Randomized controlled trial of primary prevention of atopy using house dust mite allergen oral immunotherapy in early childhood.

BACKGROUND: Children born to atopic parents are at increased risk of sensitization to environmental allergens. OBJECTIVE: We sought to demonstrate proof of concept for oral immunotherapy to high-dose house dust mite (HDM) allergen in infancy in the prevention of allergen sensitization and allergic diseases. METHODS: This was a prospective, randomized, double-blind, placebo-controlled, proof-of-concept study involving 111 infants less than 1 year of age at high risk of atopy (≥ 2 first-degree relatives with allergic disease) but with negative skin prick test responses to common allergens at randomization. HDM extract (active) and appropriate placebo solution were administered orally twice daily for 12 months, and children were assessed every 3 months. Coprimary outcomes were cumulative sensitization to HDM and sensitization to any common allergen during treatment, whereas development of eczema, wheeze, and food allergy were secondary outcomes. All adverse events were recorded. RESULTS: There was a significant (P = .03) reduction in sensitization to any common allergen (16.0%; 95% CI, 1.7% to 30.4%) in the active (5 [9.4%]) compared with placebo (13 [25.5%]) treatment groups. There was no treatment effect on the coprimary outcome of HDM sensitization and the secondary outcomes of eczema, wheeze, and food allergy. The intervention was well tolerated, with no differences between active and placebo treatments in numbers or nature of adverse events. CONCLUSION: Prophylactic HDM oral immunotherapy is well tolerated in children at high heredity risk. The results met the trial's prespecified criteria for proof of concept in reducing sensitization to any allergen; however, no significant preventive effect was observed on HDM sensitization or allergy-related symptoms.