [doi:10.1056/NEJMoa1200435]).
These 11 children then were instructed to add egg to their diet ad libitum. No adverse events were reported at the 30- and 36-month follow-ups.
Study participants were children aged 5-18 years (median, 7 years) with a convincing clinical history of egg allergy and a serum egg-specific IgE antibody level of more than 5 kU/L for those aged 6 years and older, and 12 kU/L or more for those aged 5 years. Those with a history of severe anaphylaxis after egg consumption were excluded.
The protocol for oral immunotherapy consisted of an initial-day dose escalation, a build-up phase, and a maintenance phase involving ingestion of up to 2 g of egg-white powder (equivalent of about one-third of an egg) daily.
Factors that were found to be associated with sustained unresponsiveness at 24 months were higher egg-specific IgG4 antibody levels at 10 months, smaller wheal diameter on skin-prick allergy testing at 22 months, and a decrease in wheal size from baseline to 22 months, the investigators noted.
Oral immunotherapy in this study was generally well tolerated, with adverse events occurring most frequently in association with oral-immunotherapy dosing. Most of the events were mild (grade 1), with only 1% being graded as moderate (grade 2). No severe adverse events occurred. Most events were oral or pharyngeal, and were associated with 25% of the 11,860 doses of oral immunotherapy, and with 3.9% of the 4,018 doses of placebo. The rate of symptoms decreased to 8.3% of 15,815 doses in the oral immunotherapy group after 10 months.
The findings could have important implications, given that the cumulative prevalence of egg allergy is approximately 2.6% by 2.5 years of age, and that egg avoidance (which is difficult and can adversely affect quality of life) is the only available treatment for egg allergy, investigators said.
However, for oral immunotherapy to be recommended as a standard of care, it is important to better define risks, compared with allergen avoidance; to determine the dosing regimens with the most favorable outcomes; to identify the patients most likely to benefit; and to develop postdesensitization strategies, the investigators concluded.
This study was supported by the National Institute of Allergy and Infectious Diseases and the National Institutes of Health–National Center for Research Resources Clinical Translational Science Awards and Clinical Research Centers. Dr. A. Wesley Burks has been a consultant for companies including Dannon Co. Probiotic, McNeil Nutritionals, Merck, the Food Allergy & Anaphylaxis Network, and Novartis, and has grants or grants pending from the Food Allergy Initiative, the NIH, the National Peanut Board, and others. Some of his associates were consultants for companies including DBV Technologies, Allertein Therapeutics, and Sunovion, or received grants from various companies; other associates had no relevant financial disclosures.
CLARIFICATION 7/20/2012: The institutional affiliation of Dr. Burks has been updated to reflect his current position.