- Email: [email protected]
Comparisons of the complementary effect on exhaled nitric oxide of salmeterol vs montelukast in asthmatic children taking regular inhaled budesonide
Comparisons of the complementary effect on exhaled nitric oxide of salmeterol vs montelukast in asthmatic children taking regular inhaled budesonide Frederik Buchvald, MD, PhD and Hans Bisgaard, MD, DMSci Background: Inhaled, long-acting 2-agonists or antileukotrienes are alternatives as add-on therapy for asthmatic children taking regular inhaled steroids. Any complementary effects would be relevant to the choice between these alternatives. Exhaled nitric oxide (FeNO) may reflect these effects. Objective: To compare the control of FeNO provided by salmeterol or montelukast add-on therapy in asthmatic children undergoing regular maintenance treatment with a daily dose of 400 g of budesonide. Methods: The study included children with increased FeNO despite regular treatment with budesonide, 400 g/d, and normal lung function. Montelukast, 5 mg/d, salmeterol, 50 g twice daily, or placebo was compared as add-on therapy to budesonide, 400 g, in a randomized, double-blind, double-dummy, crossover study. Results: Twenty-two children completed the trial. The geometric mean FeNO level was 20 ppb (95% confidence interval [CI], 15–27 ppb) after salmeterol, which was significantly higher than after montelukast (mean, 15 ppb; 95% CI, 11–18 ppb; P ⫽ 0.002) and placebo (mean, 15 ppb; 95% CI, 10 –21 ppb; P ⫽ 0.03). There was no difference in FeNO between the montelukast and placebo groups. Mean forced expiratory volume in 1 second (FEV1) was significantly increased after salmeterol (mean, 2.63 L; 95% CI, 2.34 –2.91 L) compared with placebo (mean, 2.48 L; 95% CI, 2.19 –2.77 L). Montelukast (mean, 2.57 L; 95% CI, 2.33–2.80 L) was no different than placebo. Conclusions: The FeNO levels were significantly higher after salmeterol add-on treatment compared with both placebo and montelukast add-on treatment. Salmeterol significantly improved lung function (FEV1) compared with placebo and nonsignificantly compared with montelukast. Montelukast failed to reduce FeNO and improve lung function compared with placebo in this group of children taking regular budesonide, 400 g. Ann Allergy Asthma Immunol. 2003;91:309–313.
INTRODUCTION Long-acting 2-agonists (LABAs) or leukotriene receptor antagonists (LTRAs) are alternatives as add-on treatment in children inadequately controlled with a moderate dose of inhaled corticosteroids (ICSs). LTRA add-on therapy in children undergoing regular ICS treatment was recently demonstrated to improve lung function and reduce asthma exacerbations.1 LABAs may also improve lung function and airway inflammation in adults,2 although such evidence in support of regular add-on therapy of LABAs in pediatric asthma is ambiguous.3 Any complementary effects would be relevant to the choice between LTRAs and LABAs. We undertook a study to compare the complementary effect of LABAs vs LTRAs on exhaled nitric oxide (FeNO) in asthmatic children undergoing regular ICS treatment.
Department of Pediatrics, Rigshospitalet, National University Hospital, Copenhagen, Denmark. This study was supported by a medical school grant from Merck. The study was initiated, conducted, analyzed, and reported by the authors without interaction with the sponsoring company. Received for publication December 5, 2003. Accepted for publication in revised form April 15, 2003.
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FeNO was the primary outcome because it is probably a more sensitive marker for asthma control than lung function.4 Children were selected among asthmatic patients with raised FeNO levels despite regular treatment with inhaled budesonide, 400 g/d. To our knowledge, this is the first head-tohead comparison of the addition of salmeterol and montelukast to regular steroid treatment in pediatric asthma management. METHODS Patients Asthmatic schoolchildren 6 to 15 years of age taking a maintenance dose of inhaled budesonide, 400 g/d, via Turbohaler (Spirocort, Astra Zeneca, Lund, Sweden) were screened for the study. Increased FeNO was defined from the upper quartile of the FeNO level (12 ppb) of that screening population. Children were qualified for the randomized trial if the FeNO level was still increased within 2 weeks before randomization. Treatment with ICSs had to be unchanged for at least 1 month before enrollment in the study. Inhaled, short-acting 2-agonists were allowed as rescue treatment. No other antiasthma treatment was allowed during the study and in the month
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before inclusion. FeNO was also measured in 31 healthy controls 6 to 15 years of age with no history of atopic disease. Study Design The study was a single-center, double-blind, placebo-controlled, double-dummy, 3-period, crossover design without washout periods. The 3 arms of treatment were either active salmeterol or placebo montelukast, active montelukast and placebo salmeterol, and placebo montelukast and placebo salmeterol. Children were randomized by a computer-generated schedule to receive 1 of the 6 combinations of treatment sequences available (salmeterol-placebo-montelukast, salmeterol-montelukast-placebo, montelukast-placebo-salmeterol, montelukast-salmeterol-placebo, placebo-montelukast-salmeterol, or placebo-salmeterol-montelukast). Montelukast was given as a 5-mg, chewable tablet in the evening or matching placebo. Salmeterol was given as 50 g or matching placebo