Dose proportionality of fluticasone propionate from hydrofluoroalkane pressurized metered dose inhalers (pMDIs) and comparability with chlorofluorocarbon pMDIs

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.

Scientific Rationale for Determining the Bioequivalence of Inhaled Drugs

In recent years, pathways for the development and approval of bioequivalent inhaled products have been established for regulated markets, including the European Union (EU), and a number of orally inhaled products (OIPs) have been approved in the EU solely on the basis of in vitro and pharmacokinetic data. This review describes how these development pathways are structured and their implications for the treatment of airway diseases such as asthma. The EU guidance follows a stepwise approach that includes in vitro criteria as the first step. If all in vitro criteria are not met, the second step is based on pharmacokinetic evaluations, which include assessments of lung and systemic bioavailability. If all pharmacokinetic criteria are not met, the third step is based on clinical endpoint studies. In this review, the scientific rationale of the European Medicines Agency guidance for the development of bioequivalent OIPs is reviewed with the focus on the development of bioequivalent OIPs in the EU. Indeed, we discuss the advantages and disadvantages of the weight-of-evidence and stepwise approaches. The evidence indicates that the EU guidance is robust and, unlike clinical endpoint studies, the pharmacokinetic studies are far more sensitive to measure the minor differences, i.e. deposition and absorption rates, in drug delivery from the test and reference products and, thus, should be best suited for assessing bioequivalence. The acceptance range of the 90% confidence intervals for pharmacokinetic bioequivalence (i.e. 80-125% for both the area under the plasma concentration-time curve and maximum plasma concentration) represent appropriately conservative margins for ensuring equivalent safety and efficacy of the test and reference products.

Beclometasone for chronic obstructive pulmonary disease

BACKGROUND

Chronic obstructive pulmonary disease (COPD) is a chronic obstructive lung condition, diagnosed in patients with dyspnoea, chronic cough or sputum production and/or a history of risk factor exposure, if their postbronchodilator forced expiratory lung volume in 1 second (FEV1)/forced vital lung capacity (FVC) ratio is less than 0.70, according to the international GOLD (Global Initiative for Obstructive Lung Disease) criteria.Inhaled corticosteroid (ICS) medications are now recommended for COPD only in combination treatment with long-acting beta2-agonists (LABAs), and only for patients of GOLD stage 3 and stage 4 severity, for both GOLD groups C and D.ICS are expensive and how effective they are is a topic of controversy, particularly in relation to their adverse effects (pneumonia), which may be linked to more potent ICS. It is unclear whether beclometasone dipropionate (BDP), an unlicensed but widely used inhaled steroid, is a safe and effective alternative to other ICS.

OBJECTIVES

To determine the effectiveness and safety in COPD of inhaled beclometasone alone compared with placebo, and of inhaled beclometasone in combination with LABAs compared with LABAs alone.

SEARCH METHODS

We searched the Cochrane Airways Group Specialised Register of trials (CAGR) (includes Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE, EMBASE, CINAHL, AMED and PsycINFO, and handsearching of respiratory journals and meeting abstracts) (February 2013), conference abstracts, ongoing studies and reference lists of articles. We contacted pharmaceutical companies and drug marketing authorisation bodies/ethics committees in 49 countries and obtained licensing information.

SELECTION CRITERIA

Randomised controlled trials of BDP compared with placebo, or BDP/LABA compared with LABA, in stable COPD. Minimum trial duration is 12 weeks.

DATA COLLECTION AND ANALYSIS

Inclusion, bias assessment and data extraction were conducted by two review authors independently. The analysis was performed by one review author. Study authors were contacted to obtain missing information.

