Analysis of montelukast in mild persistent asthmatic patients with near-normal lung function

Evaluation of switching low-dose inhaled corticosteroid to pranlukast for step-down therapy in well-controlled patients with mild persistent asthma

OBJECTIVE

Treatment guidelines for asthma recommend step-down therapy for well-controlled asthma patients. However, the precise strategy for step-down therapy has not been well defined. We investigated whether well-controlled patients with mild persistent asthma can tolerate a step-down therapy of either a reduced dose of inhaled corticosteroid (ICS) or a switch to a leukotriene receptor antagonist (LTRA), pranlukast hydrate.

METHODS

We recruited 40 adult patients with mild persistent asthma who were well-controlled for at least 3 months with a low-dose ICS therapy. The patients were randomly assigned to either an ICS dose reduction or a switch to pranlukast for 6 months.

RESULTS

FeNO levels in the pranlukast group were significantly increased over that in the ICS group. There were no significant differences between the two groups for lung function, FOT, at the endpoint. The percentage of patients with controlled asthma was 72.2% in the pranlukast group and 90% in the ICS group. No statistically significant difference between the two groups in the percentages of patients with treatment failure was observed.

CONCLUSIONS

Patients with mild persistent asthma that is well-controlled by a low dose of ICS can be switched to pranlukast safely for at least 6 months. However, 27.8% of the pranlukast group failed to maintain well-control, and FeNO levels increased with the switch to pranlukast at 6 months. This study was been limited by the small sample size and should therefore be considered preliminary. Further studies are needed to investigate the therapeutic efficacy of LTRA monotherapy as a step-down therapy.

LTC4 synthase polymorphism modifies efficacy of botanical seed oil combination in asthma

Botanical seed oils reduce the generation of leukotrienes in patients with asthma.

Our objective was to determine the efficacy of a botanical seed oil combination against airflow obstruction in asthma, and to determine the pharmacogenomic effect of the leukotriene C₄ synthase (LTC₄S) polymorphism A-444C.

We conducted a randomized, double-blind, placebo-controlled, cross-over clinical trial in mild to moderate asthmatics to determine the change in FEV₁ after 6 weeks of therapy with borage and echium seed oils versus corn oil placebo. We also examined the effect of the variant LTC₄S -444C allele on the change in lung function.

We did not identify a difference in FEV₁ in the study cohort as a whole (n = 28), nor in the group of A homozygotes. In the C allele carriers (n = 9), FEV₁ improved by 3% after treatment with borage and echium seed oils and declined by 4% after placebo corn oil (p = 0.02). All 9 C allele carriers demonstrated an improvement in their FEV₁ on active treatment compared to placebo as compared to only 7 out of 19 A allele homozygotes (p = 0.007). We observed transient differences in ex vivo leukotriene generation from circulating basophils and granulocytes. We did not observe significant differences in urinary LTE₄ levels.

We conclude that compared to corn oil, a combination of borage and echium seed oils improves airflow obstruction in mild to moderate asthmatics who carry the variant allele in the LTC₄S gene (A-444C). Botanical oil supplementation may have therapeutic potential in asthma if used in a personalized manner.

Trial registration: This trial was registered at http://www.clinicaltrials.gov as NCT00806442.

Systems pharmacology models can be used to understand complex pharmacokinetic-pharmacodynamic behavior: an example using 5-lipoxygenase inhibitors

Zileuton, a 5-lipoxygenase (5LO) inhibitor, displays complex pharmaokinetic (PK)-pharmacodynamic (PD) behavior. Available clinical data indicate a lack of dose–bronchodilatory response during initial treatment, with a dose response developing after ~1–2 weeks. We developed a quantitative systems pharmacology (QSP) model to understand the mechanism behind this phenomenon. The model described the release, maturation, and trafficking of eosinophils into the airways, leukotriene synthesis by the 5LO enzyme, leukotriene signaling and bronchodilation, and the PK of zileuton. The model provided a plausible explanation for the two-phase bronchodilatory effect of zileuton–the short-term bronchodilation was due to leukotriene inhibition and the long-term bronchodilation was due to inflammatory cell infiltration blockade. The model also indicated that the theoretical maximum bronchodilation of both 5LO inhibition and leukotriene receptor blockade is likely similar. QSP modeling provided interesting insights into the effects of leukotriene modulation.

