This study consisted of 6 visits. Visit 1 was the Medical Screening Visit (skin prick test). Visit 2 and Visit 3 consisted of 2 consecutive EEC Visits (3 hours in the EEC followed by 7 hours in the Clinic, 10 hours total, each visit) followed by 7 days of wash-out. Visit 2 and Visit 3 occurred prior to dispense and the measures obtained during these visits were used as baseline. At Visit 4 patients were randomized and dispensed the assigned study medication for 7 days of at-home dosing. Visit 5 (Day 8 of treatment) and Visit 6 (Day 9 of treatment) consisted of 2 additional consecutive EEC Visits (3 hours in the EEC followed by 7 hours in the clinic, 10 hours total, each visit). During each EEC visit, patients were exposed to either ragweed or cat allergen, depending on their skin prick test results. Of the 180 participants enrolled, 170 received at least one dose of study treatment and were randomized to one of the three study treatments.