Effect of montelukast for treatment of asthma in cigarette smokers

Risk factor analysis and nomogram for predicting poor symptom control in smoking asthmatics

BACKGROUND

Smoking induces and modifies the airway immune response, accelerating the decline of asthmatics' lung function and severely affecting asthma symptoms' control level. To assess the prognosis of asthmatics who smoke and to provide reasonable recommendations for treatment, we constructed a nomogram prediction model.

METHODS

General and clinical data were collected from April to September 2021 from smoking asthmatics aged ≥14 years attending the People's Hospital of Zhengzhou University. Patients were followed up regularly by telephone or outpatient visits, and their medication and follow-up visits were recorded during the 6-months follow-up visit, as well as their asthma control levels after 6 months (asthma control questionnaire-5, ACQ-5). The study employed R4.2.2 software to conduct univariate and multivariate logistic regression analyses to identify independent risk factors for 'poorly controlled asthma' (ACQ>0.75) as the outcome variable. Subsequently, a nomogram prediction model was constructed. Internal validation was used to test the reproducibility of the model. The model efficacy was evaluated using the consistency index (C-index), receiver operating characteristic (ROC) curve, calibration curve, and decision curve.

RESULTS

Invitations were sent to 231 asthmatics who smoked. A total of 202 participants responded, resulting in a final total of 190 participants included in the model development. The nomogram established five independent risk factors (P<0.05): FEV1%pred, smoking index (100), comorbidities situations, medication regimen, and good or poor medication adherence. The area under curve (AUC) of the modeling set was 0.824(95%CI 0.765-0.884), suggesting that the nomogram has a high ability to distinguish poor asthma control in smoking asthmatics after 6 months. The calibration curve showed a C-index of 0.824 for the modeling set and a C-index of 0.792 for the self-validation set formed by 1000 bootstrap sampling, which means that the prediction probability of the model was consistent with reality. Decision curve analysis (DCA) of the nomogram revealed that the net benefit was higher when the risk threshold probability for poor asthma control was 4.5 - 93.9%.

CONCLUSIONS

FEV1%pred, smoking index (100), comorbidities situations, medication regimen, and medication adherence were identified as independent risk factors for poor asthma control after 6 months in smoking asthmatics. The nomogram established based on these findings can effectively predict relevant risk and provide clinicians with a reference to identify the poorly controlled population with smoking asthma as early as possible, and to select a better therapeutic regimen. Meanwhile, it can effectively improve the medication adherence and the degree of attention to complications in smoking asthma patients.

Asthma aggravates alzheimer's disease by up-regulating NF- κB signaling pathway through LTD4

Clinical studies have shown that asthma is a risk factor for dementia or Alzheimer's disease (AD). To investigate whether asthma aggravates AD in APP/PS1 mice and explore the potential mechanisms, an asthma model was established using six-month-old APP/PS1 mice, and montelukast was used as a therapeutic agent in APP/PS1 mice with asthma. The Morris water maze test showed that asthma aggravates spatial learning and memory abilities. Asthma also upregulates the NF-κB inflammatory pathway in APP/PS1 mice and promotes the expression of beta-site amyloid precursor protein cleaving enzyme 1 (BACE1), amyloid-β (Aβ) deposition, neuronal damage, synaptic plasticity deficiency, activation of microglia and astrocytes. The level of LTD4 and its receptor CysLT1R in the hippocampus of APP/PS1 mice after the asthma modeling was established was higher than that in APP/PS1 mice, suggesting that asthma may affect the pathology of AD through LTD4 and its receptor Cys-LT1R. Montelukast ameliorates these pathological changes and cognitive impairment. These results suggest that asthma aggravates AD pathology and cognitive impairment of APP/PS1 mice via upregulation of the NF-κB inflammatory pathway, and montelukast ameliorates these pathological changes.

