Allergic asthma is characterised by bronchial. Montelukast as add-on therapy to b-agonists and late airway response

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1 Er Respir J 2007; 30: DOI: / CopyrightßERS Jornals Ltd 2007 Montelkast as add-on therapy to b-agonists and late airway response M. Rosewich, M.A. Rose, O. Eickmeier, M. Travaci, R. Kitz and S. Zielen ABSTRACT: The present stdy investigated whether single-dose oral lekotriene receptor antagonists as add-on therapy to short-acting b-agonists, immediately after allergen challenge, block the late-phase airway response. In total, 35 mild asthmatics (mean age 24 yrs, 19 males) sensitised for hose dst mites nderwent two corses of bronchial allergen challenge. After the early allergic response (EAR), sbjects received salbtamol once and were randomly assigned to either 10 mg of montelkast or placebo (doble-blind crossover). To identify a late allergic response, forced expiratory volme in one second (FEV1) was monitored over the following 8 h. Baseline exhaled nitric oxide (NO) was determined ahead of each allergen challenge. Baseline NO levels differed significantly depending on the reaction to allergen challenge. In total, 12 sbjects showed no significant response, 11 only showed an EAR, and 12 had a dal response and nderwent frther analysis. The area nder the FEV1 time response crve 3 8 h after bronchial allergen challenge was from the pre-challenge vales on montelkast compared with on placebo. The baseline exhaled NO fraction of sbjects withot an EAR was significantly lower than of those presenting a dal response. The reslts of the present stdy demonstrate that single-dose lekotriene receptor antagonists given orally right after the early allergic response can significantly inhibit the late allergic response after bronchial allergen challenge. AFFILIATIONS Dept of Paediatrics, Frankfrt University, Frankfrt, Germany. CORRESPONDENCE M. Rosewich Children s Hospital Goethe University Theodor Stern Kai Frankfrt Germany Fax: Martin.Rosewich@kg.de Received: May Accepted after revision: Janary STATEMENT OF INTEREST Statements of interest for all athors can be fond at com/misc/statements.shtml KEYWORDS: Asthma, bronchial allergen challenge, early asthmatic response, exhaled nitric oxide fraction, late asthmatic response, montelkast Allergic asthma is characterised by bronchial hyperresponsiveness and airway inflammation. In asthmatic patients the fraction of nitric oxide in exhaled air (Fe,NO) is increased and correlates with asthma severity, sptm eosinophils and methacholine reactivity [1 3]. As inhaled allergens contribte to asthmatic inflammation, allergen challenge is a sefl clinical tool to stdy the mechanisms nderlying asthma. Bronchial allergen challenge in ssceptible individals leads to an early asthmatic response (EAR) de to cross-linking of srfacebond immnogloblin (Ig)E on mast cells, casing the release of inflammatory mediators, sch as histamine, prostaglandins and cysteinyllekotrienes (LTs). This mediator release reslts in smooth mscle contraction and mcosal oedema-triggering bronchoconstriction [4, 5]. The EAR, althogh cased by inflammatory mediators, can be completely inhibited or resolved by bronchodilators, sch as b 2 -agonists [6]. Approximately 30 50% of asthmatic sbjects with a positive bronchial allergen challenge will experience a biphasic response to inhaled allergens [7]. The late asthmatic response (LAR), which may follow the EAR 3 8 h after allergen challenge, involves acte inflammation and swelling of the airway wall. The inflammatory process is driven by activated netrophils, eosinophils, mast cells and T-lymphocytes, and leads to epithelial desqamation, altered mcociliary fnction and redced clearance of respiratory tract secretions, ths reslting in airway obstrction [8 10]. This inflammation can be attenated by corticosteroids, anti-ige and anti-lts, whereas b-agonists only have bronchodilatory capacities and lack anti-inflammatory effects. The cysteinyl-lts LTC4, LTD4 and LTE4 are not only potent bronchoconstrictors, bt case several biological actions in the pathogenesis of asthma, inclding increased vasclar permeability, formation of oedema and enhanced mcs prodction [11]. These biological properties can be attenated by anti-lt drgs. Redction of inflammation and a decrease in Fe,NO following montelkast treatment is thoght to occr via two distinct mechanisms involving LTs, which are: Eropean Respiratory Jornal Print ISSN Online ISSN VOLUME 30 NUMBER 1 EUROPEAN RESPIRATORY JOURNAL