MAIN RESULTS

For BDP versus placebo, two studies were included, of which one trial (participants n = 194) was included in the quantitative analysis. This study was a very high-dose trial with stable stage 2 and 3 COPD participants. No statistically significant results in change in lung function, mortality, exacerbations, dyspnoea scores or withdrawal were obtained. The quality of the evidence of all these outcomes was graded low to very low. Data on risk of pneumonia were lacking.The main focus of the review was the more clinically relevant BDP/LABA versus LABA arm. Therefore the findings are reported more fully.For BDP/LABA versus LABA, one study (n = 474) was included, with a further ongoing study identified for future inclusion. The included trial was a high-dose study of stable stage 3 COPD participants. Compared with LABA, people receiving BDP/LABA showed a statistically significant improvement in FEV1 lung function measurements of 0.051 L (95% confidence Interval (CI) 0.001 to 0.102, P = 0.046) (high quality of evidence) and in (self-reported) days without rescue bronchodilators (mean difference 7.05, 95% CI 0.84 to 13.26, P = 0.03) (low quality), both of which are unlikely to be clinically significant. Participants receiving BDP/LABA also had a statistically significant increased rate of exacerbations leading to hospitalisation (risk ratio (RR) 1.84, 95% CI 1.17 to 2.90, P = 0.008) (moderate quality), although this finding is debatable as this study's post hoc analysis showed no statistically significant difference when accounting for country-specific differences in hospitalisation policies. We did not find statistically significant differences for mortality (very low quality), pneumonia (low quality), exacerbations, exercise capacity, quality of life and dyspnoea scores, adverse events and withdrawal (all moderate quality).

AUTHORS' CONCLUSIONS

We found little evidence to suggest that beclometasone is a safer or more effective treatment option for people with COPD when compared with placebo or when used in combination with LABA; when statistically significant differences were found, they mostly were not clinically meaningful or were based on data from only one study. The review was limited by an inability to obtain data from one study and likely publication bias for BDP versus placebo, and by the inclusion of one study only for BDP/LABA versus LABA. An ongoing study of BDP/LABA versus LABA may have a further impact on these conclusions.

Hydrofluoroalkane preparations of fluticasone propionate

Fluticasone propionate is approved for the long-term maintenance therapy of persistent asthma of all severities, and its safety and efficacy has been well established in clinical trials and practice. With the need to phase out chlorofluorocarbons (CFCs) as propellants in pressurized metered-dose inhalers (pMDIs), hydrofluoroalkane (HFA) propellants have been introduced as a safer, environmentally friendly alternative. A HFA formulation of fluticasone propionate has been developed as a microgram-equivalent replacement for the traditional CFC pMDI. Clinical trials have demonstrated that the fluticasone propionate HFA pMDI is an acceptable clinical alternative for the CFC pMDI with similar safety and efficacy.

Comparison of inhaled corticosteroids: an update

OBJECTIVE

To review the basis for the estimated comparative daily dosages of inhaled corticosteroids for children and adults that are presented in the National Heart, Lung, and Blood Institute's Expert Panel Report 3; in addition, the pharmacodynamic and pharmacokinetic basis for potential clinical differences among inhaled corticosteroids is discussed.

DATA SOURCES

A complete MEDLINE search was conducted of human studies of asthma pharmacotherapy published between January 1, 2001, and March 15, 2006, followed by a PubMed search up until August 2008, using ciclesonide, inhaled corticosteroids, and pharmacokinetics as key words. Product information on each inhaled corticosteroid was also included.

STUDY SELECTION AND DATA EXTRACTION

Comparative clinical trials of inhaled corticosteroids and systematic reviews for efficacy comparisons were evaluated. Extensive literature reviews, meta-analyses, and selected clinical studies that illustrate or represent specific points of view were selected. Pharmacodynamic and pharmacokinetic data extracted from previously published reviews and specific studies were included.

DATA SYNTHESIS

Pharmacodynamic characteristics (glucocorticoid receptor binding) and lung delivery determine the relative clinical efficacy and pharmacokinetic properties (oral bioavailability, lung retention, systemic clearance) and determine comparative therapeutic index of the inhaled corticosteroids. Secondary pharmacokinetic differences (intracellular fatty acid esterification, high serum protein binding) that have been posited to improve duration of action and/or therapeutic index are unproven, and current comparative clinical trials do not support the hypotheses that they provide an advantage. Ultrafine particle meter-dose inhalers (MDIs) have not demonstrated superior asthma control or improved safety over older MDIs. All of the inhaled corticosteroids demonstrate efficacy with once-daily dosing, and all are more effective when dosed twice daily.

