Systematic review of the dose-response relation of inhaled fluticasone propionate

Dangers of under-treatment and over-treatment with inhaled corticosteroids in children with asthma

Two children, both under the care of specialists for mild persistent asthma, flirted with mortality. One lost and one won the battle. A 16-year-old boy never received ICS therapy despite extensive airway inflammation and remodeling and died due to mismanagement of an asthma exacerbation. A 6-year-old girl developed iatrogenic Cushing's syndrome during 18 months of continuous treatment with high, FDA-unapproved doses of both ICS and INCS and nearly died during an adrenal crisis. The role of ICS under-treatment and over-treatment and the possibility that recommendations in asthma guidelines and information in FDA package labels could have prevented both outcomes are explored.

START CARE: a protocol for a randomised controlled trial of step-wise budesonide-formoterol reliever-based treatment in children

Background

Asthma is the most common chronic childhood respiratory condition globally. Inhaled corticosteroid (ICS)-formoterol reliever-based regimens reduce the risk of asthma exacerbations compared with conventional short-acting β2-agonist (SABA) reliever-based regimens in adults and adolescents. The current limited evidence for anti-inflammatory reliever therapy in children means it is unknown whether these findings are also applicable to children. High-quality randomised controlled trials (RCTs) are needed.

Objective

The study aim is to determine the efficacy and safety of budesonide-formoterol reliever alone or maintenance and reliever therapy (MART) compared with standard therapy: budesonide or budesonide-formoterol maintenance, both with terbutaline reliever, in children aged 5 to 11 years with mild, moderate and severe asthma.

Methods

A 52-week, multicentre, open-label, parallel group, phase III, two-sided superiority RCT will recruit 400 children aged 5 to 11 years with asthma. Participants will be randomised 1:1 to either budesonide-formoterol 100/6 µg Turbuhaler reliever alone or MART; or budesonide or budesonide-formoterol Turbuhaler maintenance, with terbutaline Turbuhaler reliever. The primary outcome is moderate and severe asthma exacerbations as rate per participant per year. Secondary outcomes are asthma control, lung function, exhaled nitric oxide and treatment step change. Assessment of Turbuhaler technique and cost-effectiveness analysis are also planned.

Conclusion

This will be the first RCT to compare the efficacy and safety of a step-wise budesonide-formoterol reliever alone or MART regimen with conventional inhaled ICS or ICS-long-acting β-agonist maintenance plus SABA reliever in children. The results will provide a much-needed evidence base for the treatment of asthma in children.

Can Pharmacokinetic Studies Assess the Pulmonary Fate of Dry Powder Inhaler Formulations of Fluticasone Propionate?

In the context of streamlining generic approval, this study assessed whether pharmacokinetics (PK) could elucidate the pulmonary fate of orally inhaled drug products (OIDPs). Three fluticasone propionate (FP) dry powder inhaler (DPI) formulations (A-4.5, B-3.8, and C-3.7), differing only in type and composition of lactose fines, exhibited median mass aerodynamic diameter (MMAD) of 4.5 μm (A-4.5), 3.8 μm (B-3.8), and 3.7 μm (C-3.7) and varied in dissolution rates (A-4.5 slower than B-3.8 and C-3.7). In vitro total lung dose (TLDin vitro) was determined as the average dose passing through three anatomical mouth-throat (MT) models and yielded dose normalization factors (DNF) for each DPI formulation X (DNFx = TLDin vitro,x/TLDin vitro,A-4.5). The DNF was 1.00 for A-4.5, 1.32 for B-3.8, and 1.21 for C-3.7. Systemic PK after inhalation of 500 μg FP was assessed in a randomized, double-blind, four-way crossover study in 24 healthy volunteers. Peak concentrations (Cmax) of A-4.5 relative to those of B-3.8 or C-3.7 lacked bioequivalence without or with dose normalization. The area under the curve (AUC0-Inf) was bio-IN-equivalent before dose normalization and bioequivalent after dose normalization. Thus, PK could detect differences in pulmonary available dose (AUC0-Inf) and residence time (dose-normalized Cmax). The differences in dose-normalized Cmax could not be explained by differences in in vitro dissolution. This might suggest that Cmax differences may indicate differences in regional lung deposition. Overall this study supports the use of PK studies to provide relevant information on the pulmonary performance characteristics (i.e., available dose, residence time, and regional lung deposition).