inhaled from a Discus (Copenhagen, Denmark) dry-powder inhaler twice daily. Each treatment period was a mean ⫾ SD of 14 ⫾ 2 days with no washout periods between treatments. All children continued taking their budesonide, 400 g, throughout the study. Study medication and terbutaline were withheld for 12 and 4 hours, respectively, before the measurements of FeNO and spirometry. Patients were excluded from the trial if they had an airway infection during the study period. Unused medication was returned to the clinic at the end of each 2-week period, and compliance was estimated from pill counts and from the dose counter on the salmeterol inhaler. Lung Function and FeNO FeNO was measured at each visit followed by spirometry. Spirometry was performed with a Master Screen unit (E. Ja¨eger GmbH, Wu¨rtzburg, Germany) in accordance with American Thoracic Society guidelines5 to calculate forced expiratory volume in 1 second (FEV1), forced vital capacity, and forced expiratory flow rate at 25%, 50%, and 75% (FEF25%, FEF50%, and FEF75%, respectively). Single-breath, on-line measurement of FeNO was performed in accordance with the recommendations of the European Respiratory Society6 with an exhalation flow of 90 to 110 mL/s and exhalation pressure of at least 5 cm H2O. Nitric oxide was measured with the Aerocrine nitric oxide system (Aerocrine AB, Stockholm, Sweden). The child inhaled to total lung capacity from nitric oxide free air and exhaled subsequently for 10 seconds against a linear resistor. A nose clip was not used. The measurement was accepted if stable exhalation flow was sustained for the last 5 seconds of exhalation. Nitric oxide was calculated as the mean value from 50% to 90% of the whole breath, and the mean of 3 approved measurements represents FeNO. We have previously described in detail the equipment used for FeNO measurements.7 Ethics The study was performed and data collected according to the principles of good clinical practice. The blinded code was
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broken after a clean file had been declared and the data files had been locked in the computer. The study was approved by the local ethics committee (KF 02-052/99) and the health authorities (2612–995). Written informed consent was obtained from the parents and verbal assent from the children. Statistics All children who completed measurements after the 3 treatment periods were included in the analysis. The study was designed with 80% power to detect a 20% reduction of FeNO for active treatment vs placebo, with the ␣ error set at .05 (2-tailed) and SD based on our previous study.7 A computer package (MedCalc version 6, MedCalc Software, Mariakerke, Belgium, and SAS System for Windows version 8, SAS Institute Inc, Cary, NC) was used for statistic calculations. Nitric oxide data were log transformed, and central tendency was expressed as geometric mean (95% confidence interval [CI]), since criteria for the normal distribution were not fulfilled (Kolmogorov-Smirnov test). Spirometry measurement exhibited a normal distribution and was expressed as mean (95% CI). Group comparisons were performed by paired t test. To estimate carryover and period effect between treatments, multifactor analysis of variance (ANOVA) was performed. RESULTS One hundred eighty-four asthmatic schoolchildren undergoing regular treatment with budesonide, 400 g/d, were screened. The geometric mean FeNO level was 7 ppb (95% CI, 6 – 8 ppb), which was significantly higher than the FeNO level in 31 healthy controls (mean, 5 ppb; 95% CI, 3–7 ppb; P ⫽ 0.01). The upper quartile (75% percentile) was 12 ppb. Twenty-three of the children with FeNO in the upper quartile (⬎12 ppb) were randomized to the controlled study. Patient characteristics for the children randomized into the trial are shown in Table 1. Compliance to montelukast was good throughout the study. Discrepancy between the number of study days and the number of doses taken ranged from –2 to ⫹5 tablets during active montelukast treatment and from 3 to ⫹3 doses during active salmeterol inhaler treatment. All children reported having taken their study medication as prescribed at least during the 6 days before each visit. Both treatments were well tolerated. Ten adverse events were reported: 6 during placebo treatment, 3 during montelukast treatment, and 1 during salmeterol treatment. Two adverse events were suspected of being drug related: 2 children complained of dizziness, nausea, and vomiting after the first dose of montelukast. However, the symptoms disappeared within 1 to 2 days. Twenty-two of 23 randomized children completed the study. One child was excluded from further analysis, because she did not show up for the last study visit. None of the children had any asthma exacerbation or airway infections during the study.
ANNALS OF ALLERGY, ASTHMA, & IMMUNOLOGY
Table 1. Patient Characteristics Characteristic
Result
No. of children Age, mean (range), y Sex, F/M Height, mean (range), cm Weight, mean (range), kg Rhinoconjunctivitis Eczema Positive allergy skin prick test result Atopy in first-degree relatives FeNO, geometric mean (95% CI), ppb Lung function, % predicted (95% CI) FEV1 FEF75% FEF50% FEF25%
23 12 (7–14) 11/12 152 (132–190) 48 (29–100) 22/23 7/23 20/23 16/23 25 (21–30) 101 (95–107) 75 (63–86) 84 (75–94) 93 (85–101)
Abbreviations: CI, confidence interval; FEF25%, FEF50%, and FEF75%, forced expiratory flow rate at 25%, 50%, and 75%, respectively; FeNO, exhaled nitric oxide; FEV1, forced expiratory volume in 1 second.
