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

Clinical asthma phenotypes in the real world: opportunities and challenges

Asthma is a common, chronic and heterogeneous syndrome, affecting people of all ages, all races and both sexes. It may range from mild disease with barely noticeable symptoms, to very severe disease with constant symptoms that greatly hinder the life of the patient. Guidelines issued by various medical societies provide guidance on how to diagnose and manage asthmatic patients. It is now increasingly recognised that asthma management must be individualised, tailored not only to the severity of the disease but to the phenotypic characteristics of each patient. The aim of asthma treatment is control of asthma and the prevention of risk of exacerbations and fixed airflow limitation. Asthma control can be easily assessed clinically through simple screening tools such as the use of validated questionnaires and spirometry. The use of inflammatory biomarkers can be an alternative approach that, however, requires more time and resources. Asthma treatment involves the use of controllers, mainly inhaled corticosteroids and long-acting β2-agonists, and relievers, mainly rapid-acting β2-agonists. Controller medications reduce airway inflammation, lead to better symptom control and reduce the risk of future exacerbations. Reliever (rescue) medications alleviate symptoms and prevent exercise-induced bronchoconstriction. Treatment must be based on a "stepwise approach" in order to achieve good control of symptoms and to minimise future risks of exacerbations. That is, less treatment for mild disease, more treatment for severe, uncontrolled disease. Once good asthma control has been achieved and maintained, treatment should be stepped down. In severe asthmatics, phenotypic characterisation becomes more clinically useful and add-on treatment such as anti-immunoglobulin E monoclonal antibodies may be required. Despite our better understanding of asthma, there are still patients who will not respond to treatment and remain symptomatic. Dissemination of guidelines and national plans allowing early diagnosis of asthma as well as access to specialised primary and secondary care for asthmatic patients, personalised treatment and continuity of care may lead to excellence in care and controlled asthma for the majority of patients. Education of the patient in asthma is also very important, as in every chronic disease, as the patients live with the disease every day while they visit a healthcare professional a few times a year. Future planning for new treatments should focus on the needs of such severe asthma patients.

Addition of long-acting beta2-agonists to inhaled corticosteroids for chronic asthma in children

BACKGROUND

Long-acting beta2-agonists (LABA) in combination with inhaled corticosteroids (ICS) are increasingly prescribed for children with asthma.

OBJECTIVES

To assess the safety and efficacy of adding a LABA to an ICS in children and adolescents with asthma. To determine whether the benefit of LABA was influenced by baseline severity of airway obstruction, the dose of ICS to which it was added or with which it was compared, the type of LABA used, the number of devices used to deliver combination therapy and trial duration.

SEARCH METHODS

We searched the Cochrane Airways Group Asthma Trials Register until January 2015.

SELECTION CRITERIA

We included randomised controlled trials testing the combination of LABA and ICS versus the same, or an increased, dose of ICS for at least four weeks in children and adolescents with asthma. The main outcome was the rate of exacerbations requiring rescue oral steroids. Secondary outcomes included markers of exacerbation, pulmonary function, symptoms, quality of life, adverse events and withdrawals.

DATA COLLECTION AND ANALYSIS

Two review authors assessed studies independently for methodological quality and extracted data. We obtained confirmation from trialists when possible.

MAIN RESULTS

We included in this review a total of 33 trials representing 39 control-intervention comparisons and randomly assigning 6381 children. Most participants were inadequately controlled on their current ICS dose. We assessed the addition of LABA to ICS (1) versus the same dose of ICS, and (2) versus an increased dose of ICS.LABA added to ICS was compared with the same dose of ICS in 28 studies. Mean age of participants was 11 years, and males accounted for 59% of the study population. Mean forced expiratory volume in one second (FEV1) at baseline was ≥ 80% of predicted in 18 studies, 61% to 79% of predicted in six studies and unreported in the remaining studies. Participants were inadequately controlled before randomisation in all but four studies.There was no significant group difference in exacerbations requiring oral steroids (risk ratio (RR) 0.95, 95% confidence interval (CI) 0.70 to 1.28, 12 studies, 1669 children; moderate-quality evidence) with addition of LABA to ICS compared with ICS alone. There was no statistically significant group difference in hospital admissions (RR 1.74, 95% CI 0.90 to 3.36, seven studies, 1292 children; moderate-quality evidence)nor in serious adverse events (RR 1.17, 95% CI 0.75 to 1.85, 17 studies, N = 4021; moderate-quality evidence). Withdrawals occurred significantly less frequently with the addition of LABA (23 studies, 471 children, RR 0.80, 95% CI 0.67 to 0.94; low-quality evidence). Compared with ICS alone, addition of LABA led to significantly greater improvement in FEV1 (nine studies, 1942 children, inverse variance (IV) 0.08 L, 95% CI 0.06 to 0.10; mean difference (MD) 2.99%, 95% CI 0.86 to 5.11, seven studies, 534 children; low-quality evidence), morning peak expiratory flow (PEF) (16 studies, 3934 children, IV 10.20 L/min, 95% CI 8.14 to 12.26), reduction in use of daytime rescue inhalations (MD -0.07 puffs/d, 95% CI -0.11 to -0.02, seven studies; 1798 children) and reduction in use of nighttime rescue inhalations (MD -0.08 puffs/d, 95% CI -0.13 to -0.03, three studies, 672 children). No significant group difference was noted in exercise-induced % fall in FEV1, symptom-free days, asthma symptom score, quality of life, use of reliever medication and adverse events.A total of 11 studies assessed the addition of LABA to ICS therapy versus an increased dose of ICS with random assignment of 1628 children. Mean age of participants was 10 years, and 64% were male. Baseline mean FEV1 was ≥ 80% of predicted. All trials enrolled participants who were inadequately controlled on a baseline inhaled steroid dose equivalent to 400 µg/d of beclomethasone equivalent or less.There was no significant group differences in risk of exacerbation requiring oral steroids with the combination of LABA and ICS versus a double dose of ICS (RR 1.69, 95% CI 0.85 to 3.32, three studies, 581 children; moderate-quality evidence) nor in risk of hospital admission (RR 1.90, 95% CI 0.65 to 5.54, four studies, 1008 children; moderate-quality evidence).No statistical significant group difference was noted in serious adverse events (RR 1.54, 95% CI 0.81 to 2.94, seven studies, N = 1343; moderate-quality evidence) and no statistically significant differences in overall risk of all-cause withdrawals (RR 0.96, 95% CI 0.67 to 1.37, eight studies, 1491 children; moderate-quality evidence). Compared with double the dose of ICS, use of LABA was associated with significantly greater improvement in morning PEF (MD 8.73 L/min, 95% CI 5.15 to 12.31, five studies, 1283 children; moderate-quality evidence), but data were insufficient to aggregate on other markers of asthma symptoms, rescue medication use and nighttime awakening. There was no group difference in risk of overall adverse effects, A significant group difference was observed in linear growth over 12 months, clearly indicating lower growth velocity in the higher ICS dose group (two studies: MD 1.21 cm/y, 95% CI 0.72 to 1.70).

