Short-term growth and adrenal function in children with asthma treated with inhaled beclomethasone dipropionate hydrofluoroalkane-134a

Knemometry is more sensitive to systemic effects of inhaled corticosteroids in children with asthma than 24-hour urine cortisol excretion

BACKGROUND

Pharmacodynamic assessment of the systemic effect of inhaled corticosteroids (ICSs) is often done by measuring 24-hour urine free cortisol (UFC) excretion. Knemometry assessing short-term lower-leg growth rate (LLGR) is a more rarely used alternative.

OBJECTIVE

The primary aim of this study was to compare the sensitivity of LLGR and 24-hour UFC excretion for evaluating systemic exposure to ICSs in prepubertal children with asthma. The secondary aim was to evaluate factors influencing the precision of LLGR calculated by the traditional 1 leg nonparametric method versus a new 2 leg parametric method.

METHODS

The study evaluated 60 children with mild asthma aged 5 to 12 years participating in a randomized controlled trial of ICSs with longitudinal concomitant assessments of LLGR and 24-hour UFC excretion. The sensitivity of the safety assessments was analyzed by comparing LLGR and 24-hour UFC in the placebo run-in period with values in the ICS treatment period by using paired t tests. Factors with a potential influence on LLGR were analyzed by means of ANOVA and the Levene test of homogeneity.

RESULTS

The mean LLGR was significantly reduced during the ICS versus placebo run-in periods: 0.18 mm/wk (SD, 0.55 mm/wk) versus 0.45 mm/wk (SD, 0.39 mm/wk), with a mean difference of 0.27 mm/wk (95% CI, 0.05-0.48 mm/wk; P = .02). In contrast, there was no difference in 24-hour UFC excretion: 6.91 nmol/mmol (SD, 4.67 nmol/mmol) versus 7.58 nmol/mmol (SD, 6.17 nmol/mmol), with a mean difference of 0.67 nmol/mmol (95% CI, -1.13 to 2.48 nmol/mmol; P = .46). We observed no significant difference in parametric determined LLGR caused by the child's age or sex, investigator, or season of measurement, whereas some differences were observed for the nonparametric LLGR.

CONCLUSION

These findings suggest that knemometry is a more sensitive pharmacodynamic measure of systemic effects of ICSs than 24-hour UFC excretion and that a parametric determination of LLGR increases the sensitivity of the method. These findings should be considered by legislative authorities in the future.

Extra-fine particle inhaled corticosteroids, pharma-cokinetics and systemic activity in children with asthma

During recent years, extra-fine particle inhaled corticosteroids with a median aerodynamic diameter ≤2 μm have been introduced in the treatment of asthma. The aim of this paper was to review pharmacokinetics and systemic activity of extra-fine particle hydroalkane pressurized metered dose inhaled (pMDI) ciclesonide and beclomethasone dipropionate in children. A literature review was performed. Systemic bioavailability of oral and pulmonary deposition of extra-fine ciclesonide and beclomethasone dipropionate was 52% and 82%, the half-life in serum 3.2 and 1.5 h and first-pass hepatic metabolism >99% and 60%, respectively. Secondary analyses of urine cortisol/creatinine excretion found no effects of ciclesonide pMDI between 40 and 320 μg/day or of beclomethasone dipropionate pMDI between 80 and 400 μg/day. Ciclesonide pMDI 40, 80 and 160 μg/day caused no effects on short-term lower leg growth rate as assessed by knemometry. Ciclesonide 320 μg/day was associated with a numerically short-term growth suppression equivalent to 30% which was similar to 25% and 36% suppression caused by beclomethasone dipropionate HFA and CFC 200 μg/day, respectively. Consistent with the differences in key pharmacokinetic features, beclomethasone dipropionate is associated with a systemic activity detected by knemometry at a lower dose than ciclesonide. Whether that correlates with a clinically important difference remains to be explored. Assessments of systemic activity of beclomethasone dipropionate <200 μg/day and of ciclesonide >180 μg/day as well as head-to-head comparisons are warranted. Preferably, such studies should apply the sensitive method of knemometry.

A Comparison of Short-Term Growth During Treatment with Two Dry Powder Combinations of Inhaled Corticosteroids and Long-Acting β₂-Agonists

BACKGROUND

A combination of the inhaled corticosteroid budesonide and the long-acting β2-agonist formoterol has been formulated in a novel dry powder inhaler, Spiromax(®). The objective was to compare lower leg growth in children with asthma treated with inhaled budesonide+formoterol (BF) delivered from the Spiromax inhaler with BF from the Symbicort Turbohaler(®).

METHODS

Prepubescent children with persistent asthma (n=75, aged 6-11 years) were included in a randomized, double-blind, double-dummy, placebo-controlled, three-way crossover study with active treatment and placebo periods of 2 weeks duration. Lower leg length was measured every second week. As a secondary outcome parameter, 24-hr urine was collected for assessment of free cortisol. Interventions were dry powder BF 160+9 μg twice daily (b.i.d.; delivered dose) from the Spiromax inhaler and dry powder BF 200+12 μg b.i.d. (metered dose) from the Symbicort Turbohaler.

