Clinical efficacy of 300IR 5-grass pollen sublingual tablet in a US study: the importance of allergen-specific serum IgE.

BACKGROUND

Previous trials have demonstrated the efficacy, safety, and optimal dosage of the 5-grass pollen sublingual tablet for adults and children with grass pollen-induced allergic rhinoconjunctivitis.

OBJECTIVES

We sought to evaluate the efficacy and safety of 300 index of reactivity (IR) 5-grass pollen sublingual tablet in US adults.

METHODS

Adults with grass pollen allergy and Rhinoconjunctivitis Total Symptom Scores of 12 or greater (scale, 0-18) during the previous grass pollen season were randomized in a double-blind, placebo-controlled study to receive 300IR 5-grass pollen sublingual tablet or placebo starting 4 months before and continuing through the pollen season. The primary efficacy end point was the daily Combined Score (CS; scale, 0-3), which integrates symptoms and rescue medication use.

RESULTS

Four hundred seventy-three participants were randomized. The mean daily CS over the pollen period was significantly lower in the active treatment group versus the placebo group (least-squares mean difference: -0.13; 95% CI, -0.19 to -0.06; P = .0003; relative reduction: 28.2%; 95% CI, 13.0% to 43.4%). In placebo-treated participants, the daily CS least-squares mean was 0.32 in the subgroup with baseline timothy grass-specific serum IgE of less than 0.1 kU/L (n = 23) and 0.46 in those with baseline timothy grass-specific serum IgE of 0.1 kU/L or greater (n = 204). The most frequent reported adverse events were oral pruritus, throat irritation, and nasopharyngitis. There were no reports of anaphylaxis, and no actively treated participant received epinephrine.

CONCLUSION

In US adults with grass pollen-induced allergic rhinoconjunctivitis, preseasonal and coseasonal treatment with 300IR 5-grass pollen sublingual tablet demonstrated clinically meaningful efficacy, especially in study subjects with measurable timothy grass-specific serum IgE. Use of 300IR 5-grass pollen sublingual tablet was safe and well tolerated. A requirement for a measurable level of allergen-specific serum IgE should be considered in future studies in this field.