AUTHORS' CONCLUSIONS

In children with persistent asthma, the addition of LABA to ICS was not associated with a significant reduction in the rate of exacerbations requiring systemic steroids, but it was superior for improving lung function compared with the same or higher doses of ICS. No differences in adverse effects were apparent, with the exception of greater growth with the use of ICS and LABA compared with a higher ICS dose. The trend towards increased risk of hospital admission with LABA, irrespective of the dose of ICS, is a matter of concern and requires further monitoring.

Primary adherence to controller medications for asthma is poor

RATIONALE

Few previous studies have evaluated primary adherence (whether a new prescription is filled within 30 d) to controller medications in individuals with persistent asthma.

OBJECTIVE

To compare adherence to the major controller medication regimens for asthma.

METHODS

This was a retrospective cohort study of enrollees from five large health plans. We used electronic medical data on patients of all ages with asthma who had experienced an asthma-related exacerbation in the prior 12 months. We studied adherence measures including proportion of days covered and primary adherence (first prescription filled within 30 d).

MEASUREMENTS AND MAIN RESULTS

Our population included 69,652 subjects who had probable persistent asthma and were prescribed inhaled corticosteroids (ICSs), leukotriene antagonists (LTRAs), or ICS/long-acting β-agonists (ICS/LABAs). The mean age was 37 years and 58% were female. We found that 14-20% of subjects who were prescribed controller medicines for the first time did not fill their prescriptions. The mean proportion of days covered was 19% for ICS, 30% for LTRA, and 25% for ICS/LABA over 12 months. Using multivariate logistic regression, subjects prescribed LTRA were less likely to be primary adherent than subjects prescribed ICS (odds ratio, 0.82; 95% confidence interval, 0.74-0.92) or ICS/LABA (odds ratio, 0.88; 95% confidence interval, 0.80-0.97). Black and Latino patients were less likely to fill the prescription compared with white patients.

CONCLUSIONS

Adherence to controller medications for asthma is poor. In this insured population, primary adherence to ICSs was better than to LTRAs and ICS/LABAs. Adherence as measured by proportion of days covered was better for LTRAs and ICS/LABAs than for ICSs.

Side Effects of Leukotriene Receptor Antagonists in Asthmatic Children

Background:

Leukotriene receptor antagonists (LTRAs) are drugs which have been widely used more than ten years. As the use of LTRAs increases, our knowledge with respect to their side effects increases as well.

Objectives:

The objective of our study was to evaluat the observed side effects of LTRAs used in patients with astma.

Patients and Methods:

1024 patients treated only with LTRAs owing to asthma or early wheezing were included in the study for a five-year period. The observed side effects of LTRAs in these patients were retrospectively investigated. The side effects were divided into two parts as psychiatric and non-psychiatric.

Results:

Among the 1024 cases included in the study, 67.5% of the patients out of 41 with side effects were male, 32.5% were female and the average age was 6.5 years. The rate of patients with asthma was 63.41% and 36.58% of the patients had early wheezing. It was determined that sex, age and diagnosis (early wheezing or asthma) of the patients were ineffective in the emergence of side effects. The average period for the emergence of side effects was the first month. It was observed that hyperactivity was the most frequently observed psychiatric side effect and that abdominal pain was the non-psychiatric side effect.

Conclusions:

The side effects of LTRAs were common in children. Therefore, patients must be informed at the beginning of the treatment and they must be evaluated at certain intervals.

