In this pivotal, multicentre, international, randomized, double-blind, placebo and active-comparator controlled, parallel study, 683 patients with SAR will be enrolled. Patients will be required to be 12-70 years old, have SAR for ≥2 years, a positive skin test, total nasal and non-nasal score (TSS) ≥36 (out of 72) during run-in, and a composite instantaneous nasal symptom score ≥6 (out of 12) the morning before randomization. The primary efficacy endpoint will be the AUC of reflective TSS from baseline to Day 14.