The bronchoprotective effect of inhaled salmeterol in preschool children: a dose-ranging study

The efficacy and safety of fluticasone/salmeterol compared to fluticasone in children younger than four years of age

BACKGROUND

Fluticasone propionate 50 μg/salmeterol xinafoate 25 μg (FP/SAL) is widely used in adults and children with asthma, but there is sparse information on its use in very young children.

METHODS

This was a randomized, double-blind, multicentre, controlled trial conducted in children aged 8 months to 4 years. During a 2-week run-in period, they all received FP twice daily. At randomization, they commenced FP/SAL or FP twice daily for 8 weeks. All were then given FP/SAL only, in a 16-week open-label study continuation. Medications were inhaled through an AeroChamber Plus with attached face mask. The primary end-point was mean change in total asthma symptom scores from baseline to the last 7 days of the double-blind period. Analyses were undertaken in all children randomized to treatment and who received at least one dose of study medication.

RESULTS

Three hundred children were randomized 1:1 to receive FP/SAL or FP. Mean change from baseline in total asthma symptom scores was -3.97 for FP/SAL and -3.01 with FP. The between-group difference was not statistically significant (P = 0.21; 95% confidence interval: -2.47, 0.54). No new safety signals were seen with FP/SAL.

CONCLUSION

This is the first randomized, double-blind study of this size to evaluate FP/SAL in very young children with asthma. FP/SAL did not show superior efficacy to FP; no clear add-on effect of SAL was demonstrated. No clinically significant differences in safety were noted with FP/SAL usage.

Pharmacological approach to wheezing in preschool children

INTRODUCTION

Wheezing disorders are very common during childhood (particularly among preschool children), and represent a significant burden for patients, their families, the healthcare system, and society as a whole. Identifying wheezing phenotypes, and recognizing the risk factors associated with each, may help to predict long-term outcomes, distinguish high-risk children who may benefit from secondary prevention measures, and ensure that the most effective therapy is prescribed for each case.

AREAS COVERED

The main aim of this review is to analyze the characteristics of the drugs currently used to treat wheezing in preschool children, and discuss the results obtained in children with different wheezing phenotypes.

EXPERT OPINION

The continuous or intermittent administration of various oral or inhaled drugs could theoretically be effective in preventing or controlling wheezing in preschool children. However, the optimal management of acute preschool wheezing episodes has not yet been determined mainly because of their phenotypical heterogeneity.

An approach to preschool wheezing: to label as asthma?

Asthma is considered a chronic disease, but not all preschool wheezing is asthma since most will eventually grow out of their symptoms. Although still a matter of debate, preschool wheezing can be classified in 2 major groups: virus-induced wheezing and multitrigger wheezing, having a different prognosis and a different treatment approach. Virus-induced wheezing is the most common phenotype of preschool wheezing and is usually associated with a good prognosis. Treatment should be conservative, but if preventive treatment is required, leukotriene-receptor antagonists might be the first choice treatment. Multitrigger wheezing is associated with an allergic disposition and has a higher risk of persistent symptoms. Inhaled corticosteroids may give short-term reduction in exacerbations, but the beneficial effect of long-term use of inhaled corticosteroids and other anti-inflammatory agents have not yet been established. This review aims to give an opinion on preschool wheezing, and its association with asthma.

Use and safety of long-acting β2-agonists for pediatric asthma

Asthma guidelines recommend the use of long-acting β2-agonists (LABAs) as the preferred add-on therapy for adults and children over 5 years of age when asthma is inadequately controlled by inhaled corticosteroids alone. It has been suggested that LABA use may be associated with an increased risk of morbidity and mortality; however, this view is controversial since study findings have been inconsistent. While the safety profile of LABA monotherapy has been questioned, the value of concomitant inhaled corticosteroids to eliminate possible risks remains unproven. There is a paucity of efficacy and safety data for LABA use in children, and existing evidence is not sufficiently convincing to demonstrate a clear position for LABAs in the management of childhood asthma. The main aims of this article are to place LABAs in context in the management of childhood asthma and evaluate the current evidence for safety and efficacy.

