Cilomilast for COPD

NHC-catalyzed enantioselective access to β-cyano carboxylic esters via in situ substrate alternation and release

A carbene-catalyzed asymmetric access to chiral β-cyano carboxylic esters is disclosed. The reaction proceeds between β,β-disubstituted enals and aromatic thiols involving enantioselective protonation of enal β-carbon. Two main factors contribute to the success of this reaction. One involves in situ ultrafast addition of the aromatic thiol substrates to the carbon-carbon double bond of the enal substrate. This reaction converts almost all enal substrate to a Thiol-click Intermediate, significantly reducing aromatic thiol substrates concentration and suppressing the homo-coupling reaction of enals. Another factor is an in situ release of enal substrate from the Thiol-click Intermediate for the desired reaction to proceed effectively. The optically enriched β-cyano carboxylic esters from our method can be readily transformed to medicines that include γ-aminobutyric acids derivatives such as Rolipram. In addition to synthetic utilities, our control of reaction outcomes via in situ substrate modulation and release can likely inspire future reaction development.

Phosphodiesterase 4B inhibition: a potential novel strategy for treating pulmonary fibrosis

Patients with interstitial lung disease can develop a progressive fibrosing phenotype characterised by an irreversible, progressive decline in lung function despite treatment. Current therapies slow, but do not reverse or stop, disease progression and are associated with side-effects that can cause treatment delay or discontinuation. Most crucially, mortality remains high. There is an unmet need for more efficacious and better-tolerated and -targeted treatments for pulmonary fibrosis. Pan-phosphodiesterase 4 (PDE4) inhibitors have been investigated in respiratory conditions. However, the use of oral inhibitors can be complicated due to class-related systemic adverse events, including diarrhoea and headaches. The PDE4B subtype, which has an important role in inflammation and fibrosis, has been identified in the lungs. Preferentially targeting PDE4B has the potential to drive anti-inflammatory and antifibrotic effects via a subsequent increase in cAMP, but with improved tolerability. Phase I and II trials of a novel PDE4B inhibitor in patients with idiopathic pulmonary fibrosis have shown promising results, stabilising pulmonary function measured by change in forced vital capacity from baseline, while maintaining an acceptable safety profile. Further research into the efficacy and safety of PDE4B inhibitors in larger patient populations and for a longer treatment period is needed.

Phosphodiesterase-4 inhibitors for chronic obstructive pulmonary disease

BACKGROUND

Chronic obstructive pulmonary disease (COPD) is associated with cough, sputum production or dyspnoea, and a reduction in lung function, quality of life, and life expectancy. Apart from smoking cessation, no other treatments that slow lung function decline are available. Roflumilast and cilomilast are oral phosphodiesterase-4 (PDE₄) inhibitors proposed to reduce the airway inflammation and bronchoconstriction seen in COPD. This Cochrane Review was first published in 2011, and was updated in 2017 and 2020.

OBJECTIVES

To evaluate the efficacy and safety of oral PDE₄ inhibitors for management of stable COPD.

SEARCH METHODS

We identified randomised controlled trials (RCTs) from the Cochrane Airways Trials Register (date of last search 9 March 2020). We found other trials at web-based clinical trials registers.

SELECTION CRITERIA

We included RCTs if they compared oral PDE₄ inhibitors with placebo in people with COPD. We allowed co-administration of standard COPD therapy.

DATA COLLECTION AND ANALYSIS

We used standard Cochrane methods. Two independent review authors selected trials for inclusion, extracted data, and assessed risk of bias. We resolved discrepancies by involving a third review author. We assessed our confidence in the evidence by using GRADE recommendations. Primary outcomes were change in lung function (minimally important difference (MID) = 100 mL) and quality of life (scale 0 to 100; higher score indicates more limitations).

MAIN RESULTS

We found 42 RCTs that met the inclusion criteria and were included in the analyses for roflumilast (28 trials with 18,046 participants) or cilomilast (14 trials with 6457 participants) or tetomilast (1 trial with 84 participants), with a duration between six weeks and one year or longer. These trials included people across international study centres with moderate to very severe COPD (Global Initiative for Chronic Obstructive Lung Disease (GOLD) grades II to IV), with mean age of 64 years. We judged risks of selection bias, performance bias, and attrition bias as low overall amongst the 39 published and unpublished trials. Lung function Treatment with a PDE₄ inhibitor was associated with a small, clinically insignificant improvement in forced expiratory volume in one second (FEV₁) over a mean of 40 weeks compared with placebo (mean difference (MD) 49.33 mL, 95% confidence interval (CI) 44.17 to 54.49; participants = 20,815; studies = 29; moderate-certainty evidence). Forced vital capacity (FVC) and peak expiratory flow (PEF) were also improved over 40 weeks (FVC: MD 86.98 mL, 95% CI 74.65 to 99.31; participants = 22,108; studies = 17; high-certainty evidence; PEF: MD 6.54 L/min, 95% CI 3.95 to 9.13; participants = 4245; studies = 6; low-certainty evidence). Quality of life Trials reported improvements in quality of life over a mean of 33 weeks (St George's Respiratory Questionnaire (SGRQ) MD -1.06 units, 95% CI -1.68 to -0.43; participants = 7645 ; moderate-certainty evidence). Incidence of exacerbations Treatment with a PDE₄ inhibitor was associated with a reduced likelihood of COPD exacerbation over a mean of 40 weeks (odds ratio (OR) 0.78, 95% CI 0.73 to 0.84; participants = 20,382; studies = 27; high-certainty evidence), that is, for every 100 people treated with PDE₄ inhibitors, five more remained exacerbation-free during the study period compared with those given placebo (number needed to treat for an additional beneficial outcome (NNTB) 20, 95% CI 16 to 27). No change in COPD-related symptoms nor in exercise tolerance was found. Adverse events More participants in the treatment groups experienced an adverse effect compared with control participants over a mean of 39 weeks (OR 1.30, 95% CI 1.22 to 1.38; participants = 21,310; studies = 30; low-certainty evidence). Participants experienced a range of gastrointestinal symptoms such as diarrhoea, nausea, vomiting, or dyspepsia. Diarrhoea was more commonly reported with PDE₄ inhibitor treatment (OR 3.20, 95% CI 2.74 to 3.50; participants = 20,623; studies = 29; high-certainty evidence), that is, for every 100 people treated with PDE₄ inhibitors, seven more suffered from diarrhoea during the study period compared with those given placebo (number needed to treat for an additional harmful outcome (NNTH) 15, 95% CI 13 to 17). The likelihood of psychiatric adverse events was higher with roflumilast 500 µg than with placebo (OR 2.13, 95% CI 1.79 to 2.54; participants = 11,168; studies = 15 (COPD pool data); moderate-certainty evidence). Roflumilast in particular was associated with weight loss during the trial period and with an increase in insomnia and depressive mood symptoms. Participants treated with PDE₄ inhibitors were more likely to withdraw from trial participation; on average, 14% in the treatment groups withdrew compared with 8% in the control groups. Mortality No effect on mortality was found (OR 0.98, 95% CI 0.77 to 1.24; participants = 19,786; studies = 27; moderate-certainty evidence), although mortality was a rare event during these trials.