2 M. ROSEWICH ET AL. MONTELUKAST AND LATE PHASE AIRWAY RESPONSE direct inhibition at the receptor level; or inhibition of eosinophil recritment into the lng, which indirectly redces the capacity for frther release of LTs [12, 13]. However, the mechanisms by which montelkast modlates nitric oxide (NO) prodction are not yet completely nderstood. Previos stdies have shown that montelkast attenates both early- and late-phase responses to aspirin [14], exerciseindced bronchoconstriction [15] and allergen challenge [16], in both children [17] and adlts [18]. Frthermore, DOCKHORN et al. [19] were able to show a qick onset of action for single doses of i.v. and oral montelkast. Orally administered montelkast led to a significant increase in the forced expiratory volme in one second (FEV1) within 2 h, sggesting LT receptor antagonists (LTRA) as a treatment option in acte asthma. However, there have been no stdies evalating the acte effects of a single dose of oral montelkast in a bronchial allergen challenge model. The present stdy soght to evalate the acte effects of montelkast on the LAR after allergen exposre in adlts with hose dst mite-indced asthma by sing a well-characterised allergen challenge model. METHODS Sbjects In total, 35 atopic adlts (19 males; mean (range) age 24 (18 31) yrs) with mild and, at the time of the stdy, stable, physician-diagnosed asthma (FEV1 o80%, vital capacity o80%) were recrited from the camps poplation (Frankfrt University, Frankfrt, Germany) by means of pblic posting. All sbjects were sensitised to hose dst mite (IgE specific for Dermatophagoides farinae at least radioallergosorbent test (RAST) class 2) and had a history of episodic asthma (table 1). Sbjects were free of controller therapy (inclding long-lasting b-agonists, anticholinergics, theophylline, oral and inhaled corticosteroids, cromoglycate, antihistamines, and LT-antagonists) 8 weeks before and dring the stdy. Seven of the sbjects smoked occasionally or reglarly (1 15 cigarettes?- day -1 ; table 1) bt did not change their smoking habits dring the stdy. None of the sbjects sed medication that cold inflence the reslts of this stdy. All sbjects were in good clinical condition; none had experienced a respiratory tract infection within 2 weeks before and dring the stdy, or sffered from any respiratory complaints on the day of the stdy. All patients spplied written informed consent prior to the stdy. Hman experimentation gidelines of good clinical practice, the German Drg Act and the declaration of Helsinki were followed in the condct of clinical research. Local ethics committee approval was obtained. Stdy design The stdy was a randomised, doble-blind, single-dose, placebo-controlled, crossover trial with a washot period of o2 weeks. Sbjects attended the department for three visits (fig. 1). On the first visit, entry criteria were assessed by interviewing the sbjects, performing a physical examination, and drawing a venos blood sample for frther analysis (total IgE, specific IgE (RAST), blood cont). On the second visit, hose dst mite sensitised sbjects were checked for signs of airway infection, nderwent spirometry and Fe,NO was determined. Only healthy sbjects with an FEV1 and forced vital capacity (FVC).80% were challenged as explained later. Sbjects nderwent spirometry 10 min after completion of the final allergen dosing. When an EAR (decrease in FEV1.20%) or a clinical reaction occrred, sbjects received one pff of salbtamol (0.1 mg) and either montelkast (265 mg tablets) or matching placebo immediately. Dring the following 8 h, FEV1 was monitored horly. If sbjects showed an LAR (FEV1 drop.15% 6 8 h after bronchial allergen challenge), they received a long-lasting b 2 -agonist (formoterol, 12 mg, one pff) after finishing the test. On the third visit o14 days later (14 42 days), the same procedre was repeated, crossing-over montelkast and placebo. Lng fnction tests Baseline spirometry (before inhalation of sterile saline 0.9% and before allergen challenge), was performed with the MasterScreen1 bodyplethysmograph (VIASYS Healthcare