The effects of house dust mite sublingual immunotherapy in patients with allergic rhinitis according to duration.

BACKGROUND: The safety and efficacy of sublingual immunotherapy (SLIT) have been demonstrated in the recent 2 decades. However, the data is still mixed regarding the efficacy of house dust mite (HDM) SLIT. The objective of this work was to evaluate the different clinical efficacy SLIT in patients with allergic rhinitis (AR) according to different durations of treatment.

METHODS: A total of 500 subjects with HDM-induced AR were randomized to receive SLIT with Dermatophagoides farinae (Der.f) drops or pharmacotherapy with oral antihistamines. Patients in the SLIT group were further divided into SLIT1, SLIT2, and SLIT3 subgroups. After SLIT completion, a yearly follow-up visit was given to patients in the SLIT1 and SLIT2 subgroups. The total nasal symptom score (TNSS), the proportion of medication withdrawal, the visual analogue scale (VAS) score, and Rhinoconjunctivitis Quality of Life Questionnaire (RQLQ) scores were assessed at each monthly visit.

RESULTS: Comparing with the baseline value, TNSS, VAS, and RQLQ were significantly improved in 3 SLIT subgroups after treatment (p < 0.05). In addition, patients in SLIT3 subgroup achieved the highest proportion of medication withdrawal compared to the SLIT1 and SLIT2 subgroups (p < 0.05). After 1-year follow-up, no significant differences were observed in TNSS, VAS scores, and the proportion of medication withdrawal of SLIT1 and SLIT2 subgroups (p > 0.05) with respect to the completion value. No severe systemic adverse events (AEs) were reported.

CONCLUSION: The randomized study suggested that 3-year courses of SLIT in patients with AR was more efficacious than 1-year or 2-year courses. Furthermore, patients achieved 1-year long-term clinical benefits from HDM SLIT.