AUTHORS' CONCLUSIONS

For this current update, five new studies from the 2020 search contributed to existing findings but made little impact on outcomes described in earlier versions of this review. PDE₄ inhibitors offered a small benefit over placebo in improving lung function and reducing the likelihood of exacerbations in people with COPD; however, they had little impact on quality of life or on symptoms. Gastrointestinal adverse effects and weight loss were common, and the likelihood of psychiatric symptoms was higher, with roflumilast 500 µg. The findings of this review provide cautious support for the use of PDE₄ inhibitors in COPD. In accordance with GOLD 2020 guidelines, they may have a place as add-on therapy for a subgroup of people with persistent symptoms or exacerbations despite optimal COPD management (e.g. people whose condition is not controlled by fixed-dose long-acting beta₂-agonist (LABA) and inhaled corticosteroid (ICS) combinations). More longer-term trials are needed to determine whether or not PDE₄ inhibitors modify FEV₁ decline, hospitalisation, or mortality in COPD.

Phosphodiesterase 4 inhibitors for chronic obstructive pulmonary disease

BACKGROUND

Chronic obstructive pulmonary disease (COPD) is associated with cough, sputum production or dyspnoea and a reduction in lung function, quality of life and life expectancy. Apart from smoking cessation, there are no other treatments that slow lung function decline. Roflumilast and cilomilast are oral phosphodiesterase 4 (PDE4) inhibitors proposed to reduce the airway inflammation and bronchoconstriction seen in COPD. This is an update of a Cochrane review first published in 2011 and updated in 2013.

OBJECTIVES

To evaluate the efficacy and safety of oral PDE4 inhibitors in the management of stable COPD.

SEARCH METHODS

We identified randomised controlled trials (RCTs) from the Cochrane Airways Trials Register (date of last search October 2016). We found other trials from web-based clinical trials registers.

SELECTION CRITERIA

We included RCTs if they compared oral PDE4 inhibitors with placebo in people with COPD. We allowed co-administration of standard COPD therapy.

DATA COLLECTION AND ANALYSIS

One review author extracted data and a second review author checked the data. We reported pooled data in Review Manager as mean differences (MD), standardised mean differences (SMD) or odds ratios (OR). We converted the odds ratios into absolute treatment effects in a 'Summary of findings' table.

MAIN RESULTS

Thirty-four separate RCTs studying roflumilast (20 trials with 17,627 participants) or cilomilast (14 trials with 6457 participants) met the inclusion criteria, with a duration of between six weeks and one year. These included people across international study centres with moderate to very severe COPD (Global Initiative for Chronic Obstructive Lung Disease (GOLD) grades II-IV), with a mean age of 64 years.We considered that the methodological quality of the 34 published and unpublished trials was acceptable overall. Treatment with a PDE4 inhibitor was associated with a significant improvement in forced expiratory volume in one second (FEV1) over the trial period compared with placebo (MD 51.53 mL, 95% confidence interval (CI) 43.17 to 59.90, 27 trials with 20,585 participants, moderate-quality evidence due to moderate levels of heterogeneity and risk of reporting bias). There were small improvements in quality of life (St George's Respiratory Questionnaire (SGRQ), MD -1.06 units, 95% CI -1.68 to -0.43, 11 trials with 7645 participants, moderate-quality evidence due to moderate levels of heterogeneity and risk of reporting bias) and COPD-related symptoms, but no significant change in exercise tolerance. Treatment with a PDE4 inhibitor was associated with a reduced likelihood of COPD exacerbation (OR 0.78, 95% CI 0.73 to 0.83; 23 trials with 19,948 participants, high-quality evidence). For every 100 people treated with PDE4 inhibitors, five more remained exacerbation-free during the study period compared with placebo (number needed to treat for an additional beneficial outcome (NNTB) 20, 95% CI 16 to 26). More participants in the treatment groups experienced non-serious adverse events compared with controls, particularly a range of gastrointestinal symptoms such as diarrhoea, nausea, vomiting or dyspepsia. For every 100 people treated with PDE4 inhibitors, seven more suffered from diarrhoea during the study period compared with placebo (number needed to treat for an additional harmful outcome (NNTH) 15, 95% CI 13 to 17). Roflumilast in particular was associated with weight loss during the trial period and an increase in insomnia and depressive mood symptoms. There was no significant effect of treatment on non-fatal serious adverse events (OR 0.99, 95% CI 0.91 to 1.07) or mortality (OR 0.97, 95% CI 0.76 to 1.23), although mortality was a rare event during the trials. Participants treated with PDE4 inhibitors were more likely to withdraw from the trials because of adverse effects; on average 14% in the treatment groups withdrew compared with 8% in the control groups.

AUTHORS' CONCLUSIONS

In people with COPD, PDE4 inhibitors offered benefit over placebo in improving lung function and reducing the likelihood of exacerbations; however, they had little impact on quality of life or symptoms. Gastrointestinal adverse effects and weight loss were common, and safety data submitted to the US Food and Drug Administration (FDA) have raised concerns over psychiatric adverse events with roflumilast. The findings of this review give cautious support to the use of PDE4 inhibitors in COPD. They may be best used as add-on therapy in a subgroup of people with persistent symptoms or exacerbations despite optimal COPD management. This is in accordance with the GOLD 2017 guidelines. Longer-term trials are needed to determine whether or not PDE4 inhibitors modify FEV1 decline, hospitalisation or mortality in COPD.

Novel class of benzoic acid ester derivatives as potent PDE4 inhibitors for inhaled administration in the treatment of respiratory diseases

The first steps in the selection process of a new anti-inflammatory drug for the inhaled treatment of asthma and chronic obstructive pulmonary disease are herein described. A series of novel ester derivatives of 1-(3-(cyclopropylmethoxy)-4-(difluoromethoxy)phenyl)-2-(3,5-dichloropyridin-4-yl) ethanol have been synthesized and evaluated for inhibitory activity toward cAMP-specific phosphodiesterase-4 (PDE4). In particular, esters of variously substituted benzoic acids were extensively explored, and structural modification of the alcoholic and benzoic moieties were performed to maximize the inhibitory potency. Several compounds with high activity in cell-free and cell-based assays were obtained. Through the evaluation of opportune in vitro ADME properties, a potential candidate suitable for inhaled administration in respiratory diseases was identified and tested in an in vivo model of pulmonary inflammation, proving its efficacy.

New drug therapies for COPD

Clinical trials with new drugs for chronic obstructive pulmonary disease (COPD) have been performed. Viruses exacerbate COPD and bacteria may play a part in severe COPD; therefore, antibiotic and antiviral approaches have a sound rationale. Antiinflammatory approaches have been studied. Advances in understanding the molecular basis of other processes have resulted in novel drugs to target reactive oxidant species, mucus, proteases, fibrosis, cachexia, and muscle wasting, and accelerated aging. Studies with monoclonal antibodies have been disappointing, highlighting the tendency for infections and malignancies during treatment. Promising future directions are lung regeneration with retinoids and stem cells.

Phosphodiesterase 4 inhibitors for chronic obstructive pulmonary disease

BACKGROUND

Chronic obstructive pulmonary disease (COPD) is associated with cough, sputum production or dyspnoea and a reduction in lung function, quality of life and life expectancy. Apart from smoking cessation, there are no other treatments that slow lung function decline. Roflumilast and cilomilast are oral phosphodiesterase 4 (PDE4) inhibitors proposed to reduce the airway inflammation and bronchoconstriction seen in COPD.

