Long-term efficacy of house dust mite sublingual immunotherapy on clinical and pulmonary function in patients with asthma and allergic rhinitis

Abstract

BackgroundA previous study reported that house dust mite (HDM) sublingual immunotherapy (SLIT) for 48 weeks was effective as add on treatment for allergic asthma; however, data regarding its long-term efficacy is scarce. ObjectiveThis open-label extension study aimed to evaluate the effect of HDM SLIT on asthma control, pulmonary function, airway inflammation and remodeling throughout the 5-year treatment period. MethodsA total of 140 patients with asthma and allergic rhinitis sensitized to HDM were randomized to receive either drugs alone or drugs plus SLIT for 5 years. Asthma Control Questionnaire (ACQ)-5, Asthma Quality of Life Questionnaire (AQLQ), Rhinoconjunctivitis Quality of Life Questionnaire (RQLQ), spirometry, quantitative computed tomography, and type 2 biomarkers were assessed. ResultsAn improvement in the ACQ-5, AQLQ, and RQLQ scores was observed in the SLIT group compared with the control group. HDM SLIT increased lung function and reduced the percentage of airway wall area (WA/Ao). The levels of fractional exhaled nitric oxide (FeNO), blood eosinophil, serum specific IgE (s-IgE) for HDM, and total IgE decreased and were sustained during the 5 years. The change in type 2 biomarkers correlated with change in AQLQ score. Based on receiver operating characteristic (ROC) analysis for predicting responders, the area under the ROC curve in FEV1% predicted, WA/Ao, FeNO, and s-IgE was high. Multivariate regression analysis showed that the strongest predictor of responders was FeNO. ConclusionsHDM SLIT continued to provide sustained efficacy, improve lung function, and prevent progression of airway inflammation and remodeling in asthma through to year 5.