Roflumilast inhibition of pulmonary leukotriene production and bronchoconstriction in ovalbumin-sensitized and -challenged Guinea pigs

Dose dependent effects of tadalafil and roflumilast on ovalbumin-induced airway hyperresponsiveness in guinea pigs

INTRODUCTION

Chronic obstructive diseases of airways associated with cough and/or airway smooth muscle hyperresponsiveness are usually treated with bronchodilating and anti-inflammatory drugs. Recently, selective phosphodiesterase (PDE) 4 inhibitors have been introduced into the therapy of chronic obstructive pulmonary disease. Several studies have demonstrated their ability to influence the airway reactivity and eosinophilic inflammation by increasing the intracellular cAMP concentrations also in bronchial asthma. Furthermore, the expression of PDE5 in several immune cells suggests perspectives of PDE5 inhibitors in the therapy of inflammation, as well.

PURPOSE

The aim of this study was to assess the dose-dependent effects of PDE4 and PDE5 inhibitors in allergic inflammation. Therefore, the effects of 7-days administration of PDE4 inhibitor roflumilast and PDE5 inhibitor tadalafil at two different doses in experimentally-induced allergic inflammation were evaluated.

MATERIALS AND METHODS

In the study, male adult guinea pigs were used. Control group was non-sensitized. Other animals were sensitized with ovalbumin over two weeks and thereafter treated intraperitoneally for 7 days with roflumilast or tadalafil (daily dose 0.5 mg/kg or 1.0 mg/kg b.w.), or with vehicle.

RESULTS

Both roflumilast and tadalafil reduced specific airway resistance after nebulization of histamine (marker of in vivo airway reactivity) at both doses used. The in vitro airway reactivity to cumulative doses of acetylcholine was significantly reduced for roflumilast at higher dose, predominantly in the lung tissue strips. Histamine-induced contractile responses were significantly influenced in both lung and tracheal tissue strips, predominantly at the higher doses. Tadalafil led to a decrease in contractile responses induced by both acetylcholine and histamine, with more significant effects in the lung tissue strips. These changes were associated with decreased numbers of circulating leukocytes and eosinophils and concentrations of interleukin (IL)-4, IL-5 and TNF-α in the lung homogenate.

CONCLUSIONS

The selective PDE4 and PDE5 inhibitors alleviated allergic airway inflammation, with more significant effects at the higher doses.

Co-inhalation of roflumilast, rather than formoterol, with fluticasone more effectively improves asthma in asthmatic mice

Roflumilast is approved as an add-on therapy for chronic obstructive pulmonary disease. The inflammation in chronic obstructive pulmonary disease is mainly neutrophilic, while in asthma it is mainly eosinophilic, studies addressing role of roflumilast in eosinophilic inflammation are recommended. Also in severe asthma, the dominant inflammatory cells are neutrophils. Thus, roflumilast has a potential off-label use in the treatment of asthma. This study was designed to evaluate the effects of co-inhalation of roflumilast and fluticasone compared to that of formoterol and fluticasone in ovalbumin-sensitized and-challenged BALB/c mice. Besides normal control group, the ovalbumin-asthmatic mice were randomly divided into seven groups (n = 8): positive control, vehicle-treated, and five drug-treated groups. Treatments (µg/kg) were given as 15 min-inhalation once/day for five days as follows: roflumilast (500), formoterol (50), fluticasone (1000), roflumilast + fluticasone (500 + 1000), and formoterol + fluticasone (50 + 1000). Penh values were measured in conscious unrestrained mice using the single-chamber whole-body plethysmography. Airway hyperreactivity to inhaled methacholine was evaluated. Bronchoalveolar lavage fluid was used for the measurements of levels of IL-4, IL-5, TNF-α, OVA-specific IgE, and total and differential white cells. Lung sections were stained with hematoxylin and eosin and periodic acid-Schiff. The asthmatic mice showed significant increases in airway hyperreactivity which were significantly reversed by the combination treatments. The asthmatic mice showed significant increases in levels of IL-4, IL-5, TNF-α, ovalbumin-specific IgE, and total and differential white cells in bronchoalveolar lavage fluid. All treatments (except formoterol) significantly reversed these changes mainly with roflumilast + fluticasone. The asthmatic mice showed severe inflammatory infiltration and goblet cell hyperplasia which were maximally reversed by roflumilast + fluticasone, while minimally reversed by formoterol. In conclusion, co-inhalation of roflumilast + fluticasone more significantly improved inflammation and histopathological changes than co-inhalation of formoterol + fluticasone in ovalumin-asthmatic mice. Further studies are needed to help confirm the potential off-label add-on use of roflumilast in typical and atypical asthma and asthma-chronic obstructive pulmonary disease overlap syndrome. Impact statement Roflumilast, a selective phosphodiesterase-4 inhibitor, was approved for the treatment of chronic obstructive pulmonary disease (COPD). This study showed that co-inhalation of roflumilast and fluticasone significantly decreased airway hyperresponsiveness in ovalumin-asthmatic mice. Also, it more significantly improved inflammation and histopathological changes than co-inhalation of formoterol and fluticasone. The current results showed that inhaled roflumilast reduced counts of eosinophils, neutrophils, and macrophages in bronchoalveolar lavage fluid. Consequently, inhaled roflumilast might be of potential off-label benefit in treatment of eosinophilic and neutrophilic asthma and asthma-COPD overlap syndrome (ACOS). These results could also support other experimental and clinical studies addressing the same issue.