Lipid mediators of inhalation exposure-induced pulmonary toxicity and inflammation

Many inhalation exposures induce pulmonary inflammation contributing to disease progression. Inflammatory processes are actively regulated via mediators including bioactive lipids. Bioactive lipids are potent signaling molecules involved in both pro-inflammatory and resolution processes through receptor interactions. The formation and clearance of lipid signaling mediators are controlled by multiple metabolic enzymes. An imbalance of these lipids can result in exacerbated and sustained inflammatory processes which may result in pulmonary damage and disease. Dysregulation of pulmonary bioactive lipids contribute to inflammation and pulmonary toxicity following exposures. For example, inhalation of cigarette smoke induces activation of pro-inflammatory bioactive lipids such as sphingolipids, and ceramides contributing to chronic obstructive pulmonary disease. Additionally, exposure to silver nanoparticles causes dysregulation of inflammatory resolution lipids. As inflammation is a common consequence resulting from inhaled exposures and a component of numerous diseases it represents a broadly applicable target for therapeutic intervention. With new appreciation for bioactive lipids, technological advances to reliably identify and quantify lipids have occurred. In this review, we will summarize, integrate, and discuss findings from recent studies investigating the impact of inhaled exposures on pro-inflammatory and resolution lipids within the lung and their contribution to disease. Throughout the review current knowledge gaps in our understanding of bioactive lipids and their contribution to pulmonary effects of inhaled exposures will be presented. New methods being employed to detect and quantify disruption of pulmonary lipid levels following inhalation exposures will be highlighted. Lastly, we will describe how lipid dysregulation could potentially be addressed by therapeutic strategies to address inflammation.

Asthma and Tobacco Smoking

Asthma is a prevalent chronic pulmonary condition with significant morbidity and mortality. Tobacco smoking is implicated in asthma pathophysiology, diagnosis, prognosis and treatment. Smokers display increased prevalence and incidence of asthma, but a causal association cannot be claimed using existing evidence. Second-hand smoking and passive exposure to tobacco in utero and early life have also been linked with asthma development. Currently, approximately one-fourth of asthma patients are smokers. Regular smokers with asthma might display accelerated lung function decline and non-reversible airflow limitation, making their distinction from chronic obstructive pulmonary disease patients challenging. Asthma patients who smoke typically have uncontrolled disease, as shown by increased symptoms, more exacerbations and impaired quality of life. On the other hand, smoking cessation improves lung function and asthma severity. Thus, asthma patients and their caregivers should be actively questioned about their smoking status at each medical encounter, and smoking cessation ought to be strongly encouraged both for patients with asthma and their close contacts. Smokers with asthma should be provided with comprehensive smoking cessation interventions on top of other anti-asthma medications.

Cigarette Smoking and Asthma

Globally, around half the adult asthma population are current or former cigarette smokers. Cigarette smoking and asthma interact to induce an "asthma-smoking phenotype(s)," which has important implications for diagnosis, pathogenic mechanisms, and management. The lack of progress in understanding the effects of smoking on adults with asthma is due in part to their exclusion from most investigative studies and large clinical trials. In this review, we summarize the adverse clinical outcomes associated with cigarette smoking in asthma, highlight challenges in diagnosing asthma among cigarette smokers with chronic respiratory symptoms, particularly in older individuals with a long-standing smoking history, and review pathogenic mechanisms involving smoking- and asthma-related airway inflammation, tissue remodeling, corticosteroid insensitivity, and low-grade systemic inflammation. We discuss the key components of management including the importance of smoking cessation strategies, evidence for the effectiveness of the Global Initiative for Asthma recommendations on treatment in cigarette smokers, and the role of treatable traits such as type 2 eosinophilic airway inflammation. Lastly, we provide an algorithm to aid clinicians to manage current and former smokers with asthma. In the future, controlled and pragmatic trials in real-world populations should include cigarette smokers with asthma to provide an evidence base for treatment recommendations.

The safety of long-term use of inhaled corticosteroids in patients with asthma: A systematic review and meta-analysis

PURPOSE

This systematic review and meta-analysis was performed to determine the safety of long-term use of ICS in patients with asthma.

METHODS

A systematic search was made of PubMed, Embase, Web of Science, Cochrane Library, and clinicaltrials.gov, without language restrictions. Randomized controlled trials (RCTs) on treatment of asthma with ICS, compared with non-ICS treatment (placebo or other active drugs), were reviewed.

RESULTS

Eighty-six RCTs (enrolling 51,538 participants) met the inclusion criteria. Oral or oropharyngeal candidiasis (RR 2.58, 95% CI 2.00 to 3.33), and dysphonia/hoarseness (RR 1.56, 95% CI 1.31 to 1.85) were less frequent in the control group. There was no statistically significant difference in the risk of upper respiratory tract infection, lower respiratory tract infection, influenza, decline in bone mineral density, and fractures between the two groups.

