Effects of varying doses of fluticasone propionate on the physiology and bronchial wall immunopathology in mild-to-moderate asthma

Improving the risk-to-benefit ratio of inhaled corticosteroids through delivery and dose: current progress and future directions

INTRODUCTION

Inhaled corticosteroids (ICS) are known to increase the risk of systemic and local adverse effects, especially with high doses and long-term use. Hence, considerable resources are invested to improve pharmacokinetic/pharmacodynamic (PK/PD) properties of ICS, effective delivery systems and novel combination therapies to enhance the risk-to-benefit ratio of ICS.

AREAS COVERED

There is an unmet need for new solutions to achieve optimal clinical outcomes with minimal dose of ICS. This paper gives an overview of novel treatment strategies regarding the safety of ICS therapy on the basis of the three most recent molecules introduced to our everyday clinical practice - ciclesonide, mometasone furoate, and fluticasone furoate. Advances in aerosol devices and new areas of inhalation therapy are also discussed.

EXPERT OPINION

Current progress in improving the risk-to-benefit ratio of ICS through dose and delivery probably established pathways for further developments. This applies both to the improvement of the PK/PD properties of ICS molecules but also includes technical aspects that lead to simplified applicability of the device with simultaneous optimal drug deposition in the lungs. Indubitably, the future of medicine lies not only in the development of new molecules but also in technology and digital revolution.

Direct and indirect bronchoprovocation tests in dose-response studies of inhaled corticosteroids: Past, present, and future directions

Inhaled corticosteroids (ICS) are a mainstay of treatment in eosinophilic asthma. Many studies have explored the dose-response effect of different formulations of ICS through direct or indirect bronchoprovocation testing. Such studies are important for investigating efficacy and identifying the relative potency between formulations. However, lack of consistency in methods and designs has hindered the comparability of study findings. This review discusses current knowledge of the dose-response, or lack thereof, of different formulations of ICS through direct and indirect bronchoprovocation testing. The strengths and weaknesses of past studies inform recommendations for future methodological considerations in this field, such as utilizing a randomized double-blind crossover design, enrolling participants likely to respond to ICS therapy, and carefully selecting treatment durations and washout periods to assess incremental improvement in airway hyperresponsiveness while reducing the likelihood of a carryover effect.

Phenotype-Guided Asthma Therapy: An Alternative Approach to Guidelines

Despite recent advances in therapy, a substantial proportion of asthmatics remain not well controlled. The classical stepwise approach to pharmacological therapy in adult asthma recommends that treatment is progressively stepped up by increasing the inhaled corticosteroid (ICS) dose or by adding another controller medication- to achieve symptom control and reduce the risk of exacerbations, and stepped down after a period of control. In general, asthma guideline recommendations do not reflect that there are significant differences between ICS in terms of potency. Moreover, they do not consider efficacy and safety separately, incorrectly assuming that "low" and "high" dose categories inevitably correspond with low and high risk of systemic effects. Another point of criticism is the fact that guidelines do not take into account the inflammatory profile of the patient, although substantial groups of patients with mild and moderate asthma have little evidence of "T2-high" inflammation, and by extension are likely to show a poor response to ICS treatment. On the other hand, the latest version of the Global Initiative for Asthma (GINA) equally recommends regular ICS and ICS/formoterol as needed to prevent exacerbations in step 2 patients, without taking into consideration that the therapeutic objectives (exacerbations, symptoms) may differ between individual patients and that different goals may warrant distinct treatment strategies. In this review, we bring to the table several controversial issues concerning asthma treatment and suggest an alternative proposal that takes into consideration the potential side effects of high ICS doses, the patient's inflammatory profile and the therapeutic goals to be achieved.

