Efficacy of inhaled fluticasone propionate in asthma results from topical and not from systemic activity

Pharmacological Basis of Differences in Dose Response, Dose Equivalence, and Duration of Action of Inhaled Corticosteroids

INTRODUCTION

Asthma treatment guidelines classify inhaled corticosteroid (ICS) regimens as low, medium, or high dose. However, efficacy and safety are not independently assessed accordingly. Moreover, differences in ICS duration of action are not considered when a dose regimen is selected. We investigated the efficacy and safety implications of these limitations for available ICS molecules.

METHODS

Published pharmacodynamic and pharmacokinetic parameters were used, alongside physiological and pharmacological principles, to estimate the efficacy and safety of available ICS molecules. Extent and duration of glucocorticoid receptor (GR) occupancy in the lung (efficacy) and cortisol suppression (systemic exposure and safety) were estimated.

RESULTS

Some ICS regimens (e.g., fluticasone furoate, fluticasone propionate, and ciclesonide) rank high for efficacy but low for systemic exposure, contrary to how ICS dose equivalence is currently viewed. Differences in dose-response relationships for efficacy and systemic exposure were unique for each ICS regimen and reflected in their therapeutic indices. Notably, even low doses of most ICSs can generate high GR occupancy (≥ 90%) across the entire dose interval at steady state, which may explain previously reported difficulties in obtaining dose responses within the clinical dose range and observations that most clinical benefit typically occurs at low doses. The estimated post dose duration of lung GR occupancy for ICS molecules was categorized as 4-6 h (short), 14-16 h (medium), 25-40 h (long), or > 80 h (ultra-long), suggesting potentially large differences in anti-inflammatory duration of action.

CONCLUSION

In a real-world clinical setting where there may be poor adherence to prescribed therapy, our findings suggest a significant therapeutic advantage for longer-acting ICS molecules in patients with asthma.

The Pharmacokinetics of Inhaled Drugs

The pharmacokinetic (PK) profile of a drug after inhalation may differ quite markedly from that seen after dosing by other routes of administration. Drugs may be administered to the lung to elicit a local action or as a portal for systemic delivery of the drug to its site of action elsewhere in the body. Some knowledge of PK is important for both locally- and systemically-acting drugs. For a systemically-acting drug, the plasma concentration-time profile shares some similarities with drug given by the oral or intravenous routes, since the plasma concentrations (after the distribution phase) will be in equilibrium with concentrations at the site of action. For a locally-acting drug, however, the plasma concentrations reflect its fate after it has been absorbed and removed from the airways, and not what is available to its site of action in the lung. Consequently, those typical PK parameters which are determined from plasma concentration measurements, e.g., area under the curve (AUC), Cmax, tmax and post-peak t1/2 may provide information on the deposition and absorption of drugs from the lung; however, the information from these parameters becomes more complicated to decipher for those drugs which are locally-acting in the lung. Additionally, the plasma concentration profile for both locally- and systemically-acting drugs will not only reflect drug absorbed from the lung but also that absorbed from the gastrointestinal (GI) tract from the portion of the dose which is swallowed. This absorption from the GI tract adds a further complication to the interpretation of plasma concentrations, particularly for locally-acting drugs. The influence of physiological and pathological factors needs to be considered in the absorption of some inhaled drugs. The absorption of some hydrophilic drugs is influenced by the inspiratory maneuver used during initial inhalation of the drug, and at later times after deposition. Similarly, the effects of smoking have been shown to increase lung permeability and increase the absorption of certain hydrophilic drugs. The effects of different disease states of the lung have less defined influences on absorption into the systemic circulation.

May a different kinetic mode explain the high efficacy/safety profile of inhaled budesonide?

The claimed functional basis for ICSs in asthma and COPD is airway selectivity, attained by inhaling a potent, lipophilic compound with long local dissolution/absorption time. The development has been empirically based, resulting in five widely used ICSs. Among them, budesonide (BUD) deviates by being less lipophilic, leading to a more rapid systemic uptake with plasma peaks with some systemic anti-inflammatory activity. By this, BUD fits less well into the current pharmacological dogma of optimal ICS profile. In this review we compared the physicochemical, pharmacological and clinical properties of BUD, fluticasone propionate (FP) and fluticasone furoate (FF), representing different levels of lipophilicity, airway and systemic kinetics, focusing on their long-acting β2-agonist (LABA) combinations, in line with current GINA and GOLD recommendations. We are aware of the differences between formoterol (FORM) and the not rapid acting LABAs such as e.g. salmeterol and vilanterol but our comparisons are based on currently available combination products. A beclomethasone dipropionate (BDP)/FORM combination is also commented upon. Based on clinical comparisons in asthma and COPD, we conclude that the BUD/formoterol (BUD/FORM) combination is as effective and safe as the FP and FF combinations, and is in some cases even better as it can be used as "maintenance plus reliever therapy" (MART) in asthma and as maintenance in COPD. This is difficult to explain by current views of required ICS's/LABAs pharmacokinetic profiles. We propose that BUD achieves its efficacy by a combination of airway and systemic activity. The airway activity is dominating. The systemic activity contributes by plasma peaks, which are high enough for supportive anti-inflammatory actions at the blood and bone marrow levels but not sufficiently long to trigger a similar level of systemic adverse effects. This may be due to BUD's capacity to exploit a systemic differentiation mechanism as programmed for cortisol's various actions. This differentiation prospect can be reached only for an ICS with short plasma half-life. Here we present an alternative mode for an ICS to reach combined efficacy and safety, based on a poorly investigated and exploited physiological mechanism. A preference of this mode is broader versatility, due to that its straighter dose-response should allow a better adaptation to disease fluctuations, and that its rapid activity enables use as "anti-inflammatory reliever".

Fluticasone Particles Bind to Motile Respiratory Cilia: A Mechanism for Enhanced Lung and Systemic Exposure?

Background: Inhaled corticosteroids (ICSs) are the main prophylactic treatment for asthma and are used in other diseases, including chronic pulmonary obstructive disease, yet the interaction of ICS particles with the ciliated epithelium remains unclear. The aim of this study was to investigate the earliest interaction of aerosolized fluticasone propionate (FP) particles with human ciliated respiratory epithelium. Methods: A bespoke system was developed to allow aerosolized FP particles to be delivered to ciliated epithelial cultures by nebulization and from a pressurized metered-dose inhaler (pMDI) through a spacer with interactions observed in real time using high-speed video microscopy. Interaction with nonrespiratory cilia was investigated using steroids on brain ependymal ciliary cultures. The dissolution rate of steroid particles was determined. Results: FP particles delivered by aerosol attached to the tips of rapidly beating cilia. Within 2 hours, 8.7% ± 1.8% (nebulization) and 12.1% ± 2.1% (pMDI through spacer) of ciliated cells had one or more particles attached to motile cilia. These levels decreased to 5.8% ± 1.6% (p = 0.59; nebulization) and 5.3% ± 2.2% (p = 0.14; pMDI through spacer) at 24 hours. Particle attachment did not affect ciliary beat frequency (p > 0.05) but significantly (p < 0.001) reduced ciliary beat amplitude. Steroid particles also attached to the tips of motile ependymal brain cilia and also reduced beat amplitude (24 hours: >2 particles bound p < 0.001). Dissolution of FP particles was slow with only 22.8% ± 1.3% of nebulized and 12.8% ± 0.5% of pMDI-delivered drug dissolving by 24 hours. Conclusions: FP particles adhere to the tips of rapidly moving cilia with significant numbers remaining bound at 24 hours, resisting the shear stress generated by ciliary beating. In vivo, this mechanism may predispose to high local drug concentrations and enhance respiratory and systemic corticosteroid exposure.

