By Ingrid Grasmo
Oral immunotherapy for the treatment of egg allergy results in desensitization with long-lasting results in three-quarters of children, show study findings.
The results are of importance, given that the only currently approved treatment for egg allergy is dietary avoidance, say the researchers.
"Avoidance places a constant responsibility on patients and caregivers, leaves patients vulnerable to unintentional ingestion and anaphylaxis, and influences quality of life," say Wesley Burks (University of North Carolina, Chapel Hill, USA) and colleagues.
To investigate whether oral immunotherapy could be a feasible treatment option, Burks and team first administered oral immunotherapy or placebo to 55 children aged 5-11 years with a confirmed egg allergy. Following initial dose escalation, build-up, and maintenance phases, children were given a food challenge with egg white powder at 10 and 22 months.
Findings from this first testing phase revealed that 55% and 75% of the 40 children who received oral immunotherapy passed the oral food challenge at 10 months (average 5 g dose) and 22 months (average 10 g dose), respectively, compared with 0% of those who received placebo.
Children who successfully completed the food challenge at 22 months discontinued oral immunotherapy and were placed on an avoidance diet for 4-6 weeks followed by an oral food challenge with egg white powder and a cooked egg to test for sustained unresponsiveness at 24 months.
Of the 29 children who underwent the oral food challenge at 22 months, 11 passed the challenge at 24 months, corresponding with a 28% success rate in the intention-to-treat analysis.
The researchers also found that of the 22 children who were desensitized at 10 months, 41% passed the oral food challenge at 24 months compared with 11% who were not desensitized.
All of the 11 children who passed the challenge at 24 months and consumed egg ad libitum thereafter had sustained unresponsiveness at 30 and 36 months.
Of the measured immune markers, small wheal diameters on skin-prick testing and increases in egg-specific immunoglobulin G4 antibody levels were associated with a successful oral food challenge at 24 months.
No severe adverse events were seen for oral immunotherapy, with oral and pharyngeal most commonly observed. These were associated with 25% of the 11,860 oral immunotherapy doses and occurred mainly within the first 10 months.
Writing in The New England Journal of Medicine, the researchers call for further quantification of the risks involved with oral immunotherapy, dosing regimens, and identification of dosing regimens with the best outcomes.
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