Scientific rationale for inhaled combination therapy with long-acting beta2-agonists and corticosteroids

Cost advantages of combination asthma therapy

The addition of long-acting beta(2)-adrenoceptor agonist (LABA) therapy to 'low dose' inhaled corticosteroids improves asthma outcomes in terms of lung function, exacerbation rates, and quality of life measures in asthmatic patients who remain symptomatic on low-dose inhaled corticosteroids alone. Such treatment is now included in guidelines of asthma therapy on the basis of class A evidence from large placebo-controlled trials. Data on the cost-benefit of such treatment is less compelling, but suggests that for patients with mild asthma this clinical improvement is gained at the expense of an increase in direct costs (mostly drug costs), whereas for patients with more severe asthma there may be a cost benefit, largely from reduced costs of exacerbations. Recently, combination inhalers containing both LABA and corticosteroid in the same device have been introduced. Although it is said that a single inhaler (with some immediate symptom relief) may aid patient adherence, there are no firm data to support this, nor are there any cost-effectiveness data on this point. Overall, these devices have been priced at less than the two drugs given separately, but prospective studies evaluating costs in clinical settings are required.

[Efficacy and acceptability of the fixed fluticasone + salmeterol combination in the treatment of acute asthma attacks. Results of a one-year comparative study]

BACKGROUND

The objective of an asthma treatment is to control asthma, particularly to prevent exacerbations.

OBJECTIVE

To study the efficacy, acceptability and safety of the fluticasone/salmeterol (FP/S) combination in preventing asthma exacerbations in comparison with the continuation of previous treatment (TA).

METHODS

This was a multicentre, randomised, parallel-group study to compare the fixed combination FP/S to TA (treatment with a free combination of an inhaled corticosteroid and a long-acting beta2-agonist) over one year in patients whose asthma was well controlled with their current treatment.

RESULTS

Five hundred and twenty patients were randomized and their data analyzed on an intent-to-treat basis. Seventy-four percent of the patients in the FP/S group and 71% in the TA group had no exacerbation. The 3.12% difference in favor of the FP/S group (90% CI: -3.32% to 9.56%) demonstrated that FP/S was at least as effective TA in preventing asthma exacerbations. Treatment acceptability, evaluated by the patient on visual analog scales (inclusion as part of the daily habits, constraint, simplicity) was better with FP/S (p<0.001) than with TA. Clinical safety was good and comparable in the two groups.

CONCLUSION

The fixed fluticasone/salmeterol combination provided a protection as good as that obtained with free combinations over a one-year treatment period, with a significant improvement in treatment acceptability and a good clinical safety.

Airway mucosal thickening and bronchial hyperresponsiveness induced by inhaled beta 2-agonist in mice

BACKGROUND

Patients with chronic persistent asthma require frequent use of inhaled beta(2)-agonist, which may result in aggravation of asthma symptoms. Our recent in vitro study has shown that beta(2)-agonist stimulates the growth of human airway epithelial cell lines.

STUDY OBJECTIVE

To determine whether beta(2)-agonist likewise affects airway epithelial cell proliferation in vivo and, if so, what the mechanism of action is, we examined the effect of salbutamol on the morphology of murine airways.

METHODS

Seventy-two BALB/c mice were administered aerosolized salbutamol using "flow-through" nose-only inhalation chambers at daily doses of 0.2 to 20 microg for up to 6 weeks. Morphology of tracheal mucosa, labeling of epithelial cells with 5-bromo-2'-deoxyuridine (BrdU), and bronchial responsiveness were assessed.

RESULTS

Exposure to salbutamol increased the thickness of tracheal epithelial layer and the number of BrdU-positive epithelial cells in a dose- and time-dependent manner: the values in mice receiving 20 microg salbutamol for 6 weeks were 247% and 642%, respectively, of those in control animals receiving saline solution alone. These effects were inhibited by the mitogen-activated protein (MAP) kinase kinase inhibitors PD98059 and U0126. Salbutamol also caused a decrease in the provocative concentration of methacholine to achieve 400% of baseline enhanced pause. Combined treatment with inhaled budesonide attenuated salbutamol-induced airway morphologic changes and bronchial hyperresponsiveness.

CONCLUSION

beta(2)-agonist stimulates proliferation of airway epithelial cells and produces airway wall thickening in vivo via MAP kinase-dependent pathway, and these effects are prevented by inhaled corticosteroid.

The effect of adjustable dosing with budesonide/formoterol on health-related quality of life and asthma control compared with fixed dosing

BACKGROUND

Budesonide/formoterol in a single inhaler is an effective therapy for asthma. We investigated whether adjustable maintenance dosing with budesonide/formoterol could maintain health-related quality of life (HRQL) and asthma control.

PATIENTS/METHODS

Asthma patients (n = 4025) received budesonide/formoterol (Symbicort 160/4.5 microg) 2 inhalations twice daily (b.i.d.) for 4 weeks during run-in of this open, multicentre study. Patients were randomised to adjustable dosing (budesonide/formoterol 1 inhalation b.i.d.; stepping up to 2 or 4 inhalations bid for 1 week if asthma worsened) or fixed dosing (budesonide/formoterol 2 inhalations b.i.d.), for 12 weeks. Change in HRQL (standardised Asthma Quality of Life Questionnaire, AQLQ[S], score) during randomised treatment was the primary efficacy variable. Secondary variables included asthma control (peak expiratory flow [PEF], symptom-severity score, nocturnal awakenings, reliever-medication use) and study-medication intake.