Critical role of interleukin-5 in the development of a mite antigen-induced chronic bronchial asthma model

OBJECTIVE AND DESIGN

Asthma is associated with eosinophilic airway inflammation and characterized by enhanced airway sensitivity. Interleukin (IL)-5 plays an important role in the pathogenesis of asthma. The involvement of IL-5 receptor-mediated cellular signals in the pathogenesis of a mite antigen-induced chronic asthma model was investigated.

SUBJECTS

In this study, 48 female C57BL/6J (WT) mice and IL-5 receptor-deficient (IL-5RKO) mice were used.

TREATMENT

Mite antigen (50 μl) was intranasally administered 13 times to WT and IL-5RKO mice.

METHODS

Airway hypersensitivity (Mch PC200) and specific antigen exposure tests were performed, and lung tissue, bronchoalveolar lavage fluid (BALF), and blood were collected to investigate the asthma pathology and differences in the local pulmonary levels of cytokines and chemokines.

RESULTS

Airway sensitivity was enhanced and antigen-specific airway resistance was increased in WT mice. In addition, the number of eosinophils and Th2 cytokine levels in the BALF were increased. In contrast, IL-5RKO mice did not acquire the asthma pathology, such as antigen-specific airway resistance and eosinophilic airway inflammation. Mch PC200 was significantly correlated with cysteinyl leukotriene levels in WT mice.

CONCLUSION

These findings suggested that both IL-5 induced eosinophils and cysteinyl leukotrienes are involved in the pathology of this mite antigen-induced chronic asthma model.

Montelukast in asthma: a review of its efficacy and place in therapy

Many studies have been published in the last 10 years on the efficacy and safety of montelukast in asthma since this drug entered the market. Experimental studies, in vitro and in vivo, and clinical studies on large numbers of patients with asthma of different severity have clearly demonstrated that montelukast is able to modify the pathophysiological mechanisms of the disease, and to improve to some extent the clinical and functional manifestations of asthma. Studies of montelukast as monotherapy or in combination with other drugs, mainly inhaled corticosteroids (ICS), versus different comparator drugs have contributed to the positioning of montelukast in the different levels of asthma treatment, according to the Global Initiative for Asthma Guidelines. Montelukast may be used as monotherapy as an alternative to low-dose ICS (particularly in a step-down strategy) or in addition to ICS for improving clinical manifestations by an increase in anti-inflammatory effects and a sparing of corticosteroids. The heterogeneity of asthma has received a large amount of attention in the last few years in order to better tailor treatment according to the different clinical and biological phenotypes of asthma. Montelukast has proven to be particularly effective in exercise-induced asthma and in asthma associated with allergic rhinitis. Other phenotypes where montelukast is effective include asthma in obese patients, asthma in smokers, aspirin-induced asthma and viral-induced wheezing episodes. The safety profile of montelukast is very good, and the suspicions of increased risk of Churg-Strauss syndrome or suicide have not been confirmed.

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. 

Leukotriene antagonists as first-line or add-on asthma-controller therapy

BACKGROUND

Most randomized trials of treatment for asthma study highly selected patients under idealized conditions.

METHODS

We conducted two parallel, multicenter, pragmatic trials to evaluate the real-world effectiveness of a leukotriene-receptor antagonist (LTRA) as compared with either an inhaled glucocorticoid for first-line asthma-controller therapy or a long-acting beta(2)-agonist (LABA) as add-on therapy in patients already receiving inhaled glucocorticoid therapy. Eligible primary care patients 12 to 80 years of age had impaired asthma-related quality of life (Mini Asthma Quality of Life Questionnaire [MiniAQLQ] score ≤6) or inadequate asthma control (Asthma Control Questionnaire [ACQ] score ≥1). We randomly assigned patients to 2 years of open-label therapy, under the care of their usual physician, with LTRA (148 patients) or an inhaled glucocorticoid (158 patients) in the first-line controller therapy trial and LTRA (170 patients) or LABA (182 patients) added to an inhaled glucocorticoid in the add-on therapy trial.

