Roflumilast is a potent and targeted PDE4 inhibitor, approved by the European Commission as an add-on to bronchodilator therapy for the treatment of severe chronic obstructive pulmonary disease (COPD) associated with chronic bronchitis in adults with a history of frequent exacerbations, and targets the underlying inflammation in COPD. Here, PDE4A is linked to chronic obstructive pulmonary disease.