Methods: 565 adults with ragweed-pollen induced allergic rhinoconjunctivitis were randomized 1:1:1 to receive daily ragweed AIT (6 Amb a 1-U, 12 Amb a 1-U) or placebo approximately 4 months prior to and throughout the ragweed pollen season. Rescue medications and symptoms were recorded in e-diaries daily during ragweed season. Efficacy end points included the total combined daily symptom and medication score (TCS), daily symptom score (DSS), and daily medication score (DMS) during the entire season. Safety was monitored on ongoing basis through adverse event (AE) reporting and by an external data and safety monitoring committee.
Results: Overall 98% of the subjects were multisensitized. The ragweed AIT 12 Amb a 1-U and 6 Amb a 1-U groups showed a 26% and 16% improvement in TCS compared to the placebo group with significant between-treatment differences (p<0.05), respectively. The DSS for 12 Amb a 1-U (17%, p=0.01) and 6 Amb a 1-U (9%, p=0.17) also improved. The DMS for 12 Amb a 1-U (46%, p<0.01) and 6 Amb a 1-U (29%, p=0.03), also improved for the active groups. The majority of AEs were mild, local, application-site reactions with no reports of systemic allergic reactions.
Conclusions: This is the first time sublingual ragweed AIT has shown efficacy in a multisensitized North American adult population. Once-daily administration of ragweed AIT pre-seasonally and continued through ragweed season was well tolerated and clinically effective and will provide a new therapeutic modality for adults with ragweed pollen ARC.