Chronic obstructive pulmonary disease (COPD) is a progressive inflammatory disease that is mainly linked to smoking and is associated with significant medical and economic burdens. For example, in the USA the estimated direct costs are US$29.5 billion, whereas at the EU level these costs are estimated to amount to approximately 56% of the costs related to respiratory diseases. COPD is characterized by chronic respiratory symptoms such as dyspnea and productive cough, which are progressive and further worsen during exacerbation of the disease. It is also associated with an abnormal lung function decline and with an increasing rate of exacerbations, the latter being responsible for most of the related direct costs. The existing inhaled therapies such as long-acting anticholinergics, long-acting β2 agonists and inhaled corticosteroids are not always able to improve the disease outcome, and therefore other more effective therapies are needed; roflumilast is a recent example of such a therapy, being authorized for use in patients with severe and very severe COPD (i.e., with a forced expiratory volume in 1 s of <50% predicted) based on its ability to significantly reduce the exacerbation rate and the severity of respiratory symptoms.