Inhaled Corticosteroid Therapy in Adult Asthma. Time for a New Therapeutic Dose Terminology

The Global Initiative for Asthma guidelines use the traditional terminology of "low," "medium," and "high" doses of inhaled corticosteroids (ICS) to define daily maintenance doses of 100 to 250 μg, >250 to 500 μg, and >500 μg, respectively, of fluticasone propionate or equivalent for adults with asthma. This concise clinical review proposes that this terminology is not evidence based and that prescribing practice based on this terminology may lead to the use of inappropriately excessive doses of ICS. Specifically, the ICS dose that achieves 80-90% of the maximum obtainable benefit is currently classified as a low dose, with the description of two higher dose levels of medium and high, which are associated with significant risk of systemic adverse effects. Asthma guidelines and clinician prescribing practice need to be modified in accordance with the currently available evidence of the dose-response relationship of ICS in adult asthma. We propose a reclassification of ICS doses based on a "standard daily dose," which is defined as 200-250 μg of fluticasone propionate or equivalent, representing the dose at which approximately 80-90% of the maximum achievable therapeutic benefit of ICS is obtained in adult asthma across the spectrum of severity. It is recommended that ICS treatment be started at these standard doses, which then represent the doses at which maintenance ICS are prescribed at step 2 and within ICS/long-acting β-agonist combination therapy at step 3. The opportunity is available to prescribe higher doses within ICS/long-acting β-agonist maintenance therapy in accordance with the stepwise approach to asthma treatment at step 4.

Fluticasone at different doses for chronic asthma in adults and children

BACKGROUND

Inhaled fluticasone propionate (FP) is a high-potency inhaled corticosteroid used in the treatment of asthma.

OBJECTIVES

1. To assess the efficacy and safety outcomes of inhaled fluticasone at different nominal daily doses in the treatment of chronic asthma.2. To test for the presence of a dose-response effect.

SEARCH STRATEGY

We searched the Cochrane Airways Group Trials Register (January 2008).

SELECTION CRITERIA

Randomised trials in children and adults comparing fluticasone at different nominal daily doses in the treatment of chronic asthma. Two reviewers independently assessed articles for inclusion and methodological quality.

DATA COLLECTION AND ANALYSIS

One review author extracted data. These were checked and verified by a second reviewer. Quantitative analyses where undertaken using Review Manager.

MAIN RESULTS

Fifty-one published and unpublished trials (representing 55 group comparisons, 10,797 participants) met the inclusion criteria. In asthmatics with mild to moderate disease who were not on oral steroids, FP did not exhibit a dose-response effect in the lower dose comparisons in FEV1 (50mcg, 100mcg, 200mcg and 4-500mcg daily). There were no statisitically significant differences between 4-500mcg and 800-1000mcg, and between 50-100 and 800-1000mcg of FP. When 200mcg was compared with 800-1000mcg daily FEV1 favoured the four/five fold increase. For PEF, a dose response was present with FP when low and moderate, and low and high doses of FP were compared. There was no evidence of a dose-response effect on symptoms or rescue beta-2 agonist use. The likelihood of hoarseness and oral candidiasis was significantly greater for the higher doses (800 to 1000 microg/day). People with oral steroid-dependent asthma treated with FP (2000 microg/day) were significantly more likely to reduce oral prednisolone than those on 1000 to 1500 microg/day (Peto odds Ratio 2.8, 95% CI 1.3 to 6.3). The highest dose also allowed a significant reduction in daily oral prednisolone dose compared to 1000 to 1500 microg/day (WMD 2.0 mg/day, 95% CI 0.1 to 4.0 mg/day).

AUTHORS' CONCLUSIONS

We have not found evidence of a pronounced dose response in FEV1 with increasing doses of fluticasone. The number of studies contributing to our primary outcomes was low. At dose ratios of 1:2, there are statistically significant differences in favour of the higher dose in morning peak flow across the low dose range. The clinical impact of these differences is open to interpretation. Patients with moderate disease achieve similar levels of asthma control on medium doses of fluticasone (400 to 500 microg/day) as they do on high doses (800 to 1000 microg/day). More work in severe asthma would help to confirm that doses of FP above 500 microg/day confer greater benefit in this subgroup than doses of around 200 microg/day. In oral corticosteroid-dependent asthmatics, reductions in prednisolone requirement may be gained with FP 2000 microg/day.

