A Study to Determine the Optimal Dose and Frequency of ALDP001 Nasal Spray in Adults With Seasonal Allergic Rhinitis Under Allergen Exposure

Inclusion Criteria: * Diagnosis of Allergic Rhinitis (AR), as determined by the presence of seasonal rhinitis symptoms for several months per year, for more than 1 year and are not attributed to infections or nasal abnormalities * Positive skin prick test (SPT) response to ragweed pollen (allergen induced wheal diameter at least 3 mm larger than the negative control) in the previous 12 months * Healthy as determined by a responsible and experienced Investigator, based on a medical evaluation including medical history, physical examination, vital signs, ECG, and lab tests. Exclusion Criteria: * Nasal abnormalities likely to affect the outcome of the study, i.e. nasal septal perforation, nasal polyps, sinusitis and other nasal malformations. * History of frequent nosebleeds. * Participants with rhinitis medicamentosa. * Current or chronic history of hepatic disease. * A QTcF (Fridericia-corrected QT interval) \>450 ms in males or \>470 ms in females.