Long-Term Efficacy of House Dust Mite Sublingual Immunotherapy on Clinical and Pulmonary Function in Patients With Asthma and Allergic Rhinitis

To evaluate the long-term efficacy of house dust mite (HDM) sublingual immunotherapy in patients with asthma and allergic rhinitis.The study included 140 subjects in Japan from age 20 to 65 years old who had HDM sensitization, as well as persistent asthma and allergic rhinitis that worsened with HDM exposure, present for at least one year. Subjects were either nonsmokers or had a prior 5 pack per year smoking history who quit one year before study. Exclusion criteria included uncontrolled asthma, recent asthma exacerbation, other more significant environmental allergen sensitization, or other severe systemic disease.This was an open-label randomized control trial that was divided through computer generated randomization. The 2 study arms included treatment group (HDM sublingual immunotherapy and standard medication therapy) versus control (standard therapy alone). Efficacy was evaluated through patient-centered questionnaires (ACQ-5 and AQLQ for asthma, RQLQ for allergic rhinitis), spirometry with fractional exhaled nitric oxide, CT chest imaging, and serum inflammatory markers.Statistically significant improvement was shown in spirometry with increase of forced expiratory volume in 1 sec (113.2 mL improvement at year 1 and 118.9 mL at year 5), reduction of wall thickness on CT, improvement of patient-centered asthma questionnaires, and reduction of fractional exhaled nitric oxide, serum eosinophils, total serum IgE, and HDM-specific IgE at the end of the 5-year period. Adverse events included localized reaction to tablet administration, oral pruritus and edema, ear pruritus, and gastroenteritis.House dust mite sublingual immunotherapy has significant and sustained improvement in symptoms, lung function, airway physiology, and allergic serum markers with 5-year treatment, compared with one year treatment with minimal adverse events.Sublingual immunotherapy has become a popular form of immunotherapy given lack of injections. For the pediatric population, this might be an appealing option for children who are resistant to subcutaneous immunotherapy. Data regarding sublingual immunotherapy has been established for treatment of one year duration, but this study elucidates the impact of 5-year duration. This study supports the sustained subjective and objective improvement with house dust mite sublingual therapy. Earlier intervention in the pediatric population should be considered.