Inuvair® is a novel fixed combination product used in the treatment of asthma and under clinical development for the treatment of COPD. Thanks to the extrafine particle size, it is able to target the whole bronchial tree, including the small airways and hence, is expected to act in these airways and it may thus be beneficial in COPD in that sense. In COPD, its action on the small airways is not directly demonstrated thus far. By way of contrast, dear evidence is present that treatment with bronchodilators alone does not beneficially alter small airway function. The study hypothesis states that the effects of inhaled corticosteroids or ICS/LABA combinations on small airway is present and can be objectivated.

Inclusion Criteria:

• clinical diagnosis COPD according to last updated GOLD guidelines (post- bronchodilator FEV/FVC below 0,70, FEV1 <80% predicted)
• ex-smokers (ie 1 year from the last cigarette) with at least 10 pack years.
• GOLD stage II and III (FEV1 > 30% predicted)
• by preference naïve to inhaled corticosteroids; in those taking inhaled corticosteroids this medication will be stopped 1 month prior to enrollment in the study
• Patients must have proven small airways dysfunction on routine spirometry as reflected by a drop in FEF25-75 and FEF75 of at least 50%. Moreover, patients must have proven small airways dysfunction on MBW as reflected by Sacin >0,120 that is considered abnormal.

Exclusion Criteria:

• Current smoking
• Active COPD exacerbation
• gold stage I and IV