The dose-response characteristics of inhaled corticosteroids when used to treat asthma: an overview of Cochrane systematic reviews

Inhaled corticosteroids form the cornerstone of treatment for most patients with asthma. A range of compounds are available with a wide range of prescribable doses. In this overview, we summarize the findings from a number of Cochrane systematic reviews that have examined the relative benefits of different doses of beclometasone dipropionate, budesonide and fluticasone propionate when used to treat children and adults. The key findings are that all inhaled corticosteroids demonstrate a dose-response relationship for efficacy measures, but most of the benefit in mild-to-moderate severity disease is gained in the low-to-moderate dose range of each drug. In this group, high doses of fluticasone lead to small improvements in measures of control at the expense of a steep increase in the incidence of oral side-effects. In patients with severe disease who are dependent on oral steroids, there may be appreciable benefit in reducing oral steroids from very high compared with high doses of fluticasone.

Effects of low doses of inhaled fluticasone propionate on inflammation and remodelling in persistent-mild asthma

In asthma a dysregulation of eosinophil apoptosis and an imbalance of metalloproteinase-9 (MMP-9) and tissue inhibitor metalloproteinase-1 (TIMP-1) play an important role in airway inflammation and remodelling. We evaluated the effects of a low dose of inhaled fluticasone proprionate (FP) (100 microg bid by Diskus) for 4 weeks in 24 steroid naive patients with mild persistent asthma, symptomatic and with a sputum eosinophilia >or=3% on clinical outcomes and inflammatory markers such as the induced sputum eosinophils, the induced sputum apoptotic eosinophils, the levels of MMP-9 and TIMP-1 and their molar ratio in the induced sputum supernatants. After FP treatment forced expiratory volume (FEV1) and FEV1/forced vital capacity values, PEF (L/min), sputum apoptotic eosinophils, and MMP-9/TIMP-1 molar ratio in sputum supernatants of asthmatic subjects were significantly increased in comparison with baseline, while sputum eosinophils significantly decreased. Change (Delta) in FEV1 after treatment with FP negatively correlated with the Delta in sputum eosinophils, while the Delta in MMP-9 values positively correlated with Delta in TIMP-1 values. This study shows that the clinical improvement achieved by the use of low doses of FP in asthmatics is related, at least in part, to the resolution of eosinophilic inflammation and the downregulation of remodelling markers.

The Bradford Hill considerations on causality: a counterfactual perspective

Bradford Hill's considerations published in 1965 had an enormous influence on attempts to separate causal from non-causal explanations of observed associations. These considerations were often applied as a checklist of criteria, although they were by no means intended to be used in this way by Hill himself. Hill, however, avoided defining explicitly what he meant by "causal effect".

This paper provides a fresh point of view on Hill's considerations from the perspective of counterfactual causality. I argue that counterfactual arguments strongly contribute to the question of when to apply the Hill considerations. Some of the considerations, however, involve many counterfactuals in a broader causal system, and their heuristic value decreases as the complexity of a system increases; the danger of misapplying them can be high. The impacts of these insights for study design and data analysis are discussed. The key analysis tool to assess the applicability of Hill's considerations is multiple bias modelling (Bayesian methods and Monte Carlo sensitivity analysis); these methods should be used much more frequently.

Inhaled fluticasone at different doses for chronic asthma in adults and children

BACKGROUND

Inhaled fluticasone propionate (FP) is a high-potency inhaled corticosteroid used in the treatment of asthma.

OBJECTIVES

1. To assess the efficacy and safety outcomes of inhaled fluticasone at different nominal daily doses in the treatment of chronic asthma. 2. To test for the presence of a dose-response effect.

