Effect of montelukast compared with inhaled fluticasone on airway inflammation

Which biomarkers are effective for identifying Th2-driven inflammation in asthma?

Recognition of asthma as a heterogeneous disease revealed different potential molecular targets and urged the development of targeted, customized treatment modalities. Evidence was provided for different inflammatory subsets of asthma and more recently, further refined to T helper (Th)2-high and Th2-low subphenotypes with different responsiveness to standard and targeted pharmacotherapy. Given these differences in immunology and pathophysiology, proof of concept studies of novel treatment modalities for asthma should be performed in adequate, well-defined phenotypes. In this review, we describe both existing and novel biomarkers of Th2-inflammation in asthma that can be applied to classify asthma subphenotypes in clinical studies and for treatment monitoring.

Urinary leukotriene E4 as a biomarker of exposure, susceptibility and risk in asthma

Measurement of urinary leukotriene E(4) (uLTE(4)) is a sensitive and noninvasive method of assaying total body cysteinyl leukotriene production and changes in cysteinyl leukotriene production. Recent studies have reported on novel uLTE(4) receptor interactions, and new applications for uLTE(4), as a biomarker of environmental exposure to tobacco smoke and ambient air pollution, a predictor of risk for asthma exacerbations related to tobacco smoke, and a marker of susceptibility to leukotriene receptor antagonists.

Anti-leukotriene agents compared to inhaled corticosteroids in the management of recurrent and/or chronic asthma in adults and children

BACKGROUND

Anti-leukotrienes (5-lipoxygenase inhibitors and leukotriene receptors antagonists) serve as alternative monotherapy to inhaled corticosteroids (ICS) in the management of recurrent and/or chronic asthma in adults and children.

OBJECTIVES

To determine the safety and efficacy of anti-leukotrienes compared to inhaled corticosteroids as monotherapy in adults and children with asthma and to provide better insight into the influence of patient and treatment characteristics on the magnitude of effects.

SEARCH METHODS

We searched MEDLINE (1966 to Dec 2010), EMBASE (1980 to Dec 2010), CINAHL (1982 to Dec 2010), the Cochrane Airways Group trials register, and the Cochrane Central Register of Controlled Trials (Dec 2010), abstract books, and reference lists of review articles and trials. We contacted colleagues and the international headquarters of anti-leukotrienes producers.

SELECTION CRITERIA

We included randomised trials that compared anti-leukotrienes with inhaled corticosteroids as monotherapy for a minimum period of four weeks in patients with asthma aged two years and older.

DATA COLLECTION AND ANALYSIS

Two review authors independently assessed the methodological quality of trials and extracted data. The primary outcome was the number of patients with at least one exacerbation requiring systemic corticosteroids. Secondary outcomes included patients with at least one exacerbation requiring hospital admission, lung function tests, indices of chronic asthma control, adverse effects, withdrawal rates and biological inflammatory markers.

MAIN RESULTS

Sixty-five trials met the inclusion criteria for this review. Fifty-six trials (19 paediatric trials) contributed data (representing total of 10,005 adults and 3,333 children); 21 trials were of high methodological quality; 44 were published in full-text. All trials pertained to patients with mild or moderate persistent asthma. Trial durations varied from four to 52 weeks. The median dose of inhaled corticosteroids was quite homogeneous at 200 µg/day of microfine hydrofluoroalkane-propelled beclomethasone or equivalent (HFA-BDP eq). Patients treated with anti-leukotrienes were more likely to suffer an exacerbation requiring systemic corticosteroids (N = 6077 participants; risk ratio (RR) 1.51, 95% confidence interval (CI) 1.17, 1.96). For every 28 (95% CI 15 to 82) patients treated with anti-leukotrienes instead of inhaled corticosteroids, there was one additional patient with an exacerbation requiring rescue systemic corticosteroids. The magnitude of effect was significantly greater in patients with moderate compared with those with mild airway obstruction (RR 2.03, 95% CI 1.41, 2.91 versus RR 1.25, 95% CI 0.97, 1.61), but was not significantly influenced by age group (children representing 23% of the weight versus adults), anti-leukotriene used, duration of intervention, methodological quality, and funding source. Significant group differences favouring inhaled corticosteroids were noted in most secondary outcomes including patients with at least one exacerbation requiring hospital admission (N = 2715 participants; RR 3.33; 95% CI 1.02 to 10.94), the change from baseline FEV(1) (N = 7128 participants; mean group difference (MD) 110 mL, 95% CI 140 to 80) as well as other lung function parameters, asthma symptoms, nocturnal awakenings, rescue medication use, symptom-free days, the quality of life, parents' and physicians' satisfaction. Anti-leukotriene therapy was associated with increased risk of withdrawals due to poor asthma control (N = 7669 participants; RR 2.56; 95% CI 2.01 to 3.27). For every thirty one (95% CI 22 to 47) patients treated with anti-leukotrienes instead of inhaled corticosteroids, there was one additional withdrawal due to poor control. Risk of side effects was not significantly different between both groups.

