Efficacy and Safety of Oral Roflumilast Taken With Low Dose Inhaled Corticosteroids in Patients With Asthma (12 to 70 y) (BY217/M2-013)

Main Inclusion Criteria: * Written informed consent * Diagnosis of persistent chronic bronchial asthma, according to Global Initiative for Asthma (GINA) guidelines * The patient has been receiving BDP - CFC ≤1000 mcg per day or equivalent for the previous four weeks * FEV1 between 60 and 90% predicted at visit 1 * No change in asthma treatment within 4 weeks prior to visit 1 Main Exclusion Criteria: * Patients with poorly controlled asthma defined as requiring a course of oral or parenteral corticosteroids, admission to hospital for asthma (including treatment in an emergency room), or exacerbation of asthma in the four weeks prior to visit 1 * Patients who suffer from seasonal asthma alone or patients who are likely to have a major exacerbation of their asthma due to seasonal effects during the study run-in or treatment period * A history of lower airway infection in the four weeks prior to visit 1 * A diagnosis of chronic obstructive pulmonary disease (COPD) and/or other relevant lung disease (e.g. cystic fibrosis, bronchiectasis) * Heavy smoker currently smoking \>20 cigarettes per day and/or \>10 pack years or the patient is an ex-smoker who has smoked \>10 pack years * Patients using \>8 puffs/day relief medication regularly prior to visit 1 * Clinically relevant abnormal laboratory values suggesting an unknown disease and requiring further clinical evaluation * A diagnosis, treatment or remission of any cancer (other than basal cell carcinoma) within two years prior to visit 1 * Patients with chronic heart failure class III or IV (New York Heart Association) * Suspected hypersensitivity and/or contraindication to any ingredients of the study medication (roflumilast, BDP, or salbutamol) * A history of alcoholism or substance abuse within the 12 months prior to visit 1 * Pregnancy or women of childbearing potential who are not using a reliable method of contraception