CONCLUSION

In addition to the mild local adverse events, the long-term use of ICS was safe in patients with asthma.

Effects of non-steroidal anti-inflammatory drugs and other eicosanoid pathway modifiers on antiviral and allergic responses: EAACI task force on eicosanoids consensus report in times of COVID-19

Non‐steroidal anti‐inflammatory drugs (NSAIDs) and other eicosanoid pathway modifiers are among the most ubiquitously used medications in the general population. Their broad anti‐inflammatory, antipyretic, and analgesic effects are applied against symptoms of respiratory infections, including SARS‐CoV‐2, as well as in other acute and chronic inflammatory diseases that often coexist with allergy and asthma. However, the current pandemic of COVID‐19 also revealed the gaps in our understanding of their mechanism of action, selectivity, and interactions not only during viral infections and inflammation, but also in asthma exacerbations, uncontrolled allergic inflammation, and NSAIDs‐exacerbated respiratory disease (NERD). In this context, the consensus report summarizes currently available knowledge, novel discoveries, and controversies regarding the use of NSAIDs in COVID‐19, and the role of NSAIDs in asthma and viral asthma exacerbations. We also describe here novel mechanisms of action of leukotriene receptor antagonists (LTRAs), outline how to predict responses to LTRA therapy and discuss a potential role of LTRA therapy in COVID‐19 treatment. Moreover, we discuss interactions of novel T2 biologicals and other eicosanoid pathway modifiers on the horizon, such as prostaglandin D2 antagonists and cannabinoids, with eicosanoid pathways, in context of viral infections and exacerbations of asthma and allergic diseases. Finally, we identify and summarize the major knowledge gaps and unmet needs in current eicosanoid research.

The Role of Comorbidities in Difficult-to-Control Asthma in Adults and Children

Assessment of asthma comorbidities, conditions that adversely affect the pathobiology of asthma or impair its response to therapies, is a fundamental step in the evaluation and management of patients with difficult-to-treat asthma. Identifying and effectively treating asthma comorbidities, such as obesity, obstructive sleep apnea, and chronic sinusitis with nasal polyps, may improve asthma control and reduce exacerbations. In addition, identifying comorbid T2 inflammatory conditions may help guide optimal selection of biologic therapies. Here, we describe common comorbid conditions found in adult and pediatric difficult-to-control asthma, discuss evidence for the association with asthma morbidity and treatment benefit, and provide information on how and when to assess comorbidities.

Update on Asthma-COPD Overlap (ACO): A Narrative Review

Although chronic obstructive pulmonary disease (COPD) and asthma are well-characterized diseases, they can coexist in a given patient. The term asthma-COPD overlap (ACO) was introduced to describe patients that have clinical features of both diseases and may represent around 25% of COPD patients and around 20% of asthma patients. Despite the increasing interest in ACO, there are still substantial controversies regarding its definition and its position within clinical guidelines for patients with obstructive lung disease. In general, most definitions indicate that ACO patients must present with non-reversible airflow limitation, significant exposure to smoking or other noxious particles or gases, together with features of asthma. In patients with a primary diagnosis of COPD, the identification of ACO has therapeutic implication because the asthmatic component should be treated with inhaled corticosteroids and some studies suggest that the most severe patients may respond to biological agents indicated for severe asthma. This manuscript aims to summarize the current state-of-the-art of ACO. The definitions, prevalence, and clinical manifestations will be reviewed and some innovative aspects, such as genetics, epigenetics, and biomarkers will be addressed. Lastly, the management and prognosis will be outlined as well as the position of ACO in the COPD and asthma guidelines.

[Smoking cessation in asthmatic patients and its impact]

INTRODUCTION

The prevalence of smoking in asthmatic patients is similar to, or even higher than in the general population.

OBJECTIVES

This systematic review addresses (1) the effects of smoking on asthma, (2) smoking cessation strategies in asthmatic patients, and (3) the consequences of smoking cessation for people with asthma.

RESULTS

Active or passive smoking can promote the development of asthma. The few studies on smoking cessation in asthma confirm the efficacy of validated smoking cessation strategies in these patients (nicotine replacement therapy, varenicline, bupropion, cognitive and behavioural therapies). Smoking cessation in parents with asthmatic children is essential and is based on the same strategies. Electronic cigarettes may be a useful help to quit smoking in some patients. Smoking cessation is beneficial in asthmatic smokers and associated with (1) a reduction of asthma symptoms, acute exacerbations, bronchial hyperresponsiveness, and bronchial inflammation, (2) decreased use of rescue medications and in doses of inhaled corticosteroids, (3) improved asthma control, quality of life, and lung function.