The results of FeNO and lung function tests in the 22 children who completed the study are summarized in Table 2. There was no carryover or period effect between treatments (multifactor ANOVA: P ⫽ 0.90). The primary analysis showed that the FeNO level was significantly higher during salmeterol treatment compared with montelukast treatment (P ⬍ 0.01; Fig 1). The FeNO level was significantly increased after salmeterol treatment compared with placebo (P ⬍ 0.05), whereas FeNO levels did not differ between the montelukast and placebo groups. FEV1 exhibited a significant improvement after salmeterol treatment (P ⫽ 0.02), with a nonsignificant improvement after montelukast treatment (P ⫽ 0.11) compared with placebo. There was no significant difference in any lung function parameter between the montelukast and salmeterol groups. FEF75% increased significantly after salmeterol (P ⫽ 0.02) and montelukast (P ⫽ 0.01) treatment compared with placebo. FEF25% and FEF50% showed no significant changes from treatments.
Figure 1. Exhaled nitric oxide (FeNO) (geometric mean) and individual values during treatment with montelukast, placebo, and salmeterol and at randomization.
DISCUSSION The FeNO levels were significantly higher after salmeterol add-on treatment compared with montelukast and placebo add-on treatment in asthmatic children undergoing regular maintenance treatment with 400 g of budesonide. These findings are in keeping with a report by Lipworth et al8 that showed a higher FeNO level with the addition of formoterol compared with zafirlukast in a comparative study of adult asthmatic patients taking 200 to 1,600 g/d of ICSs. In a subsequent study, this group found no effect on FeNO with
Table 2. Measurements of Lung Function and FeNO Test FeNO, geometric mean (95% CI), ppb (n ⫽ 22) FEV1, mean (95% CI), (n ⫽ 22) FEF75%, mean (95% CI) (n ⫽ 22)
Baseline
Placebo
Montelukast
Salmeterol
25 (21–30)*†
15 (10–21)†‡
15 (11–18)‡§
20 (15–27)¶㛳
2.54 (2.27–2.87)† 1.30 (1.05–1.54)
2.48 (2.19–2.77)† 1.17 (0.94–1.40)†
2.57 (2.33–2.80) 1.36 (1.13–1.59)*
2.63 (2.34–2.91)¶㛳 1.40 (1.18–1.62)¶
Abbreviations: CI, confidence interval; FEF75%, forced expiratory flow rate at 75%; FeNO, exhaled nitric oxide; FEV1, forced expiratory volume in 1 second. * P ⬍ 0.01 compared with placebo. † P ⬍ 0.05 compared with salmeterol. ‡ P ⬍ 0.01 compared with baseline. § P ⬍ 0.01 compared with salmeterol. ¶ P ⬍ 0.05 compared with placebo. 㛳 P ⬍ 0.05 compared with baseline.
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montelukast or salmeterol,9 but the patients had near-normal FeNO levels at randomization with little room for improvement with montelukast. Similarly, in our study the secondary comparison of montelukast vs placebo failed to show the expected reduction in FeNO levels. We have previously reported reduced FeNO levels from LTRA treatment in 23 asthmatic children,7 in whom 11 were taking a maintenance dose of ICS (mean, 273 g). This was confirmed in other studies in children10 and adults,11 also including mixed populations with and without concurrent ICS therapy. In the present study, montelukast failed to improve FeNO compared with placebo. This may partly be explained by a floor effect, since FeNO in 10 children reached a normal level during the controlled placebo treatment with their regular budesonide, 400 g, only. FeNO levels were significantly reduced by montelukast compared with placebo in the remaining 12 children. Increasing evidence of heterogeneous response to asthma treatment may be an important factor for the apparent different response between children and study reports.12,13 Finally, the children in the present study were highly selected as those children who had increased FeNO despite being well controlled with regular budesonide treatment, 400 g/d. These children served the purpose of our mechanistic study objective but may constitute a special subgroup, where FeNO might be driven by factors not fully accessible to either steroid or LTRAs. FeNO has been suggested to reflect eosinophilic inflammation14,15 and is particularly sensitive to anti-inflammatory treatment,16 although a specific relation has not been proved. FeNO was recently reported to be sensitive to adherence to steroids,15,17 and improved adherence to the maintenance steroid treatment during the trial has probably reduced FeNO levels during the treatment periods in some of the children. However, such a trial effect could hardly explain differences between treatments in this crossover design. Indeed, there were no statistically significant period effects (treatment sequence) demonstrated, and we found no carryover effect from the treatments. This is in line with the fact that FeNO levels return to baseline 14 days after montelukast use has been stopped.18 FeNO increased significantly with salmeterol compared with placebo. This is consistent with previous reports of increased FeNO with the use of LABAs.19,20 The effect of LABAs on FeNO may be confounded by the bronchodilatory effect; we and others have previously reported 5% to 10% increases in FeNO with short-acting 2-agonists.7,21 However, the observed 25% increase in FeNO 12 hours after salmeterol administration exceeds that previously reported during maximal bronchodilation and may not be solely due to bronchodilation. The mechanism by which salmeterol increases FeNO is unknown. Asthmatic children undergoing regular treatment with budesonide, 400 g/d, were screened for this study. They presented a gaussian distribution of FeNO around a geometric mean of 7 ppb, which is significantly raised compared with healthy controls. Children with FeNO levels in the upper