OBJECTIVES

To evaluate the efficacy and safety of oral PDE4 inhibitors in the management of stable COPD.

SEARCH METHODS

We identified randomised controlled trials (RCTs) from the Cochrane Airways Group Specialised Register of trials (date of last search June 2013). We found other trials from web-based clinical trial registers.

SELECTION CRITERIA

We included RCTs if they compared oral PDE4 inhibitors with placebo in people with COPD. We allowed co-administration of standard COPD therapy.

DATA COLLECTION AND ANALYSIS

One review author extracted data and a second review author checked the data, before entry into The Cochrane Collaboration software program (RevMan version 5.2). We reported pooled data as mean differences (MD), standardised mean differences (SMD) or odds ratios (OR).

MAIN RESULTS

Twenty-nine separate RCTs studying roflumilast (15 trials, 12,654 patients) or cilomilast (14 trials, 6457 patients) met the inclusion criteria, with a duration between six weeks and one year. These included people across international study centres with moderate to very severe COPD (GOLD grades II-IV), with a mean age of 64 years.Treatment with a PDE4 inhibitor was associated with a significant improvement in forced expiratory volume in one second (FEV1) over the trial period compared with placebo (MD 45.60 mL; 95% confidence interval (CI) 39.45 to 51.75, 22 trials with 15,670 participants, moderate quality evidence due to moderate levels of heterogeneity and risk of reporting bias). There were small improvements in quality of life (St George's Respiratory Questionnaire MD -1.04; 95% CI -1.66 to -0.41, 10 trials with 7618 participants, moderate quality evidence due to moderate levels of heterogeneity and risk of reporting bias) and COPD-related symptoms, but no change in exercise tolerance. Treatment with a PDE4 inhibitor was associated with a reduced likelihood of COPD exacerbation (OR 0.77; 95% CI 0.71 to 0.83, high quality evidence). For every 100 people treated with PDE4 inhibitors, six more remained exacerbation-free during the study period compared with placebo (number needed to treat for an additional beneficial effect (NNTB) 20; 95% CI 16 to 27). More participants in the treatment groups experienced non-serious adverse events compared with controls, particularly gastrointestinal symptoms and headache. Roflumilast in particular was associated with weight loss during the trial period and an increase in insomnia and depressive mood symptoms. Participants treated with PDE4 inhibitors were also more likely to withdraw from the trials because of adverse effects; on average 24% in the treatment groups withdrew compared with 19% in the control groups.

AUTHORS' CONCLUSIONS

In people with COPD, PDE4 inhibitors offered benefit over placebo in improving lung function and reducing the likelihood of exacerbations; however, they had little impact on quality of life or symptoms. Gastrointestinal adverse effects and weight loss were common, and safety data submitted to the US Food and Drug Administration (FDA) have raised concerns over psychiatric adverse events with roflumilast. The optimum place of PDE4 inhibitors in COPD management therefore remains to be defined. Longer-term trials are needed to determine whether or not PDE4 inhibitors modify FEV1 decline, hospitalisation or mortality in COPD.

Pharmacotherapies for COPD

This review article summarizes the main treatments for chronic obstructive pulmonary disease, their mechanisms, and the key evidence from trials supporting their use. Drug classes covered were short acting beta agonists (SABA), short acting muscarinic antagonists (SAMA), long acting beta agonists (LABA), long acting antimuscarinics (LAMA), inhaled corticosteroids (ICS), LABA/ICS combinations, specific phosphodiesterase (PDE4) inhibitors, non-specific PDE inhibitors, mucolytics, and oxygen. Non-specific therapies, such as opiates for relief of dyspnoea and therapies for smoking cessation, are also covered briefly. For each class of drug, mechanisms of action are described, key clinical trial results are reported, and available agents compared. Finally, the place of each drug in therapy is compared between current worldwide guidelines.

Clinical diaries in COPD: compliance and utility in predicting acute exacerbations

Background

Daily diaries are often used to collect data on disease activity, but are burdensome and compliance may be poor. Their use in chronic obstructive pulmonary disease (COPD) and impact on the prevention and treatment of exacerbations is poorly researched.

Methods

We investigated diary-keeping in COPD and ascertained items that best predicted emergency attendances for exacerbations. Participants in the active limb of a clinical trial in COPD kept daily diaries rating breathlessness, cough, sputum, physical activity, and use of reliever medication.

Results

Data on 55 participants, 67% of whom were female, showed that overall compliance with diary-keeping was 62%. Participants educated to primary school level only had lower compliance (P = 0.05). Twenty patients had at least one emergency attendance, in whom the relative risk of an acute exacerbation for an increase in item score rose from six days prior to hospitalization, most sharply in the last two days. Even for optimal combinations of items, the positive predictive value was poor, the best combination being cough, activity level, and inhaler use.

Conclusion

Good compliance can be achieved using daily diaries in COPD, although this is worse in those with a poor educational level. Diary-keeping is not accurate in predicting acute exacerbations, but could be substantially simplified without loss of efficiency.

Use of a soluble epoxide hydrolase inhibitor in smoke-induced chronic obstructive pulmonary disease

Tobacco smoke-induced chronic obstructive pulmonary disease (COPD) is a prolonged inflammatory condition of the lungs characterized by progressive and largely irreversible airflow limitation attributable to a number of pathologic mechanisms, including bronchitis, bronchiolitis, emphysema, mucus plugging, pulmonary hypertension, and small-airway obstruction. Soluble epoxide hydrolase inhibitors (sEHIs) demonstrated anti-inflammatory properties in a rat model after acute exposure to tobacco smoke. We compared the efficacy of sEHI t-TUCB (trans-4-{4-[3-(4-trifluoromethoxy-phenyl)-ureido]-cyclohexyloxy}-benzoic acid) and the phosphodiesterase-4 (PDE4) inhibitor Rolipram (Biomol International, Enzo Life Sciences, Farmingdale, NY) to reduce lung injury and inflammation after subacute exposure to tobacco smoke over a period of 4 weeks. Pulmonary physiology, bronchoalveolar lavage, cytokine production, and histopathology were analyzed to determine the efficacy of sEHI and Rolipram to ameliorate tobacco smoke-induced inflammation and injury in the spontaneously hypertensive rat. Both t-TUCB and Rolipram inhibited neutrophil elevation in bronchoalveolar lavage. sEHI t-TUCB suppressed IFN-γ, while improving lung function by reducing tobacco smoke-induced total respiratory resistance and tissue damping (small-airway and peripheral tissue resistance). Increases in tobacco smoke-induced alveolar airspace size were attenuated by t-TUCB. Rolipram inhibited the production of airway mucus. Both t-TUCB and Rolipram inhibited vascular remodeling-related growth factor. These findings suggest that sEHI t-TUCB has therapeutic potential for treating COPD by improving lung function and attenuating the lung inflammation and emphysematous changes caused by tobacco smoke. To the best of our knowledge, this is the first report to demonstrate that sEHI exerts significant protective effects after repeated, subacute tobacco smoke-induced lung injury in a rat model of COPD.