GmbH, Hoechberg, Germany). Before and 0 8 h after bronchial allergen challenge, sbjects measred FEV1 horly sing the SpiroPro1 (VIASYS Healthcare GmbH). Measrement of exhaled NO Measrements of exhalative NO were carried ot sing the NIOX1 (Aerocrine, Solna, Sweden). The NIOX1 measres NO in exhaled air according to American Thoracic Society gidelines [20]. This chemilminescence gas analyser is sensitive to NO at concentrations ranging ppb with a deviation from mean vale of 2.5 ppb at NO,50 ppb or 5% of the measred vale at.50 ppb. Allergen inhalation challenge protocol Soltions of D. farinae allergen extract (Allergopharma, Reinbek, Germany) were prepared according to the instrction manal. The lyophilised D. farinae allergen extract was resspended in the soltion provided by the manfactrer (containing sodim, phenol and water) reslting in aliqots of 5,000 mg?ml -1 ; aliqots were stored immediately after preparation at 4C ntil applied. All sbjects were exposed in a single-blinded fashion by inhalation of sterile saline 0.9% followed 5 min later by increasing concentrations of D. farinae. The soltions were delivered via a medic aid nebliser and the aerosol provocation system APS1 powered by compressed air (VIASYS Healthcare GmbH). This system calclates the administered dose by breath from a constant flow and the inspiration time of any breath cycle, ths calclating the exact dose to be administered atomatically. Mothpieces and neblisers were changed after each sbject to avoid cross contamination. The doses of inhaled D. farinae were increased every 8 min according to the following pattern, from step 1 to 8: 0, 10, 20, 40, 80, 160, 320 and 640 mg. Ths, the entire protocol delivered cmlative doses of 0, 10, 30, 70, 150, 310, 630 and 1,270 mg. This procedre had been developed in earlier stdies and was fond to be extremely safe, avoiding overdosing and detecting potential side effects as early as possible [21]. The challenge test was stopped when any of the following criteria were met: 1) the FEV1 decreased at least 20% c EUROPEAN RESPIRATORY JOURNAL VOLUME 30 NUMBER 1 57

3 MONTELUKAST AND LATE PHASE AIRWAY RESPONSE M. ROSEWICH ET AL. TABLE 1 Baseline characteristics of patients and applied allergen doses Sex Age yrs Smoker Specific IgE VC % FEV1 % eno ppb Allergen dose mg Montelkast Placebo Sbjects with no EAR 1 M 28 Yes F 20 No M 21 Yes F 27 No M 25 No F 21 Yes F 24 No M 27 No F 25 Yes F 23 No M 27 Yes F 24 No Mean Sbjects with no LAR 2 M 22 No M 21 No M 28 No M 21 No F 21 No M 23 No F 22 No F 22 No M 21 No M 23 No F 21 No Mean Sbjects with a dal response 4 M 21 No F 23 No M 31 No M 30 No F 18 Yes F 31 No F 24 No M 21 No M 22 Yes M 24 No M 30 No F 25 No Mean Ig: immnogloblin; VC: vital capacity; FEV1: forced expiratory volme in one second; eno: exhaled nitric oxide; EAR: early allergic response; LAR: late allergic response; M: male; F: female. from individal baseline (EAR); 2) significant clinical complaints were reported by the sbjects (e.g. chest pain); 3) a cmlative dose of 1,270 mg had been achieved. Clinical monitoring accompanied each provocation for o8 h, sbjects cold then leave the hospital, remaining in toch via telephone with a physician involved in the stdy. End-points and statistical analysis The primary end-point was the area nder the FEV1 time response crve (FEV1-AUC) 3 8 h after bronchial allergen challenge in those sbjects with an EAR and LAR (dal response) to bronchial allergen challenge. As established in the literatre, it is given dimensionless. To identify a dal 58 VOLUME 30 NUMBER 1 EUROPEAN RESPIRATORY JOURNAL

4 M. ROSEWICH ET AL. MONTELUKAST AND LATE PHASE AIRWAY RESPONSE FIGURE 1. Flow chart demonstrating the stdy design. response, a significant EAR was defined as a decrease in FEV1.20% and a significant LAR was defined as a drop in the FEV1.15%. The Wilcoxon matched pairs test was sed to analyse differences in FEV1 vales, Fe,NO levels were compared with the Mann Whitney U-test. The level of statistical significance was set at p,0.05. RESULTS FEV1 In total, 35 sbjects nderwent two allergen challenge tests and completed the stdy. Of these, 12 sbjects showed no significant EAR on one or both stdy days and were exclded from frther analysis. Of the remaining 23 sbjects, 12 (52%) had a dal response (EAR and LAR) and were therefore