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quartile were invited to participate in the study. They did not differ from the children in the lower 3 quartiles in terms of lung function, symptoms, atopic heredity, or allergy. They were apparently well controlled, with no daily symptoms and normal lung function. The children showed no clinical evidence of requiring intensified treatment. Still, some presented with increased FeNO, which may be a surrogate marker of disease control.4,14,22–24 This allowed us to study the specific effect on FeNO of alternative treatments added to a 400-g/d dose of budesonide, without the confounding effect from substantial changes in lung function, symptoms, and exacerbations. The study was powered to compare the effect on FeNO but not on lung function, and there was little room for improvement since the mean FEV1 was 101% predicted. Nonetheless, FEV1 improved significantly during salmeterol use, probably partly reflecting the effect on the inherent bronchomotor tone seen even in healthy controls.25 Montelukast did not change FEV1 significantly, although there was no statistical difference between FEV1 on the 2 active treatments. FEF75% at randomization was significantly reduced in the study population (75% predicted), which may reflect small airway obstruction. FEF25%-75% is a sensitive marker of airway obstruction even in children without symptoms or decreased FEV1.26,27 Small airways have been suggested as the major site of obstruction in asthma.28,29 Montelukast and salmeterol significantly improved FEF75%. In conclusion, FeNO levels were significantly higher after salmeterol add-on treatment compared with both placebo and montelukast add-on treatment. Montelukast failed to reduce FeNO levels further compared with placebo in this group of children taking regular budesonide, 400 g. Salmeterol exhibited improved bronchodilation in large and small airways after add-on to inhaled steroids compared with both placebo and montelukast. FeNO increased significantly after salmeterol treatment. The clinical relevance of this finding needs further study. REFERENCES 1. Simons FE, Villa JR, Lee BW, et al. Montelukast added to budesonide in children with persistent asthma: a randomized, double-blind, crossover study. J Pediatr. 2001;138:694 – 698. 2. Li X, Ward C, Thien F, et al. An antiinflammatory effect of salmeterol, a long-acting 2 agonist, assessed in airway biopsies and bronchoalveolar lavage in asthma. Am J Respir Crit Care Med. 1999;160:1493–1499. 3. Bisgaard H. Long-acting 2-agonists in management of childhood asthma: a critical review of the literature [see comments]. Pediatr Pulmonol. 2000;29:221–234. 4. Jones SL, Kittelson J, Cowan JO, et al. The predictive value of exhaled nitric oxide measurements in assessing changes in asthma control. Am J Respir Crit Care Med. 2001;164: 738 –743. 5. American Thoracic Society. Standardization of spirometry, 1994 update. Am J Respir Crit Care Med. 1995;152:1107–1136. 6. Kharitonov S, Alving K, Barnes PJ, The European Respiratory Society Task Force. Exhaled and nasal nitric oxide measurements: recommendations. Eur Respir J. 1997;10: 1683–1693.
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7. Bisgaard H, Loland L, Anhoj J. NO in exhaled air of asthmatic children is reduced by the leukotriene receptor antagonist montelukast. Am J Respir Crit Care Med. 1999;160:1227–1231. 8. Lipworth BJ, Dempsey OJ, Aziz I, et al. Effects of adding a leukotriene antagonist or a long-acting 2-agonist in asthmatic patients with the glycine-16 2-adrenoceptor genotype. Am J Med. 2000;109:114 –121. 9. Wilson AM, Dempsey OJ, Sims EJ, et al. Evaluation of salmeterol or montelukast as second-line therapy for asthma not controlled with inhaled corticosteroids. Chest. 2001;119: 1021–1026. 10. Bratton DL, Lanz MJ, Miyazawa N, et al. Exhaled nitric oxide before and after montelukast sodium therapy in school-age children with chronic asthma: a preliminary study. Pediatr Pulmonol. 1999;28:402– 407. 11. Kobayashi H, Takahashi Y, Mitsufuji H, et al. Decreased exhaled nitric oxide in mild persistent asthma patients treated with a leukotriene receptor antagonist, pranlukast. Jpn J Physiol. 1999;49:541–544. 12. Szefler SJ, Martin RJ, King TS, et al. Significant variability in response to inhaled corticosteroids for persistent asthma. J Allergy Clin Immunol. 2002;109:410 – 418. 13. Malmstrom K, Rodriguez-Gomez G, Guerra J, et al. Oral montelukast, inhaled beclomethasone, and placebo for chronic asthma: a randomized, controlled trial. Montelukast/ Beclomethasone Study Group. Ann Intern Med. 1999;130: 487– 495. 14. Warke TJ, Fitch PS, Brown V, et al. Exhaled nitric oxide correlates with airway eosinophils in childhood asthma. Thorax. 2002;57:383–387. 15. Mattes J, Storm van’s GK, Reining U, et al. NO in exhaled air is correlated with markers of eosinophilic airway inflammation in corticosteroid-dependent childhood asthma. Eur Respir J. 1999;13:1391–1395. 16. Kharitonov SA, Yates DH, Chung KF, et al. Changes in the dose of inhaled steroid affect exhaled nitric oxide levels in asthmatic patients. Eur Respir J. 1996;9:196 –201. 17. Beck-Ripp J, Griese M, Arenz S, et al. Changes of exhaled nitric oxide during steroid treatment of childhood asthma. Eur Respir J. 2002;19:1015–1019. 18. Ghiro L, Zanconato S, Rampon O, et al. Effect of montelukast added to inhaled corticosteroids on fractional exhaled nitric oxide in asthmatic children. Eur Respir J. 2002;20:630 – 634. 19. Fuglsang G, Vikre-Jorgensen J, Agertoft L, et al. Effect of
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20. 21. 22. 23.
24.
25.