RESULTS

Clinically significant (> or = 0.5) improvements in AQLQ(S) score (mean 0.73), morning and evening PEF (mean 42.5 and 24.8 L/min, respectively), and symptom-severity score (mean 0.36) were achieved during run-in. The improvements were maintained in both groups although, overall, adjustable-dosing patients took fewer daily inhalations of budesonide/formoterol than fixed-dosing patients (mean 2.63 versus 3.82, p < 0.001).

CONCLUSION

Adjustable maintenance dosing with budesonide/formoterol maintains HRQL and asthma control as effectively as fixed dosing and is associated with a reduced drug load overall.

Budesonide/formoterol: in chronic obstructive pulmonary disease

Budesonide/formoterol is a fixed-dose combination of the corticosteroid budesonide and the long-acting beta2-agonist formoterol, and is inhaled via the Turbuhaler device. In two large, randomised, double-blind, 12-month studies, patients with severe chronic obstructive pulmonary disease (COPD) receiving budesonide/formoterol 320/9 microg twice daily had a significantly higher forced expiratory volume in 1 second (FEV1) and significantly higher morning and evening peak expiratory flow at trial endpoint than recipients of budesonide or placebo; FEV1 was significantly higher than with formoterol in the larger study. In both studies, the rate of COPD exacerbations and exacerbations requiring oral corticosteroids was significantly reduced with budesonide/formoterol versus formoterol and placebo. Moreover, the time to first exacerbation was significantly prolonged with budesonide/formoterol versus all other treatment arms in the larger study. At 12 months, significant improvements in health-related quality-of-life scores were seen with budesonide/formoterol versus placebo in both studies. The reduction in total and individual symptom scores was significantly greater with budesonide/formoterol than with budesonide or placebo in the smaller study. Budesonide/formoterol was generally well tolerated by patients with severe COPD. The tolerability profile of the combination was similar to that of the individual components with no increase in the incidence of adverse events.

Provocation with adenosine 5'-monophosphate, but not methacholine, induces sputum eosinophilia

INTRODUCTION

Bronchial hyper-responsiveness is usually measured with direct stimuli such as methacholine (MCh) or histamine. Adenosine 5'-monophosphate (AMP), which acts indirectly via the secondary release of mediators, is another stimulus to measure bronchial hyper-responsiveness.

AIM

To investigate whether provocation with inhaled AMP itself initiates an inflammatory response resulting in an influx of eosinophils into the airway lumen.

METHODS

We have included 21 non-smoking atopic asthmatic subjects (mean FEV1 101% predicted, mean age 34 years). Each subject performed three sputum inductions on different days, at least seven days apart: one without previous provocation, one hour after PC20 methacholine, and one hour after PC20 AMP.

RESULTS

After provocation with AMP, but not methacholine, the percentage of sputum eosinophils increased significantly (from 1.9+/-0.5% to 4.5+/-1% (P<0.01) and 1.9+/-0.5% (P=0.89)). No changes in the percentages of neutrophils, lymphocytes, macrophages, or bronchial epithelial cells were found.

CONCLUSION

A provocation test with AMP leads to an increased percentage of sputum eosinophils. This observation cannot be explained by a non-specific response of the airways to a vigorous bronchoconstriction, since methacholine had no effect on inflammatory cells.

Use and misuse of corticosteroids

Corticosteroids are amongst the most common drugs used in clinical medicine. Prudent management of patients is essential to avoid steroid-induced complications.

New therapies for chronic obstructive pulmonary disease

Chronic obstructive pulmonary disease (COPD) is the most common lung disease, carrying a significant mortality and morbidity. None of the therapeutic interventions currently available alter the progression of the disease. As our understanding of the basic mechanisms of alveolar destruction and airflow limitation improves, new targets are identified that may eventually result in treatment options which will affect the progression of this disease. In this review, we discuss some of the novel therapeutic options recently developed that may have an impact on the management of COPD. Future directions in research and development of pharmacological agents based on improved understanding of COPD are also discussed.

Effects of inhaled corticosteroids, leukotriene receptor antagonists, or both, plus long-acting beta2-agonists on asthma pathophysiology: a review of the evidence

Chronic inflammation and smooth muscle dysfunction are consistent features of asthma, and are responsible for disease progression and airway remodelling. The development of chronic airway inflammation depends upon the recruitment and activation of inflammatory cells and the subsequent release of inflammatory mediators, including cytokines. Cellular and histological evaluation of drugs with anti-inflammatory activity, such as inhaled corticosteroids (ICSs), is achieved by analysing samples of lung tissue or biological fluids, obtained by techniques such as bronchial biopsy, bronchoalveolar lavage and sputum induction. These provide valuable information on the inflammatory processes occurring in the lung, although not all are equal in value. The beneficial effects of ICSs in asthma treatment are a consequence of their potent and broad anti-inflammatory properties. Furthermore, there have been promising results indicating that ICSs can reverse some of the structural changes that contribute to airway remodelling. Long-acting beta2-agonists (LABAs) added to ICSs provide greater clinical efficacy than ICSs alone, suggesting the possibility of complementary activity on the pathophysiological mechanisms of asthma: inflammation and smooth muscle dysfunction. Leukotrienes play a part in the pathogenesis of asthma. Leukotriene receptor antagonists (LTRAs) directly inhibit bronchoconstriction and may have some anti-inflammatory effects, although the extent to which inhibiting one set of inflammatory mediators attenuates the inflammatory response is questionable. In concert with their effect on a broad variety of inflammatory mediators and cells, treatment with ICSs (including ICSs and LABAs) results in superior control of the pathophysiology of asthma and superior clinical efficacy as assessed by the greater improvements in pulmonary function and overall control of asthma compared with LTRAs.