RESULTS

The least squares mean difference in lower leg growth rates (LLGR) between BF Spiromax and Symbicort Turbohaler was -0.086 mm/week [95% confidence interval (CI) -0.203, 0.032]. The pre-specified non-inferiority margin was -0.200 mm/week, so the lower limit of the 95% CI was just outside this margin. The difference between BF Spiromax and placebo was -0.20 mm/week (95% CI: -0.322, 0.086); p<0.001), between Symbicort Turbohaler and placebo -0.118 mm/week (95% CI: -0.236, -0.001; p=0.048). No statistically significant differences were seen in urine free cortisol assessments.

CONCLUSIONS

As the lower limit of the CI of LLGR was marginally outside of the pre-specified non-inferiority margin between BF Spiromax 160+9 μg b.i.d. and Symbicort Turbohaler 200+12 μg b.i.d., non-inferiority could not be demonstrated. Further studies may be needed for comparison of systemic activity of BF Spiromax and Symbicort Turbohaler in children before firm conclusions about their comparability may be drawn.

Systemic activity of inhaled beclomethasone dipropionate: a double-blind comparison of volume spacers

BACKGROUND

To which extent volume spacers may influence systemic activity of inhaled beclomethasone dipropionate (BDP) has not been evaluated.

AIM

To assess whether the AeroChamber Plus™ spacer is equivalent to the Volumatic™ spacer for administration of inhaled hydroflouroalkane 134a propelled BDP in terms of lower leg growth rate (LLGR).

PATIENTS AND METHODS

Prepubertal children with mild asthma (n = 26, aged 6-14 years) were included in a 3-time periods of 2 weeks duration randomized double-blind cross-over study with a single-blind placebo run-in and two washout periods. LLGR was measured with the knemometer. Interventions were inhaled BDP hydroflouroalkane 134a pressurized metered dose inhaler 100 μg and 200 μg b.i.d. with the AeroChamber Plus and 200 μg b.i.d. with the Volumatic spacer.

RESULTS

Beclomethasone dipropionate 200 μg b.i.d. from the AeroChamber Plus was non-inferior to BDP 200 b.i.d. from the Volumatic spacer as the lower margin of confidence interval of the difference between treatments (-0.18 to 0.13 mm/week) was greater than the prespecified lower limit for non-inferiority (-0.20 mm/week). UFC/creatinine data showed no statistically significant variations.

CONCLUSION

The systemic activity of BDP, via the Volumatic™, and AeroChamber Plus™ spacers is similar. The AeroChamber Plus spacer may be used in children without risk of increasing systemic activity of BDP.

Methodology and implications of knemometry in growth assessment of inhaled glucocorticoids

When validated recommendations for standardization and measurement procedures are used short-term assessment of lower leg growth by knemometry is a highly accurate and reproducible method for assessment of systemic activity of inhaled glucocorticoids. Crossover and parallel designs applying consistent measurement intervals can be used. Crossover designs with a single-blind run in and washout and double-blind active periods are as sensitive as designs using randomized placebo periods. In populations of children, short-term knemometry appears to be capable of defining specific glucocorticoids, application devices and doses that do not suppress long-term height growth. Although no specific cut-off level can be identified in individuals from the available randomized, double-blind short-term knemometry and intermediate-term height growth rate studies, good evidence have been provided that if the short-term lower leg growth suppression in populations of children is higher than approximately 25%, the risk of intermediate-term growth suppression becomes significant with a mean height growth rate retardation in the range of approximately 0.5-1.5 cm during the first year of treatment. Short-term knemometry should be performed as an integral part of the safety assessments of new inhaled glucocorticoids and inhalation devices in children with asthma, before intermediate-term height growth evaluations are initiated.

Cortisol suppression as a surrogate marker for inhaled corticosteroid-induced growth retardation in children

Exposure of inhaled corticosteroids (ICSs) in pediatrics results in adrenal suppression and growth inhibition. The objective of this study was to assess the relationship of ICS mediated growth retardation with cortisol suppression in asthmatic children. A meta-analysis approach was performed with 33 published articles. Growth velocity (GV) data were obtained from the literature for evaluation of growth. Cumulative cortisol suppression within 24h (CCS%) was calculated at steady state with a validated algorithm. Consolidated GV and CCS% data were employed for model development. A linear mixed effects model was developed to adequately describe the relationship between GV and CCS%. No impact of tested covariates was observed. Population estimate of the rate of change in GV was -0.06cm/year/CCS% (12.7%, coefficient of variation) for both stadiometry and knemometry methods. However, GV from stadiometry is expected to be approximately three fold higher than that from knemometry when cortisol suppression was not presented. The final model was evaluated with posterior predictive check and pattern check approaches. The results from this study elucidate CCS% as an excellent predictor of ICS mediated growth retardation in asthmatic children.

Diagnosis and treatment of asthma in childhood: a PRACTALL consensus report

Asthma is the leading chronic disease among children in most industrialized countries. However, the evidence base on specific aspects of pediatric asthma, including therapeutic strategies, is limited and no recent international guidelines have focused exclusively on pediatric asthma. As a result, the European Academy of Allergy and Clinical Immunology and the American Academy of Allergy, Asthma and Immunology nominated expert teams to find a consensus to serve as a guideline for clinical practice in Europe as well as in North America. This consensus report recommends strategies that include pharmacological treatment, allergen and trigger avoidance and asthma education. The report is part of the PRACTALL initiative, which is endorsed by both academies.