Extrafine Versus Fine Inhaled Corticosteroids in Relation to Asthma Control: A Systematic Review and Meta-Analysis of Observational Real-Life Studies

BACKGROUND

The particle size of inhaled corticosteroids (ICSs) may affect airway drug deposition and effectiveness.

OBJECTIVE

To compare the effectiveness of extrafine ICSs (mass median aerodynamic diameter, <2 μm) versus fine-particle ICSs administered as ICS monotherapy or ICS-long-acting β-agonist combination therapy by conducting a meta-analysis of observational real-life asthma studies to estimate the treatment effect of extrafine ICSs.

METHODS

MEDLINE and EMBASE databases were reviewed for asthma observational comparative effectiveness studies from January 2004 to June 2016. Studies were included if they reported odds and relative risk ratios and met all inclusion criteria (Respiratory Effectiveness Group/European Academy of Allergy and Clinical Immunology quality standards, comparison of extrafine ICSs with same or different ICS molecule, ≥12-month follow-up). End-point data (asthma control, exacerbations, prescribed ICS dose) were pooled. Random-effects meta-analysis modeling was used. The study protocol is published in the PROSPERO register CRD42016039137.

RESULTS

Seven studies with 33,453 subjects aged 5 to 80 years met eligibility criteria for inclusion. Six studies used extrafine beclometasone propionate and 1 study used both extrafine beclometasone propionate and extrafine ciclesonide as comparators with fine-particle ICSs. The overall odds of achieving asthma control were significantly higher for extrafine ICSs compared with fine-particle ICSs (odds ratio, 1.34; 95% CI, 1.22-1.46). Overall exacerbation rate ratios (0.84; 95% CI, 0.73-0.97) and ICS dose (weighted mean difference, -170 μg; 95% CI, -222 to -118 μg) were significantly lower for extrafine ICSs compared with fine-particle ICSs.

CONCLUSIONS

This meta-analysis demonstrates that extrafine ICSs have significantly higher odds of achieving asthma control with lower exacerbation rates at significantly lower prescribed doses than fine-particle ICSs.

Regional Ventilation Is the Main Determinant of Alveolar Deposition of Coarse Particles in the Supine Healthy Human Lung During Tidal Breathing

BACKGROUND

To quantify the relationship between regional lung ventilation and coarse aerosol deposition in the supine healthy human lung, we used oxygen-enhanced magnetic resonance imaging and planar gamma scintigraphy in seven subjects.

METHODS

Regional ventilation was measured in the supine posture in a 15 mm sagittal slice of the right lung. Deposition was measured by using planar gamma scintigraphy (coronal scans, 40 cm FOV) immediately postdeposition, 1 hour 30 minutes and 22 hours after deposition of ^99mTc-labeled particles (4.9 μm MMAD, GSD 2.5), inhaled in the supine posture (flow 0.5 L/s, 15 breaths/min). The distribution of retained particles at different times was used to infer deposition in different airway regions, with 22 hours representing alveolar deposition. The fraction of total slice ventilation per quartile of lung height from the lung apex to the dome of the diaphragm at functional residual capacity was computed, and co-registered with deposition data-apices aligned-using a transmission scan as reference. The ratio of fractional alveolar deposition to fractional ventilation of each quartile (r) was used to evaluate ventilation and deposition matching (r > 1, regional aerosol deposition fraction larger than regional ventilation fraction).

RESULTS

r was not significantly different from 1 for all regions (1.04 ± 0.25, 1.08 ± 0.22, 1.03 ± 0.17, 0.92 ± 0.13, apex to diaphragm, p > 0.40) at the alveolar level (r_22h). For retention times r_0h and r_1h30, only the diaphragmatic region at r_1h30 differed significantly from 1.

CONCLUSIONS

These results support the hypothesis that alveolar deposition is directly proportional to ventilation for ∼5 μm particles that are inhaled in the supine posture and are consistent with previous simulation predictions that show that convective flow is the main determinant of aerosol transport to the lung periphery.

Pharmacodynamic and pharmacokinetic considerations in choosing an inhaled corticosteroid

Inhaled corticosteroids are effective in controlling airway inflammation. Their anti-inflammatory effect is primarily topical, at the site of deposition in the airways. Consequently, traditional pharmacodynamic and pharmacokinetic concepts, which rely on measuring blood concentrations of drug, have limited applicability for evaluating the efficacy of topically acting inhaled corticosteroids. Important factors affecting efficacy of inhaled corticosteroids are: (i) intrinsic properties of the drugs, particularly their affinity for the corticosteroid receptor; and (ii) the newer pharmacodynamic concept of deposition characteristics of the drug formulation. Small particle formulations, especially those developed in the metered-dose inhaler with the new hydrofluoroalkane propellant, deposit to a much greater extent in the lung and may consequently have improved clinical efficacy. Lipid conjugation of inhaled corticosteroids within the lung may allow prolonged duration of effect, enabling once-daily administration. Pharmacodynamic and pharmacokinetic principles probably do not play a role in describing upper airway adverse effects occurring with inhaled corticosteroids. These are probably also determined by intrinsic properties of the drug and deposition characteristics. However, pharmacodynamic and pharmacokinetic principles seem to be important in addressing systemic safety concerns with inhaled corticosteroids. Those inhaled corticosteroids with a longer serum half-life, especially if they have higher affinity for the corticosteroid receptor, may be associated with greater systemic effects. A new pharmacokinetic concept suggests that increased protein binding within the systemic circulation and high systemic clearance of an inhaled corticosteroid may reduce the risk for systemic effects. These new pharmacodynamic and pharmacokinetic concepts provide a useful framework for identifying the characteristics of an inhaled corticosteroid with an improved benefit-to-risk profile. Increased lung deposition and reduced deposition in the upper airway should result in an inhaled corticosteroid with favorable clinical efficacy and a decreased risk for topical upper airway adverse effects. An inhaled corticosteroid with high plasma protein binding and rapid clearance might pose much less risk for systemic adverse effects than currently available drugs in this class.

Cortisol response to acute stress in asthma: Moderation by depressive mood

Both individuals with asthma and depression show signs of a dysregulated hypothalamus-pituitary-adrenal axis. However, little is known about the cortisol response to stress in the context of co-occurring asthma and depressive mood. Thirty-nine individuals with asthma and 41 healthy controls underwent a combined speech and mental arithmetic stressor. During the course of the laboratory session, salivary cortisol was collected 5 times, with 1 sample at 0min before the stressor and 4 samples at 0, 15, 30 and 45min after the stressor. Depressive mood in the past week was assessed with the Hospital Anxiety and Depression Scale at the beginning of the session. Depressive symptoms moderated cortisol response to the acute stressor, but only among asthmatic patients. Higher depressive mood was associated with a significant increase in cortisol, whereas low depressive mood was associated with no cortisol response. In healthy participants, depressive mood had no substantial effect on cortisol response to the stressor. These findings suggest that depressive mood and chronic inflammatory diseases such as asthma can interact to augment cortisol response to stress.