Therapy for chronic obstructive pulmonary disease in the 21st century

Chronic obstructive pulmonary disease (COPD) is a common, smoking-related, severe respiratory condition characterised by progressive, irreversible airflow limitation. Current treatment of COPD is symptomatic, with no drugs capable of halting the relentless progression of airflow obstruction. Better understanding of the airway inflammation, oxidative stress and alveolar destruction that characterise COPD has delineated new disease targets, with consequent identification of novel compounds with therapeutic potential. These new drugs include aids to smoking cessation (e.g. bupropion) and improvements to existing therapies, for example long-acting rather than short-acting bronchodilators, as well as combination therapy. New antiproteases include acyl-enzyme and transition state inhibitors of neutrophil elastase (e.g. sivelestat and ONO-6818), matrix metalloprotease inhibitors (e.g. batimastat), cathepsin inhibitors and peptide protease inhibitors (e.g. DX-890 [EPI-HNE-4] and trappin-2). New antioxidants include superoxide dismutase mimetics (e.g. AEOL-10113) and spin trap compounds (e.g. N-tert-butyl-alpha-phenylnitrone). New anti-inflammatory interventions include phosphodiesterase-4 inhibitors (e.g. cilomilast), inhibitors of tumour necrosis factor-alpha (e.g. humanised monoclonal antibodies), adenosine A(2a) receptor agonists (e.g. CGS-21680), adhesion molecule inhibitors (e.g. bimosiamose [TBC1269]), inhibitors of nuclear factor-kappaB (e.g. the naturally occurring compounds hypoestoxide and (-)-epigallocatechin-3-gallate) and activators of histone deacetylase (e.g. theophylline). There are also selective inhibitors of specific extracellular mediators such as chemokines (e.g. CXCR2 and CCR2 antagonists) and leukotriene B(4) (e.g. SB201146), and of intracellular signal transduction molecules such as p38 mitogen activated protein kinase (e.g. RWJ67657) and phosphoinositide 3-kinase. Retinoids may be one of the few potential treatments capable of reversing alveolar destruction in COPD, and a number of compounds are in clinical trial (e.g. all-trans-retinoic acid). Talniflumate (MSI-1995), an inhibitor of human calcium-activated chloride channels, has been developed to treat mucous hypersecretion. In addition, the purinoceptor P2Y(2) receptor agonist diquafosol (INS365) is undergoing clinical trials to increase mucus clearance. The challenge to transferral of these new compounds from preclinical research to disease management is the design of effective clinical trials. The current scarcity of well characterised surrogate markers predicts that long-term studies in large numbers of patients will be needed to monitor changes in disease progression.

[Pulmonary diseases in the elderly. Problems of pharmacotherapy]

In asthma, inhaled corticosteroids (ICS) can be regarded as disease-modifying drugs. They represent the mainstay of pharmacotherapy of asthma. In elderly, ICS are currently underused. In chronic obstructive pulmonary disease (COPD), there is recent evidence to suggest that ICS may reduce the rate and severity of COPD exacerbations and may improve health-related quality of life. Particularly patients with moderate-to-severe COPD appear to benefit from ICS therapy. In both asthma and COPD, fixed combinations of ICS and long-acting beta 2-agonists may provide clinically meaningful benefits to patients and may represent a further therapeutic advantage.

Inhaled corticosteroids with/without long-acting beta-agonists reduce the risk of rehospitalization and death in COPD patients

INTRODUCTION

In patients with COPD who have recently been hospitalized for their disease, we examined whether treatment with inhaled corticosteroids without or with long-acting beta-adrenoceptor agonists (beta-agonists) reduced rehospitalization and mortality.

STUDY DESIGN

Retrospective cohort analysis in the UK General Practice Research Database.

METHODS

We compared rehospitalization for a COPD-related medical condition or death within 1 year after first hospitalization, in 3636 COPD patients receiving prescriptions for inhaled corticosteroids or long-acting beta-agonists compared with 627 reference patients with COPD who were prescribed short-acting bronchodilators only.

RESULTS

Rehospitalization within a year occurred in 13.2% of the reference COPD patients, 14.0% of users of long-acting beta-agonists only, 12.3% of users of inhaled corticosteroids only, and 10.4% of users of inhaled corticosteroids and long-acting beta-agonists. Death within a year occurred in 24.3% of the reference COPD patients, 17.3% of users of long-acting beta-agonists only, 17.1% of users of inhaled corticosteroids only, and in 10.5% of users of inhaled corticosteroids and long-acting beta-agonists. In multivariate analyses the risk of rehospitalization or death was reduced by 10% in users of long-acting beta-agonists only (NS), by 16% in users of inhaled corticosteroids only, and by 41% in users of combined inhaled corticosteroids and long-acting beta-agonists (both p < 0.05).