CONCLUSIONS

Current evidence suggests that all of the inhaled corticosteroids have sufficient therapeutic indexes to provide similar efficacy and safety in low to medium doses. Whether or not some of the newer inhaled corticosteroids offer any advantages at higher doses has yet to be determined.

Systemic exposure and urinary cortisol effects of fluticasone propionate formulated with hydrofluoroalkane in 4- to 11-year-olds with asthma

The systemic exposure of fluticasone propionate with hydrofluoroalkane propellant compared with chlorofluoro-carbon propellant and the effect of fluticasone propionate hydrofluoroalkane on 24-hour urinary cortisol in children aged 4 to 11 years with asthma were evaluated. Study 1 was an open-label, 2-way crossover study in which 16 subjects were randomized to 7.5 days each of fluticasone propionate hydrofluoroalkane 88 mug twice a day or fluticasone propionate chlorofluorocarbon 88 mug twice a day. In study 2, 63 subjects received 13.5 days of placebo followed by 27.5 days of fluticasone propionate hydrofluoroalkane 88 mug twice a day. The main outcome measure for study 1 was the difference between fluticasone propionate hydrofluoroalkane and fluticasone propionate chlorofluorocarbon in fluticasone propionate AUC(last) (area under the plasma fluticasone propionate concentration-time curve from zero up to the last quantifiable plasma concentration), and for study 2, 24-hour overnight urinary cortisol excretion. In study 1, fluticasone propionate systemic exposure was significantly lower (55%) with hydrofluoroalkane metered dose inhaler compared with chlorofluorocarbon metered dose inhaler. Study 2 showed no statistically significant changes in 24-hour overnight urinary cortisol excretion and no relationship to fluticasone propionate systemic exposure at this dose. The results of these 2 studies showed that in children aged 4 to 11 years with asthma, fluticasone propionate hydrofluoroalkane has lower systemic exposure compared with chlorofluorocarbon and no hypothalamic-pituitary-adrenal axis effects as measured by 24-hour urinary cortisol excretion.

A modified prescription-event monitoring study to assess the introduction of Flixotide Evohaler into general practice in England: an example of pharmacovigilance planning and risk monitoring

INTRODUCTION

A modified prescription-event monitoring (PEM) study was conducted to examine the safety of the introduction of the metered dose inhaler (MDI) Flixotide Evohaler (fluticasone with the propellant HFA 134a).

METHODS

Patients were identified from the first NHS prescriptions dispensed in England for Flixotide Evohaler. Postal questionnaires were sent to the prescribing doctor, requesting information including: demographic characteristics, severity of indication, concomitant medication, event data 3 months prior to and 3 months after the first prescription, and any reasons for stopping Flixotide. Pregnancies, deaths and selected events were followed up. Incidence density ratios (IDRs) were calculated to compare event rates 3 months before and 3 months after the introduction of Flixotide Evohaler.

RESULTS

The cohort comprised 13 413 patients that were prescribed Flixotide Evohaler. The response rate was 64.0%. When the pre- and post-exposure periods were compared fewer patients had events in the post-exposure period, and there was no significant difference in the length of courses of oral steroid use. Eighteen patients experienced an event within 1 hour of using Flixotide Evohaler; these were minor with the exception of one case of angioneurotic facial oedema. Six of these events were assessed as possibly related to Flixotide Evohaler. During the study period there were an additional 13 patients with events assessed as possibly related to Flixotide Evohaler, including two reports of allergic reactions.

DISCUSSION

The results suggest that the transition to Flixotide Evohaler was generally well tolerated. The modified methodology has contributed to the risk management of the introduction of this product.

Lung bioavailability of hydrofluoroalkane fluticasone in young children when delivered by an antistatic chamber/mask

OBJECTIVE

To determine whether an antistatic valved holding chamber/mask improves lung bioavailability of hydrofluoroalkane (HFA) fluticasone in young children.

STUDY DESIGN

Twelve patients, age 1 to 6 years, with well-controlled asthma were treated with an HFA fluticasone metered-dose inhaler (Flovent HFA) twice daily (440 microg/day). The drug was delivered by tidal breathing through conventional (AeroChamber Plus) and antistatic (AeroChamber MAX) valved holding chambers (VHCs) with masks in a randomized, crossover manner, each for 3 to 7 days. When adherence was 100% at home, blood was collected for measurement of steady-state fluticasone plasma concentration (FPC) 1 hour after the last dose was administered in the clinic. FPC indicates systemic exposure directly and airway delivery indirectly. It was measured by liquid chromatography-mass spectrometry. Data were analyzed by regression analysis.