Selective PDE inhibitors as novel treatments for respiratory diseases

Phosphodiesterases (PDEs) are a family of enzymes which catalyse the metabolism of the intracellular cyclic nucleotides, c-AMP and c-GMP that are expressed in a variety of cell types and in the context of respiratory diseases, It is now recognised that the use of PDE3, PDE4 and mixed PDE3/4 inhibitors can provide clinical benefit to patients with asthma or chronic obstructive pulmonary disease (COPD). The orally active PDE4 inhibitor Roflumilast-n-oxide has been approved for treatment of severe exacerbations of COPD as add-on therapy to standard drugs. This review discusses the involvement of PDEs in airway diseases and various strategies that are currently being pursued to improve efficacy and reduce side-effects of PDE4 inhibitors, including delivery via the inhaled route, mixed PDE inhibitors and/or antisense biologicals targeted towards PDE4.

Tadalafil analgesia in experimental arthritis involves suppression of intra-articular TNF release

BACKGROUND AND PURPOSE

We investigated the effect of the phosphodiesterase-5 inhibitor, tadalafil, on the acute hypernociception in rat models of arthritis.

EXPERIMENTAL APPROACH

Rats were treated with either an intra-articular injection of zymosan (1 mg) or surgical transection of the anterior cruciate ligament (as an osteoarthritis model). Controls received saline intra-articular or sham operation respectively. Joint pain was evaluated using the articular incapacitation test measured over 6 h following zymosan or between 4 and 7 days after anterior cruciate ligament transection. Cell counts, tumour necrosis factor-α (TNF-α), interleukin-1 (IL-1), and the chemokine, cytokine-induced neutrophil chemoattractant-1 (CINC-1) were measured in joint exudates 6 h after zymosan. Groups received tadalafil (0.02-0.5 mg·kg⁻¹ per os) or saline 2 h after intra-articular zymosan. Other groups received the µ-opioid receptor antagonist naloxone or the cGMP inhibitor 1H-[1,2,4] oxadiazolo [4,3-a] quinoxalin-1-one (ODQ) before tadalafil.

KEY RESULTS

Tadalafil dose-dependently inhibited hypernociception in zymosan and osteoarthritis models. In zymosan-induced arthritis, tadalafil significantly decreased cell influx and TNF-α release but did not alter IL-1 or CINC-1 levels. Pretreatment with ODQ but not with naloxone prevented the anti-inflammatory effects of tadalafil.

CONCLUSIONS AND IMPLICATIONS

Therapeutic oral administration of tadalafil provided analgesia mediated by guanylyl cyclase and was independent of the release of endogenous opioids. This effect of tadalafil was associated with a decrease in neutrophil influx and TNF-α release in inflamed joints.

PDE4: a novel target in the treatment of chronic obstructive pulmonary disease

Phosphodiesterases (PDEs) are important modulators of inflammation and wound healing. In this capacity, specific targeting of PDEs for the treatment of many diseases, including chronic obstructive pulmonary disease (COPD), has been investigated. Currently, treatment of COPD is suboptimal. PDE4 modulates the inflammatory response of the lung, and inhibition of PDE4 may be a novel, COPD-specific approach toward more effective treatment strategies. This review describes the state of PDE4-inhibitor therapy for use in COPD treatment.

Roflumilast, a Novel Phosphodiesterase 4 Inhibitor, for COPD Patients with a History of Exacerbations

Acute exacerbations of COPD (AECOPD) are major clinical events. They are associated with a more rapid decline in lung function, poorer quality of life scores, and an increased risk of dying. Exacerbations that require hospitalization have particular significance. Approximately 40% of the AECOPD patients who require hospitalization will die in the subsequent year. Since many AECOPD require hospitalization, they account for most of the expense of caring for COPD patients. Treatment with long-acting bronchodilators and combination inhaled corticosteroid/long-acting bronchodilator inhalers reduces but does not eliminate AECOPD. Roflumilast, a selective phosphodiesterase 4 (PDE4) inhibitor, is an anti-inflammatory medication that improves lung function in patients with COPD. In patients with more severe airway obstruction, clinical features of chronic bronchitis, and a history of AECOPD, roflumilast reduces the frequency of AECOPD when given in combination with short-acting bronchodilators, long-acting bronchodilators, or inhaled corticosteroids. It is generally well tolerated but the most common adverse effects include diarrhea, nausea, weight loss, and headaches. In clinical trials, patients treated with roflumilast experienced weight loss that averaged just over 2 kg but was primarily due to the loss of fat tissue. Weight loss was least in underweight patients and obese patients experienced the greatest weight loss. An unexpected benefit of treatment with roflumilast was that fasting blood glucose and hemoglobin A1c levels improved in patients with comorbid type 2 diabetes mellitus. Roflumilast, the first selective PDE4 inhibitor to be marketed, is a promising drug for the management of COPD patients with more severe disease.

Phosphodiesterase inhibitors in the treatment of inflammatory diseases

Phosphodiesterase 4 (PDE4) belongs to a family of enzymes which catalyzes the breakdown of 3, 5'-adenosine cyclic monophosphate (cAMP) and is ubiquitously expressed in inflammatory cells. There is little evidence that inflammatory diseases are caused by increased expression of this isoenzyme, although human inflammatory cell activity can be suppressed by selective PDE4 inhibitors. Consequently, there is intense interest in the development of selective PDE4 inhibitors for the treatment of a range of inflammatory diseases, including asthma, chronic obstructive pulmonary disease (COPD), inflammatory bowel disease, and psoriasis. Recent clinical trials with roflumilast in COPD have confirmed the therapeutic potential of targeting PDE4 and recently roflumilast has been approved for marketing in Europe and the USA, although side effects such as gastrointestinal disturbances, particularly nausea and emesis as well as headache and weight loss, may limit the use of this drug class, at least when administered by the oral route. However, a number of strategies are currently being pursued in attempts to improve clinical efficacy and reduce side effects of PDE4 inhibitors, including delivery via the inhaled route, development of nonemetic PDE4 inhibitors, mixed PDE inhibitors, and/or antisense biologicals targeted toward PDE4.

Measuring the impact of a live, case-based, multiformat, interactive continuing medical education program on improving clinician knowledge and competency in evidence-based COPD care

BACKGROUND

Major clinical gaps impede the evidence-based treatment of chronic obstructive pulmonary disease (COPD) in the primary care setting. Studies are needed to measure the effectiveness of continuing medical education (CME) on improving physician competency and performance toward evidence-based COPD care.

METHODS

Between September 26, 2009 and December 12, 2009, 769 primary care physicians participated in a series of 12 regional, live, interactive, case-based, multiformat, half-day CME programs on COPD. A subgroup of randomly selected participants (n = 50) and demographically matched nonparticipants (n = 50) completed surveys that included case vignettes, a validated tool for measuring physician performance in clinical practice. Cohen's d was used to calculate the magnitude of difference between participants and nonparticipants in the delivery of evidence-based care.

RESULTS

Physicians who participated in CME programs were 50% more likely to provide evidence-based COPD care than physicians who did not participate. Compared with nonparticipants, participating physicians were more likely to recognize COPD correctly in a patient presenting with dyspnea (74% versus 94%, P = 0.007), recognize that women may have a greater susceptibility than men to the toxic effects of smoking (54% versus 90%, P < 0.001), and identify the mechanisms of action of emerging therapies (33% versus 65%, P = 0.003).

CONCLUSION

Physicians who participated in a half-day regional CME program on COPD diagnosis, staging, and treatment were significantly more likely than nonparticipants to deliver evidence-based COPD care. With multiformat, interactive, focused educational interventions, physicians can make diagnostic and therapeutic choices in the primary care setting that align more closely with current guidelines and clinical evidence in COPD management.

