The objective of this study is to evaluate the effect of the combination of formoterol and beclometasone dipropionate on central and peripheral airway dimensions in asthmatic patients using Computational Fluid Dynamics (CFD). Further more, the effect of this combination therapy on exhaled NO, lung function (spirometry, body plethysmography, diffusion and resistance) and subjective asthma control score as well as the safety of this combination will be assessed.

Inclusion Criteria:

• Patients with asthma as defined by the current Global INitiative for Asthma (GINA) guidelines:
• Male or female patients aged ≥18 years
• Patients with a documented positive response to the reversibility test within the 12 months preceding the screening visit or performed at screening visit after a wash-out of 2 days for long acting β2 agonists or a documented positive response to the methacholine challenge test
• Patients with a co-operative attitude and ability to be trained to correctly use the pressurized Metered Dose Inhaler (pMDI)
• Written informed consent obtained

Exclusion Criteria:

• Pregnant or lactating females or females at risk of pregnancy
• Inability to carry out pulmonary function testing
• Diagnosis of Chronic Obstructive Pulmonary Disease (COPD) as defined by the current Global initiative for chronic Obstructive Lung Disease (GOLD) guidelines
• History of near fatal asthma
• Hospitalization due to asthma or symptomatic infection of the airways in the previous 8 weeks
• Current smokers or recent (less than one year) ex-smokers, defined as smoking at least 10 cigarettes/day
• Patients with an uncontrolled disease or any condition that might, in the judgement of the investigator, place the patient at undue risk or potentially compromise the results or interpretation of the study
• Patients with a QTc interval (Bazett's formula) at the screening visit Electrocardiogram (ECG) test >450 msec
• Cancer or any other chronic disease with poor prognosis and /or affecting patient status
• History of alcohol or drug abuse
• Allergy, sensitivity or intolerance to study drugs and/or study drug formulation ingredients
• Patients unlikely to comply with the protocol or unable to understand the nature, scope and possible consequences of the study
• Patients who received any investigational new drug within the last 8 weeks prior to the screening visit
• Patients treated with any non-permitted concomitant medication