Asthma therapy and its effect on airway remodelling

Asthma remains a major health problem with significant morbidity, mortality and economic costs. In asthma, airway remodelling, which refers to all the microscopic structural changes seen in the airway tissue, has been recognised for many decades and remains one of the defining characteristics of the disease; however, it is still poorly understood. The detrimental pathophysiological consequences of some features of remodelling, like increased airway smooth muscle mass and subepithelial fibrosis, are well documented. However, whether targeting these by therapy would be beneficial is unknown. Although the prevailing thinking is that remodelling is an abnormal response to persistent airway inflammation, recent evidence, especially from studies of remodelling in asthmatic children, suggests that the two processes occur in parallel. The effects of asthma therapy on airway remodelling have not been studied extensively due to the challenges of obtaining airway tissue in the context of clinical trials. Corticosteroids remain the cornerstone of asthma therapy, and their effects on remodelling have been better studied than other drugs. Bronchial thermoplasty is the only asthma therapy to primarily target remodelling, although how it results in the apparent clinical benefits seen is not exactly clear. In this article we discuss the mechanisms of airway remodelling in asthma and review the effects of conventional and novel asthma therapies on the process.

Real-world research and its importance in respiratory medicine

EDUCATIONAL AIMS

To improve understanding of: The relative benefits and limitations of evidence derived from different study designs and the role that real-life asthma studies can play in addressing limitations in the classical randomised controlled trial (cRCT) evidence base.The importance of guideline recommendations being modified to fit the populations studied and the model of care provided in their reference studies.

KEY POINTS

Classical randomised controlled trials (cRCTs) show results from a narrow patient group with a constrained ecology of care.Patients with "real-life" co-morbidities and lifestyle factors receiving usual care often have different responses to medication which will not be captured by cRCTs if they are excluded by strict selection criteria.Meta-analyses, used to direct guidelines, contain an inherent meta-bias based on patient selection and artificial patient care.Guideline recommendations should clarify where they related to cRCT ideals (in terms of patient populations, medical resources and care received) and could be enhanced through inclusion of evidence from studies designed to better model the populations and care approaches present in routine care.

SUMMARY

Clinical practice requires a complex interplay between experience and training, research, guidelines and judgement, and must not only draw on data from traditional or classical randomised controlled trials (cRCTs), but also from pragmatically designed studies that better reflect real-life clinical practice. To minimise extraneous variables and to optimise their internal validity, cRCTs exclude patients, clinical characteristics and variations in care that could potentially confound outcomes. The result is that respiratory cRCTs often enrol a small, non-representative subset of patients and overlook the important interplay and interactions between patients and the real world, which can effect treatment outcomes. Evidence from real-life studies (e.g. naturalistic or pragmatic clinical trials and observational studies encompassing healthcare database studies and cohort studies) can be combined with cRCT evidence to provide a fuller picture of intervention effectiveness and realistic treatment outcomes, and can provide useful insights into alternative management approaches in more challenging asthma patients. The Respiratory Effectiveness Group (REG), in collaboration with the European Academy of Allergy and Clinical Immunology (EAACI) and the European Respiratory Society (ERS), is developing quality appraisal tools and methods for integrating different sources of evidence. A REG/EAACI taskforce aims to help support future guideline developers to avoid a one-size-fits-all approach to recommendations and to tailor the conclusions of their meta-analyses to the populations under consideration.

Pharmacotherapy of critical asthma syndrome: current and emerging therapies

The critical asthma syndrome (CAS) encompasses the most severe, persistent, refractory asthma patients for the clinician to manage. Personalized pharmacotherapy is necessary to prevent the next acute severe asthma exacerbation, not just the control of symptoms. The 2007 National Asthma Education and Prevention Program Expert Panel 3 provides guidelines for the treatment of uncontrolled asthma. The patient's response to recommended pharmacotherapy is highly variable which risks poor asthma control leading to frequent exacerbations that can deteriorate into CAS. Controlling asthma symptoms and preventing acute exacerbations may be two separate clinical activities with their own unique demands. Clinicians must be prepared to use the entire spectrum of asthma medications available but must concurrently be aware of potential drug toxicities some of which can paradoxically worsen asthma control. Medications normally prescribed for COPD can potentially be useful in the CAS patient, particularly those with asthma-COPD overlap syndrome. Immunomodulation with drugs like omalizumab in IgE-mediated asthma syndromes is one important approach. New and emerging drugs address unique aspects of airway inflammation and biology but at a significant financial cost. The pharmacology and toxicities of the agents that may be used in the treatment of CAS to control asthma symptoms and prevent severe exacerbations are reviewed.

Pediatric asthma: guidelines-based care, omalizumab, and other potential biologic agents

Over the past several decades, the evidence supporting rational pediatric asthma management has grown considerably. As more is learned about the various phenotypes of asthma, the complexity of management will continue to grow. This article focuses on the evidence supporting the current guidelines-based pediatric asthma management and explores the future of asthma management with respect to phenotypic heterogeneity and biologics.