RESULTS

The mean +/- SD FPC was 107 +/- 30 pg/mL after conventional VHC and 186 +/- 134 pg/mL after the antistatic VHC (P = .03). In 5 patients (40%), the antistatic VHC increased FPC by >/= 100%, to potentially excessive levels in 4 of them; it had little effect in 7 patients.

CONCLUSIONS

HFA fluticasone was delivered to the airways by both devices even though the patients could not inhale deeply and breath hold. The antistatic VHC variably increased lung bioavailability. To reduce systemic exposure, the dose should be weaned to the minimum required to maintain asthma control.

Airway and systemic effects of hydrofluoroalkane formulations of high-dose ciclesonide and fluticasone in moderate persistent asthma

BACKGROUND

There are no data comparing the relative effects of high-dose ciclesonide (CIC) and fluticasone propionate (FP) on airway and systemic outcomes in patients with moderate persistent asthma.

OBJECTIVE

We elected to evaluate the relative effects of CIC and FP on the plasma cortisol response to stimulation with human corticotropin-releasing factor (hCRF) and bronchial hyperresponsiveness to methacholine as the primary outcome variables, in addition to secondary outcomes of overnight 10-h urinary cortisol (OUC) levels, exhaled nitric oxide levels, lung function, symptoms, and quality of life.

METHODS

Fourteen patients with moderate persistent asthma (mean FEV(1), 67% predicted [prior to each randomized treatment]) completed the study, which had a randomized, double-blind, double-dummy, crossover design, per protocol. Patients stopped receiving their usual inhaled corticosteroids for the duration of the study and instead began receiving salmeterol, 50 mug twice daily, and montelukast, 10 mg once daily, for the 2-week washout periods prior to each randomized treatment, in order to prevent dropouts after withdrawal from inhaled corticosteroid therapy. Patients received 4 weeks of either CIC, 200 microg ex-valve (160 microg ex-actuator) four puffs twice daily, plus FP-placebo, four puffs twice daily, or FP, 250 microg ex-valve (220 microg ex-actuator) four puffs twice daily, plus CIC-placebo, four puffs twice daily. Salmeterol and montelukast were withheld for 72 h prior to each postwashout baseline visit, and CIC or FP was withheld for 12 h prior to each posttreatment visit.

RESULTS

FP, but not CIC, when compared to respective baseline values, significantly suppressed (p < 0.05) plasma cortisol levels as follows: FP prior to receiving hCRF: geometric mean fold difference, 1.2; 95% confidence interval (CI), 1.1 to 1.3; CIC prior to receiving hCRF: geometric mean fold difference, 0.9; 95% CI, 0.8 to 1.0; FP 30 min after receiving hCRF: geometric mean fold difference, 1.2; 95% CI, 1.1 to 1.3; CIC 30 min after receiving hCRF: geometric mean fold difference, 1.0; 95% CI, 0.9 to 1.2; OUC after FP administration: geometric mean fold difference, 1.9; 95% CI, 1.4 to 2.6; OUC after CIC administration: geometric mean fold difference, 1.2; 95% CI, 0.9 to 1.5. There was also a significantly lower (p < 0.05) mean value for OUC levels after FP administration than after CIC administration (geometric mean fold difference, 1.5; 95% CI, 1.1 to 2.0). Therapy with CIC and FP, compared to respective baselines, significantly increased (p < 0.05) the provocative concentration of methacholine causing a 20% fall in FEV(1), as follows: CIC: doubling dilution difference, 0.8; 95% CI, 0.1 to 1.6; FP: doubling dilution difference, 1.0; 95% CI, 0.1 to 2.0. It also significantly reduced (p < 0.05) exhaled nitric oxide levels, as follows: CIC: geometric mean fold difference, 1.2; 95% CI, 1.1 to 1.3; FP: geometric mean fold difference, 1.9; 95% CI, 1.3 to 2.8. There was no effect on other secondary efficacy outcomes.