Effect of common comparators in indirect comparison analysis of the effectiveness of different inhaled corticosteroids in the treatment of asthma

Purpose

Indirect comparison (IC) and direct comparison (DC) of four inhaled corticosteroid (CS) treatments for asthma were conducted, and the factors that may influence the results of IC were investigated. Among those factors, we focused on the effect of common comparator selection in the treatment of asthma, where little control group bias or placebo effect is expected.

Method

IC and DC were conducted using the change from baseline in forced expiratory volume in 1 s (FEV1(L)) as an outcome parameter. Differences between inhaled CS were evaluated to compare the results of IC and DC. As a common comparator for IC, placebo (PLB) or mometasone (MOM) was selected. Whether the results of IC are affected by the selection of a common comparator and whether the results of IC and DC are consistent were examined.

Results

23 articles were identified by a literature search. Our results showed that ICs yielded results similar to DCs in the change from baseline of FEV1(L). No statistically significant difference was observed in inconsistency analysis between ICs and DCs. It was clinically and statistically confirmed that ICs with PLB and those with MOM did not differ in terms of the results of FEV1(L) analysis in this dataset.

Conclusion

This study demonstrated that ICs among inhaled CS can deliver results consistent with those of DCs when using the change from baseline in FEV1(L) as an outcome parameter in asthma patients. It was also shown that using an active comparator has similar results if there is no effect of control group bias. It should be emphasized that the investigation of control group bias is a key factor in conducting relevant ICs so that an appropriate common comparator can be selected.

Asthma pharmacotherapy

Asthma is a chronic inflammatory disease of the airway that leads to airway obstruction via bronchoconstriction, edema, and mucus hypersecretion. The National Asthma Education and Prevention Program has outlined evidence-based guidelines to standardize asthma therapy and improve outcomes. The initial recommendation of choice for persistent asthmatic patients is an inhaled corticosteroid (ICS). Long-acting beta-2 agonists in combination with ICS, oral corticosteroids, leukotriene modifiers, and anti-IgE therapeutic options can be considered for patients with persistent or worsening symptoms. Many novel therapies are being developed, with an emphasis on anti-inflammatory mechanisms, gene expression, and cytokine modification.

Asthma outcomes and costs of therapy with extrafine beclomethasone and fluticasone

BACKGROUND

Characteristics of inhaled corticosteroids (ICSs) differ, but data comparing the real-life effectiveness of various ICSs for asthma are lacking.

OBJECTIVE

We sought to compare real-life asthma outcomes and costs of extrafine hydrofluoroalkane (HFA)-beclomethasone and fluticasone administered through a pressurized metered-dose inhaler.

METHODS

This retrospective matched cohort study examined database markers of asthma control from a large US longitudinal health care claims database over 1 baseline and 1 outcome year for 10,312 patients with asthma aged 12 to 80 years receiving their first ICS as HFA-beclomethasone or fluticasone and matched on baseline demographic characteristics and asthma severity.

RESULTS

Patients started on HFA-beclomethasone had significantly higher odds (adjusted odds ratio, 1.19; 95% CI; 1.08-1.31) of achieving overall control (risk and impairment), which was defined as no hospital attendance for asthma, oral corticosteroids, or antibiotics for lower respiratory tract infection and less than 2 puffs per day of short-acting β-agonist; they also experienced a lower rate of respiratory-related hospitalizations or referrals (adjusted rate ratio, 0.82; 95% CI, 0.73-0.93) than patients started on fluticasone. Other database outcome measures were similar in the 2 cohorts. Prescribed HFA-beclomethasone doses were lower (P < .001) than fluticasone doses (median, 320 μg/d [interquartile range, 160-320 μg/d] vs 440 μg/d [interquartile range, 176-440 μg/d]). Adjusted respiratory-related health care costs were significantly lower for HFA-beclomethasone than fluticasone (mean, $1869 [95% CI, $1727-$2032] vs $2259 [95% CI, $2111-$2404]), representing a mean annual savings of $390 (95% CI, $165-$620) per patient prescribed HFA-beclomethasone rather than fluticasone.

CONCLUSIONS

Asthma treatment outcomes were similar or better with HFA-beclomethasone prescribed at significantly lower doses and with lower costs than fluticasone.

Glucocorticoids enhance airway epithelial barrier integrity

Asthma is a chronic inflammatory disorder of the airways, but its pathogenesis is incompletely understood. While asthma is a complex disease caused by multiple factors, epithelial barrier damage is a cardinal feature. Glucocorticoids (GCs) are the most effective anti-inflammatory drugs in the treatment of asthma. However, the effects of GCs on the airway epithelial barrier have not been evaluated. Epithelial barrier functions were evaluated in cultured human airway epithelial cell monolayers, Calu-3 and 16HBE. Then, the cells were treated with dexamethasone (Dex), fulticasone propionate (FP), or budesonide (BD) for 5 days. Permeability measured by transepithelial electrical resistance was increased by treatment with Dex, FP, and BD in a dose-dependent manner. Permeability to fluorescein isothiocyanate-labeled dextran was markedly reduced by these treatments. Immunocytostaining revealed that Dex treatment potentiated tight junction formation in these polarized epithelial cells. Knockdown of epidermal growth factor receptor (EGFR) by small interference RNA blunted the effects of Dex on barrier integrity. Although EGFR expression was not affected by Dex treatment, EGFR phosphorylation was enhanced in Dex-treated cells. This is suggesting that EGFR are important for this phenomenon. These findings suggest that GC inhalation therapy can improve epithelial barrier integrity and might contribute to the therapeutic effects of GCs for treating asthma.

What is the potential for inhaled p38 inhibitors in the treatment of chronic obstructive pulmonary disease?

p38 has been an intensely studied therapeutic target in the pharmaceutical industry. With more than 20 compounds entering human trials, none have progressed beyond Phase II to the best of our knowledge. The transient efficacy seen in many of the Phase II trials has raised some concerns for the future potential of this target, particularly in rheumatoid arthritis. With this caveat, there is good evidence for p38 inhibition to be efficacious in chronic obstructive pulmonary disease and there are now several oral compounds currently in development for this disease, with encouraging data beginning to emerge. With an inhaled agent likely to improve the therapeutic window between efficacy and some of the common adverse events observed with oral p38 inhibitors it would seem a sensible approach to take for a disease of the lung. This review will highlight the potential for an inhaled p38 inhibitor in chronic obstructive pulmonary disease, as well as some of the design principles that are important to consider when developing an inhaled kinase inhibitor.

Asthma control with extrafine-particle hydrofluoroalkane-beclometasone vs. large-particle chlorofluorocarbon-beclometasone: a real-world observational study

BACKGROUND

The extrafine-particle formulation of hydrofluoroalkane-beclometasone (EF HFA-BDP; Qvar®) demonstrates improved total and small airway deposition compared with large-particle chlorofluorocarbon (CFC)-BDP. In some short-term studies, EF HFA-BDP provides greater effects on lung function than CFC-BDP, and hence is recommended to be prescribed at a lower dose, but whether there are differences in asthma outcomes during long-term treatment is unknown.