26. 27. 28. 29.
salmeterol treatment on nitric oxide level in exhaled air and dose-response to terbutaline in children with mild asthma. Pediatr Pulmonol. 1998;25:314 –321. Yates DH, Kharitonov SA, Barnes PJ. Effect of short- and long-acting inhaled 2-agonists on exhaled nitric oxide in asthmatic patients. Eur Respir J. 1997;10:1483–1488. Silkoff PE, Wakita S, Chatkin J, et al. Exhaled nitric oxide after 2-agonist inhalation and spirometry in asthma. Am J Respir Crit Care Med. 1999;159:940 –944. Kharitonov SA, Barnes PJ. Clinical aspects of exhaled nitric oxide. Eur Respir J. 2000;16:781–792. van Den Toorn LM, Prins JB, Overbeek SE, et al. Adolescents in clinical remission of atopic asthma have elevated exhaled nitric oxide levels and bronchial hyperresponsiveness. Am J Respir Crit Care Med. 2000;162:953–957. Leuppi JD, Downs SH, Downie SR, et al. Exhaled nitric oxide levels in atopic children: relation to specific allergic sensitisation, AHR, and respiratory symptoms. Thorax. 2002;57: 518 –523. Nielsen KG, Bisgaard H. Bronchodilation and bronchoprotection in asthmatic preschool children from formoterol administered by mechanically actuated dry-powder inhaler and spacer. Am J Respir Crit Care Med. 2001;164:256 –259. Lebecque P, Kiakulanda P, Coates AL. Spirometry in the asthmatic child: is FEF25–75 a more sensitive test than FEV1/FVC? Pediatr Pulmonol. 1993;16:19 –22. Mostgaard G, Siersted HC, Hansen HS, et al. Reduced forced expiratory flow in schoolchildren with respiratory symptoms: the Odense Schoolchild Study. Respir Med. 1997;91:443– 448. Hamid Q, Song Y, Kotsimbos TC, et al. Inflammation of small airways in asthma. J Allergy Clin Immunol. 1997;100:44 –51. Bousquet J. The relative importance of small airways in asthma. Respir Med. 2000;94(Suppl):S1–S2.
Requests for reprints should be addressed to: Hans Bisgaard, MD, DMSci Danish Pediatric Asthma Center Copenhagen University Hospital KAS Gentofte Pediatric Department L 213 DK 2900 Hellerup, Denmark E-mail: [email protected]
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INTRODUCTION Long-acting 2-agonists (LABAs) or leukotriene receptor antagonists (LTRAs) are alternatives as add-on treatment in children inadequately controlled with a moderate dose of inhaled corticosteroids (ICSs). LTRA add-on therapy in children undergoing regular ICS treatment was recently demonstrated to improve lung function and reduce asthma exacerbations.1 LABAs may also improve lung function and airway inflammation in adults,2 although such evidence in support of regular add-on therapy of LABAs in pediatric asthma is ambiguous.3 Any complementary effects would be relevant to the choice between LTRAs and LABAs. We undertook a study to compare the complementary effect of LABAs vs LTRAs on exhaled nitric oxide (FeNO) in asthmatic children undergoing regular ICS treatment.
Department of Pediatrics, Rigshospitalet, National University Hospital, Copenhagen, Denmark. This study was supported by a medical school grant from Merck. The study was initiated, conducted, analyzed, and reported by the authors without interaction with the sponsoring company. Received for publication December 5, 2003. Accepted for publication in revised form April 15, 2003.
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FeNO was the primary outcome because it is probably a more sensitive marker for asthma control than lung function.4 Children were selected among asthmatic patients with raised FeNO levels despite regular treatment with inhaled budesonide, 400 g/d. To our knowledge, this is the first head-tohead comparison of the addition of salmeterol and montelukast to regular steroid treatment in pediatric asthma management. METHODS Patients Asthmatic schoolchildren 6 to 15 years of age taking a maintenance dose of inhaled budesonide, 400 g/d, via Turbohaler (Spirocort, Astra Zeneca, Lund, Sweden) were screened for the study. Increased FeNO was defined from the upper quartile of the FeNO level (12 ppb) of that screening population. Children were qualified for the randomized trial if the FeNO level was still increased within 2 weeks before randomization. Treatment with ICSs had to be unchanged for at least 1 month before enrollment in the study. Inhaled, short-acting 2-agonists were allowed as rescue treatment. No other antiasthma treatment was allowed during the study and in the month
309
before inclusion. FeNO was also measured in 31 healthy controls 6 to 15 years of age with no history of atopic disease. Study Design The study was a single-center, double-blind, placebo-controlled, double-dummy, 3-period, crossover design without washout periods. The 3 arms of treatment were either active salmeterol or placebo montelukast, active montelukast and placebo salmeterol, and placebo montelukast and placebo salmeterol. Children were randomized by a computer-generated schedule to receive 1 of the 6 combinations of treatment sequences available (salmeterol-placebo-montelukast, salmeterol-montelukast-placebo, montelukast-placebo-salmeterol, montelukast-salmeterol-placebo, placebo-montelukast-salmeterol, or placebo-salmeterol-montelukast). Montelukast was given as a 5-mg, chewable tablet in the evening or matching placebo. Salmeterol was given as 50 g or matching placebo inhaled from a Discus (Copenhagen, Denmark) dry-powder inhaler twice daily. Each treatment period was a mean ⫾ SD of 14 ⫾ 2 days with no washout periods between treatments. All children continued taking their budesonide, 400 g, throughout the study. Study medication and terbutaline were withheld for 12 and 4 hours, respectively, before the measurements of FeNO and spirometry. Patients were excluded from the trial if they had an airway infection during the study period. Unused medication was returned to the clinic at the end of each 2-week period, and compliance was estimated from pill counts and from the dose counter on