CONCLUSION

FP, 2,000 microg daily, but not CIC, 1,600 microg daily, significantly suppressed hypothalamic-pituitary-adrenal axis outcomes, with OUC levels being lower after FP administration than after CIC administration. Both drugs significantly improved airway outcomes in terms of methacholine bronchial hyperresponsiveness and exhaled nitric oxide levels. The present results would therefore suggest that CIC might confer a better therapeutic ratio than FP when used at higher doses.

Comparison of the systemic pharmacodynamic effects and pharmacokinetics of salmeterol delivered by CFC propellant and non-CFC propellant metered dose inhalers in healthy subjects

This was a randomised, double-blind, placebo-controlled, cross-over study comparing the systemic pharmacodynamic effects (heart rate and serum potassium) and pharmacokinetics of salmeterol delivered by the non-CFC hydrofluoralkane (HFA) propellant 134a and the CFC propellant (propellant 11/12) metered dose inhalers (MDI) in healthy subjects. At the therapeutic dose (50 microg), salmeterol-mediated systemic pharmacodynamics were equivalent for the HFA and CFC MDIs. Higher doses of salmeterol (150 and 300 microg) produced dose-related beta-agonist pharmacodynamic effects irrespective of the propellant. However, these effects were lower with salmeterol HFA MDI than with the salmeterol CFC MDI at all dose levels. Overall, salmeterol Cmax and AUC(0-t) values were lower for salmeterol HFA compared with salmeterol CFC MDI. At the highest dose (300 microg), where a full pharmacokinetic profile was obtained, exposure to salmeterol delivered by the HFA MDI compared with the salmeterol CFC MDI was 27% and 30% lower for Cmax and AUC(0-t), respectively. Maximum plasma concentrations were generally seen in the first plasma samples taken 5 min after the start of dosing. Salmeterol HFA was well-tolerated. At supratherapeutic doses, adverse events were typical for high-dose salmeterol with fewer adverse events occurring with the HFA compared with the CFC formulation. These data indicate that the salmeterol HFA MDI would not be associated with a significantly different pharmacodynamic, safety and tolerability profile compared with the salmeterol CFC MDI.

Effects of fluticasone vs. fluticasone/salmeterol on airway calibre and airway hyperresponsiveness in mild persistent asthma

AIMS

Inhaled corticosteroids alone or in combination with long acting beta2-agonists are indicated for use in mild persistent asthmatics. We set out to evaluate effects on airway hyperresponsiveness (AHR) and airway calibre using hydrofluoroalkane fluticasone/salmeterol (FP/SM) vs. double the dose of fluticasone alone (FP).

METHODS

Fourteen mild persistent asthmatics completed a randomized double-blind crossover study with 1-week run-in and washout periods prior to treatments. Subjects received 3 weeks of FP 250 microg or FP 125 microg/SM 25 microg as 1 puff twice daily. Methacholine PD20 and lung function were measured after both baseline and treatment periods.

RESULTS

There were no significant differences in baseline values prior to randomized treatments. Compared with pooled baseline, FP/SM and FP conferred improvements (P < 0.05) on methacholine PD20: 2.5 (95% confidence interval 1.7, 3.2) and 1.6 (0.8-2.3) doubling dose improvements, respectively; between FP/SM vs. FP there was a 0.9 (0.4, 1.4) doubling dose difference (P < 0.05). For forced expiratory volume in 1 s (FEV1), forced mid-expiratory flow (FEF25-75) and morning peak expiratory flow (PEF), FP/SM but not FP conferred improvements (P < 0.05) compared with pooled baseline, with FP/SM being greater than FP (P < 0.05): differences in FEV1 of 7.2% (3.8, 10.6) predicted, FEF25-75 of 11.2% (6.3, 16.1) predicted, and morning PEF of 17 L x min(-1)(1-32).

CONCLUSIONS

FP/SM conferred improvements on AHR and airway calibre, while twice the dose of FP improved only AHR in patients with mild asthma. The differential effects of FP/SM and FP suggest separate but complementary actions of the two moieties on airway inflammation and smooth muscle stabilization. This may explain the beneficial effects of combination inhalers on exacerbations.