Mammalian lipoxygenases and their biological relevance

Lipoxygenases (LOXs) form a heterogeneous class of lipid peroxidizing enzymes, which have been implicated not only in cell proliferation and differentiation but also in the pathogenesis of various diseases with major public health relevance. As other fatty acid dioxygenases LOXs oxidize polyunsaturated fatty acids to their corresponding hydroperoxy derivatives, which are further transformed to bioactive lipid mediators (eicosanoids and related substances). On the other hand, lipoxygenases are key players in the regulation of the cellular redox homeostasis, which is an important element in gene expression regulation. Although the first mammalian lipoxygenases were discovered 40 years ago and although the enzymes have been well characterized with respect to their structural and functional properties the biological roles of the different lipoxygenase isoforms are not completely understood. This review is aimed at summarizing the current knowledge on the physiological roles of different mammalian LOX-isoforms and their patho-physiological function in inflammatory, metabolic, hyperproliferative, neurodegenerative and infectious disorders. This article is part of a Special Issue entitled "Oxygenated metabolism of PUFA: analysis and biological relevance".

Distinguishing adult-onset asthma from COPD: a review and a new approach

Adult-onset asthma and chronic obstructive pulmonary disease (COPD) are major public health burdens. This review presents a comprehensive synopsis of their epidemiology, pathophysiology, and clinical presentations; describes how they can be distinguished; and considers both established and proposed new approaches to their management. Both adult-onset asthma and COPD are complex diseases arising from gene-environment interactions. Early life exposures such as childhood infections, smoke, obesity, and allergy influence adult-onset asthma. While the established environmental risk factors for COPD are adult tobacco and biomass smoke, there is emerging evidence that some childhood exposures such as maternal smoking and infections may cause COPD. Asthma has been characterized predominantly by Type 2 helper T cell (Th2) cytokine-mediated eosinophilic airway inflammation associated with airway hyperresponsiveness. In established COPD, the inflammatory cell infiltrate in small airways comprises predominantly neutrophils and cytotoxic T cells (CD8 positive lymphocytes). Parenchymal destruction (emphysema) in COPD is associated with loss of lung tissue elasticity, and small airways collapse during exhalation. The precise definition of chronic airflow limitation is affected by age; a fixed cut-off of forced expiratory volume in 1 second/forced vital capacity leads to overdiagnosis of COPD in the elderly. Traditional approaches to distinguishing between asthma and COPD have highlighted age of onset, variability of symptoms, reversibility of airflow limitation, and atopy. Each of these is associated with error due to overlap and convergence of clinical characteristics. The management of chronic stable asthma and COPD is similarly convergent. New approaches to the management of obstructive airway diseases in adults have been proposed based on inflammometry and also multidimensional assessment, which focuses on the four domains of the airways, comorbidity, self-management, and risk factors. Short-acting beta-agonists provide effective symptom relief in airway diseases. Inhalers combining a long-acting beta-agonist and corticosteroid are now widely used for both asthma and COPD. Written action plans are a cornerstone of asthma management although evidence for self-management in COPD is less compelling. The current management of chronic asthma in adults is based on achieving and maintaining control through step-up and step-down approaches, but further trials of back-titration in COPD are required before a similar approach can be endorsed. Long-acting inhaled anticholinergic medications are particularly useful in COPD. Other distinctive features of management include pulmonary rehabilitation, home oxygen, and end of life care.

Montelukast-induced adverse drug reactions: a review of case reports in the literature

BACKGROUND

Montelukast, a leucotriene receptor antagonist, binds the cysteinyl leucotriene type 1 receptor. Montelukast is commonly prescribed to asthma patients as add-on therapy to inhaled corticosteroids. Several clinical trials emphasized that montelukast can be considered a safe drug. However, recent evidence reconsidered the benefit/risk ratio of the use of montelukast for both paediatric and adult patients.

SUMMARY

The present review analyzed the previous published case reports regarding montelukast-induced adverse drug reactions (ADRs). They included agitation, anxiety, depression, sleep disturbance, hallucinations, suicidal thinking and suicidality, tremor, dizziness, drowsiness, neuropathies and seizures. The immune system can be involved, in particular, cases of Churg-Strauss syndrome have been published. Furthermore, it can induce hypersensitivity reactions, including anaphylaxis and eosinophilic infiltration. In addition, hepatobiliary, pancreatic and uropoietic disorders have been observed. Some of these cases are characterized by severe prognosis (i.e. neurological deficit and fatal hepatotoxicity). Key Message: The use of montelukast can be burdened by several ADRs, of which physicians should be aware in their clinical practice. A better understanding of the mechanisms causing ADRs after using montelukast could help researchers and clinicians in defining a risk-reduction strategy aimed to lessen montelukast toxicity. More accurate epidemiological studies, in order to discover risk factors favouring montelukast-associated ADRs, are demanded.

Use of leukotriene receptor antagonists are associated with a similar risk of asthma exacerbations as inhaled corticosteroids

BACKGROUND

Based on results of clinical trials, inhaled corticosteroids (ICS) are the most-effective controller medications for preventing asthma-related exacerbations, yet few studies in real-life populations have evaluated the comparative effectiveness of ICS.

OBJECTIVE

To determine the likelihood of asthma exacerbations among children with asthma after initiation of controller medications: ICS, leukotriene antagonists (LTRA), and ICS-long-acting β-agonist (LABA) combination therapy.

METHODS

This was a retrospective cohort study of subjects who were part of the Population-Based Effectiveness in Asthma and Lung Diseases Network. We conducted Cox regression analyses by adjusting for baseline covariates, adherence by using proportion of days covered, and high-dimensional propensity scores. The main outcome measurements were emergency department visits, hospitalizations, or oral corticosteroid use.

