A randomized, double-blind, placebo controlled trial of sublingual immunotherapy with house-dust mite extract for allergic rhinitis

Objective: This study was designed to evaluate the efficacy and safety of sublingual immunotherapy (SLIT) with house-dust mite (HDM) extract in Chinese patients with HDM-induced allergic rhinitis (AR). Methods: A randomized, double-blind, placebo controlled trial was conducted with the outpatients of the Eye, Ear, Nose, and Throat Hospital, Fudan University. Forty-eight patients were eligible for randomization to SLIT with a mixture of Dermatophagoides pteronyssinus and Dermatophagoides farinae extract or placebo for 1 year. The primary outcome measures for efficacy were the total nasal symptom score (TNSS) and the individual nasal symptom score. Secondary end points were allergic conjunctivitis scores (ACS) and medication scores (MS). Adverse events (AE) also were monitored. Results: Intragroup analysis demonstrated a significant improvement in the active treatment group for individual nasal symptom score and TNSS (p < 0.05), although no improvement was observed in the placebo group of congestion, sneezing, and itching (p > 0.05). Furthermore, the ACS and MS in the active treatment group also statistically decreased (p > 0.05). In addition, the active treatment had significant effects on relieving nasal symptoms both in adults and children (p < 0.05), and no statistical difference was observed between these two subgroups (p > 0.05). AEs that occurred ranged from mild to moderate, and no severe systematic reactions were observed. Conclusion: SLIT with a mixture of HDM extract significantly relieved allergy symptoms and reduced the need for antiallergic drugs, which indicated the superiority of active treatment over placebo for patients with HDM-induced AR. However, due to the limited sample size, the findings need to be further confirmed.