Roflumilast

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New therapeutic options in the management of COPD - focus on roflumilast

In chronic obstructive pulmonary disease (COPD) the inflammation occurring in the airways and in other lung tissues is complex and is orchestrated by various mediators including the isoenzyme 4 of the phosphodiesterases family (PDE4), which contributes to bronchoconstriction and inflammation. Various PDE4 inhibitors have been evaluated as potential therapies in asthma or COPD but among these only roflumilast have been authorized in Europe to be used in patients with severe COPD as an add-on to the bronchodilator therapy. This review discusses the existing preclinical and clinical data supporting the use of roflumilast for this therapeutic indication and tackles some of the pending issues related to PDE4 in general and to roflumilast in particular.

Roflumilast: first phosphodiesterase 4 inhibitor approved for treatment of COPD

In April 2010, the European Medicines Agency Committee for Medicinal Products for Human Use recommended approval of roflumilast, a selective phosphodiesterase 4 inhibitor, for the “maintenance treatment of severe chronic obstructive pulmonary disease (COPD, FEV₁ postbronchodilator less than 50% predicted) associated with chronic bronchitis in adult patients with a history of frequent exacerbations as add-on to bronchodilator treatment”. This decision was based, in part, on the results of several large, international, multicenter, randomized, placebo-controlled trials of either six or 12 months’ duration that had been undertaken in COPD patients. Roflumilast 500 μg daily improved lung function and reduced exacerbations in patients with more severe COPD, especially those with chronic bronchitis, frequent exacerbations, or who required frequent rescue inhaler therapy in the placebo-controlled trials. It also improved lung function and reduced exacerbations in patients with moderately severe COPD treated with salmeterol or tiotropium. Advantages of roflumilast over inhaler therapy are that it is an oral tablet and only needs to be taken once daily. While taking roflumilast, the most common adverse effects patients experienced were gastrointestinal upset and headache. Weight loss, averaging 2.2 kg, occurred in patients treated with roflumilast. Patients taking roflumilast were more likely to drop out of the trials than patients in the control groups. Patients who discontinued therapy usually did so during the first few weeks and were more likely to have experienced gastrointestinal side effects. Roflumilast is the first selective phosphodiesterase 4 inhibitor and will offer physicians another treatment option for patients with more severe COPD.

Treatment of obstructive airway diseases with roflumilast, a novel phosphodiesterase 4 inhibitor

Obstructive airway diseases, chronic obstructive pulmonary disease (COPD) and asthma have a high prevalence worldwide and constitute a considerable burden of disease. Although various treatments have evolved for these illnesses, they are often only partially effective in relieving symptoms and reducing underlying airway abnormalities. Inhaled bronchodilators and glucocorticosteroids have been the mainstay of therapy and no new classes of drug with effective anti-inflammatory activities have been introduced to clinical practice for almost 20 years. Recently, a new class of compounds, phosphodiesterase 4 inhibitors, have undergone development. This article will examine one such compound, roflumilast, which has recently shown promise as therapy for the principal obstructive lung diseases - COPD and asthma.

Roflumilast: an oral, once-daily selective PDE-4 inhibitor for the management of COPD and asthma

BACKGROUND

Roflumilast is a selective phosphodiesterase-4 inhibitor with a broad range of anti-inflammatory actions. Studies in asthma and chronic obstructive pulmonary disease (COPD) have demonstrated that it can improve lung function and reduce inflammation.

OBJECTIVE

To review the clinical data on roflumilast in COPD and asthma.

METHODS

A PubMed search using the term roflumilast was used to identify articles, and the bibliographies of the identified articles were reviewed to identify other relevant reports. All roflumilast abstracts from the 2006 and 2007 International Meetings of the American College of Chest Physicians, American Thoracic Society and European Respiratory Society were also reviewed.

RESULTS/CONCLUSION

The preliminary studies of roflumilast in COPD and asthma have only shown modest clinical benefits and may be associated with gastrointestinal side effects. Further studies are required to clarify the role of roflumilast in the management of COPD and asthma.

Roflumilast: a phosphodiesterase-4 inhibitor for the treatment of respiratory disease

Asthma and chronic obstructive pulmonary disease (COPD) are two of the most common chronic diseases worldwide, yet the classes of drug licensed to treat these conditions have not changed appreciably over the last 20 years. Inhaled bronchodilators and glucocorticosteroids (often in combination) form the mainstay of therapy for respiratory diseases, but many patients (including the elderly and children) can have problems using inhaler devices and there is a clear preference for oral therapy. The prevalence of these respiratory diseases is on the increase worldwide and continues to represent an area of medicine with unmet medical needs, particularly in the treatment of COPD. Despite this increase, very few new classes of drugs have been introduced into clinical practice. Phosphodiesterase-4 inhibitors are a novel class of drugs in development for the treatment of respiratory diseases and there are a number of lead compounds in late clinical development. This review focuses on one of the most promising drugs in development, roflumilast, which has undergone extensive clinical evaluation.