ASCIA‐P52: TREATMENT WITH HOUSE DUST MITE TABLETS FOR SUBLINGUAL IMMUNOTHERAPY: RELATIONSHIP BETWEEN ALLERGIC DISEASE SEVERITY AND EFFICACY IN A CONFIRMATORY STUDY

Abstract

House dust mite (HDM) sublingual immunotherapy tablets administered daily in allergic rhinitis patients has been evaluated after a 12-month treatment period in a randomized, double-blind, study in 509 adults in Europe. The post-treatment effect was subsequently assessed over a 12-month period. 300IR and 500IR doses of HDM or placebo tablets were administered to adults with HDM-associated allergic rhinitis in a randomized DBPC study. After the treatment phase, subjects were monitored during a 12-month treatment-free period. Analyses were performed to evaluate the relationship between disease severity and efficacy. Centers pooled by geographical zones were ranked according to the mean average Adjusted Symptom Score (AASS, that adjusts symptom severity with rescue medication use) in the placebo group. Pooled centers were then grouped into statistical tertiles, each having about one-third of all subjects. In the 300IR group (n = 153), subjects experienced symptom improvement compared to the placebo group (n = 163). During the treatment period, the overall treatment effect estimated as the difference in AASS LS means was at 0.69, (CI95% [−1.25, 0.14], p = 0.0150), i.e., a relative difference of −17.9% from placebo. For the low-, medium- and high-severity tertiles (n = 98, 94 and 102), the relative differences in this score for subjects receiving 300IR vs. placebo were +10.3%, −7.2% and −39.3 %, respectively. During the treatment-free year, the relative differences in this score for the subjects receiving 300IR vs. placebo were −5.6%, −4.8% and −29.9% for the low-, medium- and high-severity tertiles (n = 74, 108 and 87), respectively. These results showed that the more severe the disease, the greater the treatment effect. The 300IR dose has demonstrated efficacy during treatment and over the year post-treatment. The overall treatment effect observed was driven by efficacy in the tertile of pooled centers in which subjects in the placebo group exhibited the highest level of symptoms, with about 39% improvement versus placebo.