RESULTS

Mean MiniAQLQ scores increased by 0.8 to 1.0 point over a period of 2 years in both trials. At 2 months, differences in the MiniAQLQ scores between the two treatment groups met our definition of equivalence (95% confidence interval [CI] for an adjusted mean difference, -0.3 to 0.3). At 2 years, mean MiniAQLQ scores approached equivalence, with an adjusted mean difference between treatment groups of -0.11 (95% CI, -0.35 to 0.13) in the first-line controller therapy trial and of -0.11 (95% CI, -0.32 to 0.11) in the add-on therapy trial. Exacerbation rates and ACQ scores did not differ significantly between the two groups.

CONCLUSIONS

Study results at 2 months suggest that LTRA was equivalent to an inhaled glucocorticoid as first-line controller therapy and to LABA as add-on therapy for diverse primary care patients. Equivalence was not proved at 2 years. The interpretation of results of pragmatic research may be limited by the crossover between treatment groups and lack of a placebo group. (Funded by the National Coordinating Centre for Health Technology Assessment U.K. and others; Controlled Clinical Trials number, ISRCTN99132811.).

Treatment strategies in mild asthma

PURPOSE OF THE REVIEW

More than 10 years ago the category of mild asthma was split into mild intermittent and mild persistent asthma and maintenance therapy with low dose inhaled corticosteroids (ICS) was recommended for mild persistent asthma. The threshold for instituting regular ICS therapy was arbitrarily chosen, in the absence of clinical studies specifically addressing this issue.

RECENT FINDINGS

The results of recent trials have questioned the assumption that all patients at the mild end of the asthma severity spectrum should be committed to regular anti-inflammatory treatment with inhaled corticosteroids. As a consequence, the identification of the relevant outcomes for the treatment of mild persistent asthma has become a matter of discussion, which has provided the rationale to test the efficacy and well tolerance of new strategies, other than guidelines-recommended regular low-dose ICS, for the treatment of mild persistent asthma.

SUMMARY

Several approaches have been evaluated with some promising results, to include the combination of ICS and long-acting b2-agonists, oral leukotriene antagonists, and the intermittent or as-needed use of ICS in the absence of regular treatment. Conversely, little effort has been made to evaluate therapeutic options other than as-needed bronchodilation in mild intermittent asthma.

The link between allergic rhinitis and asthma: a role for antileukotrienes?

Allergic rhinitis and asthma are both chronic heterogeneous disorders, with an overlapping epidemiology of prevalence, health care costs and social costs in quality of life. Both are inflammatory disorders with a similar pathophysiology, and both share some treatment approaches. However, each disorder has an array of treatments used separately in controlling these atopic disorders, from inhaled corticosteroids, beta(2)-agonists and antihistamines to newer monoclonal antibody-based treatments. The present article reviews the shared components of allergic rhinitis and asthma, and examines recent evidence supporting antileukotrienes as effective agents in reducing the symptoms of both diseases.

[Characteristics of mild asthma: clinical signs and medication use. Position statement of the Mild Asthma Working Group (174)]

OBJECTIVE

To update on the state of knowledge in mild asthma (intermittent and persistent mild asthma, according to the GINA classification) review the literature, and the position statement of the French Mild Asthma Working Group.

METHODS

The French Mild Asthma Working Group (11 lung specialists, 4 paediatricians, 1 pharmacologist, and 1 general practitioner) selected, analysed, and summarised the literature on the descriptive epidemiology, physiopathology, clinical signs, and management of mild asthma. The position of the working group on the descriptive epidemiology (causal factors excluded) and the nature of the bronchial inflammation has been presented in a previous article. The present article focuses on the clinical features of mild asthma and the use of medication for it.

