Efficacy and Safety of the SQ House Dust Mite Sublingual Immunotherapy Tablet in Japanese Adults and Adolescents with House Dust Mite-induced Allergic Rhinitis

Background: The SQ house dust mite (HDM) sublingual immunotherapy (SLIT) tablet has been approved in 11 European countries and Japan for patients with HDM-induced respiratory allergic disease.

Objective: This trial was conducted to confirm the efficacy and safety of the SQ HDM SLIT tablet in Japanese patients with moderate-to-severe HDM-induced allergic rhinitis (AR).

Methods: The trial was a randomized, double-blind, placebo-controlled trial including 946 Japanese adults and adolescents (12-64 years). Subjects were randomly assigned to daily treatment with the SQ HDM SLIT tablet at a dose of 10,000 Japanese allergy units (JAU) or 20,000 JAU or to placebo (1:1:1). The primary end point was the total combined rhinitis score (TCRS), which is composed of AR symptom and medication scores during the efficacy evaluation period. Symptom and medication scores of AR and conjunctivitis, rhinitis quality of life, and symptom-free and symptom-severe days were evaluated as secondary end points.

Results: Analysis of the primary end point demonstrated statistically significant reductions in TCRSs of 1.15 (22%, P < .001) in the 10,000-JAU group and 0.99 (19%, P < .001) in the 20,000-JAU group compared with the placebo group. The statistically significant treatment effect was evident from 12 weeks of treatment onward. All secondary end points, except AR medication score, were statistically significant in favor of active treatment compared with placebo. Post hoc analysis of TCRSs in adolescents showed the same efficacy as in adults (P < .05). The treatment was well tolerated by both adults and adolescents.

Conclusion: The trial confirmed the efficacy and safety profile of the SQ HDM SLIT tablet in Japanese adult and adolescent patients with moderate-to-severe HDM-induced AR. These data support the robust efficacy and safety profile of previously reported European data.