RESULTS

Our population included 15,567 health plan subjects and 10,624 TennCare Medicaid subjects with uncontrolled asthma. Overall adherence to controller medications was low, with no more than 50% of the subjects refilling the medication after the initial fill. For subjects with allergic rhinitis, the subjects in TennCare Medicaid treated with LTRAs were less likely to experience ED visits (hazard ratio 0.44 [95% CI, 0.21-0.93]) compared with the subjects treated with ICS. For all other groups, the subjects treated with LTRA or ICS-LABA were just as likely to experience ED visits or hospitalizations, or need oral corticosteroids as the subjects treated with ICS.

CONCLUSION

Risks of asthma-related exacerbations did not differ between children who initiated LTRA and ICS. These findings may be explainable by LTRA, which has similar effectiveness as ICS in real-life usage by residual confounding by indication or other unmeasured factors.

Inhaled corticosteroids in children with persistent asthma: dose-response effects on growth

BACKGROUND

Inhaled corticosteroids (ICS) are the first-line treatment for children with persistent asthma. Their potential for growth suppression remains a matter of concern for parents and physicians.

OBJECTIVES

To assess whether increasing the dose of ICS is associated with slower linear growth, weight gain and skeletal maturation in children with asthma.

SEARCH METHODS

We searched the Cochrane Airways Group Specialised Register of trials (CAGR) and the ClinicalTrials.gov website up to March 2014.

SELECTION CRITERIA

Studies were eligible if they were parallel-group randomised trials evaluating the impact of different doses of the same ICS using the same device in both groups for a minimum of three months in children one to 17 years of age with persistent asthma.

DATA COLLECTION AND ANALYSIS

Two review authors ascertained methodological quality independently using the Cochrane Risk of bias tool. The primary outcome was linear growth velocity. Secondary outcomes included change over time in growth velocity, height, weight, body mass index and skeletal maturation.

MAIN RESULTS

Among 22 eligible trials, 17 group comparisons were derived from 10 trials (3394 children with mild to moderate asthma), measured growth and contributed data to the meta-analysis. Trials used ICS (beclomethasone, budesonide, ciclesonide, fluticasone or mometasone) as monotherapy or as combination therapy with a long-acting beta2-agonist and generally compared low (50 to 100 μg) versus low to medium (200 μg) doses of hydrofluoroalkane (HFA)-beclomethasone equivalent over 12 to 52 weeks. In the four comparisons reporting linear growth over 12 months, a significant group difference was observed, clearly indicating lower growth velocity in the higher ICS dose group of 5.74 cm/y compared with 5.94 cm/y on lower-dose ICS (N = 728 school-aged children; mean difference (MD)0.20 cm/y, 95% confidence interval (CI) 0.02 to 0.39; high-quality evidence): No statistically significant heterogeneity was noted between trials contributing data. The ICS molecules (ciclesonide, fluticasone, mometasone) used in these four comparisons did not significantly influence the magnitude of effect (X(2) = 2.19 (2 df), P value 0.33). Subgroup analyses on age, baseline severity of airway obstruction, ICS dose and concomitant use of non-steroidal antiasthmatic drugs were not performed because of similarity across trials or inadequate reporting. A statistically significant group difference was noted in unadjusted change in height from zero to three months (nine comparisons; N = 944 children; MD 0.15, 95% CI -0.28 to -0.02; moderate-quality evidence) in favour of a higher ICS dose. No statistically significant group differences in change in height were observed at other time points, nor were such differences in weight, bone mass index and skeletal maturation reported with low quality of evidence due to imprecision.

AUTHORS' CONCLUSIONS

In prepubescent school-aged children with mild to moderate persistent asthma, a small but statistically significant group difference in growth velocity was observed between low doses of ICS and low to medium doses of HFA-beclomethasone equivalent, favouring the use of low-dose ICS. No apparent difference in the magnitude of effect was associated with three molecules reporting one-year growth velocity, namely, mometasone, ciclesonide and fluticasone. In view of prevailing parents' and physicians' concerns about the growth suppressive effect of ICS, lack of or incomplete reporting of growth velocity in more than 86% (19/22) of eligible paediatric trials, including those using beclomethasone and budesonide, is a matter of concern. All future paediatric trials comparing different doses of ICS with or without placebo should systematically document growth. Findings support use of the minimal effective ICS dose in children with asthma.

Update on leukotriene, lipoxin and oxoeicosanoid receptors: IUPHAR Review 7

The endogenous ligands for the LT, lipoxin (LX) and oxoeicosanoid receptors are bioactive products produced by the action of the lipoxygenase family of enzymes. The LT receptors BLT1 and BLT2 , are activated by LTB4 and the CysLT1 and CysLT2 receptors are activated by the cysteinyl-LTs, whereas oxoeicosanoids exert their action through the OXE receptor. In contrast to these pro-inflammatory mediators, LXA4 transduces responses associated with the resolution of inflammation through the receptor FPR2/ALX (ALX/FPR2). The aim of the present review is to give a state of the field on these receptors, with focus on recent important findings. For example, BLT1 receptor signalling in cancer and the dual role of the BLT2 receptor in pro- and anti-inflammatory actions have added more complexity to lipid mediator signalling. Furthermore, a cross-talk between the CysLT and P2Y receptor systems has been described, and also the presence of novel receptors for cysteinyl-LTs, such as GPR17 and GPR99. Finally, lipoxygenase metabolites derived from ω-3 essential polyunsaturated acids, the resolvins, activate the receptors GPR32 and ChemR23. In conclusion, the receptors for the lipoxygenase products make up a sophisticated and tightly controlled system of endogenous pro- and anti-inflammatory signalling in physiology and pathology.

