A broad spectrum of anti-inflammatory drugs, including inhibitors of the pro-inflammatory enzymes PDE4, Janus kinases, NF-κB kinase, p38 mitogen-activated protein kinase, and PI3 kinase-γ and -δ, were developed for COPD treatment, but side effects after oral administration limited their clinical application20. This evidence concerns the gene PDE4A and chronic obstructive pulmonary disease.