the salmeterol inhaler. Lung Function and FeNO FeNO was measured at each visit followed by spirometry. Spirometry was performed with a Master Screen unit (E. Ja¨eger GmbH, Wu¨rtzburg, Germany) in accordance with American Thoracic Society guidelines5 to calculate forced expiratory volume in 1 second (FEV1), forced vital capacity, and forced expiratory flow rate at 25%, 50%, and 75% (FEF25%, FEF50%, and FEF75%, respectively). Single-breath, on-line measurement of FeNO was performed in accordance with the recommendations of the European Respiratory Society6 with an exhalation flow of 90 to 110 mL/s and exhalation pressure of at least 5 cm H2O. Nitric oxide was measured with the Aerocrine nitric oxide system (Aerocrine AB, Stockholm, Sweden). The child inhaled to total lung capacity from nitric oxide free air and exhaled subsequently for 10 seconds against a linear resistor. A nose clip was not used. The measurement was accepted if stable exhalation flow was sustained for the last 5 seconds of exhalation. Nitric oxide was calculated as the mean value from 50% to 90% of the whole breath, and the mean of 3 approved measurements represents FeNO. We have previously described in detail the equipment used for FeNO measurements.7 Ethics The study was performed and data collected according to the principles of good clinical practice. The blinded code was
310
broken after a clean file had been declared and the data files had been locked in the computer. The study was approved by the local ethics committee (KF 02-052/99) and the health authorities (2612–995). Written informed consent was obtained from the parents and verbal assent from the children. Statistics All children who completed measurements after the 3 treatment periods were included in the analysis. The study was designed with 80% power to detect a 20% reduction of FeNO for active treatment vs placebo, with the ␣ error set at .05 (2-tailed) and SD based on our previous study.7 A computer package (MedCalc version 6, MedCalc Software, Mariakerke, Belgium, and SAS System for Windows version 8, SAS Institute Inc, Cary, NC) was used for statistic calculations. Nitric oxide data were log transformed, and central tendency was expressed as geometric mean (95% confidence interval [CI]), since criteria for the normal distribution were not fulfilled (Kolmogorov-Smirnov test). Spirometry measurement exhibited a normal distribution and was expressed as mean (95% CI). Group comparisons were performed by paired t test. To estimate carryover and period effect between treatments, multifactor analysis of variance (ANOVA) was performed. RESULTS One hundred eighty-four asthmatic schoolchildren undergoing regular treatment with budesonide, 400 g/d, were screened. The geometric mean FeNO level was 7 ppb (95% CI, 6 – 8 ppb), which was significantly higher than the FeNO level in 31 healthy controls (mean, 5 ppb; 95% CI, 3–7 ppb; P ⫽ 0.01). The upper quartile (75% percentile) was 12 ppb. Twenty-three of the children with FeNO in the upper quartile (⬎12 ppb) were randomized to the controlled study. Patient characteristics for the children randomized into the trial are shown in Table 1. Compliance to montelukast was good throughout the study. Discrepancy between the number of study days and the number of doses taken ranged from –2 to ⫹5 tablets during active montelukast treatment and from 3 to ⫹3 doses during active salmeterol inhaler treatment. All children reported having taken their study medication as prescribed at least during the 6 days before each visit. Both treatments were well tolerated. Ten adverse events were reported: 6 during placebo treatment, 3 during montelukast treatment, and 1 during salmeterol treatment. Two adverse events were suspected of being drug related: 2 children complained of dizziness, nausea, and vomiting after the first dose of montelukast. However, the symptoms disappeared within 1 to 2 days. Twenty-two of 23 randomized children completed the study. One child was excluded from further analysis, because she did not show up for the last study visit. None of the children had any asthma exacerbation or airway infections during the study.
ANNALS OF ALLERGY, ASTHMA, & IMMUNOLOGY
Table 1. Patient Characteristics Characteristic
Result
No. of children Age, mean (range), y Sex, F/M Height, mean (range), cm Weight, mean (range), kg Rhinoconjunctivitis Eczema Positive allergy skin prick test result Atopy in first-degree relatives FeNO, geometric mean (95% CI), ppb Lung function, % predicted (95% CI) FEV1 FEF75% FEF50% FEF25%
23 12 (7–14) 11/12 152 (132–190) 48 (29–100) 22/23 7/23 20/23 16/23 25 (21–30) 101 (95–107) 75 (63–86) 84 (75–94) 93 (85–101)
Abbreviations: CI, confidence interval; FEF25%, FEF50%, and FEF75%, forced expiratory flow rate at 25%, 50%, and 75%, respectively; FeNO, exhaled nitric oxide; FEV1, forced expiratory volume in 1 second.
The results of FeNO and lung function tests in the 22 children who completed the study are summarized in Table 2. There was no carryover or period effect between treatments (multifactor ANOVA: P ⫽ 0.90). The primary analysis showed that the FeNO level was significantly higher during salmeterol treatment compared with montelukast treatment (P ⬍ 0.01; Fig 1). The FeNO level was significantly increased after salmeterol treatment compared with placebo (P ⬍ 0.05), whereas FeNO levels did not differ between the montelukast and placebo groups. FEV1 exhibited a significant improvement after salmeterol treatment (P ⫽ 0.02), with a nonsignificant improvement after montelukast treatment (P ⫽ 0.11) compared with placebo. There was no significant difference in any lung function parameter between the montelukast and salmeterol groups. FEF75% increased significantly after salmeterol (P ⫽ 0.02) and montelukast (P ⫽ 0.01) treatment compared with placebo. FEF25% and FEF50% showed no significant changes from treatments.