Cysteinyl leukotriene receptor-1 antagonists as modulators of innate immune cell function

Cysteinyl leukotrienes (cysLTs) are produced predominantly by cells of the innate immune system, especially basophils, eosinophils, mast cells, and monocytes/macrophages. Notwithstanding potent bronchoconstrictor activity, cysLTs are also proinflammatory consequent to their autocrine and paracrine interactions with G-protein-coupled receptors expressed not only on the aforementioned cell types, but also on Th2 lymphocytes, as well as structural cells, and to a lesser extent neutrophils and CD8⁺ cells. Recognition of the involvement of cysLTs in the immunopathogenesis of various types of acute and chronic inflammatory disorders, especially bronchial asthma, prompted the development of selective cysLT receptor-1 (cysLTR1) antagonists, specifically montelukast, pranlukast, and zafirlukast. More recently these agents have also been reported to possess secondary anti-inflammatory activities, distinct from cysLTR1 antagonism, which appear to be particularly effective in targeting neutrophils and monocytes/macrophages. Underlying mechanisms include interference with cyclic nucleotide phosphodiesterases, 5′-lipoxygenase, and the proinflammatory transcription factor, nuclear factor kappa B. These and other secondary anti-inflammatory mechanisms of the commonly used cysLTR1 antagonists are the major focus of the current review, which also includes a comparison of the anti-inflammatory effects of montelukast, pranlukast, and zafirlukast on human neutrophils in vitro, as well as an overview of both the current clinical applications of these agents and potential future applications based on preclinical and early clinical studies.

A comparison of confounding adjustment methods for assessment of asthma controller medication effectiveness

We compared the impact of 3 confounding adjustment procedures-covariate-adjusted regression, propensity score regression, and high-dimensional propensity score regression-to assess the effects of selected asthma controller medication use (leukotriene antagonists and inhaled corticosteroids) on the following 4 asthma-related adverse outcomes: emergency department visits, hospitalizations, oral corticosteroid use, and the composite outcome of these. We examined a cohort of 24,680 new users who were 4-17 years of age at the incident dispensing from the Population-Based Effectiveness in Asthma and Lung Diseases (PEAL) Network of 5 commercial health plans and TennCare, the Tennessee Medicaid program, during the period January 1, 2004, to December 31, 2010. The 3 methods yielded similar results, indicating that pediatric patients treated with leukotriene antagonists were no more likely than those treated with inhaled corticosteroids to experience adverse outcomes. Children in the TennCare population who had a diagnosis of allergic rhinitis and who then initiated the use of leukotriene antagonists were less likely to experience an asthma-related emergency department visit. A plausible explanation is that our data set is large enough that the 2 advanced propensity score-based analyses do not have advantages over the traditional covariate-adjusted regression approach. We provide important observations on how to correctly apply the methods in observational data analysis and suggest statistical research areas that need more work to guide implementation.

Addition to inhaled corticosteroids of long-acting beta2-agonists versus anti-leukotrienes for chronic asthma

BACKGROUND

Asthma patients who continue to experience symptoms despite taking regular inhaled corticosteroids (ICS) represent a management challenge. Long-acting beta2-agonists (LABA) and anti-leukotrienes (LTRA) are two treatment options that could be considered as add-on therapy to ICS.

OBJECTIVES

To compare the safety and efficacy of adding LABA versus LTRA to the treatment regimen for children and adults with asthma who remain symptomatic in spite of regular treatment with ICS. We specifically wished to examine the relative impact of the two agents on asthma exacerbations, lung function, symptoms, quality of life, adverse health events and withdrawals.

SEARCH METHODS

We searched the Cochrane Airways Group Specialised Register until December 2012. We consulted reference lists of all included studies and contacted pharmaceutical manufacturers to ask about other published or unpublished studies.

SELECTION CRITERIA

We included randomised controlled trials (RCTs) conducted in adults or children with recurrent asthma that was treated with ICS along with a fixed dose of a LABA or an LTRA for a minimum of four weeks.

DATA COLLECTION AND ANALYSIS

Two review authors independently assessed the risk of bias of included studies and extracted data. We sought unpublished data and further details of study design when necessary.