AUTHORS' CONCLUSIONS

As monotherapy, inhaled corticosteroids display superior efficacy to anti-leukotrienes in adults and children with persistent asthma; the superiority is particularly marked in patients with moderate airway obstruction. On the basis of efficacy, the results support the current guidelines' recommendation that inhaled corticosteroids remain the preferred monotherapy. 

Comparison of inhaled corticosteroids and leukotriene receptor antagonists in adolescents and adults with mild to moderate asthma: a meta-analysis

INTRODUCTION

Inhaled corticosteroids (ICS) and oral leukotriene receptor antagonists (LTRA) are effective drugs used in the management of asthma as controller monotherapy in adolescents and adults, although there are debates as to which one is better.

OBJECTIVES

To thoroughly compare the efficacy and tolerability of ICS vs LTRA in adolescents and adults with mild to moderate asthma.

METHODS

Relative database were searched for the review. Randomized controlled trials of more than or equal to 4 weeks' treatment duration comparing ICS with LTRA were reviewed.

RESULTS AND CONCLUSION

Twenty-four trials with 6197 randomized adolescents and adults with mild to moderate asthma met the inclusion criteria with a minimum duration of 4 weeks' treatment. Significant differences favouring ICS were found in all indices of pulmonary function. Other significant benefits of ICS were shown in symptoms, nocturnal awakenings, rescue-medication use, symptom-free days and quality of life. As to each special symptom of adverse effects, ICS was similar to LTRA in the incidence of headache, nausea and throat discomfort, but significantly higher in the incidence of hoarseness and oral pharyngeal candidiasis. Concerning withdrawal because of adverse events potentially related to treatment, ICS was similar to LTRA but significantly superior to LTRA in decreasing the asthma exacerbations or attacks during the treatment period. These results show that ICS may be the better drug in terms of efficacy and tolerability, except hoarseness and oral pharyngeal candidiasis, and should thus have priority over LTRA in asthma monotherapy in adolescents and adults.

Beclomethasone dipropionate blunts allergen-induced early increase in urinary LTE4

BACKGROUND

The inhibitory effect of corticosteroids (CS) on the secretions of cysteinyl-leukotrienes (Cys-LTs) in asthma is controversial. The aim of this study was to evaluate the effect of CS on allergen-induced increase in urinary leukotriene E4 (uLTE4) during early (EAR) and late (LAR) asthmatic responses in mild untreated asthmatics.

MATERIAL AND METHODS

Nine subjects with mild untreated allergic asthma performed two allergen challenges, after 1-week treatment with beclomethasone dipropionate (BDP, 500 microg b.i.d) or placebo. Forced Expiratory Volume in one second 1 (FEV1) was monitored to assess EAR and LAR, and uLTE4 was measured before and during EAR and LAR.

RESULTS

After placebo, uLTE4 increased significantly during EAR, but not during and after LAR, in comparison with baseline values. Beclomethasone dipropionate induced a significant attenuation of the uLTE4 increase during EAR, in comparison with placebo, in association with a good protection of LAR (P = 0.002) and a mild protection of EAR (P = 0.07).

CONCLUSIONS

Beclomethasone dipropionate blunts the early increase in uLTE4 excretion due to allergen challenge, in association with a significant effect on the severity of LAR. These data support the hypothesis that inhaled CS may inhibit the allergen-induced release of cys-LTs in asthma.

