A comparison of the safety, efficacy and budesonide pharmacokinetics of the currently approved Pulmicort Turbuhaler with a new version of the inhaler, in adult patients who have asthma and are currently being treated with inhaled steroids. In addition the study evaluated the functionality of the new inhaler at the end of its intended life.

Inclusion Criteria:

• Males and females at least 18 years old with a diagnosis of asthma (as defined by the ATS) for at least 6 months.
• To enter the run in period, subjects were also required to have the following:
• A forced expiratory volume (FEV1) in 1 second of 60% to 90% of predicted normal, airway reversibility of at least 12% and 0.20 L, use of orally inhaled corticosteroids for at least 3 months prior to the study.
• At Visit 2, subjects who met additional entry criteria related to rescue medication use and asthma symptom scores during the run in period plus visit specific FEV1 requirements were assigned to randomized treatments

Exclusion Criteria:

• Life threatening asthma, Two or more overnight hospitalisations for asthma within 1 year or any emergency room visit for asthma within 6 months of starting study.
• Use of steroid tablets or injections during the month (28 days) prior to Visit 1 and use of other asthma medicines (except rescue medication) within 2 weeks prior to the study.
• Any acute exacerbation of asthma or a respiratory tract infection within 30 days prior to the study. Subject must not smoke or have smoked within 6 months of the study.