OBJECTIVE

To compare the effectiveness of EF HFA-BDP vs. CFC-BDP over 1 year.

METHODS

This retrospective matched cohort study examined outcomes in a large primary care database for patients aged 5-60 years with asthma receiving their first inhaled corticosteroid (ICS) prescription (initiation population) or first ICS dose increase (step-up population) by a pressurized metered-dose inhaler (pMDI) as EF HFA-BDP or CFC-BDP. Patients were matched on baseline demographic and asthma severity measures in EF HFA-BDP:CFC-BDP ratios of 1:3 and 1:2 for initiation and step-up populations, respectively. Step-up patients were matched also on ICS dose during a baseline year. Co-primary endpoints were asthma control (composite measure comprising no recorded hospital attendance for asthma, oral corticosteroids, or antibiotics for lower respiratory infection) and exacerbation rate during the outcome year.

RESULTS

For the initiation population (EF HFA-BDP n=2882; CFC-BDP n=8646), adjusted odds of achieving asthma control with EF HFA-BDP vs. CFC-BDP was 1.15 (95% CI 1.02-1.28). For the step-up population (n=258 and 516), adjusted odds of asthma control with EF HFA-BDP was 1.72 (95% CI 1.14-2.56). EF HFA-BDP was prescribed at a median dose half that of CFC-BDP.

CONCLUSION AND CLINICAL RELEVANCE

During 1 year after initiating or stepping up ICS therapy by pMDI, patients who received EF HFA-BDP were more likely to achieve asthma control than those receiving CFC-BDP. These findings suggest that ICS formulation, particle size, and deposition characteristics play important roles in real-life effectiveness of asthma therapy. This study shows that an EF-particle formulation of beclometasone can be used at half the dose of the large-particle formulation with at least as good clinical outcomes.

Particle size of inhaled corticosteroids: does it matter?

A question with respect to asthma therapy revolves around the issue of whether better efficacy occurs with an ultrafine-particle inhaled corticosteroid because of better lung deposition into the distal airways. This article reviews particle size and delivery devices of different steroids, clinical outcomes of small- versus large-particle steroids, and the issue of pharmacoeconomics.

Fluticasone versus placebo for chronic asthma in adults and children

BACKGROUND

Inhaled fluticasone propionate (FP) is a relatively new inhaled corticosteroid for the treatment of asthma.

OBJECTIVES

To assess efficacy and safety outcomes in studies that compared FP to placebo for treatment of chronic asthma.

SEARCH STRATEGY

We searched the Cochrane Airways Group Specialised Register (January 2008), reference lists of articles, contacted trialists and searched abstracts of major respiratory society meetings (1997-2006).

SELECTION CRITERIA

Randomised trials in children and adults comparing FP to placebo in the treatment of chronic asthma. Two reviewers independently assessed articles for inclusion and risk of bias.

DATA COLLECTION AND ANALYSIS

Two review authors extracted data. Quantitative analyses were undertaken using Review Manager software.

MAIN RESULTS

Eighty-six studies met the inclusion criteria, recruiting 16,160 participants. In non-oral steroid treated asthmatics with mild and moderate disease FP resulted in improvements from baseline compared with placebo across all dose ranges (100 to 1000 mcg/d) in FEV1 (between 0.1 to 0.43 litres); morning PEF (between 23 and 46 L/min); symptom scores (based on a standardised scale, between 0.44 and 0.7); reduction in rescue beta-2 agonist use (between 1 and 1.4 puffs/day). High dose FP increased the number of patients who could withdraw from prednisolone: FP 1000-1500 mcg/day Peto Odds Ratio 14.07 (95% CI 7.17 to 27.57). FP at all doses led to a greater likelihood of sore throat, hoarseness and oral Candidiasis.

AUTHORS' CONCLUSIONS

Doses of FP in the range 100-1000 mcg/day are effective. In most patients with mild-moderate asthma improvements with low dose FP are only a little less than those associated with high doses when compared with placebo. High dose FP appears to have worthwhile oral-corticosteroid reducing properties. FP use is accompanied by an increased likelihood of oropharyngeal side effects.

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.

Impact of inhaled corticosteroids on cortisol suppression in adults with asthma: a quantitative review

BACKGROUND

Studies examining the effects of inhaled corticosteroids (ICSs) on cortisol suppression show inconsistent results, and there is uncertainty regarding the dose-response relationship between ICSs and cortisol suppression.

OBJECTIVE

To determine, using meta-analysis, the extent of cortisol suppression after administration of clinically relevant ICS doses in adults with asthma.

METHODS

Database searches (MEDLINE, EMBASE, and The Cochrane Library) using appropriate indexed terms were performed to identify eligible articles for review. Articles reporting the effects of ICSs on cortisol levels in asthmatic adults, measured using the cumulative serum or plasma cortisol, morning serum or plasma cortisol, or cumulative overnight urinary free cortisol method, were identified. All available cortisol measurements were extracted. Cortisol suppression was estimated, and treatment arms were grouped into low-, medium-, and high-dose ranges according to the Global Initiative for Asthma guidelines. A multivariate model was used to determine relationships between ICS dose and cortisol suppression and to explore sources of heterogeneity among trials.

RESULTS

Thirty-one studies providing information on 216 measures of cortisol suppression were included in this meta-analysis. Cortisol suppression in the low-, medium-, and high-dose groups were estimated to be 17.92% (95% confidence interval [CI], 11.08%-24.77%), 26.55% (95% CI, 17.29%-35.80%), and 36.31% (95% CI, 26.48%-46.13%), respectively.

CONCLUSIONS

Statistically significant cortisol suppression was evident at low doses of ICSs and increased with dose. These results support an impact of all ICSs on endogenous cortisol levels and underscore the importance of titrating ICS doses to the minimum required to maintain symptom control.

Do airway clearance mechanisms influence the local and systemic effects of inhaled corticosteroids?

The role of airway clearance in inhaled drug therapy is complex. Disease-induced bronchoconstriction results in a central drug-deposition pattern where mucociliary clearance is most efficient. When drug-induced bronchodilation is achieved, deposition and uptake becomes more peripheral, and because there is less mucociliary clearance in the periphery, this will lead to an unintentional increase in lung exposure and enhance the risk of systemic side effects. In addition, mucociliary clearance is pathologically reduced in both asthma and chronic obstructive pulmonary disease. Among inhaled corticosteroids, rate of dissolution and lung uptake differs considerably. For the slowly dissolving, lipophilic steroids, the contribution of mucociliary clearance to these findings appears significant, and variability in lung and systemic exposure resulting from variable mucociliary function appears to be amplified. In addition, dose optimisation of non-stable asthma becomes more complex. The present review highlights the impact of mucociliary clearance on inhaled corticosteroid disposition and identifies critical areas where more research is needed.

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.

Fluticasone versus placebo for chronic asthma in adults and children

BACKGROUND

Inhaled fluticasone propionate (FP) is a relatively new inhaled corticosteroid for the treatment of asthma.

OBJECTIVES

1. To assess efficacy and safety outcomes in studies that compared FP to placebo for treatment of chronic asthma.2. To explore the presence of a dose-response effect.