Montelukast and bronchial inflammation in asthma: a randomised, double-blind placebo-controlled trial

BACKGROUND

Examination of bronchoalveolar lavage, induced sputum, and peripheral blood indicate that cysteinyl leukotriene receptor blockers decrease inflammatory cells in asthma but these do not examine airway tissue per se.

OBJECTIVES

Our objective was to determine the effect of montelukast, a leukotriene receptor antagonist, on airway tissue inflammatory cells by direct bronchoscopic examination of the bronchial mucosa.

METHODS

Adult subjects with mild asthma (pre-bronchodilator FEV(1)> or =70% predicted; PC(20) of < or =4 mg/mL) were given 10mg/day oral montelukast (N=38) or placebo (N=37) for 6 weeks. Bronchial mucosal eosinophils and mast cells were identified and counted.

RESULTS

Change from baseline in numbers of biopsy EG2+ ("activated") eosinophils was the primary endpoint; numbers of total (chromotrope 2R+) eosinophils and (tryptase+) mast cells were secondary. Unexpectedly, there were many patients with zero EG2+ eosinophils at baseline. There was a within-group decrease in EG2+ cells, from 13.54 cells/mm (at baseline) to 0.79 cells/mm at 6 weeks in the montelukast group (LS mean change; 95% confidence interval=-13.59 [-25.45, -1.74]cells/mm; P<0.05), a change not observed in the placebo group (-1.17 [-13.26, 10.91]cells/mm; NS). The zero-inflated Poisson statistical model demonstrated that montelukast significantly reduced post-treatment EG2+ cells by 80% compared with placebo (95% CI [70.6-86.8%]; P<0.0001). The data for total eosinophils showed similar changes. The reduction in mast cell numbers was 12% (95% CI [7.9, 16.0]; P<0.0001).

CONCLUSION

Direct examination of airway tissue confirms that montelukast decreases the number of eosinophils and mast cells in asthma.

Effect of fluticasone 250 microg/salmeterol 50 microg and montelukast on exhaled nitric oxide in asthmatic patients

BACKGROUND

Monitoring noninvasive biomarkers of inflammation is an important adjunct in asthma therapy.

OBJECTIVE

The goal of the present study was to identify airway and alveolar site(s) of inflammation using exhaled nitric oxide (NO) as a marker in asthmatic patients, and to evaluate the NO response to maintenance fluticasone 250 microg/salmeterol 50 microg (F/S) and add-on montelukast 10 mg (M).

METHODS

Thirty (24 women) nonsmoking, mild to moderate asthmatic patients were studied, mean age (+/- SD) 43+/-9 years, treated with F/S for more than one year. All were clinically stable for longer than eight weeks and had not taken oral corticosteroids and/or leukotriene antagonists for eight weeks before the present study. Spirometry, Juniper asthma symptom score, fractional exhaled NO (FENO) 100 mL/s, bronchial NO and alveolar NO concentration (CANO) were measured in a single-blind, nonrandomized crossover study.

PROTOCOL

Visit 1: baseline F/S; visit 2: after four weeks of F/S plus M; visit 3: after four weeks of S plus M; and visit 4: after four weeks of S only. Values in asthmatic patients were also compared with 34 nonsmoking age-matched healthy controls with normal lung function.

RESULTS

After 180 microg aerosolized metered dose inhaler albuterol, the forced expiratory volume in 1 s at baseline was 2.6+/-0.8 L (86%+/-16% of the predicted value) and the forced expiratory volume in 1 s over the forced vital capacity was 77%+/-9% (mean +/- SD), and was similar at visits 2 to 4. Juniper scores were mildly abnormal at visits 1 to 3, but significantly worse (P=0.03) at visit 4 versus visits 1 to 3. FENO values at visits 1 to 3 were similar but significantly increased (P=0.007) at visit 4. Bronchial NO was higher (P=0.03) at visit 4, versus visits 1 and 2, and was no different at visit 3. Compared with the healthy subjects, FENO and bronchial NO values were abnormal (greater than the normal mean plus 2 SD) in 33% of asthmatic patients at visits 1 to 3. CANO was similar for visits 1 to 4. CANO was abnormal (greater than the normal mean + 2 SD) in 20% of asthmatic patients.

