Main Inclusion Criteria:

• Written informed consent
• Good health with the exception of asthma
• Clinical diagnosis of moderate persistent asthma during the last 6 months prior to visit B0
• Pre-treatment with inhaled corticosteroids dose equivalent to 250 - 500 mcg BDP / day at stable dosing during the last 4 weeks prior to visit B0, concomitant or not to short-acting beta2-agonists treatment as rescue medication
• FEV1 ≥ 70% and ≤ 90% predicted measured at least 4 h after the last use of rescue medication at visit B0
• Reversibility ≥ 12% and ≥ 200 mL in B0, B0 or T0, after inhalation of 400 mcg of salbutamol
• Patients compliant to recommended pre-treatment

Main Exclusion Criteria:

• Concomitant severe diseases or diseases which are contraindications for the use of inhaled steroids
• Chronic obstructive pulmonary disease (COPD)
• Hospitalization within previous four weeks from baseline
• Hospitalization due to asthma within the last twelve months
• Asthma exacerbation within two months previous to baseline
• History of almost fatal asthma at any moment
• Pregnancy, breast feeding, intention to become pregnant during the course of the study or lack of safe contraception in pre-menopausal women
• Exacerbation of asthma within 2 months prior to entry into the baseline period
• Use of systemic steroids up to 2 months (injectable depot steroids 6 months) before entry into the baseline period, or more than 3 times during the last 6 months