analysed. There were no significant differences in baseline lng fnction between these three grops (table 1). In eight ot of 12 sbjects the dose applied varied only within one dosage step, ths making the provocation schedle comparable. Six ot of 12 sbjects tolerated higher hose dst mite doses on the montelkast day. The difference in FEV1 from baseline vales 3 8 h after allergen challenge was expressed as the area nder the dimensionless FEV1-AUC (fig. 2). The FEV1 vales of each patient dring the LAR (3 8 h after bronchial allergen challenge) on placebo were compared with the reslts from patients on montelkast. One of the sbjects with a dal response had a smaller decrease of FEV1-AUC on placebo than on montelkast, while 11 showed better reslts with montelkast. The FEV1-AUC of the 12 sbjects receiving placebo was of the pre-challenge vales compared with receiving montelkast (p,0.005). In order to control for an inflence of the allergen dose applied, an additional sbgrop analysis was carried ot of those who received the same allergen does on both visits. Sbjects treated with montelkast experienced significantly less FEV1 decrease than those after placebo (FEV1-AUC; p ). When pooling data from all stdy sbjects, a trend of higher FEV1 vales was also fond after montelkast (mean verss %), which did not reach statistical significance. Additionally, the baseline FEV1 vales of each patient were matched with the greatest decrease in FEV1 6 8 h after bronchial allergen challenge following placebo or montelkast, respectively (fig. 3). FIGURE 2. Area nder the forced expiratory volme in one second time response crve 3 8 h after bronchial allergen challenge, for montelkast and placebo respectively (shown are maximm and minimm vales, the 95% confidence interval and the median). Exhaled NO fraction In total, 35 sbjects performed baseline Fe,NO measrements. The 12 sbjects showing no EAR on one or both stdy days had baseline NO levels of 21.0 ppb (95% confidence interval (CI) ) compared with 39.0 ppb (95% CI ) in those sbjects with an EAR on both stdy days and 56.4 ppb (95% CI ) of the sbjects with a dal response. The comparison of the sbjects withot an EAR and those with a dal response reached statistical significance (p,0.05). There was no correlation between baseline Fe,NO and response to montelkast in the sbjects of the present stdy, althogh there was a slight trend towards higher baseline Fe,NO vales in the sbjects with a poor response to montelkast. In a sbgrop of sbjects (n58), Fe,NO was followed p ntil 24 h after bronchial allergen challenge. There was no significant difference between pre-challenge Fe,NO (median (range); verm: 24.3 (15 120); placebo: 34.0 (12 82)) and Fe,NO after 8 h (verm: 36.5 (12 150); placebo: 27.1 (9 60)), % Placebo * Montelkast FIGURE 3. Comparison of individal forced expiratory volme in one second vales in patients on placebo and montelkast respectively: baseline (100%) verss late asthmatic response (maximm per cent fall 6 8 h after bronchial challenge). Mean vales are marked. *: p,0.05. c EUROPEAN RESPIRATORY JOURNAL VOLUME 30 NUMBER 1 59

5 MONTELUKAST AND LATE PHASE AIRWAY RESPONSE M. ROSEWICH ET AL. respectively. After 24 h there was a significant increase in both grops (verm: 73.6 (30 219); placebo: 90.8 (29 248)), bt the crrent athors were not able to show a significant difference between verm and placebo at any time point. DISCUSSION Cysteinyl-LTs play a pivotal role in different types of inflammatory lng diseases inclding allergic asthma [22]. They are particlarly involved in the mechanisms leading to bronchoconstriction dring the early and late asthmatic response. There are also sfficient data demonstrating that activation of LT receptors reslts in indction of NO release [23 25]. Stdies on an effect of flticasone or bdesonide compared with montelkast revealed a positive impact of all three sbstances on an early asthmatic response, with steroids being sperior in improving bronchial hyperresponsiveness [26, 27]. Additionally, a positive impact of inhaled corticosteroids on the late asthmatic response cold also be demonstrated [28]. Keeping the side-effects of steroids in mind, the goal of the present stdy was to frther investigate montelkast as an add-on option to b-mimetics in mild bronchial asthma. Sbjects with a history of