SEARCH STRATEGY

We searched the Cochrane Airways Group Specialised Register (January 2005), reference lists of articles, contacted trialists and searched abstracts of major respiratory society meetings (1997-2004).

SELECTION CRITERIA

Randomised trials in children and adults comparing FP to placebo in the treatment of chronic asthma. Two reviewers independently assessed articles for inclusion and methodological quality.

DATA COLLECTION AND ANALYSIS

Two reviewers extracted data. Quantitative analyses were undertaken using RevMan 4.2

MAIN RESULTS

Seventy-five studies met the inclusion criteria (14,208 participants). Methodological quality was high. In non-oral steroid treated asthmatics with mild and moderate disease FP resulted in improvements from baseline compared with placebo across all dose ranges (100 to 1000 mcg/d) in FEV1 (between 0.13 to 0.45 litres); morning PEF (between 23 and 47 L/min); symptom scores (based on a standardised scale, between 0.5 and 0.85); reduction in rescue beta-2 agonist use (between 1.2 and 2.2 puffs/day). High dose FP increased the number of patients who could withdraw from prednisolone: FP 1000-1500 mcg/day Peto Odds Ratio 14.07 (95% CI 7.17 to 27.57). FP at all doses led to a greater likelihood of sore throat, hoarseness and oral Candidiasis. Twenty-one patients would need to be treated for one extra to develop Candidiasis (FP 500 mcg/day), whilst only three or four patients need to be treated to avoid one extra patient being withdrawn due to lack of efficacy at all doses of FP.

AUTHORS' CONCLUSIONS

Doses of FP in the range 100-1000 mcg/day are effective. In most patients with mild-moderate asthma improvements with low dose FP are only a little less than those associated with high doses when compared with placebo. High dose FP appears to have worthwhile oral-corticosteroid reducing properties. FP use is accompanied by an increased likelihood of oropharyngeal side effects.

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.

Biological availability of inhaled fluticasone propionate in horses

Healthy horses received aerosolised, intranasal or oral doses of 3 mg of fluticasone propionate evenly divided over morning and evening treatments for seven days. The bioavailability of the drug was determined in terms of the suppression of the endogenous cortisol concentrations in the horses during the period of treatment. The horses which received the aerosolised drug had significantly lower concentrations of endogenous cortisol on days 5 and 8 than the horses which received aerosolised placebo. The horses which received nasal and oral doses of fluticasone propionate showed no significant changes in their endogenous cortisol concentrations.

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.

Fluticasone propionate and mometasone furoate have equivalent transcriptional potencies

BACKGROUND

Glucocorticoids exert their anti-inflammatory effects mainly through transrepression of the transcription factors activator protein-1 (AP-1) and nuclear factor-kappa B (NF-kappaB). Certain adverse effects of glucocorticoids are mediated through gene transactivation. Fluticasone propionate (FP) and mometasone furoate (MF) are the most recently developed topical glucocorticoids for the treatment of airway disorders. Their relative capacities to repress AP-1 and NF-kappaB activities are not known and comparison of their transactivation potencies has given unclear results.

OBJECTIVE

To determine the relative transactivation and transrepression potencies of FP and MF.

METHODS

Transactivation assays were performed in HeLa cells carrying a glucocorticoid-inducible luciferase gene. To measure transrepressive potencies of FP and MF, A549 lung epithelial cells were transiently transfected with an AP-1- or NF-kappaB-dependent luciferase gene. Using an immunoassay, we also evaluated the ability of MF and FP to inhibit the production of Regulated upon Activation, Normal T-cell Expressed and Secreted (RANTES), a pro-inflammatory cytokine, whose gene is controlled by AP-1 and NF-kappaB. Areas under the dose-response curve were calculated to determine relative potencies.

RESULTS

FP and MF are equipotent for transactivation. Both molecules show globally the same potency to inhibit AP-1 and NF-kappaB activities and RANTES production. MF and FP have very significant transcriptional effects at 2x10(-10) M, which is the peak concentration reached in the plasma after inhalation of high dosages. Indeed, they produce a 17-fold induction of luciferase in the transactivation assay, and inhibit AP-1 activity, NF-kappaB activity and RANTES release by approximately 40%.

CONCLUSION

FP and MF have the same ability to trigger gene activation and also the same potency to inhibit AP-1 and NF-kappaB activities. Their strong transcriptional effects at 2x10(-10) M suggest that these compounds act not only topically but also systemically, with the risk of provoking concomitant adverse effects at high dosages.

Dosage regimens for inhaled therapy in children should be reconsidered

In current asthma guidelines, dosage regimens for inhalation therapy in children are based on adult doses and are generally titrated per kilogram of bodyweight or per square metre of body surface area. However, these recommendations do not correspond well with current knowledge of aerosol therapy in childhood. Lung deposition of the aerosolised drug is the key determinant for clinical efficacy and for systemic side effects of inhalation therapy. Lung deposition increases with age, whereas lung deposition expressed as a percentage per kilogram bodyweight is age-independent. This finding is explained by the self-regulating effect of age-dependent airway anatomy on lung deposition. Therefore, it is more likely that adult doses translate into paediatric doses only by virtue of the differences in self-limiting pulmonary deposition when using the same absolute nominal doses of the medication. Adapting the adult dose to a paediatric dose calculated on body size might be unnecessary and could lead to insufficient pulmonary deposition of medication. These findings suggest that dosage regimens for inhalation therapy for children may have to be reconsidered, and should be determined from dose-ranging studies rather than calculated from adult doses based on body size.

Dose-response relation of inhaled fluticasone propionate in adolescents and adults with asthma: meta-analysis

OBJECTIVE

To examine the dose-response relation of inhaled fluticasone propionate in adolescents and adults with asthma.

DESIGN

Meta-analysis of placebo controlled, randomised clinical trials that presented data on at least one outcome measure of asthma and that used at least two different doses of fluticasone.

SETTING

Medline, Embase, and GlaxoWellcome's internal clinical study registers.

MAIN OUTCOME MEASURES

FEV(1), morning and evening peak expiratory flow, night awakenings, beta agonist use, and major exacerbations.

RESULTS

Eight studies, with 2324 adolescents and adults with asthma, met the inclusion criteria. Data on doses of >500 microg/day were limited. The dose-response curve for the raw data began to reach a plateau at around 100-200 microg/day and peaked by 500 microg/day. A negative exponential model for the data, without meta-analysis, indicated that 80% of the benefit at 1000 microg/day was achieved at doses of 70-170 microg/day and 90% by 100-250 microg/day. A quadratic meta-regression showed that the maximum achievable efficacy was obtained by doses of around 500 microg/day. The odds ratio for patients remaining in a study at a dose of 200 microg/day, compared with higher doses, was 0.73 (95% confidence interval 0.49 to 1.08). Comparison of the standardised difference in FEV(1 )for an inhaled dose of 200 microg/day against higher doses showed a difference in FEV(1) of 0.13 of a standard deviation (-0.02 to 0.29).

CONCLUSIONS

In adolescent and adult patients with asthma, most of the therapeutic benefit of inhaled fluticasone is achieved with a total daily dose of 100-250 microg, and the maximum effect is achieved with a dose of around 500 microg/day. However, these findings were limited by the lack of data on individual patients and by the paucity of dose-response studies that included doses of >500 microg/day.

