The aim of the study is to compare the safety and efficacy of ciclesonide versus fluticasone propionate on the lung function, symptoms, use of rescue medication, and occurrence of side effects (such as candidiasis, hoarseness) in adults with persistent asthma. Ciclesonide will be inhaled twice daily at one dose level; fluticasone propionate will be inhaled twice daily at one dose level. The study duration consists of a baseline period (2 weeks) and a treatment period (24 weeks). The study will provide further data on safety and tolerability of ciclesonide.

Main Inclusion Criteria:

• Written informed consent
• History of bronchial asthma for at least 6 months
• Pre-treatment with CFC-beclomethasone dipropionate (CFC-BDP) ≥ 1000 mcg/day or equivalent and a long-acting beta agonist (LABA) either in free or fixed combination
• FEV1 ≥ 80% of predicted

Main Exclusion Criteria:

• Concomitant severe diseases or diseases which are contraindications for the use of inhaled steroids or contraindications for the use of LABAs
• COPD
• Smoking with ≥10 pack-years
• Pregnancy
• Intention to become pregnant during the course of the study
• Breast feeding
• Lack of safe contraception