Unmet needs in asthma

Despite advances in the diagnosis and management of asthma, uncontrolled disease is still associated with a substantial mortality and morbidity burden. Patients often overestimate their level of asthma control while also reporting that asthma symptoms affect their quality of life and ability to work or study. There is some evidence of success with primary prevention measures in high-risk children and the secondary prevention of asthma in sensitized individuals or those at risk of developing occupational asthma. There are challenges with diagnosis – with under- and overdiagnosis and misdiagnosis being common – and in the treatment of asthma, despite clear treatment guidelines. In particular, severe asthma presents a huge challenge to the clinician, and its complex and heterogeneous nature warrants a personalized medicine approach to match therapies to individual patients. However, the tools for this are currently lacking in primary care. This article reviews the current unmet need in the diagnosis and clinical management of asthma, and provides an overview of the limitations of current therapies.

Preseasonal treatment with either omalizumab or an inhaled corticosteroid boost to prevent fall asthma exacerbations

BACKGROUND

Short-term targeted treatment can potentially prevent fall asthma exacerbations while limiting therapy exposure.

OBJECTIVE

We sought to compare (1) omalizumab with placebo and (2) omalizumab with an inhaled corticosteroid (ICS) boost with regard to fall exacerbation rates when initiated 4 to 6 weeks before return to school.

METHODS

A 3-arm, randomized, double-blind, double placebo-controlled, multicenter clinical trial was conducted among inner-city asthmatic children aged 6 to 17 years with 1 or more recent exacerbations (clincaltrials.gov #NCT01430403). Guidelines-based therapy was continued over a 4- to 9-month run-in phase and a 4-month intervention phase. In a subset the effects of omalizumab on IFN-α responses to rhinovirus in PBMCs were examined.

RESULTS

Before the falls of 2012 and 2013, 727 children were enrolled, 513 were randomized, and 478 were analyzed. The fall exacerbation rate was significantly lower in the omalizumab versus placebo arms (11.3% vs 21.0%; odds ratio [OR], 0.48; 95% CI, 0.25-0.92), but there was no significant difference between omalizumab and ICS boost (8.4% vs 11.1%; OR, 0.73; 95% CI, 0.33-1.64). In a prespecified subgroup analysis, among participants with an exacerbation during the run-in phase, omalizumab was significantly more efficacious than both placebo (6.4% vs 36.3%; OR, 0.12; 95% CI, 0.02-0.64) and ICS boost (2.0% vs 27.8%; OR, 0.05; 95% CI, 0.002-0.98). Omalizumab improved IFN-α responses to rhinovirus, and within the omalizumab group, greater IFN-α increases were associated with fewer exacerbations (OR, 0.14; 95% CI, 0.01-0.88). Adverse events were rare and similar among arms.

CONCLUSIONS

Adding omalizumab before return to school to ongoing guidelines-based care among inner-city youth reduces fall asthma exacerbations, particularly among those with a recent exacerbation.

Pharmacotherapy of critical asthma syndrome: current and emerging therapies

The critical asthma syndrome (CAS) encompasses the most severe, persistent, refractory asthma patients for the clinician to manage. Personalized pharmacotherapy is necessary to prevent the next acute severe asthma exacerbation, not just the control of symptoms. The 2007 National Asthma Education and Prevention Program Expert Panel 3 provides guidelines for the treatment of uncontrolled asthma. The patient's response to recommended pharmacotherapy is highly variable which risks poor asthma control leading to frequent exacerbations that can deteriorate into CAS. Controlling asthma symptoms and preventing acute exacerbations may be two separate clinical activities with their own unique demands. Clinicians must be prepared to use the entire spectrum of asthma medications available but must concurrently be aware of potential drug toxicities some of which can paradoxically worsen asthma control. Medications normally prescribed for COPD can potentially be useful in the CAS patient, particularly those with asthma-COPD overlap syndrome. Immunomodulation with drugs like omalizumab in IgE-mediated asthma syndromes is one important approach. New and emerging drugs address unique aspects of airway inflammation and biology but at a significant financial cost. The pharmacology and toxicities of the agents that may be used in the treatment of CAS to control asthma symptoms and prevent severe exacerbations are reviewed.