CONCLUSION

In asthmatic patients, it is essential to assess smoking status and health professionals must assist them to quit smoking.

Impact of Air Pollution on Asthma Outcomes

Asthma is a chronic respiratory disease characterized by variable airflow obstruction, bronchial hyperresponsiveness, and airway inflammation. Evidence suggests that air pollution has a negative impact on asthma outcomes in both adult and pediatric populations. The aim of this review is to summarize the current knowledge on the effect of various outdoor and indoor pollutants on asthma outcomes, their burden on its management, as well as to highlight the measures that could result in improved asthma outcomes. Traffic-related air pollution, nitrogen dioxide and second-hand smoking (SHS) exposures represent significant risk factors for asthma development in children. Nevertheless, a causal relation between air pollution and development of adult asthma is not clearly established. Exposure to outdoor pollutants can induce asthma symptoms, exacerbations and decreases in lung function. Active tobacco smoking is associated with poorer asthma control, while exposure to SHS increases the risk of asthma exacerbations, respiratory symptoms and healthcare utilization. Other indoor pollutants such as heating sources and molds can also negatively impact the course of asthma. Global measures, that aim to reduce exposure to air pollutants, are highly needed in order to improve the outcomes and management of adult and pediatric asthma in addition to the existing guidelines.

The pharmacological management of asthma-chronic obstructive pulmonary disease overlap syndrome (ACOS)

Introduction: Asthma-chronic obstructive pulmonary disease overlap syndrome (ACOS) is a disease phenotype that shares T helper lymphocyte cell Th1/neutrophilic/non-Type-2 Inflammation pathways thought to be key in COPD and Th2/eosinophilic/Type-2 inflammatory pathways of asthma. The pharmacology of treating ACOS is challenging in severe circumstances.Areas covered: This review evaluates the stepwise treatment of ACOS using pharmacological treatments used in both COPD and asthma. The most common medications involve the same inhalers used to treat COPD and asthma patients. Advanced stepwise therapies for ACOS patients are based on patient characteristics and biomarkers. Very few clinical trials exist that focus specifically on ACOS patients.Expert opinion: After inhalers, advanced therapies including phosphodiesterase inhibitors, macrolides, N-acetylcysteine and statin therapy for those ACOS patients with a COPD appearance and exacerbations are available. In atopic ACOS patients with exacerbations, advanced asthma therapies (leukotriene receptor antagonists and synthesis blocking agents.) are used. ACOS patients with elevated blood eosinophil/IgE levels are considered for immunotherapy or therapeutic monoclonal antibodies blocking specific Th2/Type-2 interleukins or IgE. Symptom control, stabilization/improvement in pulmonary function and reduced exacerbations are the metrics of success. More pharmacological trials of ACOS patients are needed to better understand which patients benefit from specific treatments.Abbreviations: 5-LOi: 5-lipoxygenase inhibitor; ACOS: asthma - COPD overlap syndrome; B₂AR: Beta₂ adrenergic receptors; cAMP: cyclic adenosine monophosphate; cGMP: cyclic guanosine monophosphate; CI: confidence interval; COPD: chronic obstructive pulmonary disease; CRS : chronic rhinosinusitis; cys-LT: cysteinyl leukotrienes; DPI: dry powder inhaler; EMA: European Medicines Agency; FDA: US Food and Drug Administration; FDC: fixed-dose combination; FeNO: exhaled nitric oxide; FEV₁: forced expiratory volume in one second; FVC: forced vital capacity; GM-CSF: granulocyte-macrophage colony-stimulating factor; ICS : inhaled corticosteroids; IL: interleukin; ILC2: Type 2 innate lymphoid cells; IP₃: Inositol triphosphate; IRR: incidence rate ratio; KOLD: Korean Obstructive Lung Disease; LABA: long-acting B₂ adrenergic receptor agonist; LAMA: long-acting muscarinic receptor antagonist; LRA: leukotriene receptor antagonist; LT: leukotrienes; MDI: metered-dose inhalers; M_N: M-subtype muscarinic receptors; MRA: muscarinic receptor antagonist; NAC: N-acetylcysteine; NEB: nebulization; OR: odds ratio; PDE: phosphodiesterase; PEFR: peak expiratory flow rate; PGD2: prostaglandin D2; PRN: as needed; RR: risk ratio; SABA: short-acting B₂ adrenergic receptor agonist; SAMA: short-acting muscarinic receptor antagonist; SDMI: spring-driven mist inhaler; Th1: T helper cell 1 lymphocyte; Th2: T helper cell 2 lymphocytes; TNF-α: tumor necrosis factor alpha; US : United States.