MAIN RESULTS

We included 18 RCTs (7208 participants), of which 16 recruited adults and adolescents (6872) and two recruited children six to 17 years of age (336) with asthma and significant reversibility to bronchodilator at baseline. Fourteen (79%) trials were of high methodological quality.The risk of exacerbations requiring systemic corticosteroids (primary outcome of the review) was significantly lower with the combination of LABA + ICS compared with LTRA + ICS-from 13% to 11% (eight studies, 5923 adults and 334 children; risk ratio (RR) 0.87, 95% confidence interval (CI) 0.76 to 0.99; high-quality evidence). The number needed to treat for an additional beneficial outcome (NNTB) with LABA compared with LTRA to prevent one additional exacerbation over four to 102 weeks was 62 (95% CI 34 to 794). The choice of LTRA, the dose of ICS and the participants' age group did not significantly influence the magnitude of effect. Although results were inconclusive, the effect appeared stronger in trials that used a single device rather than two devices to administer ICS and LABA and in trials of less than 12 weeks' duration.The addition of LABA to ICS was associated with a statistically greater improvement from baseline in lung function, as well as in symptoms, rescue medication use and quality of life, although the latter effects were modest. LTRA was superior in the prevention of exercise-induced bronchospasm. More participants were satisfied with the combination of LABA + ICS than LTRA + ICS (three studies, 1625 adults; RR 1.12, 95% CI 1.04 to 1.20; moderate-quality evidence). The overall risk of withdrawal was significantly lower with LABA + ICS than with LTRA + ICS (13 studies, 6652 adults and 308 children; RR 0.84, 95% CI 0.74 to 0.96; moderate-quality evidence). Although the risk of overall adverse events was equivalent between the two groups, the risk of serious adverse events (SAE) approached statistical significance in disfavour of LABA compared with LTRA (nine studies, 5658 adults and 630 children; RR 1.33, 95% CI 0.99 to 1.79; P value 0.06; moderate-quality evidence), with no apparent impact of participants' age group.The following adverse events were reported, but no significant differences were demonstrated between groups: headache (11 studies, N = 6538); cardiovascular events (five studies, N = 5163), osteopenia and osteoporosis (two studies, N = 2963), adverse events (10 studies, N = 5977 adults and 300 children). A significant difference in the risk of oral moniliasis was noted, but this represents a low occurrence rate.

AUTHORS' CONCLUSIONS

In adults with asthma that is inadequately controlled by predominantly low-dose ICS with significant bronchodilator reversibility, the addition of LABA to ICS is modestly superior to the addition of LTRA in reducing oral corticosteroid-treated exacerbations, with an absolute reduction of two percentage points. Differences favouring LABA over LTRA as adjunct therapy were observed in lung function and, to a lesser extend, in rescue medication use, symptoms and quality of life. The lower overall withdrawal rate and the higher proportion of participants satisfied with their therapy indirectly favour the combination of LABA + ICS over LTRA + ICS. Evidence showed a slightly increased risk of SAE with LABA compared with LTRA, with an absolute increase of one percentage point. Our findings modestly support the use of a single inhaler for the delivery of both LABA and low- or medium-dose ICS. Because of the paucity of paediatric trials, we are unable to draw firm conclusions about the best adjunct therapy in children.

An official American Thoracic Society research statement: comparative effectiveness research in pulmonary, critical care, and sleep medicine

BACKGROUND

Comparative effectiveness research (CER) is intended to inform decision making in clinical practice, and is central to patient-centered outcomes research (PCOR).

PURPOSE

To summarize key aspects of CER definitions and provide examples highlighting the complementary nature of efficacy and CER studies in pulmonary, critical care, and sleep medicine.

METHODS

An ad hoc working group of the American Thoracic Society with experience in clinical trials, health services research, quality improvement, and behavioral sciences in pulmonary, critical care, and sleep medicine was convened. The group used an iterative consensus process, including a review by American Thoracic Society committees and assemblies.

RESULTS

The traditional efficacy paradigm relies on clinical trials with high internal validity to evaluate interventions in narrowly defined populations and in research settings. Efficacy studies address the question, "Can it work in optimal conditions?" The CER paradigm employs a wide range of study designs to understand the effects of interventions in clinical settings. CER studies address the question, "Does it work in practice?" The results of efficacy and CER studies may or may not agree. CER incorporates many attributes of outcomes research and health services research, while placing greater emphasis on meeting the expressed needs of nonresearcher stakeholders (e.g., patients, clinicians, and others).

CONCLUSIONS

CER complements traditional efficacy research by placing greater emphasis on the effects of interventions in practice, and developing evidence to address the needs of the many stakeholders involved in health care decisions. Stakeholder engagement is an important component of CER.

Addition of anti-leukotriene agents to inhaled corticosteroids in children with persistent asthma

BACKGROUND

In the treatment of children with mild persistent asthma, low-dose inhaled corticosteroids (ICS) are recommended as the preferred monotherapy (referred to as step 2 of therapy). In children with inadequate asthma control on low doses of ICS (step 2), asthma management guidelines recommend adding an anti-leukotriene agent to existing ICS as one of three therapeutic options to intensify therapy (step 3).

OBJECTIVES

To compare the efficacy and safety of the combination of anti-leukotriene agents and ICS to the use of the same, an increased, or a tapering dose of ICS in children and adolescents with persistent asthma who remain symptomatic despite the use of maintenance ICS. In addition, we wished to determine the characteristics of people or treatments, if any, that influenced the magnitude of response attributable to the addition of anti-leukotrienes.

SEARCH METHODS

We identified trials from the Cochrane Airways Group Specialised Register of Trials (CAGR), which were derived from systematic searches of bibliographic databases including the Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE, EMBASE, PsycINFO, AMED, and CINAHL; and the handsearching of respiratory journals and meeting abstracts, as well as the www.clinicaltrials.gov website. The search was conducted until January 2013.

