Background: Specific immunotherapy is the only treatment modality that has the potential to alter the natural course of allergic diseases. Sublingual immunotherapy has been developed to facilitate access to this form of treatment and to minimize serious adverse events.
Objective: To investigate the efficacy and safety of sublingual grass allergen tablets in seasonal allergic rhinoconjunctivitis.
Methods: A multinational, multicenter, randomized, placebo-controlled trial conducted during 2002 and 2003. Fifty-five centers in 8 countries included 855 participants age 18 to 65 years who gave a history of grass pollen-induced allergic rhinoconjunctivitis and had a positive skin prick test and elevated serum allergen-specific IgE to Phleum pratense. Participants were randomized to 2500, 25,000, or 75,000 SQ-T grass allergen tablets (GRAZAX; ALK-Abelló, Hørsholm, Denmark) or placebo for sublingual administration once daily. Mean duration of treatment was 18 weeks.
Results: Average rhinoconjunctivitis scores during the season showed moderate reductions of symptoms (16%) and medication use (28%) for the grass allergen tablet 75,000 SQ-T (P = .0710; P = .0470) compared with placebo. Significantly better rhinoconjunctivitis quality of life scores (P = .006) and an increased number of well days (P = .041) were also observed. Efficacy was increased in the subgroup of patients who completed the recommended preseasonal treatment of at least 8 weeks before the grass pollen season (symptoms, 21%, P = .0020; and medication use, 29%, P = .0120). No safety concerns were observed.
Conclusion: This study confirms dose-dependent efficacy of the grass allergen tablet. Although further studies are required, the greater tolerability of the tablet may permit immunotherapy to be available to a much broader group of patients with impaired quality of life caused by grass pollen allergy.
Clinical implications: For patients with grass pollen allergy, sublingual immunotherapy is well tolerated and can reduce symptoms and improve quality of life.