Management of asthma: the current US and European guidelines

Asthma management guidelines aim to improve the implementation of current knowledge into daily clinical practice by establishing a consensus of scientific practices for the management of asthma. Initial guidelines were based on consensus of expert opinion in order to employ a severity-based classification system as a guide to treatment. However, advances in asthma research led to the development of evidence-based guidelines and a major paradigm shift to control-based asthma management. Control-based management is central to the published guidelines developed by The National Heart, Lung, and Blood Institute (NHLBI), The Global Initiative for Asthma (GINA), and The British Thoracic Society (BTS), each one using the same volume of evidence but emphasizing aspects particular to their specific patient populations and socioeconomic needs. This chapter summarizes the evolution of these guidelines and summarizes the key points and evidence used in the recommendations for the assessment, monitoring, and management of asthma in all ages, with particular emphasis on the NHLBI guidelines.

International consensus on (ICON) pediatric asthma

Asthma is the most common chronic lower respiratory disease in childhood throughout the world. Several guidelines and/or consensus documents are available to support medical decisions on pediatric asthma. Although there is no doubt that the use of common systematic approaches for management can considerably improve outcomes, dissemination and implementation of these are still major challenges. Consequently, the International Collaboration in Asthma, Allergy and Immunology (iCAALL), recently formed by the EAACI, AAAAI, ACAAI, and WAO, has decided to propose an International Consensus on (ICON) Pediatric Asthma. The purpose of this document is to highlight the key messages that are common to many of the existing guidelines, while critically reviewing and commenting on any differences, thus providing a concise reference. The principles of pediatric asthma management are generally accepted. Overall, the treatment goal is disease control. To achieve this, patients and their parents should be educated to optimally manage the disease, in collaboration with healthcare professionals. Identification and avoidance of triggers is also of significant importance. Assessment and monitoring should be performed regularly to re-evaluate and fine-tune treatment. Pharmacotherapy is the cornerstone of treatment. The optimal use of medication can, in most cases, help patients control symptoms and reduce the risk for future morbidity. The management of exacerbations is a major consideration, independent of chronic treatment. There is a trend toward considering phenotype-specific treatment choices; however, this goal has not yet been achieved.

Inhaled corticosteroids should be the first line of treatment for children with asthma

Although montelukast is claimed to be preferable to inhaled corticosteroids in children with asthma and allergic rhinitis, virus-induced exacerbations, exercise induced asthma, and in those experiencing difficulties with inhalation therapy, there is no scientific evidence to support any of these claims. In comparative trials and systematic reviews, inhaled corticosteroids are clearly more effective than montelukast in reducing asthma exacerbations, improving lung function, symptom scores, and rescue medication use. The effects on exercise induced bronchoconstriction appear to be similar. Because of their superior efficacy and excellent long-term efficacy and safety profile, inhaled corticosteroids are the treatment of first choice for the maintenance therapy of childhood asthma, irrespective of age or clinical phenotype.

Comparison of Inhaled Corticosteroids: What You Need to Know in Choosing a Product

Inhaled corticosteroids (ICS) are recommended by The National Asthma Education and Prevention Program's Expert Panel Report 3 for all levels of persistent asthma in the pediatric population. The recommended ICS doses are based on assessment of severity and control of asthma. The pharmacodynamics and pharmacokinetics of the current ICSs are reviewed. While comparable efficacy can be achieved with equipotent dosing, some of the newer ICSs, fluticasone propionate, mometasone furoate, and ciclesonide, have pharmacokinetic profiles that produce less risk of systemic effects. However, at high doses systemic activity increases with all ICSs. The clinicians need to weigh the benefits and risks of these different products and dosing schemes in their patients for optimal use.

Inhaled corticosteroid dosing: double for nothing?

