Consistent efficacy and safety of sublingual immunotherapy tablets across allergens and geographic regions

Background: The clinical development program of the SQ grass, ragweed, tree, and house dust mite (HDM) sublingual immunotherapy (SLIT)-tablets for allergic rhinitis/conjunctivitis (AR/C) included clinical trials conducted in North America, Europe, and Japan. Objective: Data from these trials were analyzed to assess efficacy, immunologic mechanisms, and safety outcomes across allergens and geographic regions. Methods: Thirteen phase III, double-blind, placebo controlled trials in the subjects with AR/C were conducted in North America, Europe (including Russia), and Japan (N = 7763 analyzed). Trials were generally similar with respect to medical practice, target population, eligibility criteria, and efficacy and safety monitoring. Data were analyzed for the approved doses in North America and Europe. Four statistical models were used to enhance comparison of the efficacy end points among the trials. Results: The SLIT-tablets demonstrated consistent efficacy across allergens and regions, regardless of the statistical analysis used. Relative improvement in the primary efficacy end point compared with placebo by using the predefined protocol analysis ranged from 17.9% to 32.8%, 17.5% to 19.3%, 20.6% to 38.3%, and 39.6% with the grass, HDM, ragweed, and tree SLIT-tablets, respectively. The kinetics of specific immunoglobulin E (IgE) and IgG4 responses were similar among the allergens and regions. Local application-site reactions were the most common adverse events for all allergens and in all regions. Most treatment-related adverse events for all allergens and in all regions were mild in severity. The rate of systemic allergic reactions was similar across regions (0%-0.54%). Conclusion: Confirmatory phase III trials for SLIT-tablets in the treatment of AR/C showed consistent efficacy, immunologic, and safety outcomes across allergens and geographic regions.