Summary. Immunotherapy is the only treatment for allergy that has the potential to alter the natural course of the disease. Sublingual immunotherapy for grass pollen-induced rhinoconjunctivitis has been developed to make immunotherapy available to a broader group of allergic patients. Here, a safe dose range and the safety during daily sublingual administration were investigated for a new tablet-based sublingual immunotherapy for grass pollen allergy. Simultaneously, immunological changes were monitored.
A randomized, double-blind, placebo-controlled phase I trial was undertaken, with stepwise dose-escalation during the dose-finding period, and afterwards with daily dosing 8 weeks prior to and 15 weeks during the grass pollen season (2500, 25 000, or 75 000 standardized quality tablet [SQ-T] units, or placebo). Fifty-two participants with
grass pollen-induced rhinoconjunctivitis and a positive skin prick test and specific IgE to Phleum pratense entered the trial.
During the daily-dose treatment periods, 67% of the participants reported adverse events. The most frequent were itching in the mouth, eyes, or throat, and rhinitis, and most were mild and resolved within 1 day. Two participants withdrew due to adverse events (sting and blisters in the mouth and itching in the mouth). Time- and dosedependent
increases of P pratense-specific IgG, IgA, IgE, and IgE-competing components were found in serum during the first 8 weeks of daily dosing, indicating that the treatment had a significant allergen-specific effect on the immune system.
In conclusion, the grass allergen tablet, administered in a dose of 75 000 SQ-T once daily, was well tolerated and displayed systemic immunogenicity.

Key words: Grass pollen allergy. Immunological changes. Safety. Sublingual immunotherapy. Tablet