Targeting lipid mediators in asthma: time for reappraisal

PURPOSE OF REVIEW

In the past decades, cysteinyl leukotrienes (CysLTs) and prostaglandin D2 have been recognized as key mediators of asthma and comorbid conditions for their potent broncho-active and proinflammatory properties. However, both the development and initial positioning of small molecules targeting these lipid mediators [i.e., leukotriene-synthesis inhibitors, CysLT-antagonists, and chemoattractant receptor homologous molecule on T-helper2-cells (CRTH2) antagonists] experienced drawbacks by lacking adequate biomarkers to define potential responders.

RECENT FINDINGS

New insights into the mechanisms of airway inflammation in asthma including the interaction of leukotrienes and prostanoids has uncovered potential therapeutic targets. Emerging application of biomarkers in more recent clinical studies helped identify responders to therapies targeting lipid mediators and demonstrated their clinical efficacy in distinct asthma phenotypes and endotypes.

SUMMARY

Interest in small molecules targeting lipid mediators in asthma and related conditions is emerging. Several clinical trials evaluating the efficacy and safety of CRTH2 (Prostaglandin D2 receptor 2) antagonists are ongoing. There is an urgent need for sensitive biomarkers to identify responders to such therapies and for monitoring of (long-term) effects. Furthermore, evaluation of effectiveness of combining different agents targeting lipid mediators or combining them with available or emerging biologics may uncover other potential benefits in certain asthma populations warranting future research.

G Protein-Coupled Receptors in Asthma Therapy: Pharmacology and Drug Action

Asthma is a heterogeneous inflammatory disease of the airways that is associated with airway hyperresponsiveness and airflow limitation. Although asthma was once simply categorized as atopic or nonatopic, emerging analyses over the last few decades have revealed a variety of asthma endotypes that are attributed to numerous pathophysiological mechanisms. The classification of asthma by endotype is primarily routed in different profiles of airway inflammation that contribute to bronchoconstriction. Many asthma therapeutics target G protein-coupled receptors (GPCRs), which either enhance bronchodilation or prevent bronchoconstriction. Short-acting and long-acting β 2-agonists are widely used bronchodilators that signal through the activation of the β 2-adrenergic receptor. Short-acting and long-acting antagonists of muscarinic acetylcholine receptors are used to reduce bronchoconstriction by blocking the action of acetylcholine. Leukotriene antagonists that block the signaling of cysteinyl leukotriene receptor 1 are used as an add-on therapy to reduce bronchoconstriction and inflammation induced by cysteinyl leukotrienes. A number of GPCR-targeting asthma drug candidates are also in different stages of development. Among them, antagonists of prostaglandin D2 receptor 2 have advanced into phase III clinical trials. Others, including antagonists of the adenosine A2B receptor and the histamine H4 receptor, are in early stages of clinical investigation. In the past decade, significant research advancements in pharmacology, cell biology, structural biology, and molecular physiology have greatly deepened our understanding of the therapeutic roles of GPCRs in asthma and drug action on these GPCRs. This review summarizes our current understanding of GPCR signaling and pharmacology in the context of asthma treatment. SIGNIFICANCE STATEMENT: Although current treatment methods for asthma are effective for a majority of asthma patients, there are still a large number of patients with poorly controlled asthma who may experience asthma exacerbations. This review summarizes current asthma treatment methods and our understanding of signaling and pharmacology of G protein-coupled receptors (GPCRs) in asthma therapy, and discusses controversies regarding the use of GPCR drugs and new opportunities in developing GPCR-targeting therapeutics for the treatment of asthma.

