The SQ tree SLIT-tablet is highly effective and well tolerated: Results from a randomized, double-blind, placebo-controlled phase III trial

Background: The SQ tree sublingual immunotherapy (SLIT)tablet (ALK-Abello, Horsholm, Denmark) is developed for treatment of tree pollen-induced allergic rhinoconjunctivitis (ARC). Objective: The aim of this pivotal phase III trial was to demonstrate the efficacy and safety of the SQ tree SLIT-tablet. Methods: This was a randomized, double-blind, placebo-controlled trial with 634 subjects (12-65 years) with moderate-to-severe ARC despite use of symptom-relieving medication. Eligible subjects were randomized 1:1 to active or placebo treatment. The primary end point was the average daily ARC total combined score (TCS) during the birch pollen season (BPS) analyzed for subjects with diary data during the BPS. Secondary end points included average daily symptom scores (DSS) during the BPS, average TCS and DSS during the tree pollen season (TPS), and average daily medication scores (DMS) in the BPS and TPS. Results: The primary and key secondary end points demonstrated statistically significant and clinically relevant effects of the SQ tree SLIT-tablet compared with placebo. For the BPS, absolute (relative) differences from placebo were 3.02 (40%) for TCS, 1.32 (37%) for DSS, and 1.58 (49%) for DMS (all P < .0001). For the TPS, absolute (relative) differences from placebo were 2.27 (37%) for TCS, 0.99 (33%) for DSS, and 1.20 (47%) for DMS (all P < .0001). Treatment was well tolerated. The most frequently reported treatment-related adverse events were mild or moderate local reactions related to sublingual administration. Conclusion: The trial demonstrated the efficacy and safety of the SQ tree SLIT-tablet compared with placebo during the BPS and TPS in adolescents and adults with birch pollen-induced ARC (EudraCT 2015-004821-15).