Disease-modifying effect of ASP3258, a novel phosphodiesterase type 4 inhibitor, on subchronic cigarette smoke exposure-induced lung injury in guinea pigs

ASP3258 is a novel, orally active, selective phosphodiesterase (PDE) 4 inhibitor which has an improved therapeutic window over second generation compounds such as roflumilast and cilomilast. Here, we investigated the effect of ASP3258 on cigarette smoke exposure-induced lung injury in guinea pigs, a well-defined model for chronic obstructive pulmonary disease (COPD). COPD-like lung injury was induced by repeated cigarette smoke exposure (10 cigarettes/day, 5 days/week, for 4 weeks). Orally administered ASP3258 (0.3, 1, and 3mg/kg) dose-dependently suppressed pulmonary accumulation of mononuclear cells and neutrophils, and the inhibitory effect of ASP3258 (1mg/kg) was almost the same as that of roflumilast (1mg/kg). In contrast, a glucocorticoid prednisolone (10mg/kg, p.o.) did not show any effect. Histological examination revealed that ASP3258 treatment significantly inhibited infiltration of neutrophils and macrophages into either or both alveolar or peribronchiolar areas, as well as hyperplastic and squamous metaplastic changes of epithelium in the bronchi. Decreasing trends in histological scores for accumulation of lymphocytes in the alveoli and alveolar wall thickening were also observed in ASP3258-treated animals. Further, ASP3258 attenuated augmentation of matrix metalloproteinase-9 activity in the bronchoalveolar lavage fluid. These findings suggest that ASP3258 has therapeutic potential for treating COPD not only through inhibition of pulmonary cellular accumulation but also by preventing lung structural alterations initiated by repeated cigarette smoke exposure. To our knowledge, this is the first paper demonstrating that PDE4 inhibitors exert significant inhibitory effects on subchronic cigarette smoke exposure-induced lung injury in guinea pigs.

Phosphodiesterase 4 inhibitors for chronic obstructive pulmonary disease

BACKGROUND

Chronic obstructive pulmonary disease (COPD) affects symptoms, lung function, quality of life and life expectancy. Apart from smoking cessation, there are no other treatments that slow lung function decline. Roflumilast and cilomilast are oral phosphodiesterase 4 (PDE(4)) inhibitors proposed to reduce the airway inflammation and bronchoconstriction seen in COPD.

OBJECTIVES

To evaluate the efficacy and safety of PDE(4) inhibitors in the management of people with stable COPD. Outcomes included lung function, quality of life, symptoms, exacerbations and adverse effects.

SEARCH STRATEGY

We identified randomised controlled trials (RCTs) from the Cochrane Airways Group Specialised Register of trials (date of last search 6 August 2010). We found other trials from web-based clinical trial registers.

SELECTION CRITERIA

We included RCTs if they compared oral PDE(4) inhibitors with placebo in people with COPD. We allowed co-administration of standard COPD therapy.

DATA COLLECTION AND ANALYSIS

One review author extracted data and a second review author checked the data, before entry into The Cochrane Collaboration software programme (RevMan version 5.1). We reported pooled data as mean differences (MD), standardised mean differences (SMD), or odds ratios (OR).

MAIN RESULTS

Twenty-three separate RCTs studying roflumilast (nine trials, 9211 patients) or cilomilast (fourteen trials, 6457 patients) met the inclusion criteria. None of the trials exceeded a year in duration.Treatment with a PDE(4) inhibitor was associated with a significant improvement in FEV(1)over the trial period compared with placebo (MD 45.59 mL; 95% confidence interval (CI) 39.15 to 52.03), regardless of COPD severity or concomitant COPD treatment. There were some small improvements in quality of life (St George's Respiratory Questionnaire MD -1.04; 95% CI -1.66 to -0.41) and COPD-related symptoms, but no change in exercise tolerance. Treatment with a PDE(4) inhibitor was associated with a reduced likelihood of COPD exacerbation (OR 0.78; 95% CI 0.72 to 0.85). More participants in the treatment groups experienced non-serious adverse events compared with controls, particularly gastrointestinal symptoms and headache. Roflumilast was associated with weight loss during the trial period.

AUTHORS' CONCLUSIONS

In people with COPD, PDE(4) inhibitors offered benefit over placebo in improving lung function and reducing likelihood of exacerbations, however, they had little impact on quality of life or symptoms. Gastrointestinal adverse effects and weight loss were common. The optimum place of PDE(4) inhibitors in COPD management remains to be defined. Longer-term trials are needed to determine whether or not PDE(4) inhibitors modify FEV(1) decline, healthcare utilisation or mortality in COPD.

Update on pharmaceutical and minimally invasive management strategies for chronic obstructive pulmonary disease

Chronic obstructive pulmonary disease (COPD) is a debilitating pulmonary disorder with systemic effects, and it is the fourth leading cause of death in the United States. COPD patients not only develop respiratory limitations, but can also demonstrate systemic wasting, features of depression, and can succumb to social isolation. Smoking cessation is crucial, and pharmacotherapy with bronchodilators is helpful in symptom management. Inhaled corticosteroids may be beneficial in some patients. In addition, pulmonary rehabilitation and palliative care are important components under the right clinical circumstance. This review highlights current guidelines and management strategies for COPD and emphasizes novel pharmacotherapy and minimally invasive (nonsurgical) lung-volume reduction interventions that may prove to be of significant benefit in the future.

A new strategy with proton pump inhibitors for the prevention of acute exacerbations in COPD

Acute exacerbations of chronic obstructive pulmonary disease (COPD), an acute worsening of respiratory symptoms, generally result in a poor prognosis. Successful prevention and management of such exacerbations is thus important for patient care. Viral infection, primarily with rhinovirus (RV), is the foremost cause of exacerbations in COPD patients. Proton pump inhibitors (PPIs) have been reported to inhibit RV infection in human airway epithelial cells in vitro. Furthermore, clinical trials of PPIs in patients with COPD resulted in a reduction in rates of both common cold and COPD exacerbations. In this review, we discuss the significance of COPD exacerbations, summarize a published trial of the effect of low-dose PPIs on COPD exacerbations, and postulate a mechanism for this effect.

PDE4-inhibitors: a novel, targeted therapy for obstructive airways disease

Roflumilast is a selective once daily, oral phosphodiesterase-4 inhibitor that has recently been registered in all European Union countries as novel targeted therapy for COPD, while FDA approval for the USA market is expected in 2011. In several phase III trials in patients with moderate to (very) severe COPD and in patients with symptoms of chronic bronchitis and recurrent exacerbations, roflumilast showed sustained clinical efficacy by improving lung function and by reducing exacerbation rates. These beneficial effects have also been demonstrated when added to long-acting bronchodilators (both LABA and LAMA), underscoring the anti-inflammatory activity of roflumilast in COPD. Pooled data analysis showed overall mild to moderate, mostly self-limiting adverse events, mainly consisting of nausea, diarrhea and weight loss. In this review we discuss the results of the 4 registration studies showing promising effects of roflumilast in COPD and provide an overview of the topics that still need to be addressed.