CONCLUSION

Use of inhaled corticosteroids with/without long-acting beta-agonists was associated with a reduction of rehospitalization or death in COPD patients.

[Bronchodilators in COPD: latest recommendations, recent data and perspectives]

DEMONSTRATED EFFICACY: Inhaled bronchodilators improve the quality of life of COPD patients by reducing dyspnea and exacerbation frequency. There is no data supporting the superiority of one of the families of inhaled bronchodilators (i.e. beta 2 agonists and anticholinergic agents) over the other. Thus, the choice has to be based on the individual symptomatic response. These agents can be combined. OTHER POSSIBILITIES: Long-acting beta 2 agonists are already available and long-acting anticholinergics should be marketed soon. Theophylline has a lower efficacy/tolerance ratio than inhaled bronchodilators but can provide additional benefits when associated with the latter in some patients. Phosphodiesterase inhibitors with both bronchodilating and anti-inflammatory effect are being developed. THE BENEFITS OF CORTICOSTEROIDS: Finally, in symptomatic patients with FEV1<50% predicted and repeated exacerbations despite bronchodilators, inhaled corticosteroids can be added.

Inhibitors of p38 mitogen-activated protein kinase: potential as anti-inflammatory agents in asthma?

Asthma is an inflammatory disease of the airways, which in patients with mild to moderate symptoms is adequately controlled by either beta(2)-adrenoceptor agonists or corticosteroids, or a combination of both. Despite this, there are classes of patients that fail to respond to these treatments. In addition, there is a general trend towards increasing morbidity and mortality due to asthma, which suggests that there is a need for new and improved treatments. The p38 mitogen-activated protein kinases (MAPKs) represent a point of convergence for multiple signalling processes that are activated in inflammation and that impact on a diverse range of events that are important in inflammation. Small molecule pyridinyl imidazole inhibitors of p38 MAPK have proved to be highly effective in reducing various parameters of inflammation, in particular cytokine expression. Like corticosteroids, inhibitors of p38 MAPK appear to be able to repress gene expression at multiple levels, for example, by transcriptional, posttranscriptional and translational repression, and this raises the possibility of a similarly broad spectrum of anti-inflammatory activities. Indeed these molecules have proved to be effective in numerous in vitro and in vivo models of inflammation and septicaemia, which suggests that such compounds may be effective as therapeutic agents against inflammatory disorders. Despite these very promising indications of the possible therapeutic use of p38 MAPK inhibitors, a number of events that are p38-dependent are in fact also beneficial to the resolution or modulation of diseases such as asthma. We conclude that the overall effect of p38 MAPK inhibition would be beneficial in inflammatory diseases such as rheumatoid arthritis and asthma. However, these drugs may result in a complex phenotype that will require careful evaluation. Currently, a number of second or third generation inhibitors of p38 MAPK are being tested in phase I and phase II clinical trials.

Adjustable maintenance dosing with budesonide/formoterol compared with fixed-dose salmeterol/fluticasone in moderate to severe asthma

BACKGROUND

Current asthma guidelines recommend that patients are educated to adjust their medication according to their asthma severity using physician-guided self-management plans. However, many patients take a fixed dose of their controller medication and adjust their reliever medication according to asthma symptoms.

OBJECTIVES

This study examined whether asthma control improved if patients adjusted the maintenance dose of budesonide/formoterol (Symbicort Turbuhaler* 160/4.5 microg) according to asthma severity compared with traditional fixed dosing (FD) regimens.

METHODS

Symptomatic patients with asthma (n = 658, mean symptom score 1.5, mean inhaled corticosteroids 735 microg/day, mean forced expiratory volume in 1 second [FEV(1)] 84% predicted) were randomised after 2 weeks' run-in to either: budesonide/formoterol adjustable maintenance dosing (AMD), budesonide/formoterol FD or salmeterol/fluticasone (Seretide Diskus dagger 50/250 microg) FD. In a 4-week double-blind period, both budesonide/formoterol AMD and FD groups received two inhalations twice daily (bid) and salmeterol/fluticasone FD patients received one inhalation bid. In the following 6-month open extension, both FD groups continued with the same treatment. Patients in the AMD group with well-controlled asthma stepped down to one inhalation bid; others continued with two inhalations bid. All AMD patients could increase to four inhalations bid for 7-14 days if symptoms worsened. All patients used terbutaline or salbutamol for symptom relief throughout. The primary variable was the odds of achieving a well-controlled asthma week (WCAW).

RESULTS

The odds ratio for achieving a WCAW did not differ between the FD regimens; however, during the open period, budesonide/formoterol AMD increased the odds of achieving a WCAW vs. budesonide/formoterol FD (odds ratio 1.335; 95% CI: 1.001, 1.783; p = 0.049) despite a 15% reduction in average study drug use. Budesonide/formoterol AMD patients had a lower exacerbation rate over the study: 40% lower vs. salmeterol/fluticasone FD (p = 0.018); 32% lower vs. budesonide/formoterol FD (NS). During the double-blind period, there were no clinically relevant differences between the budesonide/formoterol FD and salmeterol/fluticasone FD groups. Budesonide/formoterol AMD patients used less reliever medication in the open extension: 0.58 vs. 0.92 occasions/day for budesonide/formoterol FD (p = 0.001) and 0.80 occasions/day for salmeterol/fluticasone FD (p = 0.011).