Two recent trials from the National Heart, Lung, and Blood Institute's asthma clinical trials networks raise a concern about using double the dose of an inhaled corticosteroid (ICS) as a positive control arm in clinical trials of add-on therapy. The literature evaluating the response to doubling the dose of an ICS is briefly reviewed. The vast majority of studies do not demonstrate a significant positive benefit from doubling the dose of an ICS but do show improvement with 4-fold increases that is equal to or greater than that of add-on long-acting bronchodilators. It is recommended that doubling the dose of an ICS no longer be considered a positive comparator arm in clinical trials, although it might be beneficial in individual patients.

Dose response of inhaled corticosteroids in children with persistent asthma: a systematic review

OBJECTIVE

To assess the dose-response relationship (benefits and harms) of inhaled corticosteroids (ICSs) in children with persistent asthma.

METHODS

We conducted a systematic review and meta-analysis of randomized controlled trials (RCTs) that compared ≥2 doses of ICSs in children aged 3 to 18 years with persistent asthma. Medline was searched for articles published between 1950 and August 2009. Main outcomes of our analyses included morning and evening peak expiratory flow, forced expiratory volume in 1 second, asthma symptom score, β(2)-agonist use, withdrawal because of lack of efficacy, and adverse events. Meta-analyses were performed to compare moderate (300-400 μg/day) with low (≤200 μg/day beclomethasone-equivalent) doses of ICSs.

RESULTS

Fourteen RCTs (5768 asthmatic children) that evaluated 5 ICSs were included. The pooled standardized mean difference from 6 trials revealed a small but statistically significant increase of moderate over low doses in improving forced expiratory volume in 1 second (standardized mean difference: 0.11 [95% confidence interval: 0.01-0.21]) among children with mild-to-moderate asthma. There was no significant difference between 2 doses in terms of other efficacy outcomes. Local adverse events were uncommon, and there was no evidence of dose-response relationship at low-to-moderate doses.

CONCLUSIONS

Compared with low doses, moderate doses of ICSs may not provide clinically relevant therapeutic advantage in children with mild-to-moderate persistent asthma. Additional RCTs are needed to clarify the dose-response relationship of ICSs in persistent childhood asthma.

Acute adrenal crisis in an asthmatic child treated with inhaled fluticasone proprionate

Adrenal suppression secondary to prolonged inhaled corticosteroid use is usually limited to biochemical abnormalities, with no obvious clinical effects. Acute adrenal crisis is much rarer event but has been reported with increasing frequency. We report a case of a 7-year-old asthmatic child who presented with an acute history of lethargy after a respiratory infection. He was maintained on 220 mug/day of fluticasone propionate for several years. Initial evaluation revealed severe adrenal suppression, with undetectable cortisol levels and minimal response after stimulation with ACTH. After fluticasone was discontinued, a gradual recovery of the adrenal axis was seen. This case shows that acute adrenal crisis may be a consequence even at the usual prescribed doses, stressing the importance of using the lowest dose of inhaled steroids needed to control symptoms and having an increased awareness of this complication.

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.

Inhaled corticosteroids and asthma control in children: assessing impairment and risk

OBJECTIVE

To review the use of inhaled corticosteroids on asthma control in children by using the new therapeutic paradigm outlined in the Expert Panel Report 3: Guidelines for the Diagnosis and Management of Asthma.

METHODS

A systematic review of the literature was performed by using the Medline and Embase databases (January 1996 to October 2007).

RESULTS

A total of 18 placebo-controlled, clinical trials in >8000 children (aged 0-17 years) with asthma met the criteria for evaluating monotherapy with inhaled corticosteroids: 13 double-blind studies of inhaled corticosteroids versus placebo and 5 controlled studies that compared inhaled corticosteroids to a nonsteroid antiinflammatory agent. The findings can be summarized as follows: (1) Compared with placebo, inhaled corticosteroid treatment was associated with reductions in both the impairment and risk domains. (2) Improvements in impairment and risk observed with inhaled corticosteroids were generally greater than those observed with nonsteroid antiinflammatory comparator medications. (3) Inhaled corticosteroids were well tolerated. (4) Small reductions in growth rates were evident when compared with placebo and/or comparator nonsteroid antiinflammatory medication use in the long-term (>1-year) studies, but when measured, the reductions diminished with time.