Pharmacology, clinical efficacy, and tolerability of phosphodiesterase-4 inhibitors: impact of human pharmacokinetics

Since more than two decades anti-inflammatory effects of inhibitors of phosphodiesterase-4 have been described in numerous cellular and animal studies and were finally confirmed in clinical trials. The path from an early, pioneering study with Ro20-1724 showing reduction of psoriatric plaque size in 1979 to modern PDE4 inhibitors such as oral apremilast in development for psoriasis, the inhaled PDE4 inhibitor GSK256066 in development for asthma and COPD and finally roflumilast, the first PDE4 inhibitor approved and currently marketed as an oral, once-daily remedy for severe COPD was marked by large progress in chemical optimization based on improved understanding of PDE4 biology and drug-like properties determining the appropriate pharmacokinetic profile. In this chapter aspects of the pharmacology and clinical efficacy of PDE4 inhibitors, which have been in clinical development over the years are summarized with specific emphasis on their clinical pharmacokinetic properties.

Mitigation of chlorine lung injury by increasing cyclic AMP levels

Chlorine is considered a chemical threat agent to which humans may be exposed as a result of accidental or intentional release. Chlorine is highly reactive, and inhalation of the gas causes cellular damage to the respiratory tract, inflammation, pulmonary edema, and airway hyperreactivity. Drugs that increase intracellular levels of the signaling molecule cyclic AMP (cAMP) may be useful for treatment of acute lung injury through effects on alveolar fluid clearance, inflammation, and airway reactivity. This article describes mechanisms by which cAMP regulates cellular processes affecting lung injury and discusses the basis for investigating drugs that increase cAMP levels as potential treatments for chlorine-induced lung injury. The effects of beta(2)-adrenergic agonists, which stimulate cAMP synthesis, and phosphodiesterase inhibitors, which inhibit cAMP degradation, on acute lung injury are reviewed, and the relative advantages of these approaches are compared.

Multiple pharmacophore models combined with molecular docking: a reliable way for efficiently identifying novel PDE4 inhibitors with high structural diversity

Multiple pharmacophore models were constructed based on the 18 crystal structures of phosphodiesterase 4 (PDE4) in complex with different inhibitors for discovering new potential PDE4 inhibitors. After validation of their efficiency in screening, 10 of the pharmacophore models were confirmed effective. Remarkably, the hits retrieved by these effective pharmacophore models were different, demonstrating that different pharmacophore models may have different performances in database screening. Therefore, all these models were employed to screen the compound database SPECS for finding potent leads with much structural diversity. Combining all the screened hits based on the 10 pharmacophore models, followed by molecular docking and bioassay, 4 of 53 tested compounds were found as active as rolipram (a well studied PDE4 inhibitor). More impressively, the four potent inhibitors with different chemical scaffolds were discovered by three different pharmacophore models separately, suggesting that a single pharmacophore model-based screening might not be efficient in thoroughly identifying potential hits from a compound database. This study also revealed that ligand-receptor complex structure-based pharmacophore is more efficient for identifying potent hits with great structural diversity in comparison with ligand-based pharmacophore and similarity search approaches. Therefore, multiple pharmacophore model-based virtual screenings should be used, if available, in combination with molecular docking for fully discovering hit compounds from compound databases.

Protease inhibitors in respiratory disease: focus on asthma and chronic obstructive pulmonary disease

Respiratory diseases, such as asthma and chronic obstructive pulmonary disease (COPD), are a major health burden on society and current treatment modalities for these diseases have not significantly changed over the past 40 years. The only major pharmacological advancement for the treatment of these diseases has been to increase the duration of action of bronchodilators (asthma: salmeterol; COPD: tiotropium bromide) and glucocorticosteroids (asthma: fluticasone propionate) and, increasingly, to formulate these agents in the same delivery device. Despite our increasing understanding of the cell and molecular biology of these diseases, the development of novel treatments remains beyond the reach of the scientific community. Proteases are a family of proteins with diverse biological activity, which are found in abundance within the airways of asthma and COPD, and have been implicated in the pathogenesis of these diseases. The targeting of proteases, including mast cell tryptase, neutrophil elastase and matrix metalloprotease with low-molecular-weight inhibitors, has highlighted the potential role of these enzymes in mediating certain aspects of the disease process in preclinical studies. Several challenges remain regarding the development of protease inhibitors, including the synthesis of highly potent and specific inhibitors, and target validation in man.

Effects of phosphodiesterase 4 inhibition on bleomycin-induced pulmonary fibrosis in mice

Background

Pulmonary fibrosis (PF) is a group of devastating and largely irreversible diseases. Phosphodiesterase (PDE) 4 is involved in the processes of remodeling and inflammation, which play key role in tissue fibrosis. The aim of the study was, therefore, to investigate the effect of PDE4 inhibition in experimental model of PF.

Methods

PF was induced in C57BL/6N mice by instillation of bleomycin. Pharmacological inhibition of PDE4 was achieved by using cilomilast, a selective PDE4 inhibitor. Changes in either lung inflammation or remodeling were evaluated at different stages of experimental PF. Lung inflammation was assessed by bronchoalveolar lavage fluid (BALF) differential cell count and reverse transcription quantitative polymerase chain reaction (RT-qPCR) for inflammatory cytokines. Changes in tissue remodeling were evaluated by pulmonary compliance measurement, quantified pathological examination, measurement of collagen deposition and RT-qPCR for late remodeling markers. Survival in all groups was analyzed as well.

Results

PDE4 inhibition significantly reduced the total number of alveolar inflammatory cells in BALF of mice with bleomycin-induced PF at early fibrosis stage (days 4 and 7). Number of macrophages and lymphocytes, but not neutrophils, was significantly reduced as well. Treatment decreased lung tumor necrosis factor (TNF)-α mRNA level and increased mRNA level of interleukin (IL)-6 but did not influence IL-1β. At later stage (days 14 and 24) cilomilast improved lung function, which was shown by increase in lung compliance. It also lowered fibrosis degree, as was shown by quantified pathological examination of Hematoxilin-Eosin stained lung sections. Cilomilast had no significant effect on the expression of late remodeling markers such as transforming growth factor (TGF)-β1 and collagen type Ia1 (COL(I)α1). However, it tended to restore the level of lung collagen, assessed by SIRCOL assay and Masson's trichrome staining, and to improve the overall survival.

Conclusions

Selective PDE4 inhibition suppresses early inflammatory stage and attenuates the late stage of experimental pulmonary fibrosis.

Is there a role for antiinflammatory treatment in COPD?

By definition, chronic obstructive pulmonary disease (COPD) is associated with an abnormal inflammatory response of affected lungs. Therefore, the search for an effective anti-inflammatory therapy for this debilitating disease is intense. However, to date, there is no such anti-inflammatory treatment for COPD. While there are some modest effects of inhaled corticosteroids on selected clinical endpoints in COPD, it remains to be proven that the observed effects are due to changes in the underlying inflammation, in particular since relevant clinical endpoints of COPD can be significantly improved by treatments not targeting inflammation. Therefore, it appears justified to reconsider the present knowledge about any linkage of local and systemic inflammation and clinical features of COPD, including lung function, exacerbations, disease progression, and mortality. Any such link needs to be carefully established before future anti-inflammatory therapies for COPD are developed and investigated in clinical trials, in particular since proof-of-concept trials aiming merely at inflammatory markers in COPD may not be predictive of clinical success or failure. The present review summarizes current knowledge about the role of inflammation in COPD, and critically analyzes results from clinical trials with inhaled corticosteroids and phosphodiesterase-4 inhibitors in COPD, the two classes of putative antiinflammatory agents with the richest body of evidence from controlled studies.

