The preclinical pharmacology of roflumilast--a selective, oral phosphodiesterase 4 inhibitor in development for chronic obstructive pulmonary disease.

After more than two decades of research into phosphodiesterase 4 (PDE4) inhibitors, roflumilast (3-cyclopropylmethoxy-4-difluoromethoxy-N-[3,5-di-chloropyrid-4-yl]-benzamide) may become the first agent in this class to be approved for patient treatment worldwide. Within the PDE family of 11 known isoenzymes, roflumilast is selective for PDE4, showing balanced selectivity for subtypes A-D, and is of high subnanomolar potency. The active principle of roflumilast in man is its dichloropyridyl N-oxide metabolite, which has similar potency as a PDE4 inhibitor as the parent compound. The long half-life and high potency of this metabolite allows for once-daily, oral administration of a single, 500-microg tablet of roflumilast. The molecular mode of action of roflumilast--PDE4 inhibition and subsequent enhancement of cAMP levels--is well established. To further understand its functional mode of action in chronic obstructive pulmonary disease (COPD), for which roflumilast is being developed, a series of in vitro and in vivo preclinical studies has been performed. COPD is a progressive, devastating condition of the lung associated with an abnormal inflammatory response to noxious particles and gases, particularly tobacco smoke. In addition, according to the Global Initiative for Chronic Obstructive Lung Disease (GOLD), significant extrapulmonary effects, including comorbidities, may add to the severity of the disease in individual patients, and which may be addressed preferentially by orally administered remedies. COPD shows an increasing prevalence and mortality, and its treatment remains a high, unmet medical need. In vivo, roflumilast mitigates key COPD-related disease mechanisms such as tobacco smoke-induced lung inflammation, mucociliary malfunction, lung fibrotic and emphysematous remodelling, oxidative stress, pulmonary vascular remodelling and pulmonary hypertension. In vitro, roflumilast N-oxide has been demonstrated to affect the functions of many cell types, including neutrophils, monocytes/macrophages, CD4+ and CD8+ T-cells, endothelial cells, epithelial cells, smooth muscle cells and fibroblasts. These cellular effects are thought to be responsible for the beneficial effects of roflumilast on the disease mechanisms of COPD, which translate into reduced exacerbations and improved lung function. As a multicomponent disease, COPD requires a broad therapeutic approach that might be achieved by PDE4 inhibition. However, as a PDE4 inhibitor, roflumilast is not a direct bronchodilator. In summary, roflumilast may be the first-in-class PDE4 inhibitor for COPD therapy. In addition to being a non-steroid, anti-inflammatory drug designed to target pulmonary inflammation, the preclinical pharmacology described in this review points to a broad functional mode of action of roflumilast that putatively addresses additional COPD mechanisms. This enables roflumilast to offer effective, oral maintenance treatment for COPD, with an acceptable tolerability profile and the potential to favourably affect the extrapulmonary effects of the disease.

Hatzelmann A ，Morcillo EJ ，Lungarella G ，Adnot S ，Sanjar S ，Beume R ，Schudt C ，Tenor H ... -  《-》

[Pharmacological profile of roflumilast].

Roflumilast (3-cyclopropylmethoxy-4-difluoromethoxy-n-(3,5-dichloropyrid-4-yl)benzamide) was the first agent of a novel pharmacological class, selective phosphodiesterase 4 (PDE(4)) inhibitors, approved for the use of chronic obstructive pulmonary disease (COPD). The molecular mechanism of action of roflumilast is inhibition of the PDE(4) isoenzyme with a consequent increase of cyclic adenosine monophosphate. Roflumilast evidently has several pharmacological effects: antiinflammatory, anti-emphysema, and antibiotic actions. This drug also inhibits pulmonary hypertension and reduces mucus hypersecretion. The pharmacological actions leading to these effects are: a) inhibition of reactive oxygen species formation in epithelial cells, neutrophils and smooth muscle cells; b) inhibition of smooth muscle cell proliferation in the pulmonary artery, endothelial cells and probably some inflammatory cells causing pulmonary vascular remodeling; c) inhibition of fibroblasts, with a consequent reduction in pulmonary remodeling and, finally, d) inhibition of mucus production and improved ciliary beat frequency. In summary, roflumilast is the first non-steroidal anti-inflammatory drug that can be used in the treatment of COPD.

Cortijo Gimeno J ，Morcillo Sánchez E 《-》

Roflumilast for the treatment of chronic obstructive pulmonary disease.

Rabe KF 《-》

The potential role of roflumilast: the new phosphodiesterase-4 inhibitor.

Karish SB ，Gagnon JM 《ANNALS OF PHARMACOTHERAPY》

Phosphodiesterase inhibitors in airways disease.

Fan Chung K 《EUROPEAN JOURNAL OF PHARMACOLOGY》