CONCLUSIONS

Treatment with inhaled corticosteroids improves the asthma-control domains of impairment and risk in children. Differences in study protocols make detailed comparisons difficult. Specific needs for additional trials include (1) more studies using appropriate indicators for impairment (eg, rescue-medication use; symptoms scores; asthma/episode-free days) and risk (eg, forced expiratory volume in 1 second in children who can perform spirometry; exacerbations requiring oral corticosteroids; urgent care usage) and (2) more studies evaluating adolescents; the majority of the data reported were for children up to the age of 12 years, and data for adolescents are often lost (either grouped with adults [eg, studies in patients > or =12 years old] or not included [eg, studies of school-aged children < or =12 years old]). Attention should be given to standardizing variables that will permit comparison of outcomes between trials.

Asthma exacerbations in African Americans treated for 1 year with combination fluticasone propionate and salmeterol or fluticasone propionate alone

OBJECTIVE

This long-term prospective study was conducted in African Americans with persistent asthma to examine the safety and effectiveness of the combination of the inhaled corticosteroid, fluticasone propionate (FP), and the long-acting beta-agonist, salmeterol, compared with FP alone.

RESEARCH AND DESIGN METHODS

This was a randomized, double-blind, parallel group, multi-center trial in adolescent and adult subjects >/=12 years of age symptomatic on a low dose of an inhaled corticosteroid (ICS). The study consisted of a 2-week screening period on low dose ICS; a 4-week open-label FP 250 mcg twice daily (BID) run-in; a 52-week double-blind period (FP/salmeterol [FSC] 100/50 mcg [n=239] or FP 100 mcg [n=236] BID), and a 4-week FP 250 mcg BID run-out period. Annualized exacerbation rate was the primary outcome for comparing the two treatments. Other measures of asthma control included peak expiratory flow, asthma symptoms, and albuterol use. Safety was assessed through adverse events.

RESULTS

Exacerbation rates were not significantly different in those treated with FSC 100/50 mcg (0.449 per year) compared with FP 100 mcg (0.529 per year, p=0.169). When the per-protocol analysis was applied, the rates were 0.465 and 0.769 per year for FSC 100/50 mcg and FP 100 mcg, respectively. Treatment with FSC 100/50 mcg provided statistically greater improvements in lung function measures and nighttime awakenings (p</=0.050) and demonstrated numerically lower daily symptoms (p=0.216) and albuterol use (p=0.122). Two subjects treated with FSC 100/50 mcg were hospitalized for an asthma exacerbation compared to three treated with FP 100 mcg. The overall incidence of adverse effects during double-blind treatment was similar between the FSC 100/50 mcg and FP 100 mcg treatment groups (61% and 68%, respectively). Frequent study visits were required of subjects during this long-term study, and it remains unknown whether this intervention may affect generalizability.

CONCLUSION

In this large, prospective study among African Americans with asthma, the addition of salmeterol to FP resulted in a similar low rate of exacerbations and improved other markers of asthma control. Both FSC 100/50 mcg and FP 100 mcg were well-tolerated, and the overall safety-profiles were similar over 1 year of treatment.

Inhaled corticosteroids in children with asthma: pharmacologic determinants of safety and efficacy and other clinical considerations

