The objectives of this study are: to confirm the superiority of TAU-284 over placebo after two weeks of administration to pediatric patients with perennial allergic rhinitis, and to investigate the dose response, safety, and plasma concentrations of TAU-284.

This is a randomized, double-blind, placebo-controlled, 3-arm parallel-group comparative study to confirm the superiority of TAU-284 over placebo after two weeks of administration of TAU-284 (10 mg/day or 20 mg/day) or placebo to pediatric patients with perennial allergic rhinitis, with "the change from baseline in total nasal symptom score (total score for the three major nasal symptoms [sneezing, rhinorrhea, and nasal congestion])" as the primary endpoint; and to investigate the dose response, safety, and plasma concentrations of TAU-284.

Inclusion Criteria:

• Patients aged between 7 and 15 years
• Patients with a weight of at least 20 kg
• Patients who have received a diagnosis of perennial allergic rhinitis according to the diagnostic criteria
• Patients with a mean rhinorrhea score of at least 2 and a mean total score for the three major nasal symptoms [sneezing, rhinorrhea, and nasal congestion] of at least 4 on the basis of symptoms recorded in the nasal allergy diary during the observation period

Exclusion Criteria:

• Patients with vasomotor rhinitis or eosinophilic rhinitis
• Patients who have concurrent nasal disease that may affect the efficacy of TAU-284
• Patients with a history of any of the nasal surgical procedures
• Patients who have a positive result for pollen antigens which are dispersed during the study period
• Patients who have a positive result for dog dander or cat dander antigen
• Patients with current or previous history of drug allergy
• Patients who concurrently have renal function abnormalities that may cause safety problems