Chronic obstructive pulmonary disease: towards pharmacogenetics

Chronic obstructive pulmonary disease (COPD) is a common problem worldwide, and it is recognized that the term encompasses overlapping sub-phenotypes of disease. The development of a sub-phenotype may be determined in part by an individual's genetics, which in turn may determine response to treatment. A growing understanding of the genetic factors that predispose to COPD and its sub-phenotypes and the pathophysiology of the condition is now leading to the suggestion of individualized therapy based on the patients' clinical phenotype and genotype. Pharmacogenetics is the study of variations in treatment response according to genotype and is perhaps the next direction for genetic research in COPD. Here, we consider how knowledge of the pathophysiology and genetic risk factors for COPD may inform future management strategies for affected individuals.

The impact of concurrent heart failure on prognosis in patients with chronic obstructive pulmonary disease

AIMS

To compare prognosis in patients with chronic obstructive pulmonary disease (COPD) with or without concomitant heart failure.

METHODS AND RESULTS

Patients aged 65 years or over with a general practitioner (GP)'s diagnosis of COPD but without a prior diagnosis of heart failure underwent an extensive diagnostic work-up including echocardiography and pulmonary function tests in the period 2001-03. An expert panel then confirmed the presence or absence of COPD according to the GOLD criteria and (previously undiagnosed) heart failure according to the criteria of the ESC heart failure guidelines. This cohort of 405 patients was followed up for a mean duration of 4.2 (SD 1.4) years. The GP's electronic medical files relating to the participants, including any specialist letters, were scrutinized until April 2007 for information about drug use, exacerbations of COPD, pneumonia, hospitalizations, death, and cause of death. The mean age of patients at the start of the study was 73.0 (SD 5.3) years, and 54% were male. The presence of newly detected heart failure significantly increased all-cause mortality independent of gender, age, history of ischaemic heart disease, hypertension, diabetes mellitus, atrial fibrillation, smoking, and cardiovascular drug use at baseline (adjusted hazard ratio, 2.1; 95% confidence interval, 1.2-3.6; P = 0.01).

CONCLUSION

Heart failure is a strong independent predictor of all-cause mortality in patients with a diagnosis of COPD.

New drugs for exacerbations of chronic obstructive pulmonary disease

Tobacco smoking is the dominant risk factor for chronic obstructive pulmonary disease (COPD), but viral and bacterial infections are the major causes of exacerbations in later stages of disease. Reactive oxygen species (ROS), pathogen-associated molecular patterns (PAMPs), and damage-associated molecular patterns (DAMPs) activate families of pattern recognition receptors (PRRs) that include the toll-like receptors (TLRs). This understanding has led to the hypothesis that COPD is an archetypal disease of innate immunity. COPD is characterised by abnormal response to injury, with altered barrier function of the respiratory tract, an acute phase reaction, and excessive activation of macrophages, neutrophils, and fibroblasts in the lung. The activated non-specific immune system then mediates the processes of inflammation and repair, fibrosis, and proteolysis. COPD is also associated with corticosteroid resistance, abnormal macrophage and T-cell populations in the airway, autoinflammation and autoimmunity, aberrant fibrosis, accelerated ageing, systemic and concomitant disease, and defective regeneration. Such concepts have been used to generate a range of molecular targets, and clinical trials are taking place to identify effective drugs for the prevention and treatment of COPD exacerbations.

Exacerbation rate, health status and mortality in COPD--a review of potential interventions

COPD is prevalent in Western society and its incidence is rising in the developing world. Acute exacerbations of COPD, about 50% of which are unreported, lead to deterioration in quality of life and contribute significantly to disease burden. Quality of life deteriorates with time; thus, most of the health burden occurs in more severe disease. COPD severity and frequent and more severe exacerbations are all related to an increased risk of mortality. Inhaled corticosteroids (ICS) have similar effects on quality of life but ICS/long-acting bronchodilator combinations and the long-acting antimuscarinic tiotropium all improve health status and exacerbation rates and are likely to have an effect on mortality but perhaps only with prolonged use. Erythromycin has been shown to decrease the rate of COPD exacerbations. Pulmonary rehabilitation and regular physical activity are indicated in all severities of COPD and improve quality of life. Noninvasive ventilation is associated with improved quality of life. Long-term oxygen therapy improves mortality but only in hypoxic COPD patients. The choice of an inhaler device is a key component of COPD therapy and this requires more attention from physicians than perhaps we are aware of. Disease management programs, characterized as they are by patient centeredness, improve quality of life and decrease hospitalization rates. Most outcomes in COPD can be modified by interventions and these are well tolerated and have acceptable safety profiles.

A multi-target antisense approach against PDE4 and PDE7 reduces smoke-induced lung inflammation in mice

Background

Recent development in the field of COPD has focused on strategies aimed at reducing the underlying inflammation through selective inhibition of the phosphodiesterase type IV (PDE4) isoform. Although the anti-inflammatory and bronchodilator activity of selective PDE4 inhibitors has been well documented, their low therapeutic ratio and dose-dependent systemic side effects have limited their clinical utility. This study examined the effect of 2'-deoxy-2'-Fluoro-β-D-Arabinonucleic Acid (FANA)-containing antisense oligonucleotides (AON) targeting the mRNA for the PDE4B/4D and 7A subtypes on lung inflammatory markers, both in vitro and in vivo.

Methods

Normal human bronchial epithelial (NHBE) cells were transfected with FANA AON against PDE4B/4D and 7A alone or in combination. mRNA levels for target PDE subtypes, as well as secretion of pro-inflammatory chemokines were then measured following cell stimulation. Mice were treated with combined PDE4B/4D and 7A AON via endo-tracheal delivery, or with roflumilast via oral delivery, and exposed to cigarette smoke for one week. Target mRNA inhibition, as well as influx of inflammatory cells and mediators were measured in lung lavages. A two-week smoke exposure protocol was also used to test the longer term potency of PDE4B/4D and 7A AONs.

Results

In NHBE cells, PDE4B/4D and 7A AONs dose-dependently and specifically inhibited expression of their respective target mRNA. When used in combination, PDE4B/4D and 7A AONs significantly abrogated the cytokine-induced secretion of IL-8 and MCP-1 to near baseline levels. In mice treated with combined PDE4B/4D and 7A AONs and exposed to cigarette smoke, significant protection against the smoke-induced recruitment of neutrophils and production of KC and pro-MMP-9 was obtained, which was correlated with inhibition of target mRNA in cells from lung lavages. In this model, PDE AONs exerted more potent and broader anti-inflammatory effects against smoke-induced lung inflammation than roflumilast. Moreover, the protective effect of PDE4B/4D and 7A AON was maintained when a once-weekly treatment schedule was used.

Conclusion

These results indicate that inhaled AON against PDE4B/4D and 7A have unique effects on biomarkers that are believed to be important in the pathophysiology of COPD, which supports further development as a potential therapy in this disease.

