Efficacy and safety of sublingual immunotherapy with grass allergen tablets for seasonal allergic rhinoconjunctivitis

BackgroundAllergen immunotherapy (desensitization) by injection is effective for seasonal allergic rhinitis and has been shown to induce long-term disease remission. The sublingual route also has potential, although definitive evidence from large randomized controlled trials has been lacking.ObjectiveThe aim was to confirm the efficacy of a rapidly dissolving grass allergen tablet (GRAZAX, ALK-Abelló, Hørsholm, Denmark) compared with placebo in patients with seasonal rhinoconjunctivitis.MethodsA longitudinal, double-blind, placebo-controlled, parallel-group study that included 51 centers from 8 countries. Subjects were randomized (1:1) to receive a grass allergen tablet or placebo once daily. A total of 634 subjects with a history of grass pollen–induced rhinoconjunctivitis for at least 2 years and confirmation of IgE sensitivity (positive skin prick test and serum-specific IgE) were included in the study. Subjects commenced treatment at least 16 weeks before the grass pollen season, and treatment was continued throughout the entire season.ResultsThe primary efficacy analysis showed a reduction of 30% in rhinoconjunctivitis symptom score (P < .0001) and a reduction of 38% in rhinoconjunctivitis medication score (P < .0001) compared with placebo. Side effects mainly comprised mild itching and swelling in the mouth that was in general well tolerated and led to treatment withdrawal in less than 4% of participants. There were no serious local side effects and no severe systemic adverse events.ConclusionSublingual immunotherapy with grass allergen tablets was effective in grass pollen–induced rhinoconjunctivitis. The tablet was well tolerated with minor local side effects.Clinical implicationsThe grass allergen tablet represents a safe alternative to injection immunotherapy suitable for home use.