Methods: The response to treatment from 5 pivotal, placebo-controlled trials of grass AIT (n=1793) and from 2 pivotal, placebo-controlled trials of ragweed AIT (n=644) were characterized. For each trial, subjects took daily tablet treatment for at least 8 weeks prior to and during the specific pollen seasons. Rescue medications and symptoms were recorded in eDiaries daily. The total combined daily symptom and medication scores (TCS), daily symptom scores (DSS), and daily medication scores (DMS) were calculated during the entire pollen seasons. Pollen counts were collected during each trial.
Results: Seasons with high peak pollen counts generally favored larger treatment effects. Average peak season pollen counts varied between 48 to 106 grains/m3 for grass pollen and from 193 to 227 grains/m3 for ragweed pollen. The average TCS among grass AIT treated subjects and among ragweed AIT treated subjects were reduced by 23% (p<0.001 for between-treatment differences) and 25% (p<0.001) relative to placebo, respectively. However, the effect of treatment varied from 10% to 41% dependent on the season and pollen exposure. In particular, the treatment impact on use of rescue medications increased during more robust pollen seasons, with DMS varying from 20% to 46%. The majority of AEs were mild, local, application-site reactions with no reports of anaphylactic shock.
Conclusions: These results provide evidence of a consistent treatment effect of ragweed and grass AIT across multiple seasons. The treatment effect generally had a tendency of being larger in studies with higher pollen counts and longer seasons, but also has been replicated for shorter seasons and lower pollen counts.