The role of inhaled corticosteroids (ICS) in the treatment of childhood asthma has been well established. An ideal corticosteroid should demonstrate high pulmonary deposition and residency time, in addition to a low systemic bioavailability and rapid systemic clearance. The lung depositions of the ICS have been compared, with beclomethasone (beclometasone)-hydrofluoroalkane (HFA) and ciclesonide showing the highest lung deposition. Lung deposition is influenced by not only the inhalation device and type of propellant (HFA or chlorofluorocarbon), but also by whether the aerosol is a solution or suspension, and the particle size of the respirable fraction. Pulmonary residency time increases when budesonide and des-ciclesonide undergo reversible fatty acid esterification. The bioavailability of the drug depends on the oral bioavailable fraction and the amount absorbed directly from the pulmonary vasculature. The clearance rate of des-ciclesonide is very high (228 L/h), increasing its safety profile by utilizing extra-hepatic clearance mechanisms. Both des-ciclesonide and mometasone have a high protein binding fraction (98-99%). The volume of distribution (Vd) is proportional to the lipophilicity of the drug, with the Vd of fluticasone being 332L compared with 183L for budesonide. Increasing the Vd will also increase the elimination half-life of a drug. The pharmacodynamics of ICS depend on both the receptor binding affinity and the dose-response curve. Among the ICS, fluticasone and mometasone have the highest receptor binding affinity (1800 and 2200, respectively), followed by budesonide at 935 (relative to dexamethasone = 100). Compared with other nonsteroid asthma medications (long-acting beta-agonists, theophylline, and montelukast) ICS have proven superiority in improving lung function, symptom-free days, and inflammatory markers. One study suggests that early intervention with ICS reduces the loss in lung function (forced expiratory volume in 1 second) over 3 years. Whether airway remodeling is reduced or prevented in the long term is unknown. Potential adverse drug effects of ICS include adrenal and growth suppression. While in low-to-medium doses ICS have shown little suppression of the adrenal pituitary axis, in high doses the potential for significant adrenal suppression and adrenal crisis exists. Several longitudinal studies evaluating the effect of ICS on growth have shown a small decrement in growth velocity (approximate 1-2 cm) during the first year of treatment. However, when investigators followed children treated with budesonide for up to 10 years, no change in target adult height was noted. In conclusion, the development of optimal delivery devices for young children, as well as optimizing favorable pharmacokinetic properties of ICS should be priorities for future childhood asthma management.

Evidence-based selection of inhaled corticosteroid for treatment of chronic asthma

Published literature relevant to comparison of various inhaled corticosteroids (ICSs) was reviewed. Marked heterogeneity was found in the reported results. The efficacy and side effects of ICSs depend on their formulation, dosing and device used, and the subjects' age, severity of asthma, and inhaler technique. All these factors have not been included uniformly in most study designs. Notwithstanding this limitation, it appears that fluticasone is generally very effective and safe in low-to-medium doses and may be used for most patients. Budesonide is the only Pregnancy Category B ICSs, all others being Category C, and it is available as nebulizer suspension suitable for use in children over 6 months of age. Budesonide, also available as dry powder inhaler, and beclomethasone, available as metered-dose inhaler, are equal in efficacy, and side effects and may be chosen according to the patient's ability to handle the device. Flunisolide causes fewer side effects but is also relatively less effective. Triamcinolone is generally less effective and causes more side effects than most of the other ICSs. Mometasone may be preferred if once-daily dosing is desired. Ciclesonide has been found highly effective in once-daily dose and without side effects even in high doses. Further studies comparing it with other ICSs over longer periods of use will determine its place in treatment of chronic asthma.

[Fluticasone propionate in children and infants with asthma]

The known efficacy of fluticasone propionate in adults, comparable at half-dosage of corticosteroids has been validated by the market authorization (MA) and by the national and international guidelines for beclomethasone. This could be partly explained by its pharmacological properties, affinity for glucocorticosteroid receptors, lung deposition and lipophilicity. The limited systemic adverse events is due to its low bioavailability, optimal hepatic clearance, high plasma protein binding. The efficacy in asthmatic children has been confirmed in clinical studies showing a "plateau" efficacy between 100 and 200 microg/d for the majority of children. Most children are controlled by such dosages: the added value of increasing posology on asthma control exists but is small. A high off-label posology does not allow more quickly asthma control and therefore is not justified. A twice daily dosing is more efficient, particularly for initiation of maintenance therapy, than a once daily dosing. A literature survey confirms that, at MA recommended daily doses in children (100-200 microg), fluticasone propionate has no clinically significant effect either on hypothalamic-pituitary-adrenal (HPA) axis (basal function or stimulation tests), bone or growth velocity. However, high daily doses (higher to 500 microg/day) for long periods expose to systemic adverse effects with measurable consequences on growth rate, bone density (decreasing biochemical makers of bone formation) and HPA function. Several cases of adrenal insufficiency that may have led to acute adrenal crisis have been reported in 4- to 10-year-old children receiving fluticasone propionate in doses between 500 to 2000 microg daily. In case of surgery or infection, a preventive treatment of adrenal insufficiency with hydrocortisone should be proposed for children treated for more than 6 months with such high daily doses. Such children need definitely an advice from paediatricians specialized in chest diseases as well as in endocrinology. It is important to recall that the clinical benefit of daily doses of inhaled corticosteroids higher than recommended is low and that the good use of inhaled corticosteroids particularly in children lays on the careful search of the minimal efficient daily doses.