Management of paediatric asthma

Paediatric asthma best practice not only includes prescribing the correct therapeutic mix based on consensus guidelines, but also reducing therapy once control has been achieved. Clinicians should also be aware that asthma in young children is a heterogeneous entity, and a beneficial response to bronchodilators and/or inhaled steroids is not inevitable. In general, preschool children and infants should not be prescribed inhaled corticosteroids above 200 microg beclometasone dipropionate equivalent twice a day, or regular oral steroids, or long acting beta2-adrenoceptor agonists. New therapies such as anti-IgE antibodies are on the horizon, but these are unlikely to replace the established drug combinations. More likely is that the delivery of established drugs will become more convenient (for example, once a day inhaled corticosteroids, or season dependent prophylactic therapy).

Treating the wheezing infant

The management of infants and small children with asthma is a challenging task because of the many issues unique to this age group that deserve special consideration. The diagnosis of asthma is limited by inherent difficulties in obtaining objective measures of lung function and airway inflammation. In persistently symptomatic patients, the decision to initiate controller therapy is not as great an issue as it is in infants and young children with recurrent episodic wheeze in whom early intervention may allow a window of opportunity potentially to alter the course of the disease. The reality is that even if atopy has been consistently implicated in the development of persistent asthma, there is not a well-established set of criteria by which patients who are likely to benefit from early intervention controller therapy can be identified. Hence, large prospective studies need to be performed evaluating the impact of early pharmacologic intervention on the natural history of infantile asthma. Many areas needing investigation involve what medications to use, how best to deliver the medications, and how to monitor the response to treatment. Only a few medications have been approved for use in this population. Long-term studies evaluating available drugs such as inhaled glucocorticoids, LABAs, and the leukotriene-modifying agents in young children still need to be performed.

Inhaled corticosteroids plus long-acting beta2-agonists as a combined therapy in asthma

Inhaled corticosteroids (ICS) are the mainstay of asthma treatment. Since 1994, when the first trial showed an equivalent effect of doubling the ICS dose or adding salmeterol, it has repeatedly been shown that the combinations of beclomethasone dipropionate and salmeterol, budesonide and formoterol, or fluticasone propionate and salmeterol have at least the same efficacy as doubling the dose of the ICS in adults, though a conclusive trial in asthmatic children is still lacking. The addition of a long-acting beta(2)-agonist (LABA) to ICS appears more efficacious than adding a short-acting beta(2)-agonist or an antileukotriene, even though available data are sparse. Concurrent (two inhalers) and combination (same inhaler) modes of administration are equivalent from the clinical point of view, as is also true regarding administration via metered dose inhaler or dry powder inhaler. Using a single inhaler might eventually have a positive effect on treatment compliance, but there are no confirmatory data yet. Despite some clues regarding a presumed agonist effect of ICS and LABAs, there are still more doubts than certainties. Even though there are still unanswered questions, the data available strongly suggest that the fixed combination of ICS and LABAs using the same inhaler is an efficacious, safe and practical approach for those asthmatic patients who are not well controlled with low doses of ICS alone.

Salmeterol 100 microg: an analysis of its tolerability in single- and chronic-dose studies

BACKGROUND

A combination product containing fluticasone propionate 100 or 250 microg and salmeterol 50 microg has recently been made available in the United States. Some patients, if previously instructed to double their inhaled corticosteroids, may double this product, inadvertently receiving higher doses of salmeterol, potentially causing systemic beta2-agonist-related effects.

OBJECTIVES

To examine the systemic effects of single and chronic doses of salmeterol 100 microg.

METHODS

Forty-four studies including a salmeterol 100 microg treatment arm were identified. Data on predictable systemic effects were available in 10 single-dose and 9 chronic-dose studies lasting more than 7 days, in patients with asthma (6 adult, 2 pediatric) or chronic obstructive pulmonary disease (1 study), which were included in a weighted, pooled analysis.

RESULTS

Single 100-microg dose studies: mean change from baseline in heart rate was +2.3 beats per minute and systolic blood pressure +0.4 mm Hg. Tremor and palpitations were reported in 5.7% and 2.8%. Other systemic effects included a decrease in serum potassium for 3 subjects (2.1%); an increase in serum glucose, 1 subject (0.7%); and electrocardiographic (ECG) events, 24 cases (17.0%). Twenty-three of these were from one crossover study which reported 27 ECG events after placebo. Chronic dose studies (salmeterol 100 microg): mean change in heart rate and systolic blood pressure were +1.8 beats per minute and -0.2 mm Hg. Tremor and palpitations were reported in 5.6% and 1.7% of 1,504 patients. Thirteen recorded a decrease in serum potassium (0.9%) and 5 an increase in serum glucose (0.3%). Nine patients had ECG events (0.6%). Eight of these were "arrhythmia" from one study, which also reported 12 events before treatment.