RESULTS

Mild asthma was more frequent, more symptomatic, and less well controlled in children than in adults. Its generally benign evolution may in some (<10%) cases be complicated by severe episodes. Patients with mild persistent asthma require controller medication every day: permanent low-dose inhaled corticosteroid monotherapy is the reference foundation treatment for persistent mild asthma.

CONCLUSIONS

The present findings should help clinicians and guide them in their approach to managing this condition.

Mild asthma: an expert review on epidemiology, clinical characteristics and treatment recommendations

This review is the synthesis of a working group on mild asthma. Mild asthma includes intermittent and persistent mild asthma according to the Global Initiative for Asthma (GINA) classification, and affects between 50% and 75% of asthmatic patients. Mild asthma is more frequent, more symptomatic, and less well controlled in children than in adults. Cohort studies from childhood to adulthood show that asthma severity usually remains stable over time. Nevertheless, mild asthma can lead to severe exacerbations, with a frequency ranging from 0.12 to 0.77 per patient-year. Severe exacerbations in mild asthma represent 30-40% of asthma exacerbations requiring emergency consultation. In mild asthma, inflammation and structural remodelling are constant, of varying intensity, but nonspecific. Therapy with inhaled corticosteroids (ICS) decreases bronchial inflammation, but has only a slight effect on structural remodelling, and, when stopped, inflammation immediately recurs. Permanent low-dose ICS therapy is the reference treatment for persistent mild asthma. Effectiveness is to be reassessed at 3 months, and if it is insufficient the patient is no longer considered mildly asthmatic, and treatment has to be stepped up. As mild asthma is the most frequent form of the disease, diagnosis and management require physicians' particular attention.

The challenge of mild persistent asthma

OBJECTIVE

To review the current data and treatment options for mild persistent asthma.

DATA SOURCES

A MEDLINE search was performed for relevant articles.

STUDY SELECTION

The expert opinion of the author was used to select studies for inclusion in this review.

RESULTS

Current data suggest that asthma severity is determined early in life and that disease progression may not occur outside early childhood. Furthermore, no therapy has been demonstrated to clearly prevent or reverse structural airway changes in patients with persistent asthma. Thus, the primary goal of asthma therapy is to prevent disease exacerbations rather than to halt disease progress, at least in patients past early childhood. Published reports of severe exacerbations in patients with reported mild asthma may actually reflect inclusion of patients with more severe forms of the disease who were inappropriately classified in terms of asthma severity.

CONCLUSION

Unlike the case for moderate and severe asthma, where regular therapy with inhaled corticosteroids is clearly the treatment of choice, clear guidelines for treating patients with mild persistent asthma have not been established. Patients with mild disease without severe exacerbations may require only the minimum therapy necessary for disease control.

Montelukast in asthmatic patients 6 years-14 years old with an FEV1 > 75%

OBJECTIVES

Montelukast is a potent leukotriene receptor antagonist effective for treating asthma symptoms in adult and pediatric patients. The purpose of this analysis was to assess the clinical efficacy of montelukast, a potent leukotriene-receptor antagonist, in a subgroup analysis of patients aged 6 years-14 years with milder asthma, defined as a percentage predicted forced expiratory volume in 1 s (FEV1) > 75% using data from a clinical trial of pediatric patients with a broad range of asthma severities.

RESEARCH DESIGN AND METHODS

The original previously published clinical trial was an 8-week multi-center, randomized, double-blind, parallel-group study conducted in 47 centers in the United States and Canada. The study compared the efficacy of once daily montelukast 5 mg to placebo in patients 6 years-14 years old with persistent asthma and an FEV1 ranging from 50% to 85% of predicted. A total of 87 patients in the montelukast group and 51 patients in the placebo group were selected from the original cohort of 336 patients based on percentage predicted FEV1 of > 75%. The primary endpoint was percentage change in FEV1 from baseline compared with placebo over 8 weeks of active treatment.

