Roflumilast (3-cyclopropylmethoxy-N-(3,5-dichloropyridin-4-yl)-4-(difluoromethoxy)benzamide; CAS Registry number: 162401-32-3; molecular formula: C17H14Cl2F2N2O3) is a selective, oral, once-daily phosphodiesterase 4 (PDE4) inhibitor that has shown anti-inflammatory activity in pre-clinical studies [1-4], and in patients with chronic obstructive pulmonary disease (COPD) [5]. This evidence concerns the gene PDE4A and chronic obstructive pulmonary disease.