CONCLUSIONS

Adjustable maintenance dosing with budesonide/formoterol provides more effective asthma control by reducing exacerbations and reliever medication usage compared with fixed-dose salmeterol/fluticasone.

Formoterol (Foradil) and medium-high doses of inhaled corticosteroids are more effective than high doses of corticosteroids in moderate-to-severe asthma

This double-blind, randomised, multi-centre, parallel-group study compared the effect of adding Foradil (formoterol fumarate) to existing medium-high doses of inhaled corticosteroids (ICS) with that of doubling the dose of ICS in patients with sub-optimally controlled asthma. After a run-in period, 203 patients with moderate-to-severe asthma who remained symptomatic despite treatment with 500 microg beclomethasone twice daily, were randomised to receive either 12 microg formoterol twice daily (Foradil Aerolizer), Novartis) in addition to beclomethasone 500 microg twice daily, or beclomethasone 1000 microg twice daily and placebo for 12 weeks. The primary efficacy variable was mean morning pre-medication peak expiratory flow (PEF) during the last seven days of treatment. The difference in PEF between treatments was 27.78 l/min in favour of the formoterol/beclomethasone combination (95% CI 13.42, 42.14 l/min, p=0.0002, intention-to-treat population). Significant differences in the urinary cortisol/creatinine ratio between treatment groups at 12 weeks (p=0.001) indicated suppression of the hypothalamic-pituitary-adrenal axis in the patients on beclomethasone 1000 microg twice daily. The addition of formoterol 12 microg twice daily to beclomethasone in patients with asthma who were poorly controlled with beclomethasone 500 microg twice daily was more effective than doubling the ICS dose and resulted in less suppression of the hypothalamic-pituitary-adrenal axis.

Pharmacology of airway inflammation in asthma and COPD

The current asthma therapies are not cures and symptoms return soon after treatment is stopped even after long term treatment. Although inhaled glucocorticoids are highly effective in controlling airway inflammation in asthma, they are ineffective in the small group of patients with glucocorticoid-dependent and -resistant asthma. With very few exceptions, COPD is caused by tobacco smoking, and smoking cessation is the only truly effective treatment of COPD available. Current pharmacological treatment of COPD is unsatisfactory, as it does not significantly influence the severity of the disease or its natural course. Glucocorticoids are scarcely effective in COPD patients without concomitant asthma. Bronchodilators improves symptoms and quality of life, in COPD patients, but, with the exception of tiotropium, they do not significantly influence the natural course of the disease. Theophylline is the only drug which has been demonstrated to have a significant effect on airway inflammation in patients with COPD. Here we review the pharmacology of currently used antiinflammatory therapies for asthma and COPD and their proposed mechanisms of action. Recent understanding of disease mechanisms in severe steroid-dependent and -resistant asthma and in COPD, has lead to the development of novel compounds, which are in various stages of clinical development. We review the current status of some of these new potential drugs.

Differential modulation of glucocorticoid action by FK506 in A549 cells

Glucocorticoids inhibit the release of eicosanoid pro-inflammatory mediators. The immunosuppressant FK506 is known to enhance many aspects of glucocorticoid action. In the present study we show that FK506 (1 microM or 10 microM) inhibits the release of arachidonic acid and prostaglandin E2 from A549 cells and also inhibits their proliferation. Simultaneous treatment of FK506 together with the glucocorticoids dexamethasone, methyl-prednisolone, fluticasone or mometasone (10 nM) enhances the growth inhibitory effect of these steroids. Furthermore, the simultaneous use of FK506 and these glucocorticoids similarly results in enhanced inhibition of arachidonic acid release. When pretreated for 2 h, FK506 enhances glucocorticoid inhibition of COX2 (cyclo-oxygenase 2) expression. However, when administered simultaneously, FK506 blocks glucocorticoid inhibition of COX2 expression. Nuclear uptake of glucocorticoid receptors mediated by glucocorticoids is also blocked by the simultaneous administration of FK506. These results suggest that the effect of simultaneous treatment of FK506 with glucocorticoids differs significantly from that where pre-treatment of the immunosuppressant is used. Recently, immunophilin interchange has been identified as a first step in glucocorticoid receptor activation following ligand activation. We show here that the FKB51 (FK506-binding protein 51)-FKB52 switch is differentially regulated by glucocorticoid and FK506 treatment strategy.

Contemporary management of chronic obstructive pulmonary disease: scientific review

CONTEXT

The care of patients with chronic obstructive pulmonary disease (COPD) has changed radically over the past 2 decades, and novel therapies can not only improve the health status of patients with COPD but also modify its natural course.

OBJECTIVE

To systematically review the impact of long-acting bronchodilators, inhaled corticosteroids, nocturnal noninvasive mechanical ventilation, pulmonary rehabilitation, domiciliary oxygen therapy, and disease management programs on clinical outcomes in patients with COPD.