RESULTS

Montelukast significantly improved the primary endpoint of percentage change in FEV1 compared with placebo (p = 0.005). Other efficacy endpoints were significantly improved on montelukast similar to efficacy in the original study.

CONCLUSION

Montelukast significantly improved FEV1, clinic measured peak expiratory flow (PEF), reduced nocturnal awakenings, and improved quality of life in children with milder persistent asthma defined as an FEV1 > 75% of predicted.

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

BACKGROUND

Anti-leukotrienes agents are currently being studied as alternative first line agents to inhaled corticosteroids in mild to moderate chronic asthma.

OBJECTIVES

To compare the safety and efficacy of anti-leukotriene agents with inhaled glucocorticoids (ICS) and to determine the dose-equivalence of anti-leukotrienes to daily dose of ICS.

SEARCH STRATEGY

We searched MEDLINE (1966 to Aug 2003), EMBASE (1980 to Aug 2003), CINAHL (1982 to Aug 2003), the Cochrane Airways Group trials register, and the Cochrane Central Register of Controlled Trials (August 2003), abstract books, and reference lists of review articles and trials. We contacted colleagues and international headquarters of anti-leukotrienes producers.

SELECTION CRITERIA

Randomised controlled trials that compared anti-leukotrienes with inhaled corticosteroids during a minimal 30-day intervention period in asthmatic patients aged 2 years and older.

DATA COLLECTION AND ANALYSIS

Two reviewers independently assessed the methodological quality or trials and extracted trial data. The primary outcome was the rate of exacerbations requiring systemic corticosteroids. Secondary outcomes included lung function, indices of chronic asthma control, adverse effects and withdrawal rates.

MAIN RESULTS

27 trials (including 1 trial testing two protocols) met the inclusion criteria; 13 were of high methodological quality; 20 are published in full-text. All trials pertained to patients with mild to moderate persistent asthma. Only 3 trials focused on children and adolescents. Trial duration varied from 4 to 37 weeks. In most trials, daily dose of ICS was 400 mcg of beclomethasone or equivalent. Patients treated with anti-leukotrienes were 65% more likely to suffer an exacerbation requiring systemic steroids [Relative Risk 1.65; 95% Confidence Interval (CI) 1.36 to 2.00]. Twenty six (95% CI: 17 to 47) patients must be treated with anti-leukotrienes instead of inhaled corticosteroids to cause one extra exacerbation. Significant differences favouring ICS were noted in secondary outcomes where()the improvement in FEV(1) reached 130 mL [13 trials; 95% CI: 50, 140 mL ]. Other significant benefits of ICS were seen for symptoms, nocturnal awakenings, rescue medication use, symptom-free days, and quality of life. Anti-leukotriene therapy was associated with 160% increased risk of withdrawals due to poor asthma control. Twenty nine (95% CI 20 to 48) patients must be treated with anti-leukotrienes instead of inhaled corticosteroids to cause one extra withdrawal due to poor control. Risk of side effects was not different between groups.

REVIEWERS' CONCLUSIONS

Inhaled steroids at a dose of 400 mcg/day of beclomethasone or equivalent are more effective than anti-leukotriene agents given in the usual licensed doses. The exact dose-equivalence of anti-leukotriene agents in mcg of ICS remains to be determined. Inhaled glucocorticoids should remain the first line monotherapy for persistent asthma.

Leukotriene receptor antagonists in asthma therapy

In persons with asthma, the cysteinyl leukotrienes possess multiple inflammatory properties in vitro and have long been considered to be a potentially important mediator of asthma and an attractive target for therapeutic intervention. Controlled clinical trials have documented the efficacy of leukotriene receptor antagonists in asthma treatment, but reservations about their use for asthma therapy center on two main issues: the heterogeneity of patient responses and their reduced potency relative to other asthma medications. For example, leukotriene receptor antagonists also have been shown to be less efficacious than inhaled corticosteroids for several end points, including symptom relief, reduced markers of inflammation, and improved pulmonary function. This review explores several underappreciated aspects of asthma therapy: heterogeneity of patient responses to medication, the failure of symptoms to correlate with commonly used end points, and the potential of delivery to distal airways for producing important and novel benefits.