mild allergic asthma and no need for a controller therapy (Global Initiative for Asthma (GINA) I) were challenged twice with hose dst mite allergen. Of these, 23 (65.7%) sbjects had an EAR on both stdy days (decrease in FEV1.20%) and only 12 (34.3%) had a dal response. Frthermore, as baseline Fe,NO levels differed significantly among the patients, the reslts sggest that baseline Fe,NO might be sefl to distingish between sbjects who develop an LAR from the sbjects who do not. This is in keeping with the findings of KHARITONOV et al. [29]. The present stdy is the first to evalate the acte effects of a single dose of montelkast on airway fnction when being given orally after an early asthmatic response. It was shown that montelkast significantly blocked the late asthmatic response in sbjects responding dally to an allergen challenge. These reslts sggest an acte inhibiting effect on an LT-driven inflammatory process as the LAR generally leads to bronchoconstriction de to inflammation. Frthermore, the reslts sggest a rapid onset of action of montelkast even when only administered once orally. This is of clinical vale, as many patients se a short-acting b 2 -agonist (SABA) for symptom relief after allergen exposre. In the absence of a preventive effect, they have to be administered repeatedly once LAR occrs. Ths, LTRA offer a new therapetic option in this setting. However, it is known from the literatre that there are some sbjects who have little response to LTs. The present findings concr well with these reslts. It is essential to determine predictors for a positive response to montelkast, as the rapid onset of montelkast action indicates that LTRA are sitable medications for asthma patients. SZEFLER et al. [30] recently identified the female sex, a greater decrease in FEV1 from baseline, yong age or a short dration of the disease, and the FEV1/FVC ratio as predictors for a better LTRA response. In contrast, allergies and high levels of Fe,NO indicated a response to corticosteroids. The crrent athors cold not confirm the positive and negative predictive vales of those parameters with the restriction of a small sample size not only in the stdy by SZEFLER et al. [30], bt also in the present stdy. The crrent athors and other investigators showed that single doses of montelkast initiated sstained effects. DOCKHORN et al. [19] compared the kinetics of i.v. montelkast with oral montelkast and placebo in patients with severe asthma. They were able to demonstrate an effect of montelkast on FEV1 when administered intravenosly within 1 h. This was confirmed by other athors [31 34]. Additionally, they showed that a single dose of oral montelkast led to a significant increase in FEV1 within 2 3 h. Other stdies have shown the protective effect of an orally administered single-dose LTRA in exercise-indced asthma in children and adlts [13, 18]. In these stdies, montelkast was demonstrated to improve plmonary fnction within 3 12 h after ingestion. This effect of a single-dose lasted p to 24 h. In other trials, the onset of action of montelkast applied orally was in the range of 1 3 days [12, 15, 16]. Frthermore, it was sggested that LTRA are able to redce both the early and late asthmatic response in allergic sbjects when given before allergen challenge [32]. The aim of the present stdy was to investigate a therapetic option to better control late asthmatic symptoms in mild allergic asthmatics. The property of SABA to potentially attenate the LAR has been stdied extensively and was fond to have no sstained effect on bronchial obstrction after 4 8 h. It is possible that a very mild and early LAR cold be missed in the setting of the present stdy. Conversely, the placebo control wold have had the potential to distingish when a more prononced LAR occrred. Moreover, the crrent athors fond it not ethically jstified to withhold SABA in this setting. Ths, SABA was rotinely provided after the challenge, which is a rotine procedre according to GINA gidelines and ensres the patients safety. Despite this manoevre being performed in all sbjects, better lng fnction vales cold clearly be demonstrated in the montelkast grop. The present stdy was not designed as a therapetic trial bt to provide pharmacological proof of concept. 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