Adrenal responses to low dose synthetic ACTH (Synacthen) in children receiving high dose inhaled fluticasone

BACKGROUND AND AIMS

Clinical adrenal insufficiency has been reported with doses of inhaled fluticasone proprionate (FP) > 400 microg/day, the maximum dose licensed for use in children with asthma. Following two cases of serious adrenal insufficiency (one fatal) attributed to FP, adrenal function was evaluated in children receiving FP outwith the licensed dose.

METHODS

Children recorded as prescribed FP > or = 500 microg/day were invited to attend for assessment. Adrenal function was measured using the low dose Synacthen test (500 ng/1.73 m2 intravenously) and was categorised as: biochemically normal (peak cortisol response > 500 nmol/l); impaired (peak cortisol < or = 500 nmol/l); or flat (peak cortisol < or = 500 nmol/l with increment of < 200 nmol/l and basal morning cortisol < 200 nmol/l).

RESULTS

A total of 422 children had been receiving FP alone or in combination with salmeterol; 202 were not investigated (137 FP within license; 24 FP discontinued); 220 attended and 217 (age 2.6-19.3 years) were successfully tested. Of 194 receiving FP > or = 500 microg/day, six had flat responses, 82 impaired responses, 104 were normal, and in 2 the LDST was unsuccessful. Apart from the index child, the other five with flat responses were asymptomatic; a further child with impairment (peak cortisol 296 nmol/l) had encephalopathic symptoms with borderline hypoglycaemia during an intercurrent illness. The six with flat responses and the symptomatic child were all receiving FP doses of > or = 1000 microg/day.

CONCLUSION

Overall, flat adrenal responses in association with FP occurred in 2.8% of children tested, all receiving > or = 1000 microg/day, while impaired responses were seen in 39.6%. Children on above licence FP doses should have adrenal function monitoring as well as a written plan for emergency steroid replacement.

Very high dose inhaled corticosteroids: panacea or poison?

Perspective on the paper by Paton et al (see page 808)

In VitroValidation of99mTc-HFA-FP Delivered via pMDI-Spacer

The purpose of the study was to label Flixotide (fluticasone propionate [FP] with HFA propellant), with technetium-99m and validate that (99m)Tc acts as a suitable marker for FP when delivered via pMDI-spacer. Sodium pertechnetate was mixed with 5 mL of butanone. (99m)Tc was extracted into butanone and transferred into an empty canister. The (99m)Tc lined canister was heated, and the butanone evaporated to dryness. A supercooled commercial Flixotide canister was decrimped, and the contents transferred to the (99m)Tc lined canister and recrimped. The particle size distribution of FP and (99m)Tc from 10 radiolabeled canisters was measured using an Anderson cascade impactor calibrated to 28.3 L/min, and compared to commercial FP. The drug (FP) content of each particle size fraction was measured using ultraviolet spectrophotometry and the (99m)Tc level in each fraction was measured using an ionization chamber. The percentage of particles in the fine particle fraction (<;4.7 microm) and the percentage of (99m)Tc from commercial and radiolabeled canisters were compared. The mean (SD) % FP in the fine particle fraction, before and after label was 43.2 (1.8) % and 43.9 (2.6) %, respectively. The mean (SD) % (99m)Tc in the fine particle fraction was 42.1 (5.1) %. The mean %FP exiting spacer at (<4.7 microm) before labeling was not significantly different from the mean % FP exiting spacer at (<4.7 microm) after labeling (p > 0.05). The mean % (99m)Tc attached to particles at (<4.7 microm) after radiolabeling was not significantly different from the mean % FP levels (p > 0.05). The validation in this study indicates that (99m)Tc can act as a suitable marker for HFAFP, delivered via pMDI-spacer.