Asthma pharmacotherapy: an update on leukotriene treatments

Introduction: Asthma is a chronic inflammatory disease of the airways with a large heterogeneity of clinical phenotypes. There has been increasing interest regarding the role of cysteinyl leukotriene (LT) and leukotriene receptor antagonists (LTRA) in asthma treatment.Areas covered: This review summarized the data (published in PubMed during 1984-2019) regarding LTRA treatment in asthma and LTs-related airway inflammation mechanisms. Involvement of LTs C₄/D₄/E₄ has been demonstrated in the several aspects of airway inflammation and remodeling. Novel pathways related to LTE₄, the most potent mediator, and its respective receptors have recently been studied. Antagonists against cysteinyl leukotriene receptor (CysLTR) type 1, including montelukast, pranlukast and zafirlukast, have been widely prescribed in clinical practices; however, some clinical trials have shown insignificant responses to LTRAs in adult asthmatics, while some phenotypes of adult asthma showed more favorable responses to LTRAs including aspirin-exacerbated respiratory disease, elderly asthma, asthma associated with smoking, obesity and allergic rhinitis.Expert opinion: Further investigations are needed to understand the role of LTs in airway inflammation and remodeling of the asthmatic airways. There is a lack of biomarkers to predict responsiveness to LTRA, especially in adult asthmatics. Besides CysLTR1 antagonists, targets aiming other LT pathways should be considered.

Challenges in the management of asthma associated with smoking-induced airway diseases

INTRODUCTION

Smoking-induced airway diseases such as chronic bronchitis, emphysema, and small airway dysfunction contribute to the chronic respiratory symptoms experienced by adults with asthma, including those with spirometric chronic obstructive pulmonary disease (COPD), termed asthma-COPD overlap (ACO). Drug treatment of symptomatic smokers with asthma or ACO is uncertain due to their exclusion from most clinical trials.

AREAS COVERED

This review summarizes evidence for the efficacy of small molecule drugs used in the clinic to treat current and former smokers with a diagnostic label of asthma or ACO. Other therapeutic interventions are reviewed, including smoking cessation and biologics.

EXPERT OPINION

Clinical trials and observational studies suggest that smoking cessation and approved drugs used to treat non-smokers with asthma produce clinical benefits in smokers with asthma or ACO, although the overall quality of evidence is low. The efficacy of some treatments for asthma is altered in current smokers, including reduced responsiveness to short-term inhaled corticosteroids and possibly improved responsiveness to leukotriene receptor antagonists. Preliminary findings suggest that low-dose theophylline, statins, and biologics, such as omalizumab, mepolizumab, and dupilumab, may improve clinical outcomes in smokers with asthma or ACO. Improved phenotyping and endotyping of asthma and smoking-induced airway diseases should lead to better targeted therapies.

Asthma and smoking-induced airway disease without spirometric COPD

Due to the high prevalence rates of cigarette smoking and asthma, current and ex-smokers frequently develop chronic airway disease without spirometric evidence of chronic obstructive pulmonary disease (COPD), either alone or associated with asthma. This review considers the classification, clinical outcomes, inflammatory and imaging variables, phenotypes, and management of current and ex-smokers with airway disease without COPD, focusing on overlaps in those with and without asthma. These individuals have more respiratory symptoms, worse quality of life, increased exacerbation rates, reduced lung function and more comorbidities than never-smokers with asthma or healthy never-smokers. As well as clinical features, airway inflammatory and structural changes in smoking-induced airway disease without COPD overlap with those found in smokers with asthma. Cigarette smoking is associated with worse clinical outcomes in some phenotypes of asthma. Management involves public health measures to control exposure to tobacco smoke, personal advice on smoking cessation and the use of appropriate targeted therapies, although evidence is limited on their effectiveness. Understanding the mechanisms, natural history and management of current and ex-smokers with asthma and smoking-induced airway disease without COPD is a priority for future research.

Addition of anti-leukotriene agents to inhaled corticosteroids for adults and adolescents with persistent asthma

BACKGROUND

Asthma management guidelines recommend low-dose inhaled corticosteroids (ICS) as first-line therapy for adults and adolescents with persistent asthma. The addition of anti-leukotriene agents to ICS offers a therapeutic option in cases of suboptimal control with daily ICS.

OBJECTIVES

To assess the efficacy and safety of anti-leukotriene agents added to ICS compared with the same dose, an increased dose or a tapering dose of ICS (in both arms) for adults and adolescents 12 years of age and older with persistent asthma. Also, to determine whether any characteristics of participants or treatments might affect the magnitude of response.