DATA SOURCES

MEDLINE and Cochrane databases were searched to identify all randomized controlled trials and systematic reviews from 1980 to May 2002 evaluating interventions in patients with COPD. We also hand searched bibliographies of relevant articles and contacted experts in the field.

STUDY SELECTION AND DATA EXTRACTION

We included randomized controlled trials that had follow-up of at least 3 months and contained data on at least 1 of these clinical outcomes: health-related quality of life, exacerbations associated with COPD, or death. For pulmonary rehabilitation, we included studies that had a follow-up of at least 6 weeks. Using standard meta-analytic techniques, the effects of interventions were compared with placebo or with usual care. In secondary analyses, the effects of interventions were compared against each other, where possible.

DATA SYNTHESIS

Long-acting beta2-agonists and anticholinergics (tiotropium) reduced exacerbation rates by approximately 20% to 25% (relative risk [RR] for long-acting beta2-agonists, 0.79; 95% CI, 0.69-0.90; RR for tiotropium, 0.74; 95% CI, 0.62-0.89) in patients with moderate to severe COPD. Inhaled corticosteroids also reduced exacerbation rates by a similar amount (RR, 0.76; 95% CI, 0.72-0.80). The beneficial effects were most pronounced in trials enrolling patients with FEV1 between 1 L and 2 L. Combining a long-acting beta2-agonist with an inhaled corticosteroid resulted in an approximate 30% (RR, 0.70; 95% CI, 0.62-0.78) reduction in exacerbations. Pulmonary rehabilitation improved the health status of patients with moderate to severe disease, but no material effect was observed on long-term survival or hospitalization rates. Domiciliary oxygen therapy improved survival by approximately 40% in patients with PaO2 lower than 60 mm Hg, but not in those without hypoxia at rest. The data on disease management programs were heterogeneous, but overall no effect was observed on survival or risk of hospitalization. Noninvasive mechanical ventilation was not associated with improved outcomes.

CONCLUSIONS

A significant body of evidence supports the use of long-acting bronchodilators and inhaled corticosteroids in reducing exacerbations in patients with moderate to severe COPD. Domiciliary oxygen therapy is the only intervention that has been demonstrated to prolong survival, but only in patients with resting hypoxia.

An update on asthma management

Asthma remains a major cause of morbidity in the Australian community, despite enhanced strategies and interventions for achieving optimal outcomes. Although there is some evidence of over use of high doses of inhaled corticosteroids (ICS), there is also evidence for under use of ICS, despite long-term data demonstrating clear benefits of low doses. The present paper briefly discusses some of the issues that are pertinent to the development of sensitization and atopic disease, but focuses mainly on the current understanding of best clinical practice for adults with asthma and the optimal approach to management. A clear definition of asthma control and a systematic approach to down-titration to minimize ICS doses is crucial to achieving better outcomes. Patient self-management education and optimal therapy are the keys to achieving better outcomes, although uncertainty remains about recommendations for mild asthma, despite new data.

Glucocorticoid-induced skeletal muscle atrophy is associated with upregulation of myostatin gene expression

The mechanisms by which excessive glucocorticoids cause muscular atrophy remain unclear. We previously demonstrated that dexamethasone increases the expression of myostatin, a negative regulator of skeletal muscle mass, in vitro. In the present study, we tested the hypothesis that dexamethasone-induced muscle loss is associated with increased myostatin expression in vivo. Daily administration (60, 600, 1,200 micro g/kg body wt) of dexamethasone for 5 days resulted in rapid, dose-dependent loss of body weight (-4.0, -13.4, -17.2%, respectively, P < 0.05 for each comparison), and muscle atrophy (6.3, 15.0, 16.6% below controls, respectively). These changes were associated with dose-dependent, marked induction of intramuscular myostatin mRNA (66.3, 450, 527.6% increase above controls, P < 0.05 for each comparison) and protein expression (0.0, 260.5, 318.4% increase above controls, P < 0.05). We found that the effect of dexamethasone on body weight and muscle loss and upregulation of intramuscular myostatin expression was time dependent. When dexamethasone treatment (600 micro g. kg-1. day-1) was extended from 5 to 10 days, the rate of body weight loss was markedly reduced to approximately 2% within this extended period. The concentrations of intramuscular myosin heavy chain type II in dexamethasone-treated rats were significantly lower (-43% after 5-day treatment, -14% after 10-day treatment) than their respective corresponding controls. The intramuscular myostatin concentration in rats treated with dexamethasone for 10 days returned to basal level. Concurrent treatment with RU-486 blocked dexamethasone-induced myostatin expression and significantly attenuated body loss and muscle atrophy. We propose that dexamethasone-induced muscle loss is mediated, at least in part, by the upregulation of myostatin expression through a glucocorticoid receptor-mediated pathway.

Enhanced synergy between fluticasone propionate and salmeterol inhaled from a single inhaler versus separate inhalers

BACKGROUND

The coadministration of long-acting inhaled beta(2)-agonists and inhaled corticosteroids is the most effective treatment for persistent asthma.

OBJECTIVE

This meta-analysis aimed to determine the efficacy of fluticasone propionate and salmeterol inhaled from a single inhaler (combination therapy) or from separate inhalers (concurrent therapy).

