Oral immunotherapy for peanut allergy in Singaporean kids?
Peanut oral immunotherapy appears to be safe and effective in a small cohort of Singaporean children with peanut allergy, suggests a pilot study.
“Strict avoidance [of peanut] is ideal, but challenging as peanut is ubiquitous in Asian cuisine,” said the researchers led by Dr Soh Jian Yi from the Department of Paediatrics at Yong Loo Lin School of Medicine, National University of Singapore.
Nine children in the open-label study underwent dose escalation of immunotherapy fortnightly until a final maintenance dose of 3,000 mg peanut protein, which continued for 12 months. The children were subjected to an oral food challenge at 6 months into the maintenance phase, and 4 weeks after the end of maintenance phase (discontinuation of immunotherapy). [Asia Pac Allergy 2019;doi:10.5415/apallergy.2019.9.e1]
Of the seven children who completed the maintenance phase, all were able to tolerate ≥3,000 mg of peanut protein by 6 months into the maintenance phase, with six of them being able to tolerate up to 6,000 mg of peanut protein — indicating that the oral immunotherapy was effective.
Wheal size on skin prick test also reduced significantly from 13 mm at baseline to 4 mm at 6 months during maintenance (p<0.05).
Among the seven subjects, three who adhered to abstinence from peanut for 4 weeks before another challenge after completing the maintenance phase were assessed for sustained unresponsiveness. Only one out of the three children successfully passed the food challenge with 6,000 mg peanut protein while the other two had significantly decreased tolerance to peanut protein.
“This supports the concept that tolerance does wear off over time even if there initially appears to be sustained unresponsiveness,” said Soh and co-authors.
“Children who have completed peanut oral immunotherapy should diligently continue to consume peanut as sustained unresponsiveness was not typical,” they advised.
Nonetheless, four of the five children who were contactable by the researchers during follow-up 2–3 years after immunotherapy discontinuation were still able to consume peanuts regularly at an acceptable dose.
Quality of life also trended towards improvement at 4 weeks after the maintenance phase, as indicated by the FAQLQ-PF scores reported by parents and FAQLQ-CF/-TF scores reported by children.
In terms of safety, side effects mainly involve the gastrointestinal system, in particular transient abdominal cramps, followed by those involving the skin such as urticaria and itch. According to the researchers, side effects were more commonly observed during the dose escalation phase than the maintenance phase. “All side effects were mild, with no incident of anaphylaxis attributable to peanut oral immunotherapy during treatment,” they noted.
Another immunotherapy that has previously been studied for this condition is omalizumab. However, the researchers noted that “due to the subcutaneous route of administration, [omalizumab] is less desirable for use in young children.”