Safety and effectiveness of a 300 IR house dust mite sublingual tablet: descriptive 4-year final analysis of a post-marketing surveillance in Japan

Data are limited for clinical outcomes with house dust mite (HDM) allergen immunotherapy beyond 2 years' observation. A post-marketing drug-use survey assessed the safety and effectiveness of the 300 index of reactivity (IR) HDM tablet during use for up to 4 years in Japan. 538 patients were evaluable for safety and 383 for effectiveness. Most adverse drug reactions (ADRs) occurred early and were local reactions; 5.6% of 249 total events were reported during years 2 to 4 as new ADRs after the interim analysis. The CAP-RAST score was identified as a potential risk factor for ADRs. The proportion of evaluable patients with severe allergic rhinitis symptoms decreased from 46.4% at baseline (n = 317) to 1.0% at 4 years (n = 104). Patients (n = 16) who discontinued 300 IR HDM tablet due to symptomatic improvement had sustained improvement relative to baseline 1 to 2 years later. Long-term use of the 300 IR HDM tablet is safe and effective. The 300 index of reactivity house dust mite (HDM) sublingual tablet (Actair ) is a treatment option for people with HDM allergy. A Japanese study investigated the safety and effectiveness of the HDM sublingual tablet during its use for up to 4 years. Less than a third of patients (29%) reported adverse effects, mainly itching or irritation in the mouth. The percentage of patients with no allergic rhinitis symptoms increased from 0.3% before treatment to 57.7% after 4 years of use. The percentage of patients who perceived that their allergic rhinitis had improved ‘substantially’ compared with before treatment increased from 22.3% at 6 months to 73.5% at 4 years. Patients who ended treatment with the HDM sublingual tablet because their symptoms had improved continued to perceive benefit 1 to 2 years later. University hospital Medical Information Network (UMIN) Clinical Trials Registry identifier: UMIN000042840. Long-term use of the 300 IR HDM tablet is safe and effective.