Efficacy and safety of sublingual tablets of house dust mite allergen extracts in adults with allergic rhinitis

Background: Preliminary studies have suggested the efficacy of sublingual tablets of house dust mite (HDM) extracts in adults with allergic rhinitis. Objectives: We sought to assess the efficacy and safety of 2 doses of HDM sublingual tablets over 1 treatment year and the subsequent immunotherapy-free year. Methods: Adults with HDM-associated allergic rhinitis were randomized in a double-blind, placebo-controlled study to receive 500 index of reactivity (IR) tablets, 300IR tablets, or placebo administered once daily for 1 year and were followed for the subsequent year. The primary efficacy variable was the Average Adjusted Symptom Score over the year 1 primary period (ie, October 1 to December 31). Symptoms and rescue medication scores, onset of action, patient-reported outcomes, and safety were secondary variables. The same end points were evaluated during the immunotherapy-free year. The primary efficacy end point was analyzed by using analysis of covariance. Results: Five hundred nine participants were randomized, and 427 continued in the immunotherapy-free year. Both the 500IR and 300IR HDM sublingual tablets significantly reduced mean Average Adjusted Symptom Scores compared with placebo by -20.2% (P = .0066) and -17.9% (P = .0150), respectively. Efficacy of both doses was maintained during the treatment-free follow-up phase. The onset of action was at 4 months. Participants' global evaluation of treatment success was significantly higher in the 500IR and 300IR groups compared with the placebo group (P = .0206 and P = .0001, respectively). Adverse events were generally application-site reactions. There were no reports of anaphylaxis. Conclusions: Twelve months of treatment with 500IR and 300IR sublingual tablets of HDM allergen extracts was efficacious and well tolerated. Efficacy was maintained during the treatment-free follow-up year.