Optimizing drug delivery to the lung: design of a CFC-free corticosteroid metered-dose aerosol system

The mandatory replacement of chlorofluorocarbons (CFCs) with ozone-friendly propellants, such as hydrofluoroalkanes (HFAs), has provided an opportunity to optimize aerosol design and improve drug delivery to pulmonary tissue. Asthma is an inflammatory disorder of the lungs that appears to affect both small and large airways, so ideally, inhaled corticosteroid should reach both central and peripheral sites. This review considers the development of an aerosol system containing beclomethasone dipropionate in hydrofluoroalkane-134a (HFA) propellant (Qvar, 3M Health Care, Loughborough, UK) designed to target medication delivery throughout the bronchopulmonary tree and to improve the therapeutic ratio (topical efficacy: systemic safety), thereby offering potential clinical benefits to asthma patients.

Fluticasone propionate versus zafirlukast: effect in patients previously receiving inhaled corticosteroid therapy

BACKGROUND

The use of inhaled corticosteroids compared with leukotriene modifying drugs in the treatment of persistent asthma has not been extensively studied.

OBJECTIVE

To compare the efficacy and safety of a low dose of fluticasone propionate (FP) and zafirlukast in patients previously maintained on inhaled corticosteroids.

METHODS

Patients (> or = 12 years old; FEV1 = 60% to 85% of predicted) with persistent asthma who were previously treated with low doses of triamcinolone acetonide (TAA) 400 to 800 microg/day or beclomethasone dipropionate (BDP) 168 to 336 microg/day were randomized to treatment with FP aerosol 88 microg BID (FP, n = 221) or zafirlukast 20 mg BID (n = 216) over 6 weeks.

RESULTS

Treatment with FP significantly increased the mean change at endpoint (the last post-baseline observation) in FEV1 (0.22 L versus 0.03 L, P < .001), morning PEF (17.8 versus 3.1 L/min, P = .004), evening PEF (16.7 versus 2.6 L/min, P = .002), the percentage of symptom-free days (16.2 versus 7.1%, P = .007), and the percentage of rescue-free days (23.4 versus 9.3%, P < .001), and significantly decreased rescue albuterol use (-0.66 puffs/day versus an increase of 0.27 puffs/day, P < .001) and combined symptom scores (-0.13 versus an increase of 0.08, P < .001) compared with zafirlukast. Treatment with FP maintained the percentage of awakening-free nights (-1.0 +/- 1.0); in contrast, treatment with zafirlukast reduced the percentage of awakening-free nights (-9.0 +/- 1.6, P < .001). A clinically meaningful difference (change of > or = 0.5; P < .001) was observed between FP and zafirlukast in the Asthma Quality of Life Questionnaire (AQLQ) global score and for each domain score except activity limitation (change of 0.3, P < .001). Significantly more patients in the zafirlukast group experienced an asthma exacerbation (n = 14) compared with FP-treated patients (n = 5, P = .035). Patients in the zafirlukast group were significantly more likely to be withdrawn due to lack of efficacy (P < .001).

CONCLUSION

Switching patients from low doses of inhaled corticosteroids to a lower total microgram dose of FP improves pulmonary function, asthma symptoms, and quality of life, while switching to the leukotriene receptor antagonist zafirlukast may result in worsening of asthma control. This was indicated by the significant number of zafirlukast-treated patients who were dropped from the study due to lack of efficacy within 6 weeks of discontinuing inhaled corticosteroids.

Efficacy and safety of dry powder fluticasone propionate in children with persistent asthma

BACKGROUND

Flovent Diskus is a powder formulation of the inhaled corticosteroid fluticasone propionate (FP) delivered via a breath-actuated, multidose inhaler.

OBJECTIVE

To determine the efficacy and safety of dry powder FP administered once or twice daily (200 microg per day) to children with persistent asthma.

METHODS

Twelve-week, randomized, double-blind, placebo-controlled, multicenter trial with a 52-week, open-label extension. Children aged 4 to 11 were required to have pulmonary function 50% to 85% of predicted values. The population was stratified for baseline therapy (inhaled corticosteroid/cromolyn or bronchodilators only). After a 2-week placebo run-in, 242 patients received dry powder FP 200 microg each morning, dry powder FP 100 microg BID, or placebo for 12 weeks; 192 were rerandomized to the QD or BID regimen for an additional 52 weeks of open-label treatment. Primary endpoints were mean changes in FEV1 and morning PEF recorded at clinic visits.

RESULTS

Both dry powder FP regimens significantly improved FEV1, evening PEF, and asthma symptoms at the double-blind phase endpoint (P < or = .017 compared with placebo). The BID regimen also significantly improved morning PEF and nighttime awakenings due to asthma (P < or = .005). Among patients previously treated with inhaled corticosteroids/cromolyn, improvements observed with the QD and BID regimens were similar. Patients switched from BID to open-label QD treatment showed additional improvements at week 52 generally comparable to patients who received the BID regimen during both phases. Fluticasone propionate was well tolerated for up to 64 weeks with few reports of drug-related adverse events or morning plasma cortisol abnormalities.

CONCLUSIONS

Once daily dosing of dry powder FP 200 microg is an effective and convenient alternative for children whose asthma is controlled with a more frequent dosing regimen of inhaled corticosteroids.

Fluticasone propionate: a potent inhaled corticosteroid for the treatment of asthma

Fluticasone propionate (FP) is a potent inhaled corticosteroid (ICS) for the treatment of asthma. It is currently marketed in both the United States (as Flovent) and Europe (as Flixotide). Fluticasone is available in both aerosolised metered dose inhaler (MDI) and dry powder devices, with dosages ranging from 44-500 micrograms/puff. FP has been extensively studied in both children and adults; efficacy has been documented across the entire spectrum of asthma severity, including corticosteroid-dependent disease. Clinical data with FP strongly corroborates the in vitro pharmacokinetic and pharmacodynamic studies that FP is at least twice as potent as beclomethasone dipropionate (BDP), budesonide (BUD) or triamcinolone acetonide (TAA). Both objective (lung function) and subjective (symptoms, beta-agonist use and quality of life) outcomes are improved with FP treatment. Extensive post-marketing surveillance with FP suggests that it is more cost-effective than BUD and flunisolide (FLU) when analysed by an overall healthcare cost perspective. Most of the benefits arise from decreased hospitalizations, emergency room visits and physician-office visits. Extensive safety data with FP documents no clinically meaningful effects on bone mass, nor impairment of growth velocity in children. Considering the efficacy and safety data along with the ability to optimise patient's asthma therapy using the delivery devices and strengths available, FP has become a leader in the ICS marketplace to date.

Commentary on the FDA draft guidance for bioequivalence studies for nasal aerosols and nasal sprays for local action: an industry view

In June 1999, the Food and Drug Administration issued draft guidance for bioequivalence studies for nasal aerosols and nasal sprays for local action. The purpose of this opinion paper is to highlight the need for a balanced scientific debate before this guidance is used by underscoring the areas in the document that are in opposition to prevailing scientific understanding.

