The house dust mite (HDM) is one of the commonest causative agents in allergic rhinitis (AR), affecting patients across all demographics. Recently, sublingual immunotherapy (SLIT) has been shown in clinical trials and meta-analysis to be effective compared to placebo in relieving symptoms of HDM allergic rhinitis with quality of life improvement. However, these studies were only limited to adolescents (>12 years of age) and in adults, with little known about its effect in the paediatric population. In this large-scale multicentre, double-blinded, randomised, placebo-controlled Japanese study, 438 paediatric patients (five to 16 years old) with perennial AR were enrolled to assess the efficacy and tolerability of HDM sublingual immunotherapy. The 300IR tablet used contains extracts from Dermatophagoides pteronyssinus and D. farinae. The treatment period was 52 weeks. The HDM tablet regime comprised of 100IR on day one, 200IR on day two, followed by a maintenance dose of 300IR once daily from day three to week 52.
The efficacy end-points were patient or guardian-reported outcome measures, clinical assessments and mite-specific IgE and IgG4 antibodies responses. Compared to the placebo, significant improvements were observed in all aspects in the SLIT arm. Almost all patients in both arms reported an adverse event. However, these were mostly mild in the form of oral or ear pruritus, mouth oedema and throat irritation.
No anaphylaxis or death was recorded. Although the cohort was not followed up for more than one week after treatment completion, the improvement in symptoms was reportedly sustained and significant during the 52-week treatment period. The authors have therefore concluded that in children with HDM-induced allergic rhinitis the sublingual tablet is safe and well-tolerated, and thus should form an integral part of the rhinitis therapy.