The role of antileukotrienes in the treatment of asthma

Cysteinyl leukotrienes (Cys-LTs) are mediators released in asthma and are both direct bronchoconstrictors and proinflammatory substances that mediated several steps in the pathophysiology of chronic asthma, including inflammatory cells recruitment, vascular leakage, and possibly airway remodelling. Available evidence from clinical trials and real world experience derived from managing patients with asthma justifies a broader role for antiLTRAs in asthma management than that recommended in the National Asthma Education and Prevention Programm (NAEPP) and National Health Lung and Blood Institute (NHLBI) treatment guidelines. Leukotriene-receptor antagonist drugs (LTRAs) seem to be effective alternatives to inhaled corticosteroids (ICS) either as monotherapy or as adjunctive therapy that reduces the need for higher doses of ICS in patients with mild-to-moderate persistent asthma. LTRAs may be used as adjunctive therapy for al levels of disease severity because they are effective in combination with ICS during long-term maintenance therapy. The agents seem especially effective in preventing aspirin-induced asthma, exercise-induced asthma (EIA) and they may provide an additional advantage of reducing nasal congestion in patients with both asthma and rhinitis.

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

BACKGROUND

Anti-leukotrienes agents are currently being studied as alternative first line agents to inhaled corticosteroids in mild to moderate chronic asthma.

OBJECTIVES

To compare the safety and efficacy of anti-leukotriene agents with inhaled glucocorticoids (ICS) and to determine the dose-equivalence of anti-leukotrienes to daily dose of ICS.

SEARCH STRATEGY

Medline (1966 to Jan 2002), Embase (1980 to Jan 2002), and Cinahl (1982 to Jan 2002) were searched and reference lists of review articles and trials. We contacted colleagues and international headquarters of anti-leukotrienes producers.

SELECTION CRITERIA

Randomised controlled trials that compared leukotriene antagonists with inhaled corticosteroids during a minimal 30-day intervention period in asthmatic patients aged 2 years and older.

DATA COLLECTION AND ANALYSIS

Two reviewers performed assessments of methodological quality and data extraction independently and blindly. The primary outcome was the rate of exacerbations requiring systemic corticosteroids. Secondary outcomes included lung function, indices of chronic asthma control, adverse effects and withdrawal rates.

MAIN RESULTS

14 trials met the inclusion criteria; 10 were of high methodological quality; 8 are published in full-text. All were in mild-to-moderate chronic asthma, Two included children or adolescents. Trial duration was 4 - 37 weeks. In most trials, daily dose of ICS was 400 mcg of beclomethasone-equivalent. Patients treated with anti-leukotrienes were 60% more likely to suffer an exacerbation requiring systemic steroids [12 trials; Relative Risk 1.61; 95% Confidence Interval (CI) 1.15, 2.25]. Significant differences favouring ICS were noted in most secondary outcomes, eg improvement in FEV1 [7 trials; Weighted Mean Difference 120 ml; 95% CI: 80, 170 ml ]; symptom scores [5 trials: Standardized Mean Difference 0.3; 95% CI 0.2, 0.4]. Other significant benefits of ICS were seen for nocturnal awakenings, rescue medication use, and quality of life. Risk of side effects was not different between groups, but anti-leukotriene therapy was associated with 30% increased risk of "withdrawals for any cause" or "withdrawals due to poor asthma control".

REVIEWER'S CONCLUSIONS

For most asthma outcomes, ICS at 400 mcg/day of beclomethasone-equivalent are more effective than anti-leukotriene agents given in the usual licensed doses. The exact dose-equivalence of anti-leukotriene agents in mcg of ICS remains to be determined.