Use of the low-dose corticotropin stimulation test for the monitoring of children with asthma treated with inhaled corticosteroids

OBJECTIVE

Subnormal hypothalamic-pituitary-adrenal (HPA) function and rare cases of adrenal crisis have been reported in asthmatic children treated with inhaled corticosteroids. We investigated subnormal HPA activity and followed up affected patients until recovery of normal HPA functions.

STUDY DESIGN

100 children with persistent asthma underwent low-dose corticotropin testing, with the administration of 1 microg of 1-24 ACTH intravenously. Treatments were beclomethasone dipropionate as a metered-dose inhaler, n = 14, budesonide as a dry-powder inhaler, n = 16, fluticasone propionate as a metered-dose inhaler n = 31 or a dry-powder inhaler n = 39. The mean commercially labelled dose was 520 +/- 29 microg/day (mean +/- SEM, range: 160-1,000) and the equipotent dose (which compares the efficiency of these drugs for treating asthma and their responsibility for systemic effects) was 890 +/- 55 microg/day (range: 200-2,000).

RESULTS

The mean stimulated cortisol level +/- SEM (and range) of the patient was 482 +/- 12 (148-801), and that of 40 age-matched controls was 580 +/- 12.5 (439-726), (SD = 79). The result was subnormal (more than 2 SD below the mean of the controls) in28 of the 100 patients. One-four stepwise decreases of 10-100% in the daily equipotent doses received by the patients with abnormal low-dose corticotropin testing results led to normal results in subsequent low-dose corticotropin testing in 27 retested patients. The mean time interval between two tests was 5 months (range: 2-6 months) and the mean period required for normalization of the test was 13 months (range: 2-21). Only one case of asthma exacerbation and no adrenal crisis were observed over these periods.

CONCLUSIONS

Decreasing daily equipotent doses led to recovery of normal HPA function without asthma exacerbation. Thus, a revision of the doses of inhaled corticosteroids used in asthmatic children with a progressive decrease to the consensus-recommended doses should decrease the systemic effects of inhaled corticosteroids, while minimizing the risk of asthma exacerbation.

Inhaled fluticasone reduces bronchial responsiveness and airway inflammation in cats with mild chronic bronchitis

This study investigated the effect of inhaled fluticasone on lower airway inflammation and bronchial responsiveness (BR) to inhaled carbachol in cats with very mild, chronic bronchitis (n = 5) that were compared with healthy cats serving as controls (n = 6). Chest radiographs, BR tests performed non-invasively by barometric whole body plethysmography (BWBP) and bronchoalveolar lavage (BAL) were performed before and after treatment. BR was quantified by calculating the concentration of carbachol inducing bronchoconstriction (C-Penh300%), defined as a 300% increase of baseline Penh, an index of bronchoconstriction obtained by BWBP. BAL fluid was analyzed cytologically and the oxidant marker 8-iso-PGF2alpha was determined. At test 1, healthy cats and cats with bronchitis were untreated, whereas for test 2 inhalant fluticasone (250 microg once daily) was administrated for 2 consecutive weeks to cats with bronchitis. Control cats remained untreated. Inhaled fluticasone induced a significant increase in C-Penh300% and a significant decrease of BAL fluid total cells, macrophages, neutrophils and 8-iso-PGF2alpha in cats with bronchitis, whilst untreated control cats did not show significant changes over time. This study shows that a 2-week fluticasone treatment significantly reduced lower airway inflammation in very mild bronchitis. BR could be successfully monitored in cats using BWPB and decreased significantly in response to inhaled fluticasone. 8-Iso-PGF2alpha in BAL fluid was responsive to treatment and appeared as a sensitive biomarker of lower airway inflammation in cats.

Effects of glucocorticoids on the hypothalamic-pituitary-adrenal axis in children and adults

Inhaled and intranasal corticosteroids are widely used as effective, first-line treatments for asthma and allergic rhinitis. Despite a good safety profile of these formulations, there is increasing concern about their propensity to produce systemic adverse effects. Suppression of the hypothalamic-pituitary-adrenal axis is one of the most important potential complications. This article reviews the effects of inhaled and intranasal corticosteroids on the hypothalamic-pituitary-adrenal axis function in adults and children.

The dose-response relationship of inhaled corticosteroids in asthma

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