Figure 1. Exhaled nitric oxide (FeNO) (geometric mean) and individual values during treatment with montelukast, placebo, and salmeterol and at randomization.
DISCUSSION The FeNO levels were significantly higher after salmeterol add-on treatment compared with montelukast and placebo add-on treatment in asthmatic children undergoing regular maintenance treatment with 400 g of budesonide. These findings are in keeping with a report by Lipworth et al8 that showed a higher FeNO level with the addition of formoterol compared with zafirlukast in a comparative study of adult asthmatic patients taking 200 to 1,600 g/d of ICSs. In a subsequent study, this group found no effect on FeNO with
Table 2. Measurements of Lung Function and FeNO Test FeNO, geometric mean (95% CI), ppb (n ⫽ 22) FEV1, mean (95% CI), (n ⫽ 22) FEF75%, mean (95% CI) (n ⫽ 22)
Baseline
Placebo
Montelukast
Salmeterol
25 (21–30)*†
15 (10–21)†‡
15 (11–18)‡§
20 (15–27)¶㛳
2.54 (2.27–2.87)† 1.30 (1.05–1.54)
2.48 (2.19–2.77)† 1.17 (0.94–1.40)†
2.57 (2.33–2.80) 1.36 (1.13–1.59)*
2.63 (2.34–2.91)¶㛳 1.40 (1.18–1.62)¶
Abbreviations: CI, confidence interval; FEF75%, forced expiratory flow rate at 75%; FeNO, exhaled nitric oxide; FEV1, forced expiratory volume in 1 second. * P ⬍ 0.01 compared with placebo. † P ⬍ 0.05 compared with salmeterol. ‡ P ⬍ 0.01 compared with baseline. § P ⬍ 0.01 compared with salmeterol. ¶ P ⬍ 0.05 compared with placebo. 㛳 P ⬍ 0.05 compared with baseline.
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montelukast or salmeterol,9 but the patients had near-normal FeNO levels at randomization with little room for improvement with montelukast. Similarly, in our study the secondary comparison of montelukast vs placebo failed to show the expected reduction in FeNO levels. We have previously reported reduced FeNO levels from LTRA treatment in 23 asthmatic children,7 in whom 11 were taking a maintenance dose of ICS (mean, 273 g). This was confirmed in other studies in children10 and adults,11 also including mixed populations with and without concurrent ICS therapy. In the present study, montelukast failed to improve FeNO compared with placebo. This may partly be explained by a floor effect, since FeNO in 10 children reached a normal level during the controlled placebo treatment with their regular budesonide, 400 g, only. FeNO levels were significantly reduced by montelukast compared with placebo in the remaining 12 children. Increasing evidence of heterogeneous response to asthma treatment may be an important factor for the apparent different response between children and study reports.12,13 Finally, the children in the present study were highly selected as those children who had increased FeNO despite being well controlled with regular budesonide treatment, 400 g/d. These children served the purpose of our mechanistic study objective but may constitute a special subgroup, where FeNO might be driven by factors not fully accessible to either steroid or LTRAs. FeNO has been suggested to reflect eosinophilic inflammation14,15 and is particularly sensitive to anti-inflammatory treatment,16 although a specific relation has not been proved. FeNO was recently reported to be sensitive to adherence to steroids,15,17 and improved adherence to the maintenance steroid treatment during the trial has probably reduced FeNO levels during the treatment periods in some of the children. However, such a trial effect could hardly explain differences between treatments in this crossover design. Indeed, there were no statistically significant period effects (treatment sequence) demonstrated, and we found no carryover effect from the treatments. This is in line with the fact that FeNO levels return to baseline 14 days after montelukast use has been stopped.18 FeNO increased significantly with salmeterol compared with placebo. This is consistent with previous reports of increased FeNO with the use of LABAs.19,20 The effect of LABAs on FeNO may be confounded by the bronchodilatory effect; we and others have previously reported 5% to 10% increases in FeNO with short-acting 2-agonists.7,21 However, the observed 25% increase in FeNO 12 hours after salmeterol administration exceeds that previously reported during maximal bronchodilation and may not be solely due to bronchodilation. The mechanism by which salmeterol increases FeNO is unknown. Asthmatic children undergoing regular treatment with budesonide, 400 g/d, were screened for this study. They presented a gaussian distribution of FeNO around a geometric mean of 7 ppb, which is significantly raised compared with healthy controls. Children with FeNO levels in the upper
