A Study to Assess Intranasal Repeat Dose Effect of Levocabastine in the Subjects With Allergic Rhinitis

This study will be a randomized, double blind, placebo controlled, 3-way cross over design in allergic rhinitis subjects. Subjects will receive repeat doses of intra-nasal levocabastine for 7 days in each period and the duration of the study will be about 13 weeks. An Environmental Exposure Chamber (EEC) will be used in this study. The primary objective of the study is to investigate the non-inferiority effect of 7 days treatment with levocabastine on nasal symptoms elicited by an EEC when administered once daily (QD) compared with twice daily (BID). Also study will be conducted to investigate the superiority of effect of 7 days treatment with levocabastine (QD and BID) on nasal symptoms elicited by an EEC in subjects compared to placebo.