SELECTION CRITERIA

We considered for inclusion randomised controlled trials (RCTs) conducted in children and adolescents, aged one to 18 years, with asthma, who remained symptomatic despite the use of a stable maintenance dose of ICS and in whom anti-leukotrienes were added to the ICS if they were compared to the same, an increased, or a tapering dose of ICS for at least four weeks.

DATA COLLECTION AND ANALYSIS

We used standard methods expected by The Cochrane Collaboration.

MAIN RESULTS

Five paediatric (parallel group or cross-over) trials met the inclusion criteria. We considered two (40%) trials to be at a low risk of bias. Four published trials, representing 559 children (aged ≥ six years) and adolescents with mild to moderate asthma, contributed data to the review. No trial enrolled preschoolers. All trials used montelukast as the anti-leukotriene agent administered for between four and 16 weeks. Three trials evaluated the combination of anti-leukotrienes and ICS compared to the same dose of ICS alone (step 3 versus step 2). No statistically significant group difference was observed in the only trial reporting participants with exacerbations requiring oral corticosteroids over four weeks (N = 268 participants; risk ratio (RR) 0.80, 95% confidence interval (CI) 0.34 to 1.91). There was also no statistically significant difference in percentage change in FEV₁ (forced expiratory volume in 1 second) with mean difference (MD) 1.3 (95% CI -0.09 to 2.69) in this trial, but a significant group difference was observed in the morning (AM) and evening (PM) peak expiratory flow rates (PEFR): N = 218 participants; MD 9.70 L/min (95% CI 1.27 to 18.13) and MD 10.70 (95% CI 2.41 to 18.99), respectively. One trial compared the combination of anti-leukotrienes and ICS to a higher-dose of ICS (step 3 versus step 3). No significant group difference was observed in this trial for participants with exacerbations requiring rescue oral corticosteroids over 16 weeks (N = 182 participants; RR 0.82, 95% CI 0.54 to 1.25), nor was there any significant difference in exacerbations requiring hospitalisation. There was no statistically significant group difference in withdrawals overall or because of any cause with either protocol. No trial explored the impact of adding anti-leukotrienes as a means to taper the dose of ICS.

AUTHORS' CONCLUSIONS

The addition of anti-leukotrienes to ICS is not associated with a statistically significant reduction in the need for rescue oral corticosteroids or hospital admission compared to the same or an increased dose of ICS in children and adolescents with mild to moderate asthma. Although anti-leukotrienes have been licensed for use in children for over 10 years, the paucity of paediatric trials, the absence of data on preschoolers, and the variability in the reporting of relevant clinical outcomes considerably limit firm conclusions. At present, there is no firm evidence to support the efficacy and safety of anti-leukotrienes as add-on therapy to ICS as a step-3 option in the therapeutic arsenal for children with uncontrolled asthma symptoms on low-dose ICS.

This asthma treatment has a lasting side effect in children

A new study finds that when children with asthma use inhaled corticosteroids, the effect on growth may not be temporary, as once thought.

Management of asthma in the elderly patient

A significant number of older asthmatics, more often than in previous ages, have poorly controlled asthma, leading to increased morbidity and mortality. On the other hand, current guidelines suggest that most asthmatics can obtain achievement and maintenance of disease control and do not include sections specific to the management of asthma in the elderly so that it is more evident the contrast between poor control of asthma in the elderly and the lack of specific guidance from guidelines on asthma management in older asthmatics. Inhaled corticosteroids are the cornerstone for older asthmatics, eventually with add-on inhaled long-acting beta-agonists; inhaled short acting beta-agonists can be used as rescue medications. Triggers exacerbating asthma are similar for all ages, but inhaled viruses and drug interactions have greater clinical significance in the elderly. Older asthmatics have an increased likelihood of comorbidities and polypharmacy, with possible worsening of asthma control and reduced treatment adherence. Physicians and older asthmatics probably either do not perceive or accept a poor asthma control. We conclude that specific instruments addressed to evaluate asthma control in the elderly with concomitant comorbidities and measurements for improving self-management and adherence could assure better disease control in older asthmatics.

Inhaled corticosteroids in lung diseases

Inhaled corticosteroids (ICSs) are used extensively in the treatment of asthma and chronic obstructive pulmonary disease (COPD) due to their broad antiinflammatory effects. They improve lung function, symptoms, and quality of life and reduce exacerbations in both conditions but do not alter the progression of disease. They decrease mortality in asthma but not COPD. The available ICSs vary in their therapeutic index and potency. Although ICSs are used in all age groups, younger and smaller children may be at a greater risk for adverse systemic effects because they can receive higher mg/kg doses of ICSs compared with older children. Most of the benefit from ICSs occurs in the low to medium dose range. Minimal additional improvement is seen with higher doses, although some patients may benefit from higher doses. Although ICSs are the preferred agents for managing persistent asthma in all ages, their benefit in COPD is more controversial. When used appropriately, ICSs have few adverse events at low to medium doses, but risk increases with high-dose ICSs. Although several new drugs are being developed and evaluated, it is unlikely that any of these new medications will replace ICSs as the preferred initial long-term controller therapy for asthma, but more effective initial controller therapy could be developed for COPD.