Poster 1000: Efficacy and safety of specific sublingual immunotherapy with carbamylated allergoid tablets of ragweed pollen: a dose-ranging study

Methods A prospective multicenter double-blind randomized dose-ranging study (EudraCT number 2011-004522-10) was conducted following GCP rules in patients with history of ragweed-related moderate-to-severe allergic rhinoconjunctivitis for at least 2 years, with or without controlled seasonal allergic asthma, and positive response to allergen specific nasal provocation test (NPT). Before the 2013 ragweed pollen season adult patients were assigned to different daily dosages (3001000-2000 UA) of tablets of ragweed pollen carbamylated extract given for 4 months. The primary end-point was the individual change in the response to NPT before and after the treatment (allergic symptoms and threshold provocative dose to identify improved, unchanged, worsened subjects). Secondary end-points included the analysis of this improvement considering the severity level (depending on symptoms score and provocative dose), the change of nasal peak inspiratory flow (NPIF) in response to NPT, and the incidence of adverse events. Results Seventy-three subjects were enrolled and 52 were randomized (1:1:1) and treated. The proportion of improved patients was 77%, 88% and 81% in the 300 UA, 1000UA and 2000 UA groups respectively. A progressive trend to increased efficacy with flattening of the slope (mean severity level improvement: +1.38, +1.71 and +1.90 respectively) and a statistically significant difference between 300 UA and 2000 UA (p = 0.0187) were found. NPIF improved in all groups at the end of the study without significant differences among treatments (p = 0.41). One probable treatment-related AE occurred in group 1, 3 probable and 1 certain (mild) in group 2, 3 possible and 1 certain (moderate) in group 3. No serious treatment-related AEs occurred.