Sustained 3-year efficacy of pre- and coseasonal 5-grass-pollen sublingual immunotherapy tablets in patients with grass pollen–induced rhinoconjunctivitis

Background Seasonal allergic rhinoconjunctivitis affects millions of persons. The efficacy of allergen sublingual immunotherapy (SLIT) was demonstrated in previous short-term studies. Objectives We sought to evaluate the sustained efficacy of 2 dosing regimens of a pre- and coseasonal treatment with 300 IR (index of reactivity) 5-grass-pollen SLIT tablets (Oralair) compared with placebo assessed by using the average adjusted symptom score (AAdSS) at season 3 in adults with grass pollen–induced rhinoconjunctivitis. Methods Six hundred thirty-three patients were treated for either 2 or 4 months before and then during the grass pollen season with active or placebo treatment for 3 consecutive seasons. The primary outcome was the AAdSS, a symptom score adjusted for rescue medication use, after 3 consecutive treatment seasons. Secondary outcomes were symptoms and rescue medication score, quality-of-life, and safety assessments. Results The mean AAdSS was reduced by 36.0% and 34.5% at season 3 in the 2- and 4-month pre- and coseasonal active treatment groups, respectively, compared with that in the placebo group ( P < .0001 for both). Reductions were observed in total symptom scores and ISSs and the medication score, with a marked improvement in quality of life for both active groups compared with the placebo group at season 3. Most treatment-emergent adverse events were local reactions expected with SLIT, decreasing in number and intensity in each treatment season. Conclusions Sustained efficacy of 2- and 4-month pre- and coseasonal treatment with the 300 IR tablet over 3 pollen seasons was demonstrated, with reduction in symptoms and rescue medication use. The treatment was well tolerated. Adverse events decreased in number and intensity over the 3 seasons.