 This double-blind, stratified, parallel group study is to determine whether aiming for Total control results in better airway hyper-responsiveness than maintaining the treatment level at which Well-controlled asthma was achieved. The primary endpoint is the mean change in PC20 methacholine. Well controlled subjects as assessed after a 12 week run-in period will enter a 24 week treatment period during which they will record PEFPeak Expiratory Flow, symptoms, rescue beta2-agonist use over 24 hours, night time awakenings, asthma exacerbations, emergency visits due to asthma and Adverse Events. At every visit lung function measurements and airway hyper-responsiveness will be measured. 