BACKGROUND: The SQ HDM SLIT-tablet (ALK) has been developed for treatment of house dust mite (HDM)-induced respiratory allergic disease.

OBJECTIVE: This trial investigated the efficacy and safety of the SQ HDM SLIT-tablet in adults with moderate-to-severe HDM-induced allergic rhinitis (AR).

METHODS: The trial was a randomized, double-blind, placebo-controlled phase III trial conducted in 12 European countries including 992 adults with moderate-to-severe HDM-induced AR despite treatment with pharmacotherapy. Subjects were randomized 1:1:1 to 1 year of daily treatment with placebo, 6 SQ-HDM, or 12 SQ-HDM. The primary end point was the total combined rhinitis score (ie, the sum of rhinitis symptom and medication scores) during the efficacy assessment period (approximately the last 8 weeks of the treatment period). Key secondary end points were rhinitis symptoms, medication scores, quality of life, and the combined rhinoconjunctivitis score.

RESULTS: Analysis of the primary end point (observed data) demonstrated absolute reductions in total combined rhinitis score of 1.18 (P = .002) and 1.22 (P = .001) compared with placebo for 6 SQ-HDM and 12 SQ-HDM, respectively. The statistically significant treatment effect was evident from 14 weeks of treatment onward. For all key secondary end points, efficacy was confirmed for 12 SQ-HDM, with statistically significant reductions of rhinitis symptoms and medication scores, improved quality of life, and a reduced combined rhinoconjunctivitis score in the efficacy assessment period compared with placebo. The treatment was well tolerated.

CONCLUSION: The trial confirmed the efficacy and favorable safety profile of both 6 SQ-HDM and 12 SQ-HDM in adults with HDM-induced AR. The treatment effect was present from 14 weeks of treatment onward.