CONCLUSION

In clinically stable asthmatic patients, despite controller treatment including moderate-dose inhaled corticosteroids and add-on M, 33% of mild to moderate asthmatic patients have ongoing nonsuppressed bronchial sites of increased NO production, compared with healthy control subjects. These controllers have no effect on CANO, which was abnormal in 20% of the asthmatic patients studied. The addition of add-on M to baseline moderate-dose inhaled corticosteroid did not further reduce total exhaled, bronchial and/or alveolar NO production.

Tolerance and rebound with zafirlukast in patients with persistent asthma

BACKGROUND

The potential for tolerance to develop to zafirlukast, a cysteinyl leukotriene (CysLT) receptor antagonist (LRA) in persistent asthma, has not been specifically examined.

OBJECTIVE

To look for any evidence of tolerance and potential for short-term clinical worsening on LRA withdrawal. Outcome measures included changes in; airway hyperresponsiveness to inhaled methacholine (PD20FEV1), daily symptoms and peak expiratory flows (PEF), sputum and blood cell profiles, sputum CysLT and prostaglandin (PG)E2 and exhaled nitric oxide (eNO) levels.

METHODS

A double blind, placebo-controlled study of zafirlukast, 20 mg twice daily over 12 weeks in 21 asthmatics taking beta2-agonists only (Group I), and 24 subjects treated with ICS (Group II).

RESULTS

In Group I, zafirlukast significantly improved morning PEF and FEV1compared to placebo (p < 0.01), and reduced morning waking with asthma from baseline after two weeks (p < 0.05). Similarly in Group II, FEV1 improved compared to placebo (p < 0.05), and there were early within-treatment group improvements in morning PEF, beta2-agonist use and asthma severity scores (p < 0.05). However, most improvements with zafirlukast in Group I and to a lesser extent in Group II deteriorated toward baseline values over 12 weeks. In both groups, one week following zafirlukast withdrawal there were significant deteriorations in morning and evening PEFs and FEV1 compared with placebo (p < or = 0.05) and increased nocturnal awakenings in Group II (p < 0.05). There were no changes in PD20FEV1, sputum CysLT concentrations or exhaled nitric oxide (eNO) levels. However, blood neutrophils significantly increased in both groups following zafirlukast withdrawal compared to placebo (p = 0.007).

CONCLUSION

Tolerance appears to develop to zafirlukast and there is rebound clinical deterioration on drug withdrawal, accompanied by a blood neutrophilia.

Urinary leukotriene E4

Measurement of urinary leukotriene E4 (LTE4) is a sensitive and noninvasive method of assaying total body cysteinyl leukotriene production and changes in cysteinyl leukotriene levels in specific microenvironments, such as the airway. Urinary LTE4 measurements can be used as sensitive biomarkers of exposure to asthma triggers, such as air pollution and viral infections. Recent studies suggest the potential of using urinary LTE4 concentrations as predictors of asthma control and markers of susceptibility to treatment with leukotriene receptor antagonists.

Measuring asthma severity: instrument refinement

The focus of this study is to evaluate a brief parent-report instrument, the Severity of Chronic Asthma (SCA) scale, that conforms to the national guidelines for assessing asthma. Convergent validity was found between the SCA and other measures related to asthma severity including an illness severity scale (How Bad is the Asthma?), asthma management scales for parents and children, and the pediatric quality-of-life scale. The SCA is a multidimensional scale with appropriate evidence of reliability and validity that may be a heuristic and effective measure in both clinical practice and research endeavors.

Eosinophil cationic protein: is it useful in asthma? A systematic review

INTRODUCTION

Eosinophil cationic protein (ECP) has been widely investigated as a potential biomarker of airway inflammation.

METHOD

A systematic review was performed using Medline with key terms eosinophil cationic protein and asthma, limiting the search to titles or abstracts. Out of 688 potential papers found, abstracts were reviewed based on the following criteria: (1) ECP was used as a biological marker, (2) asthma was the index disease studied, (3) it was a controlled clinical study and (4) ECP was assessed as a diagnostic, assessment or management tool. One hundred and sixty-nine articles satisfied the selection criteria and their full-text versions were reviewed. Only 53 papers were found to provide clinically useful information.

