Preventing Childhood Asthma Using Prophylactic House Dust Mite Allergen Immunotherapy (PAPA)

Children's Hospital Medical Center, Cincinnati, University of North Carolina, Chapel Hill, George Washington University, Emory University, University of Southampton, Imperial College London

To establish efficacy and safety of HDM sublingual Immunotherapy (HDM-SLIT) by comparing Odactra and placebo, when given sublingually for 3 years to high risk infants aged between 6 to 12 months at enrollment in preventing the development of asthma, assessed 1.5 years after discontinuation of treatment.

Aim to prevent the development of asthma in children by intervening at a time when the developing system in still amenable to immune modulation, by using the only therapy that has proven ability to change the natural history of allergic diseases and induce clinical remission. We hypothesize that three years of HDM Immunotherapy in high-risk infants will prevent the development of asthma assessed over a period of 1.5 years after discontinuation of treatment and HDM immunotherapy will result in (a) a significant reduction in the number and pathogenic features of HDM-reactive TH2 cells, and (b) an increase in the numbers of HDM-reactive TH and TREG cells expressing the interferon-response signature. The study is a Randomized (1:1), double blinded, placebo controlled, parallel arms, multi-site, Phase II study with a 3 year treatment phase and further 1.5 year follow-up phase. The study duration for each participant is 4.5 years. Overall study duration is 84 months (7 years); which include 9 months preparation and regulatory approvals, 15 months accrual, 36 months treatment and 18 months follow-up observation period.

Randomized (1:1), double blinded, placebo controlled, parallel arms, multi-site, Phase II study; 3 year treatment phase with further 1.5 year follow-up phase.

HDM sublingual Immunotherapy (HDM-SLIT) with Odactra® for 3 years to high-risk infants aged between 6 to 12 months at enrollment in preventing the development of asthma, assessed 1.5 years after discontinuation of treatment.

Placebo administered sublingually for 3 years to high-risk infants aged between 6 to 12 months with outcome of asthma development assessed 1.5 years after discontinuation of treatment.

HDM-SLIT tablet (Odactra®/Acarizax®) is a rapidly dissolving, freeze-dried, oral lyophilizate for oromucosal treatment, which contains a 1:1 mixture of two allergen extracts derived for the cultivated house dust mites, D. pteronyssinus and D. farinae. These species are included in SLIT tablet and subcutaneous immunotherapy administered for the treatment of allergic rhinitis and asthma in the pediatric and adult populations. The tablet dissolves within seconds after contact with a wet surface such as the oral mucosa. Participants will be administered the drug sublingually for 3 years.

Inclusion Criteria: Aged 6 to 12 months of age history of physician diagnosed atopic dermatitis OR allergen sensitization OR family history of asthma or allergy Exclusion Criteria: Evidence of sensitization to house dust mite (SPT ≥3 mm OR sIgE (> 0.35 kU/L) Prematurity (<37 weeks) Failure to thrive Need for oxygen for more than 5 days in the neonatal period history of intubation or mechanical ventilation