Methods: Seventy-eight subjects with allergic rhinitis were exposed to ragweed pollen in the EEC at an interval of 27 (+5) days between visits. During the EEC visits, subjects recorded their total nasal symptoms using an electronic diary (ePDAT®) prior to EEC entry and every 30 minutes over a 2 hour period.
Results: The mean TNSS levels at both Visits 1 and 2 increased and peaked at similar levels with average maximum TNSS scores (1st visit = 8.86 ± 0.22; 2nd visit = 8.37 ± 0.24). Consistent pollen levels were observed throughout the EEC visits. A highly significant correlation was shown of the overall average TNSS over time between Visits 1 and 2 (r = 0.9964, p = 0.0003). The average TNSS of each subject over both EEC visits showed a correlation coefficient of r = 0.5722, p<0.0001. In addition, a Bland-Altman plot had a mean difference of 0.6667 and 95% limits of agreement between -5.713 and 7.047 indicating a good clinical agreement between the two visits.
Conclusions: The ability of the EEC to elicit repeatable nasal symptoms at clinically significant levels in allergic rhinitis individuals will be a positive step forward in the evaluation of treatment outcomes and allergic rhinitis efficacy trials.