RESULTS

ECP has been measured in serum, plasma, sputum, saliva and broncho-alveolar lavage fluids but serum and sputum are the most established. Levels of ECP in normal and asthmatic subjects in various body fluids were identified. ECP correlates well with airway inflammation but not airway hyper-responsiveness. It is raised in other atopic diseases and hence is not diagnostic for asthma. However, it has been shown to be useful in assessing asthma severity, compliance with anti-inflammatory asthma therapy and as a guide to tailing down inhaled corticosteroid therapy. Although there is some evidence that ECP levels are affected by age, smoking, circadian rhythm and seasonal variation, only smoking appears to be of clinical significance.

DISCUSSION

Despite its limitations, ECP remains potentially useful in asthma management. Future research on ECP should focus on using serial measurements and combining it with other markers of asthma which may increase its clinical usefulness.

Montelukast treatment attenuates the increase in myofibroblasts following low-dose allergen challenge

RATIONALE

Airway remodeling is believed to be important in the pathophysiology of asthma, and myofibroblasts are increased in the airways of asthmatic individuals 24 h after allergen challenge. Leukotriene receptor antagonists exert antiinflammatory activity in asthma, but it is unknown whether they influence indices of airway remodeling. In the present study, we evaluated the effect of montelukast on airway myofibroblasts following low-dose allergen challenge (LDAC).

METHODS

Stable subjects with mild asthma were included in a two-center, randomized, parallel-group study. A 2-week run-in period was followed by LDAC and endobronchial biopsy. Subjects were then randomized to receive either montelukast, 10 mg/d, or placebo (n = 10 in each group) for 8 weeks in a double-blind manner; at the end of the treatment period, subjects underwent a second LDAC and endobronchial biopsy. The effect of treatment on myofibroblasts, fibroblasts, and inflammatory cells was examined using electron microscopy techniques.

RESULTS

Treatment with montelukast showed no significant difference by comparison with placebo but did show a significant within-group treatment-related decrease in airway wall myofibroblasts not seen in the placebo group. In addition, the montelukast-treated group also showed a significant within-group reduction in lymphomononuclear cells and increased neutrophils.

CONCLUSIONS

The results suggest that montelukast has an inhibitory effect on airway structural cells that play a key role in airway remodeling in allergic airway inflammation, and that montelukast may be a useful therapy to attenuate airway remodeling in asthma.

Characterization of within-subject responses to fluticasone and montelukast in childhood asthma

BACKGROUND

Responses to inhaled corticosteroids (ICSs) and leukotriene receptor antagonists (LTRAs) vary among asthmatic patients.

OBJECTIVE

We sought to determine whether responses to ICSs and LTRAs are concordant for individuals or whether asthmatic patients who do not respond to one medication respond to the other.

METHODS

Children 6 to 17 years of age with mild-to-moderate persistent asthma were randomized to one of 2 crossover sequences, including 8 weeks of an ICS, fluticasone propionate (100 microg twice daily), and 8 weeks of an LTRA, montelukast (5-10 mg nightly depending on age), in a multicenter, double-masked, 18-week trial. Response was assessed on the basis of improvement in FEV 1 and assessed for relationships to baseline asthma phenotype-associated biomarkers.

RESULTS

Defining response as improvement in FEV 1 of 7.5% or greater, 17% of 126 participants responded to both medications, 23% responded to fluticasone alone, 5% responded to montelukast alone, and 55% responded to neither medication. Compared with those who responded to neither medication, favorable response to fluticasone alone was associated with higher levels of exhaled nitric oxide, total eosinophil counts, levels of serum IgE, and levels of serum eosinophil cationic protein and lower levels of methacholine PC(20) and pulmonary function; favorable response to montelukast alone was associated with younger age and shorter disease duration. Greater differential response to fluticasone over montelukast was associated with higher bronchodilator use, bronchodilator response, exhaled nitric oxide levels, and eosinophil cationic protein levels and lower methacholine PC(20) and pulmonary function values.

CONCLUSIONS

Response to fluticasone and montelukast vary considerably. Children with low pulmonary function or high levels of markers associated with allergic inflammation should receive ICS therapy. Other children could receive either ICSs or LTRAs.