Comparison of once- and twice-daily dosing of fluticasone propionate 200 micrograms per day administered by diskus device in patients with asthma treated with or without inhaled corticosteroids

BACKGROUND

There are limited published data regarding the efficacy of once- versus twice-daily administration of flutica-sone propionate.

OBJECTIVE

Our purpose was to evaluate the effectiveness of fluticasone propionate powder 200 microg/d administered as a once- or twice-daily dosage regimen in patients who were currently being treated with bronchodilators only (BD patients) and in patients who required inhaled corticosteroids for maintenance treatment of asthma (ICS patients).

METHODS

Five hundred seventy patients were randomly assigned to receive one of the following inhaled treatments through the Diskus device (Glaxo Wellcome, Research Triangle Park, NC) for 12 weeks: fluticasone propionate 100 microg twice daily (FP100BID) or 200 microg once daily (FP200QD) or placebo.

RESULTS

BD patients treated with FP100BID, FP200QD, and placebo had mean increases in FEV(1) from baseline to end point of 0. 49 L, 0.37 L, and 0.21 L, respectively (P <.001, FP100BID vs placebo; P =.05, FP200QD vs placebo). ICS patients treated with FP100BID and FP200QD had mean increases in FEV(1) of 0.27 L and 0.11 L, respectively, compared with a decrease in FEV(1) of -0.08 L with placebo (P <.001, FP100BID vs placebo; P =.023, FP200QD vs placebo). BD patients treated with FP100BID and FP200QD had mean increases in morning peak expiratory flow from baseline to end point of 31 L/min and 27 L/min, respectively, compared with a 1 L/min increase in patients treated with placebo. ICS patients treated with FP100BID had a mean increase in morning peak expiratory flow (from baseline to end point) of 18 L/min compared with mean decreases of -3 L/min and -12 L/min in the FP200QD and placebo groups, respectively. More patients were withdrawn from placebo (26% and 48%, in BD and ICS patients, respectively) than from fluticasone propionate (7%-9% [BID-QD] and 18%-32% [BID-QD], in BD and ICS patients, respectively) because of failure to meet predetermined asthma stability criteria.

CONCLUSION

The efficacies of FP100BID and FP200QD were comparable with regard to improvement in pulmonary function and asthma stability in BD patients. In ICS patients, asthma control was maintained with FP200QD, whereas FP100BID provided greater improvements in pulmonary function and asthma stability.

Pharmacokinetic differences between chlorofluorocarbon and chlorofluorocarbon-free metered dose inhalers of beclomethasone dipropionate in adult asthmatics

We have compared the serum pharmacokinetics of the metabolites of beclomethasone dipropionate after inhalation from chlorofluorocarbon (CFC) and hydrofluoroalkane HFA-134a (HFA) formulations in asthmatic patients. Twenty-three patients completed this open-label, randomized, single-dose, three-period crossover study. Each patient received in separate periods 200 microg or 400 microg HFA-beclomethasone dipropionate, or 400 microg CFC-beclomethasone dipropionate. Venous blood samples were collected over 24 h for the determination of beclomethasone esters and beclomethasone in the serum. Significant differences in pharmacokinetics following HFA- and CFC-beclomethasone dipropionate were observed. Following a 400 microg beclomethasone dipropionate dose, the HFA formulation gave mean maximum concentrations (Cmax) and area under the curve (AUC) values of beclomethasone esters of 1153 pg mL(-1) and 4328 pg h mL(-1), respectively, and beclomethasone Cmax and AUC values of 69 pg mL(-1) and 682 pg h mL(-1), respectively. These values were approximately 2-3-fold those seen with the CFC formulation (beclomethasone esters Cmax and AUC of 380 pg mL(-1) and 1764 pg h mL(-1), respectively; beclomethasone Cmax and AUC of 41 pg ml(-1) and 366 pg h mL(-1), respectively). Beclomethasone esters, the major component of beclomethasone dipropionate in the serum, peaked significantly earlier for the HFA formulation (0.8 h) than for the CFC formulation (2 h). Tests for dose proportionality of beclomethasone esters pharmacokinetics following HFA-beclomethasone dipropionate showed that the two hydrofluoroalkane strengths were proportional. The more rapid and greater efficiency of systemic drug delivery of the HFA formulation compared with the CFC formulation can be explained if most of each inhalation from CFC-beclomethasone dipropionate is swallowed and absorbed orally, whereas most of each inhalation from HFA-beclomethasone dipropionate is absorbed through the lungs. There is a need for comprehensive dose-response efficacy trials, with the use of the steep portion of the dose-response relationship, to evaluate the significance of these pharmacokinetic differences.

Effects of inhaled fluticasone and oral prednisolone on clinical and inflammatory parameters in patients with asthma

BACKGROUND

Guidelines state that oral and inhaled corticosteroids are the cornerstone of asthma treatment. The effect of both types of treatment can be assessed by measuring lung and systemic parameters. Treatment for two weeks with either oral prednisolone (30 mg/day), high dose fluticasone propionate (2000 microg/day, FP2000), or lower dose FP (500 microg/day, FP500), both given by a dry powder inhaler, were compared.

METHODS

One hundred and twenty patients with asthma were treated for two weeks in a double blind parallel group design. Lung function, asthma symptoms, airway hyperresponsiveness (PC(20) methacholine and adenosine-5'-monophosphate), sputum eosinophil and eosinophilic cationic protein (ECP) levels were measured as lung parameters. In addition, morning serum blood cortisol, blood eosinophil, and serum ECP levels were measured as systemic parameters.

RESULTS

PC(20) methacholine and adenosine-5'-monophosphate showed significantly greater improvement with FP2000 (1.99 and 4.04 doubling concentrations (DC), respectively) than prednisolone (0.90 DC, p = 0.02; 2.15 DC, p = 0. 05) and marginally more than with FP500 (1.69 and 3.54 DC). Changes in sputum eosinophil and ECP concentrations showed similar trends; the decrease in ECP was significantly greater with FP2000 than with FP500. In contrast, the systemic parameters of steroid activity (cortisol, peripheral blood eosinophils, and serum ECP) decreased to a similar extent with FP2000 and prednisolone but significantly less with FP500.

CONCLUSIONS

Oral prednisolone (30 mg/day) was inferior to FP2000 in improving airway hyperresponsiveness to both methacholine and AMP, with similar trends in forced expiratory volume in one second (FEV(1)), sputum eosinophil and ECP concentrations. Systemic effects were similar with prednisolone and FP2000 and less with FP500.

Early effects of inhaled steroids on airway hyperreactivity and pulmonary function in asthma

While inhaled steroids (IS) are increasingly recognized as having a more rapid onset of action than was once thought, little is known about the early changes in objective measures of respiratory function that follow the inhalation of repeated doses. These early effects were examined in a randomized, double-blind, placebo-controlled, crossover study of 20 children aged 10-16 years with stable mild asthma. Beclomethasone dipropionate (BDP) 2,000 mcg, fluticasone propionate (FP) 400 mcg, and placebo were given twice daily for three doses. Airway hyperreactivity (AHR) to methacholine (PC20), pulmonary function tests (PFT: FVC, FEV1, FEF25-75%), and the rate of recovery from methacholine-induced bronchospasm following administration of salbutamol were determined at 8 h (after 1 dose) and at 32 h (after three doses). At 8 h, minor improvements in AHR were demonstrated, averaging 0.32 doubling doses in PC20. At 32 h, significant improvements in AHR and PFTs were present, averaging 0.92 doubling doses in PC20, 3.96% of predicted values in FEV1, and 7.74% of predicted values in FEF25-75%. No significant changes occurred in FVC. There were no significant differences between the effects of BDP and FP. Inhaled steroids were associated with a slower response to salbutamol following methacholine challenge testing at 32 h. We conclude that IS, given in repeated high doses, result in significant improvements within 32 h in both AHR and PFTs, along with changes in response to beta2 agonists. These effects are likely to be the result of the topical activity of IS.