SEARCH STRATEGY

We searched the Cochrane Airways Group Trials Register (January 2005) and reference lists of articles. We contacted trialists and pharmaceutical companies for additional studies and searched abstracts of major respiratory society meetings (1997 to 2004).

SELECTION CRITERIA

Randomised trials in children and adults comparing fluticasone at different nominal daily doses in the treatment of chronic asthma. Two reviewers independently assessed articles for inclusion and methodological quality.

DATA COLLECTION AND ANALYSIS

One reviewer extracted data. These were checked and verified by a second reviewer. Quantitative analyses where undertaken using RevMan (Analyses 1.0.2).

MAIN RESULTS

Forty-three studies (45 data sets with 8913 participants) met the inclusion criteria. Methodological quality was high. In asthmatics with mild to moderate disease who were not on oral steroids a dose-response effect was present with FP for change in morning peak expiratory flow (PEF). For low doses (100 versus 200 microg/day) the weighted mean difference (WMD) was 6.29 litres/min, 95% confidence interval (CI) 2.28 to 10.29. Comparing medium (400 to 500 microg/day) to low dose (200 microg/day) FP the WMD was 6.46 litres/min (95% CI 3.02 to 9.89); this effect was more pronounced in one trial with more severely asthmatic children. For FP 100 versus 400 to 500 microg/day the WMD was 8 litres/min (95% CI 1 to 15) and at high versus low doses (800 to 1000 versus 50 to 100 microg/d) the WMD was 22 litres/min (95% CI 15 to 29). When high and medium doses were compared there was no significant difference in the change in morning PEF: at 400 to 500 versus 800 to 1000 microg/day the WMD was 0.16 litres/min (95% CI 6.95 to 6.63). There was no dose-response effect on symptoms or rescue beta-2 agonist use. The likelihood of hoarseness and oral candidiasis was significantly greater for the higher doses (800 to 1000 microg/day). People with oral steroid-dependent asthma treated with FP (2000 microg/day) were significantly more likely to reduce oral prednisolone than those on 1000 to 1500 microg/day (Peto odds Ratio 2.8, 95% CI 1.3 to 6.3). The highest dose also allowed a significant reduction in daily oral prednisolone dose compared to 1000 to 1500 microg/day (WMD 2.0 mg/day, 95% CI 0.1 to 4.0 mg/day).

AUTHORS' CONCLUSIONS

Effects of fluticasone are dose dependent but relatively small. At dose ratios of 1:2, there are significant differences in favour of the higher dose in morning peak flow across the low dose range. The clinical impact of these differences is open to interpretation. Patients with moderate disease achieve similar levels of asthma control on medium doses of fluticasone (400 to 500 microg/day) as they do on high doses (800 to 1000 microg/day). More work in severe asthma would help to confirm that doses of FP above 500 microg/day confer greater benefit in this subgroup than doses of around 200 microg/day. In oral corticosteroid-dependent asthmatics, reductions in prednisolone requirement may be gained with FP 2000 microg/day.

Effect of montelukast compared with inhaled fluticasone on airway inflammation

BACKGROUND

Inhaled corticosteroids are currently regarded as the gold standard in anti-inflammatory therapy, however, leukotriene receptor antagonists have been ascribed anti-inflammatory properties.

OBJECTIVE

We directly compared the anti-inflammatory effects of inhaled fluticasone propionate (FP, 100 microg Diskus, twice daily) and oral montelukast (MON 10 mg, nocte) in bronchial biopsies of patients with asthma in a double-blind, double-dummy, parallel-group design.

METHODS

Bronchial biopsies, serum and urine samples were collected from 36 atopic asthmatics before and after 8 weeks of treatment. Activated T cells (CD25+), eosinophils (MBP+) and mast cells (tryptase+) were analysed by immunohistochemistry. Serum eosinophil cationic protein (ECP) and IL-5 were analysed by radio and enzyme immunoassay (EIA), respectively. Urinary 9alpha-11beta-PGF2 and leukotriene E4 (LTE4) were measured by EIA.