The efficacy and safety of cilomilast in COPD

The aim of this review is to present the clinical data on the efficacy and safety of cilomilast in patients with chronic obstructive pulmonary disease (COPD). Over 6000 COPD patients received cilomilast during an extensive clinical development programme performed by GlaxoSmithKline (GSK).Five phase III randomized, double-blind, placebo-controlled, parallel-group pivotal studies were conducted in poorly reversible patients (<15% or <200 mL improvement over baseline in forced expiratory volume in 1 second (FEV(1)) after salbutamol). Patients were randomized to receive oral cilomilast 15 mg (n = 2088) or placebo (n = 1408) twice daily for 24 weeks. The co-primary efficacy variables were changes from baseline in trough (predose) FEV(1) and in total score of the St George's Respiratory Questionnaire (SGRQ).Additional studies were performed to investigate the anti-inflammatory actions of cilomilast by measuring inflammatory cells and mediators in biopsies and induced sputum; to assess the long-term effects of cilomilast; to assess the cardiac safety of cilomilast; and to assess the efficacy of cilomilast on hyperinflation. Results from one of the phase III and from one supportive study have been previously published.In the phase III pivotal studies, when averaged over 24 weeks, the mean change from baseline in FEV(1) in the cilomilast group showed improvement compared with placebo in all studies (range 24-44 mL treatment difference). When averaged over 24 weeks, there was a similar improvement in the mean total SGRQ score in both treatment groups with a decrease ranging from -1.8 to -4.2 units in the cilomilast group and 0.4 to -4.9 units in the placebo group. Only one study, however, showed both a statistically and clinically meaningful difference between the two treatment groups (treatment difference -4.1 units; p < 0.001). Although cilomilast was shown to reduce COPD exacerbations in some of these studies, there was no effect on the incidence of COPD exacerbations in a study specifically powered to detect a difference compared with placebo.No significant change was found in the primary endpoints of the anti-inflammatory studies, although some anti-inflammatory activity was detected, including a reduction in tissue CD8+ T lymphocytes and CD68+ macrophages in airway biopsies. In addition, studies did not demonstrate a consistent significant effect of cilomilast on hyperinflation.In all studies, adverse events associated with the gastrointestinal body system were reported more frequently in the cilomilast group than the placebo group and predominantly occurred within the first 2 weeks of initiating cilomilast therapy.During the cilomilast development programme a number of different endpoints were investigated to characterize the efficacy and safety of this second-generation phosphodiesterase 4 inhibitor. Safety assessments throughout the late-phase programme did not reveal any evidence of serious safety concerns with the use of cilomilast. Previous studies in phase II and early phase III had shown improvements in efficacy endpoints and some evidence of an anti-inflammatory mechanism of action. However, subsequent phase III studies failed to definitively confirm the earlier programme results, which led to termination of the development of cilomilast.

Treating patients with respiratory disease who smoke

The high prevalence of cigarette smoking in patients with respiratory disease puts them at risk of developing clinically important drug interactions. Cigarette smoking reduces the therapeutic response to certain drugs such as theophyllines through the induction of hepatic cytochrome P450 isoenzymes. Smokers with asthma and patients with COPD have reduced sensitivity to corticosteroids, possibly due to non-eosinophilic airway inflammation, altered glucocorticoid receptor activity or reduced histone deacetylase activity. Although all smokers should be encouraged to stop smoking, there is limited information on the influence of smoking cessation on the therapeutic and anti-inflammatory effects of a number of the drugs used in the treatment of respiratory disease.

Targeting the COPD exacerbation

Exacerbations of COPD have a profound detrimental effect on the patient and impose a significant burden on healthcare resource utilization. Prevention and treatment of exacerbations are major objectives of the clinical management of COPD. For this approach to be successful, clinicians must combine both pharmacologic approaches and non-pharmacologic strategies aimed at improving the patient's disease management. Non-pharmacologic approaches include those that can be incorporated into the office setting as well as intervention strategies that are integrated into the lifelong management of COPD. These strategies include developing a partnership with the patient and their social supports, encouraging and facilitating smoking cessation, immunizations, proper use of supplemental oxygen, and most importantly, giving the patient the tools to manage their illness appropriately. Moreover there is clear evidence of an irrevocable decline in pulmonary function after each exacerbation, usually resulting in reduced physical activity and impaired skeletal muscle function. Not surprisingly, pulmonary rehabilitation after such events has been shown to prevent relapse, improve survival and enhance patients' overall function after acute exacerbations.

PDE4 inhibitors: current status

Phosphodiesterase4 inhibitors are currently under development for the treatment of respiratory diseases including asthma and chronic obstructive pulmonary disease. The rationale for the development of this drug class stems from our understanding of the role of PDE4 in suppressing the function of a range of inflammatory and resident cells thought to contribute toward the pathogenesis of these diseases. Similarly, numerous preclinical in vivo studies have shown that PDE4 inhibitors suppress characteristic features of these diseases, namely, cell recruitment, activation of inflammatory cells and physiological changes in lung function in response to a range of insults to the airways. These potentially beneficial actions of PDE4 inhibitors have been successfully translated in phase II and III clinical trials with roflumilast and cilomilast. However, dose limiting side effects of nausea, diarrhoea and headache have tempered the enthusiasm of this drug class for the treatment of these respiratory diseases. A number of strategies are currently being pursued in attempts to improve clinical efficacy and reduce side effects, including delivery via the inhaled route, and/or development of non-emetic PDE4 inhibitors and mixed PDE inhibitors.

Airways inflammation and treatment during acute exacerbations of COPD

INTRODUCTION

Inflammation is a core feature of acute chronic obstructive pulmonary disease (COPD) exacerbations. It is important to focus on inflammation since it gives insight into the pathological changes causing an exacerbation, thereby possibly providing directions for future therapies which modify inflammation.

OBJECTIVES

To provide a cell-by-cell overview of the inflammatory processes during COPD exacerbations. To evaluate cell activation, and cytokine production, cellular interactions, damaging effects of inflammatory mediators to tissue, and the relation to symptoms at the onset of COPD exacerbations. To speculate on future therapeutic options to modify inflammation during COPD exacerbations.

RESULTS

During COPD exacerbations, there is increased airway wall inflammation, with pathophysiological influx of eosinophils, neutrophils, and lymphocytes. Although links have been suggested between the increase in eosinophils and lymphocytes and a viral etiology of the exacerbation, and between the increase in neutrophils and a bacterial aetiology, these increases in both inflammatory cell types are not limited to the respective aetiologies and the underlying mechanisms remain elusive.

CONCLUSION

Further research is required to fully understand the inflammatory mechanisms in the onset and development of COPD exacerbations. This might make inflammatory pathway-specific intervention possible, resulting in a more effective treatment of COPD exacerbations with fewer side effects.

Optimizing bronchodilator therapy in emphysema

The treatment objectives for chronic obstructive pulmonary disease (COPD) include relieving symptoms such as dyspnea and cough, slowing the accelerated decline in lung function, decreasing exacerbations, and improving quality of life. All major guidelines for COPD management recommend beginning treatment with bronchodilators. There are several classes of bronchodilators, including beta-agonists, anticholinergics, and phosphodiesterase inhibitors, each with a specific mechanism of action. The overall approach to managing stable COPD involves a stepwise increase in treatment. Because of the progressive nature of emphysema, such an approach often involves combining bronchodilators from different pharmacologic classes. This review focuses on the pharmacologic properties of various bronchodilators and on recent studies that have examined combination therapy as a means to optimize treatment.