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quartile were invited to participate in the study. They did not differ from the children in the lower 3 quartiles in terms of lung function, symptoms, atopic heredity, or allergy. They were apparently well controlled, with no daily symptoms and normal lung function. The children showed no clinical evidence of requiring intensified treatment. Still, some presented with increased FeNO, which may be a surrogate marker of disease control.4,14,22–24 This allowed us to study the specific effect on FeNO of alternative treatments added to a 400-g/d dose of budesonide, without the confounding effect from substantial changes in lung function, symptoms, and exacerbations. The study was powered to compare the effect on FeNO but not on lung function, and there was little room for improvement since the mean FEV1 was 101% predicted. Nonetheless, FEV1 improved significantly during salmeterol use, probably partly reflecting the effect on the inherent bronchomotor tone seen even in healthy controls.25 Montelukast did not change FEV1 significantly, although there was no statistical difference between FEV1 on the 2 active treatments. FEF75% at randomization was significantly reduced in the study population (75% predicted), which may reflect small airway obstruction. FEF25%-75% is a sensitive marker of airway obstruction even in children without symptoms or decreased FEV1.26,27 Small airways have been suggested as the major site of obstruction in asthma.28,29 Montelukast and salmeterol significantly improved FEF75%. In conclusion, FeNO levels were significantly higher after salmeterol add-on treatment compared with both placebo and montelukast add-on treatment. Montelukast failed to reduce FeNO levels further compared with placebo in this group of children taking regular budesonide, 400 g. Salmeterol exhibited improved bronchodilation in large and small airways after add-on to inhaled steroids compared with both placebo and montelukast. FeNO increased significantly after salmeterol treatment. The clinical relevance of this finding needs further study. REFERENCES 1. Simons FE, Villa JR, Lee BW, et al. Montelukast added to budesonide in children with persistent asthma: a randomized, double-blind, crossover study. J Pediatr. 2001;138:694 – 698. 2. Li X, Ward C, Thien F, et al. An antiinflammatory effect of salmeterol, a long-acting 2 agonist, assessed in airway biopsies and bronchoalveolar lavage in asthma. Am J Respir Crit Care Med. 1999;160:1493–1499. 3. Bisgaard H. Long-acting 2-agonists in management of childhood asthma: a critical review of the literature [see comments]. Pediatr Pulmonol. 2000;29:221–234. 4. Jones SL, Kittelson J, Cowan JO, et al. The predictive value of exhaled nitric oxide measurements in assessing changes in asthma control. Am J Respir Crit Care Med. 2001;164: 738 –743. 5. American Thoracic Society. Standardization of spirometry, 1994 update. Am J Respir Crit Care Med. 1995;152:1107–1136. 6. Kharitonov S, Alving K, Barnes PJ, The European Respiratory Society Task Force. Exhaled and nasal nitric oxide measurements: recommendations. Eur Respir J. 1997;10: 1683–1693.
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7. Bisgaard H, Loland L, Anhoj J. NO in exhaled air of asthmatic children is reduced by the leukotriene receptor antagonist montelukast. Am J Respir Crit Care Med. 1999;160:1227–1231. 8. Lipworth BJ, Dempsey OJ, Aziz I, et al. Effects of adding a leukotriene antagonist or a long-acting 2-agonist in asthmatic patients with the glycine-16 2-adrenoceptor genotype. Am J Med. 2000;109:114 –121. 9. Wilson AM, Dempsey OJ, Sims EJ, et al. Evaluation of salmeterol or montelukast as second-line therapy for asthma not controlled with inhaled corticosteroids. Chest. 2001;119: 1021–1026. 10. Bratton DL, Lanz MJ, Miyazawa N, et al. Exhaled nitric oxide before and after montelukast sodium therapy in school-age children with chronic asthma: a preliminary study. Pediatr Pulmonol. 1999;28:402– 407. 11. Kobayashi H, Takahashi Y, Mitsufuji H, et al. Decreased exhaled nitric oxide in mild persistent asthma patients treated with a leukotriene receptor antagonist, pranlukast. Jpn J Physiol. 1999;49:541–544. 12. Szefler SJ, Martin RJ, King TS, et al. Significant variability in response to inhaled corticosteroids for persistent asthma. J Allergy Clin Immunol. 2002;109:410 – 418. 13. Malmstrom K, Rodriguez-Gomez G, Guerra J, et al. Oral montelukast, inhaled beclomethasone, and placebo for chronic asthma: a randomized, controlled trial. Montelukast/ Beclomethasone Study Group. Ann Intern Med. 1999;130: 487– 495. 14. Warke TJ, Fitch PS, Brown V, et al. Exhaled nitric oxide correlates with airway eosinophils in childhood asthma. Thorax. 2002;57:383–387. 15. Mattes J, Storm van’s GK, Reining U, et al. NO in exhaled air is correlated with markers of eosinophilic airway inflammation in corticosteroid-dependent childhood asthma. Eur Respir J. 1999;13:1391–1395. 16. Kharitonov SA, Yates DH, Chung KF, et al. Changes in the dose of inhaled steroid affect exhaled nitric oxide levels in asthmatic patients. Eur Respir J. 1996;9:196 –201. 17. Beck-Ripp J, Griese M, Arenz S, et al. Changes of exhaled nitric oxide during steroid treatment of childhood asthma. Eur Respir J. 2002;19:1015–1019. 18. Ghiro L, Zanconato S, Rampon O, et al. Effect of montelukast added to inhaled corticosteroids on fractional exhaled nitric oxide in asthmatic children. Eur Respir J. 2002;20:630 – 634. 19. Fuglsang G, Vikre-Jorgensen J, Agertoft L, et al. Effect of
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Requests for reprints should be addressed to: Hans Bisgaard, MD, DMSci Danish Pediatric Asthma Center Copenhagen University Hospital KAS Gentofte Pediatric Department L 213 DK 2900 Hellerup, Denmark E-mail: [email protected]
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