A comparison of multiple doses of fluticasone propionate and beclomethasone dipropionate in subjects with persistent asthma

BACKGROUND

Inhaled corticosteroids are recommended for the treatment of persistent asthma. Comparative clinical studies evaluating 2 or more doses of these agents are few.

OBJECTIVE

We sought to compare the efficacy and safety of 2 doses of fluticasone propionate (88 micrograms twice daily and 220 micrograms twice daily) with 2 doses of beclomethasone dipropionate (168 micrograms twice daily and 336 micrograms twice daily) in subjects with persistent asthma.

METHODS

Three hundred ninety-nine subjects participated in this randomized, double-blind, parallel-group clinical trial. Eligible subjects were using daily inhaled corticosteroids and had an FEV1 of 45% to 80% of predicted value. Clinic visits, including spirometry, were conducted every 1 to 2 weeks. Subjects recorded symptoms, use of albuterol, and peak expiratory flows on daily diary cards.

RESULTS

Fluticasone propionate treatment resulted in significantly (P </=.034) greater improvements in objective pulmonary function parameters than did beclomethasone dipropionate treatment and significantly greater reductions in daily albuterol use (P </=.010) and asthma symptoms (P </=.027). Both low-dose (88 micrograms twice daily) and medium-dose (220 micrograms twice daily) fluticasone propionate significantly increased FEV1 compared with higher doses of beclomethasone dipropionate (P =. 006). Low-dose and medium-dose fluticasone propionate improved FEV1 by 0.31 L (14%) and 0.36 L (15%), respectively, compared with improvements of 0.18 L (8%) and 0.21 L (9%) with low-dose and medium-dose beclomethasone dipropionate. The adverse event profiles were similar for both medications.

CONCLUSION

Fluticasone propionate provides greater asthma control at roughly half the dose of beclomethasone dipropionate, with a comparable adverse event profile.

Inhaled fluticasone propionate: a review of its therapeutic efficacy at dosages < or = 500 microg/day in adults and adolescents with mild to moderate asthma

Fluticasone propionate is a corticosteroid with comparatively high receptor affinity and topical activity. Inhaled fluticasone propionate < or =500 microg/day provided effective corticosteroid maintenance treatment in patients with mild to moderate asthma in randomised, controlled clinical studies of 4 to 24 weeks in duration. Dosages of 50 to 250 microg twice daily produced consistent improvement in spirometric measures of lung function, reduced the frequency of as-needed beta2-agonist bronchodilator use, asthma symptom scores and night-time wakenings, and prevented asthma exacerbations compared with placebo. Fluticasone propionate < or =250 microg twice daily provided significantly greater improvements in lung function than nedocromil 4 mg 4 times daily, theophylline (5 to 15 mg/L) or zafirlukast 20 mg twice daily. Health-related quality of life improved significantly with fluticasone propionate 88 microg twice daily, but not zafirlukast 20 mg twice daily or placebo. In comparative trials in which fluticasone propionate was given at half the dosage of beclomethasone dipropionate, budesonide or flunisolide, fluticasone propionate < or =250 microg twice daily produced equivalent or greater improvement in spirometric parameters and equivalent reductions in the use of as-needed beta2-agonists than beclomethasone dipropionate, budesonide or flunisolide. Fluticasone propionate 250 microg twice daily was generally more effective than triamcinolone acetonide 200 microg 4 times daily in two 24-week trials. The combination of inhaled fluticasone propionate < or =250 plus salmeterol < or =50 microg twice daily allowed for the use of lower dosages of the inhaled corticosteroid. The incidence of adverse events in patients receiving inhaled fluticasone propionate 50 to 250 microg twice daily was similar to that in beclomethasone dipropionate 168 to 500 microg twice daily and budesonide 100 to 600 microg twice daily recipients and greater than that in recipients of triamcinolone acetonide 200 microg 4 times daily in comparative trials. The incidence of oral candidiasis was < or =8% in patients treated with fluticasone propionate < or =250 microg twice daily or other agents. There was no evidence of clinically significant hypothalamo-pituitary-adrenal (HPA) axis suppression with fluticasone propionate < or =250 microg twice daily in comparative trials.

CONCLUSIONS

Inhaled fluticasone propionate < or =500 microg/day is an effective antiinflammatory therapy for mild to moderate asthma in adolescents and adults. The drug is more effective than nedocromil, theophylline or zafirlukast and is at least as effective as other inhaled corticosteroids administered at twice the fluticasone propionate dosage. The addition of inhaled salmeterol allows the use of lower maintenance dosages of fluticasone propionate. The drug is well tolerated and there is no evidence of a clinically significant effect of this dosage on HPA axis function. Hence, fluticasone propionate < or =500 microg/day is a particularly suitable agent for patients with mild to moderate asthma.

Fluticasone propionate results in improved glucocorticoid receptor binding affinity and reduced oral glucocorticoid requirements in severe asthma

BACKGROUND

Inhaled glucocorticoids (iGC) have become important first line agents in the management of moderate-to-severe asthma. Severe asthma is associated with reduced glucocorticoid receptor (GCR) binding affinity.

METHODS

To evaluate the potential impact of inhaled fluticasone propionate on markers of airway inflammation [GCR binding affinity (Kd) and eosinophil cationic protein (ECP)] and oral GC requirements in steroid-dependent asthmatics, we examined the effects of fluticasone propionate (FP) 500 microg or 1000 microg BID and placebo in a double-blind, randomized study of 13 steroid-dependent asthmatics at a single center. Glucocorticoid receptor binding affinity and ECP values were obtained at baseline, 4, 6, 26, and 52 weeks after patients were enrolled into the study. Oral GC dose and FEV1 values were also recorded at each visit.

RESULTS

Inhaled FP resulted in large reductions in oral GC requirement by 6 weeks of therapy while no reduction was seen in the placebo group. All patients in the FP 2000 microg/d group who continued double-blind therapy at 52 weeks were able to eliminate oral prednisone use. In contrast, every patient in the placebo group had to be withdrawn from the study due to poor asthma control. Associated with the oral GC dose reduction on high dose FP therapy, were improvements in GCR binding affinity with the GCR Kd falling from 42.5 nM at baseline to 19.5 nM at 6 weeks (P=.08). The GCR KD values remained stable thereafter with values of 23.5 nM at 26 weeks (P=.02) and 19.5 nM at 52 weeks (P=.01). In addition, high dose FP therapy resulted in reductions in serum ECP values.

CONCLUSION

This study suggests that high dose FP therapy results in significant oral GC sparing effects associated with improved GCR binding affinity and reductions in serum ECP levels in patients with steroid-dependent asthma.