Sublingual immunotherapy in pollen-induced seasonal rhinitis and conjunctivitis: a randomized controlled trial

Background: Sublingual immunotherapy (SLIT) is a recognized and safe treatment for allergic rhinitis and conjunctivitis. The aim was to evaluate the efficacy and safety of tablets for grass and rye pollen-induced rhinitis and conjunctivitis. Methods: A double-blind, randomized, placebo-controlled trial was carried out over 9 months. 105 patients received a standardized grass/rye mix extract or a placebo using sublingual drops during the build-up phase. Drops were replaced by sublingual tablets during the maintenance phase (300 IR/daily). Results: In patients that received active treatment, a significantly lower total symptom score (rhinitis and conjunctivitis) compared to the placebo group was observed (p = 0.038). The investigators' assessment revealed a significant improvement in favor of the active treatment group (p = 0.018). Skin reactivity to grass and rye pollen was significantly reduced in the active treatment group (p < 0.05). No statistical difference was observed between the two groups for serum-specific IgG4 levels. Side effects were local and mild, and no severe systemic reactions were reported. Conclusion: This study indicates that tablet-based sublingual immunotherapy was safe and significantly improved grass/rye pollen-induced rhinoconjunctivitis symptoms. It was also associated with a significant inhibition of the immediate skin response.