ABSTRACT
BACKGROUND: Investigations meeting current standards are limited for the effect of house dust mite (HDM) allergy immunotherapy in asthmatic patients. OBJECTIVE: This trial investigated the efficacy and safety of a standardized quality (SQ; allergen standardization method proprietary to the trial sponsor) HDM SLIT-tablet (ALK, Hørsholm, Denmark) in adults and adolescents with HDM respiratory allergic disease. This publication reports the results of the endpoints related to asthma. METHODS: Six hundred four subjects 14 years or older with HDM allergic rhinitis and mild-to-moderate asthma were randomized 1:1:1:1 to double-blind daily treatment with one of 3 active doses (1, 3, or 6 SQ-HDM) or placebo. Their use of inhaled corticosteroid (ICS) was standardized and adjusted at baseline and the end of treatment to the lowest dose providing asthma control. The primary end point was a reduction in ICS dose from the individual subject's baseline dose after 1 year of treatment. RESULTS: The primary analysis revealed a mean difference between 6 SQ-HDM and placebo in the reduction in daily ICS dose of 81 µg (P = .004). Relative mean and median reductions were 42% and 50% for 6 SQ-HDM and 15% and 25% for placebo, respectively. No statistically significant differences were observed for the other assessed asthma parameters, reflecting the intended controlled status of the trial subjects. The most common adverse events were local reactions in the mouth. The rate and severity of adverse events were higher for 3 and 6 SQ-HDM than for 1 SQ-HDM and placebo. CONCLUSION: Efficacy in mild-to-moderate asthma of 6 SQ-HDM relative to placebo was demonstrated by a moderate statistically significant reduction in the ICS dose required to maintain asthma control. All active doses were well tolerated.