SEARCH METHODS

We identified relevant studies from the Cochrane Airways Group Specialised Register of Trials, which is derived from systematic searches of bibliographic databases including the Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE, Embase, PsycINFO, the Allied and Complementary Medicine Database (AMED), the Cumulative Index to Nursing and Allied Health Literature (CINAHL) and the trial registries clinicaltrials.gov and ICTRP from inception to August 2016.

SELECTION CRITERIA

We searched for randomised controlled trials (RCTs) of adults and adolescents 12 years of age and older on a maintenance dose of ICS for whom investigators added anti-leukotrienes to the ICS and compared treatment with the same dose, an increased dose or a tapering dose of ICS for at least four weeks.

DATA COLLECTION AND ANALYSIS

We used standard methods expected by Cochrane. The primary outcome was the number of participants with exacerbations requiring oral corticosteroids (except when both groups tapered the dose of ICS, in which case the primary outcome was the % reduction in ICS dose from baseline with maintained asthma control). Secondary outcomes included markers of exacerbation, lung function, asthma control, quality of life, withdrawals and adverse events.

MAIN RESULTS

We included in the review 37 studies representing 6128 adult and adolescent participants (most with mild to moderate asthma). Investigators in these studies used three leukotriene receptor antagonists (LTRAs): montelukast (n = 24), zafirlukast (n = 11) and pranlukast (n = 2); studies lasted from four weeks to five years. Anti-leukotrienes and ICS versus same dose of ICSOf 16 eligible studies, 10 studies, representing 2364 adults and adolescents, contributed data. Anti-leukotriene agents given as adjunct therapy to ICS reduced by half the number of participants with exacerbations requiring oral corticosteroids (risk ratio (RR) 0.50, 95% confidence interval (CI) 0.29 to 0.86; 815 participants; four studies; moderate quality); this is equivalent to a number needed to treat for additional beneficial outcome (NNTB) over six to 16 weeks of 22 (95% CI 16 to 75). Only one trial including 368 participants reported mortality and serious adverse events, but events were too infrequent for researchers to draw a conclusion. Four trials reported all adverse events, and the pooled result suggested little difference between groups (RR 1.06, 95% CI 0.92 to 1.22; 1024 participants; three studies; moderate quality). Investigators noted between-group differences favouring the addition of anti-leukotrienes for morning peak expiratory flow rate (PEFR), forced expiratory volume in one second (FEV1), asthma symptoms and night-time awakenings, but not for reduction in β2-agonist use or evening PEFR. Anti-leukotrienes and ICS versus higher dose of ICSOf 15 eligible studies, eight studies, representing 2008 adults and adolescents, contributed data. Results showed no statistically significant difference in the number of participants with exacerbations requiring oral corticosteroids (RR 0.90, 95% CI 0.58 to 1.39; 1779 participants; four studies; moderate quality) nor in all adverse events between groups (RR 0.96, 95% CI 0.89 to 1.03; 1899 participants; six studies; low quality). Three trials reported no deaths among 834 participants. Results showed no statistically significant differences in lung function tests including morning PEFR and FEV1 nor in asthma control measures including use of rescue β2-agonists or asthma symptom scores. Anti-leukotrienes and ICS versus tapering dose of ICSSeven studies, representing 1150 adults and adolescents, evaluated the combination of anti-leukotrienes and tapering-dose of ICS compared with tapering-dose of ICS alone and contributed data. Investigators observed no statistically significant difference in % change from baseline ICS dose (mean difference (MD) -3.05, 95% CI -8.13 to 2.03; 930 participants; four studies; moderate quality), number of participants with exacerbations requiring oral corticosteroids (RR 0.46, 95% CI 0.20 to 1.04; 542 participants; five studies; low quality) or all adverse events (RR 0.95, 95% CI 0.83 to 1.08; 1100 participants; six studies; moderate quality). Serious adverse events occurred more frequently among those taking anti-leukotrienes plus tapering ICS than in those taking tapering doses of ICS alone (RR 2.44, 95% CI 1.52 to 3.92; 621 participants; two studies; moderate quality), but deaths were too infrequent for researchers to draw any conclusions about mortality. Data showed no improvement in lung function nor in asthma control measures.