CONCLUSIONS

The mean systemic effects of salmeterol 100 microg are small and of doubtful clinical relevance. Patients (and their caregivers) can be reassured that inadvertently taking double doses of the new combination product are unlikely to affect them adversely.

Evaluation of particle size distribution of salmeterol administered via metered-dose inhaler with and without valved holding chambers

BACKGROUND

Administration of inhaled medications to very young children is sometimes difficult. Administration of inhaled medications via metered dose inhalers (MDIs) to pediatric patients younger than 4 years of age requires use of a holding chamber/spacer with an attached facemask.

OBJECTIVE

This in vitro study was conducted to determine the particle size distribution and overall dose of salmeterol delivered in conjunction with the use of various US-marketed valved holding chambers (VHCs) in comparison to the dose-delivered via MDI without VHCs.

METHODS

Cascade impaction methodology with high-performance liquid chromatography was used to evaluate the fine particle mass (FPM) of salmeterol administered without and with the use of the following VHCs: Optichamber, medium and large Aerochambers, adult Aerochamber, and medium Aerochamber Plus.

RESULTS

Particle size distributions for the Optichamber, various sizes of Aerochamber, and the Aerochamber Plus were very similar and the particle size distributions for all VHCs were similar to the distribution of the control. The FPM for particles ranging from 0.7 to <3.3 microm in diameter (in the range shown to provide the greatest lung dose to negotiate the small airways of infants) was similar across the various VHCs tested. Statistical comparison of the fine particle fraction for these stages shows a very similar profile when differences from the salmeterol MDI control were evaluated.

CONCLUSIONS

In vitro results obtained under these test conditions demonstrate that all FPM values for the VHCs tested were within 15% of the control range, a difference that is unlikely to be clinically meaningful. These results indicate that the difference in FPM does not warrant a change in the recommended dosage of salmeterol administered when using the VHCs tested. Our results demonstrate that the use of an MDI and VHC provides a reasonable therapeutic approach for administration of salmeterol MDI to young children and other patients who have difficulties administering the MDI alone.

Salmeterol in paediatric asthma

BACKGROUND

The addition of long acting inhaled beta(2) agonists is recommended at step 3 of the British guidelines on asthma management but a recent study suggested no additional benefit in children with asthma.

METHODS

The aim of this study was to compare, in a double blind, three way, crossover study, the effects of the addition of salmeterol 50 microg bd, salmeterol 100 microg bd, and salbutamol 200 microg qds in asthmatic children who were symptomatic despite treatment with inhaled corticosteroids in a dose of at least 400 microg/day over a one month period. Symptom scores, morning and evening peak expiratory flow (PEF) rates, use of rescue medication, spirometric indices, and histamine challenge were measured.

RESULTS

Forty five children aged 5-14 years were enrolled. All three treatments improved asthma control, morning and evening PEF rates, and spirometric indices with no change in bronchial hyperreactivity. Mean morning PEF was significantly better during the salmeterol treatment periods than with salbutamol treatment (p<0.05). The analysis of mean morning PEF gave an estimated treatment difference of 9.6 l/min for salmeterol 50 microg bd versus salbutamol 200 microg qds (95% confidence interval (CI) 2.1 to 17.1), and an estimated treatment difference of 13.8 l/min for salmeterol 100 microg bd versus salbutamol 200 microg qds (95% CI 6.0 to 21.5). There were no significant differences between the two doses of salmeterol and all treatments were well tolerated.

CONCLUSIONS

In this population of moderate to severe asthmatic children on inhaled corticosteroids, salmeterol in a dose of either 50 microg bd or 100 microg bd is significantly more effective at increasing the morning PEF rate over a one month period than salbutamol 200 microg qds. The data provided no significant evidence of a difference in efficacy between the two doses of salmeterol, 50 microg and 100 microg. A trial of salmeterol 100 microg bd may be worth considering in those still symptomatic on the lower dose.