Efficacy of Allergen Immunotherapy for Allergic Asthma in Real World Practice

Purpose: Allergen immunotherapy (AIT) induces immunological tolerance, and there is increasing evidence of the clinical efficacy of AIT in the treatment of allergic asthma. However, the optimal parameters for asthma control in clinical trials are still unclear. We investigated the efficacy of AIT with respect to changes in the inhaled corticosteroid (ICS) dose in patients with allergic asthma. Methods: A total of 117 adults with allergic asthma who had used ICS for more than 1 year in a single tertiary hospital in Korea were included in this retrospective study. We compared the clinical parameters and outcomes between the AIT group (ICS with AIT, n = 48) and the non-AIT group (ICS without AIT, n = 69) by applying an inverse probability of treatment weighting method. The patients in the AIT group had received subcutaneous AIT monthly as a maintenance treatment for more than 1 year. The changes in the ICS dose from baseline were evaluated in the 2 groups for 3 years. Results: The proportion of responders who discontinued or decreased in the ICS dose with achieving control status of asthma was significantly higher in the AIT group than in the non-AIT group throughout the study period (at 6 months, 52.1% vs. 24.6%; at 1 year, 70.8% vs. 34.7%; at 2 years, 89.5% vs. 35.6%; at 3 years, 96.3% vs. 51.2%). Treatment responses did not differ significantly by type of allergen (single-or multi-allergens or 3 different products) used throughout the study period. Conclusions: Irrespective of the type of allergen, long-term maintenance AIT helps to spare ICS dose and achieve better control in patients with allergic asthma in real-world clinical practice.