METHODS

Four similarly designed double-blind studies individually confirmed equivalence between combination and concurrent therapy on the basis of the primary efficacy measure (morning peak expiratory flow [PEF]). Each study showed a consistent trend in favor of combination therapy. Individual patient data from these studies were combined to provide overall estimates of treatment effect for morning PEF and other efficacy measures.

RESULTS

Fixed-effects meta-analysis showed a significant advantage for combination therapy compared with concurrent therapy in morning PEF (mean difference between groups in change from baseline over 12 weeks of 5.4 L/min; P =.006; 95% CI = 1.5-9.2). Logistic regression analysis showed that the odds of achieving a greater than 15 or greater than 30 L/min improvement with combination therapy were increased by approximately 40% compared with those after concurrent therapy (15 L/min: odds ratio = 1.42, P =.008, 95% CI = 1.1-1.8; 30 L/min: odds ratio = 1.40, P =.006, 95% CI = 1.1-1.8), representing an additional 7% to 9% and 5% to 14% more patients, respectively, on combination therapy responding compared with those on concurrent therapy.

CONCLUSION

The meta-analysis indicates that the fluticasone propionate plus salmeterol combination offers the potential for increased clinical efficacy over concurrent use of the same doses of the same 2 drugs. After administration from a single inhaler, fluticasone propionate and salmeterol might codeposit in the airways. It is hypothesized that this codeposition offers an increased opportunity for synergistic interaction to occur.

Combination therapy: appropriate for everyone?

The severity of asthma often varies throughout the course of the disease. At times the symptoms and underlying inflammation that are characteristic of asthma can worsen. Thus during an episode of viral-induced asthma or during a seasonal increase in asthma severity, a patient may be directed to increase his or her dosage of asthma controllers (i.e., inhaled corticosteroid) or add a long-acting bronchodilator (or other controller medications such as antileukotrienes) to manage symptoms, as recommended in guidelines published by the National Institutes of Health (NIH). Similarly, when symptoms are stable, decreasing dosages or discontinuing certain medications may be appropriate. The recent introduction of a combination product, of a long-acting bronchodilator formulated in the same dry powder device with an inhaled corticosteroid raises new challenges for the step care approach to asthma management recommended by the NIH in 1997. Although unquestionably more convenient for the patient, a combination formulation has the potential to decrease the flexibility required to successfully manage asthma over long periods. In addition, controversy exists regarding long-acting beta-agonists alone because their regular use may mask inflammation in the lung and decrease responsiveness to the bronchodilating effects of rescue medications (i.e., short-acting beta-agonists). The purpose of this article is to help physicians make informed therapeutic decisions for their patients with asthma. It focuses on the advantages and potential disadvantages of using combination products, which contain both an inhaled corticosteroid and a long-acting beta-agonist in the context of the NIH step care approach. Recent publications outlining the use of other add-on controller medications are also discussed.

Effects of montelukast on surrogate inflammatory markers in corticosteroid-treated patients with asthma

We evaluated whether montelukast conferred additive effects in patients with asthma receiving fluticasone/salmeterol (FP/SM) combination and FP alone. Twenty-two patients with mild to moderate asthma completed a double-blind, placebo-controlled study. After a 2-week run-in using FP 250 microg/SM 50 microg 1 puff twice daily, patients entered a randomized crossover period to receive additional montelukast 10 mg daily or placebo for 3 weeks each. For the first 2 weeks, they received FP/SM 1 puff BID, and then they received FP 250 microg 1 puff BID for the 3rd week. The primary outcome was adenosine monophosphate challenge threshold and recovery time; secondary outcomes included surrogate inflammatory markers and lung function. Compared with FP/SM run-in, adding montelukast to FP/SM was better (p < 0.05) than placebo for inflammatory markers but not for lung function. For adenosine monophosphate threshold, recovery, exhaled nitric oxide, and blood eosinophils, there were 1.4 (95% confidence interval, 1.1-1.8) geometric mean fold, 10 minutes (3-17 minutes), 2.1 parts per billion (0.2-3.9 parts per billion), and 88 (34-172) x 10(6)/L differences, respectively. The combination of FP plus montelukast was superior to FP/SM for inflammatory markers but was inferior for lung function. Thus, in patients taking FP/SM or FP, montelukast conferred complimentary effects on surrogate inflammatory markers, which were dissociated from lung function. Further studies are required to evaluate whether these effects of montelukast translate into clinical benefits.

Combined salmeterol and fluticasone in the treatment of chronic obstructive pulmonary disease: a randomised controlled trial

BACKGROUND

Inhaled long-acting beta2 agonists improve lung function and health status in symptomatic chronic obstructive pulmonary disease (COPD), whereas inhaled corticosteroids reduce the frequency of acute episodes of symptom exacerbation and delay deterioration in health status. We postulated that a combination of these treatments would be better than each component used alone.

METHODS

1465 patients with COPD were recruited from outpatient departments in 25 countries. They were treated in a randomised, double-blind, parallel-group, placebo-controlled study with either 50 microg salmeterol twice daily (n=372), 500 microg fluticasone twice daily (n=374), 50 microg salmeterol and 500 microg fluticasone twice daily (n=358), or placebo (n=361) for 12 months. The primary outcome was the pretreatment forced expiratory volume in 1s (FEV1) after 12 months treatment' and after patients had abstained from all bronchodilators for at least 6h and from study medication for at least 12h. Secondary outcomes were other lung function measurements, symptoms and rescue treatment use, the number of exacerbations, patient withdrawals, and disease-specific health status. We assessed adverse events, serum cortisol concentrations, skin bruising, and electrocardiograms. Analysis was as predefined in the study protocol.

