OC000459 Dose Finding Study in Patients With Mild to Moderate Persistent Asthma

This will be a double blind, randomised, 4 arm, parallel group, placebo controlled study of three dose levels of OC000459 tablets in patients with asthma controlled by beta agonist drugs alone. This study will compare the patients on OC000459 at three different dose levels (25mg once daily, 100mg twice daily and 200mg once daily) with patients on placebo after dosing for 17 weeks. The trial will be undertaken in an outpatient population. Each treatment arm will consist of at least 110 subjects. The objective is to assess the efficacy of these dose levels on the patients asthma.