The aim of this study is to evaluate the involvement of small airways in asthma, as determined by bronchial challenges, CT-scanning, and cellular markers of inflammation. Ciclesonide will be inhaled at one dose level once daily. The study duration consists of a baseline period (2 to 3 weeks) and a treatment period (5 to 6 weeks). The study will provide further data on safety and tolerability of ciclesonide.

Main Inclusion Criteria:

• Written informed consent
• History of bronchial asthma
• FEV1 more than or equal to 60% of predicted
• Stable asthma
• Patients who are in good health with the exception of asthma

Main Exclusion Criteria:

• Concomitant severe diseases, diseases expected to interfere with the outcome of the study, or diseases which are contraindications for the use of ICS
• COPD (i.e. chronic bronchitis or emphysema) and/or other relevant lung diseases causing alternating impairment in lung function
• Use of ICS 4 weeks before entry into the baseline period
• Pregnancy
• Intention to become pregnant during the course of the study
• Breast feeding
• Lack of safe contraception
• Use of other drugs not allowed
• Current smokers and ex-smokers with more than or equal to 10 pack-years