FINDINGS

All active treatments improved lung function, symptoms, and health status and reduced use of rescue medication and frequency of exacerbations. Combination therapy improved pretreatment FEV1 significantly more than did placebo (treatment difference 133 mL, 95% CI 105-161, p<0.0001), salmeterol (73 mL, 46-101, p<0.0001), or fluticasone alone (95 mL, 67-122, p<0.0001). Combination treatment produced a clinically significant improvement in health status and the greatest reduction in daily symptoms. All treatments were well tolerated with no difference in the frequency of adverse events, bruising, or clinically significant falls in serum cortisol concentration.

INTERPRETATION

Because inhaled long-acting beta2 agonists and corticosteroid combination treatment produces better control of symptoms and lung function, with no greater risk of side-effects than that with use of either component alone, this combination treatment should be considered for patients with COPD.

Inhaled salmeterol/fluticasone propionate combination: a pharmacoeconomic review of its use in the management of asthma

Asthma guidelines recommend an inhaled corticosteroid plus a long-acting inhaled beta(2)-agonist (beta(2)-adrenoceptor agonist) as the preferred maintenance therapy for moderate and severe persistent asthma. Advair/Seretide Diskus also registered as Accuhaler is fixed-dose salmeterol (a long-acting inhaled beta(2)-agonist) and fluticasone propionate (a corticosteroid) administered via a single powder inhalation device. The clinical effectiveness of salmeterol/fluticasone propionate in patients with persistent asthma symptoms has been established in comparative clinical trials. Pharmacoeconomic analyses, based on data from these clinical trials, have been conducted from a healthcare payer perspective in various countries. In patients with asthma not controlled with inhaled corticosteroids, salmeterol/fluticasone propionate was associated with more favourable (lower) cost-effectiveness ratios than fluticasone propionate monotherapy, oral montelukast plus inhaled fluticasone propionate, inhaled budesonide, and inhaled formoterol plus budesonide. As the initial maintenance therapy in patients with persistent asthma symptoms while receiving short-acting beta(2)-agonists alone, salmeterol/fluticasone propionate was cost effective relative to montelukast monotherapy. Although the total cost of asthma management tended to be slightly higher with salmeterol/fluticasone propionate than with fluticasone propionate or montelukast monotherapy, salmeterol/fluticasone propionate consistently had a more favourable cost-effectiveness ratio in terms of per successfully treated week or symptom-free day and/or was associated with small incremental costs to achieve significant additional clinical benefits. In clinical practice, salmeterol plus fluticasone propionate was associated with lower asthma-related costs than treatment with other maintenance therapies.In patients with asthma symptoms despite treatment with inhaled corticosteroids, salmeterol/fluticasone propionate produced clinically meaningful improvements in overall Asthma Quality of Life Questionnaire (AQLQ) scores relative to salmeterol or placebo monotherapy, in emotional function domain scores relative to fluticasone propionate or budesonide, and in asthma symptoms domain scores relative to budesonide. In patients with persistent asthma symptoms while receiving short-acting beta(2)-agonists alone, salmeterol/fluticasone propionate produced clinically meaningful improvements in overall AQLQ scores compared with fluticasone propionate or montelukast.

CONCLUSIONS

Pharmacoeconomic analyses indicate that salmeterol/fluticasone propionate administered via a single inhaler represents a cost-effective treatment option (relative to fluticasone propionate at the same nominal dosage, budesonide, formoterol plus budesonide and montelukast plus fluticasone propionate) in patients with asthma not controlled with inhaled corticosteroid therapy. In patients with asthma not controlled with short-acting beta(2)-agonists alone, salmeterol/fluticasone propionate is a cost effective treatment relative to monotherapy with montelukast. Importantly, salmeterol/fluticasone propionate is also associated with improvements in health-related quality of life.

Possibilities of formoterol to enhance the peripheral lung deposition of the inhaled liposome corticosteroids

The pulmonary distribution and clearance of 99m-Tc-labelled beclomethasone dipropionate (Bec)--dilauroylphosphatidylcholine (DLPC) were compared in nine asthmatic patients on inhaled steroids after a 1-week medical treatment period of long-acting beta2-agonist formoterol. The patients were given formoterol 12 microg (OxisTurbuhaler) twice daily in addition to their own regular inhaled corticosteroid therapy. Gamma lung scintigraphy and lung function tests were performed before and after formoterol treatment. The bronchodilating effect ofthe combined therapy was significant: 1-week usage of inhaled formoterol enhanced peripheral lung deposition of beclomethasone liposome and thus diminished central/peripheral deposition ratio (C/P ratio). All measured lung function values except FEV1/FVC% improved after the medication period, although statistically significant levels were not reached. A systemic positive connection was seen between enhanced lung functions and greater lung deposition measured as AUC(0-24h)/24 Beclomethasone liposome formulation maintained its long-lasting effect in connection with formoterol treatment. At the 4-h measurement, 76% of the liposome-entrapped radioactivity still remained in the lungs before and 75% after the medication period.