RESULTS

A comparison of changes from baseline [FP/MON ratio (95% confidence interval)] of activated T cells was not different when subjects were treated with FP compared to treatment with MON [1.00 (0.18-4.86); P=0.924]. Following treatment, mast cells in the FP group were significantly lower than in the group treated with MON [0.39 (0.16-0.97); P=0.041]. There was no difference in the number of eosinophils in the lamina propria following either treatment [0.54 (0.05-2.57); P=0.263]. However, treatment with FP resulted in a significantly greater decrease in serum ECP, compared to treatment with MON [0.37 (0.25-0.71); P=0.002].

CONCLUSIONS

FP appears to be superior to MON as an anti-inflammatory therapy in mild asthmatics.

The dose-response relationship of inhaled corticosteroids in asthma

Inhaled corticosteroids are the only class of asthma medication that can reduce symptoms, improve lung function, reduce the frequency of severe exacerbations, including hospital and ICU admissions, and decrease the risk of mortality. The therapeutic dose range for all clinical outcome measures in adults is 100 to 1000 mg/d of beclomethasone dipropionate or budesonide, or 50 to 500 mg/d of fluticasone propionate. Doses in excess of this range are not recommended for routine use because they are likely to increase the risk of systemic side-effects without further major improvement in efficacy. The recommendations are qualified by the recognition that there is considerable individual variability in the response to inhaled corticosteroids in asthma, which would suggest that some patients might obtain greater benefit at higher doses, just as some might obtain maximum benefit at lower doses.

Categorizing asthma severity: an overview of national guidelines

Asthma is an inflammatory disease of the airways associated with intermittent episodes of bronchospasm. Corticosteroids are the most effective anti-inflammatory class of medication currently available for the treatment of asthma. However, as higher doses of inhaled corticosteroids are used the risks of systemic exposure and side effects will correspondingly increase. Justification of the benefits from higher doses of inhaled corticosteroids can only be made if patients with more severe asthma can be identified. Methods to categorize asthma severity have been introduced in various national asthma management guidelines. Unfortunately, there are substantial conceptual and practical differences among these recommended approaches to asthma severity categorization. Furthermore, these recommended approaches suffer from a focus on features of asthma control, such as symptoms, short-acting beta-agonist use, and lung function rather than actual measures of asthma severity that would encompass markers of airway inflammation. Without the endpoints necessary to assess airway inflammation, current recommendations for asthma severity categorization may lead to systematic under dosing of appropriate anti-inflammatory therapy with subsequent perpetuation of the asthma exacerbation cycle.

[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.

Effect of the addition of montelukast to inhaled fluticasone propionate on airway inflammation

The aim of the study was to investigate the effect of addition of montelukast to inhaled fluticasone propionate (FP) therapy, compared with FP therapy alone (100 microg twice a day) on airway immunopathology in individuals with mild asthma. Twenty-eight subjects received FP (100 microg twice a day) or FP (100 microg twice a day) plus montelukast (10 mg at night) for 8 weeks and were then crossed over to the alternate treatment for a further 8 weeks. Physiological measurements and bronchial biopsies were obtained at +/- 2 days before treatment and +/- 2 days at the end of each treatment period. A two-period crossover analysis was performed and the mean and SE were calculated. There was no significant difference in percent predicted FEV1 (p = 0.51) or PC20 mg/ml (p = 0.81) between the two treatment regimes after 8 weeks of therapy. There was no difference in the efficacy of either treatment in decreasing T cell (p = 0.97), CD45RO+ (p = 0.37), mast cell (p = 0.37), or activated eosinophils (p = 0.55) numbers in bronchial biopsies. There was no significant difference in the percentage area stained for IFN-gamma (p = 0.76) or interleukin-4 (p = 0.61) between treatments. Reduction of inflammatory cell numbers in the bronchial mucosa achieved with FP plus montelukast was not significantly different from the reduction observed with FP alone in individuals with mild asthma.