AUTHORS' CONCLUSIONS

For adolescents and adults with persistent asthma, with suboptimal asthma control with daily use of ICS, the addition of anti-leukotrienes is beneficial for reducing moderate and severe asthma exacerbations and for improving lung function and asthma control compared with the same dose of ICS. We cannot be certain that the addition of anti-leukotrienes is superior, inferior or equivalent to a higher dose of ICS. Scarce available evidence does not support anti-leukotrienes as an ICS sparing agent, and use of LTRAs was not associated with increased risk of withdrawals or adverse effects, with the exception of an increase in serious adverse events when the ICS dose was tapered. Information was insufficient for assessment of mortality.

Evaluating the role of leukotriene-modifying drugs in asthma management: Are their benefits 'losing in translation'?

Leukotrienes (LTs) initiate a cascade of reactions that cause bronchoconstriction and inflammation in asthma. LT-modifying drugs have been proved very effective to reduce inflammation and associated exacerbation however despite some illustrious clinical trials the usage of these drugs remains overlooked because the evidence to support their utility in asthma management has been mixed and varied between studies. Although, there are plenty of evidences which suggest that the leukotriene-modifying drugs provide consistent improvement even after just the first oral dose and reduce asthma exacerbations, the beneficial effect of these drugs has remained sparse and widely debated. And these beneficial effects are often overlooked because most of the clinical studies include a mixed population of asthmatics who do not respond to LT-modifiers equally. Therefore, in the present era of personalized medicine, it is important to properly stratify the patients and non-invasive measurements of biomarkers may warrant the possibility to characterize biological/pathological pathway to direct treatment to those who will benefit from it. Endotyping based on individual's leukotriene levels should probably ascertain a subgroup of patients that would clearly benefit from the treatment even though the trial fails to show overall significance. In this article, we have methodically evaluated contemporary literature describing the efficacy of LT-modifying drugs in the management of asthma and highlighted the importance of phenotyping the asthmatics for better treatment outcomes.

Asthma phenotypes: the intriguing selective intervention with Montelukast

Asthma is a heterogeneous disease, usually characterized by chronic airway inflammation and a variable course associated with various underlying mechanisms that can differ between individuals. Patients with asthma can therefore exhibit different phenotypes, a term used to define the observable characteristics of an organism resulting from the interaction between its genetic makeup and the environment. 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 the disease. Specific asthma phenotypes may require an approach to treatment sometimes different from that recommended by current guidelines, so a personalized approach to asthma pharmacotherapy is recommended. Growing evidence suggests that leukotrienes play an important role in the pathogenesis of bronchial asthma. The mechanisms of action of leukotriene-receptor antagonists theoretically predict a good response in some asthma “phenotypes”.In this article we have performed an analysis of the recent literature (controlled clinical trials and real-life studies) about a possible selective intervention with Montelukast in specific asthma phenotypes.

Montelukast, current indications and prospective future applications

INTRODUCTION

Montelukast is recommended for the treatment of asthma, exercise -induced bronchospasm and allergic rhinitis. Several trials demonstrated potential therapeutic effects in other respiratory conditions, and different animal-model-based studies explored potential pharmacological actions in non-respiratory conditions.

AREAS COVERED

Clinical investigations on the pharmacotherapeutic effects of montelukast, in addition to in-vivo studies on animal models of non-respiratory diseases. The data discussed in this review were mainly obtained from clinical randomized trials, real-life studies, and studies based on animal models as approve of concept. As a condition, all of the discussed articles were published in journals cited by Pubmed. Expert commentary: The current clinical data are in favor of montelukast use in the management of chronic asthma as an add-on or alternative therapy to the inhaled corticosteroids. Further clinical trials are required to confirm the effectiveness and feasibility of montelukast for the treatment of conditions other than the current clinical indications.

The management of asthmatic smokers

Asthma is still a major public health problem in most countries; new strategies to better control this disease are necessary. Such strategies must include predisposing factors. One of these factors is smoking and a significant fraction of asthmatics are smokers. However, clinical trials studying new drugs or newer therapeutic regimens for asthma generally exclude smokers. Therefore, there is a lack of specific information about the treatment of asthma in smokers. The asthmatic smoker is a special phenotype with important therapeutic and prognostic clinical implications. Any form of tobacco use, especially cigarette smoking, plays an important role in this disease. Asthmatic smokers are prone to several negative outcomes. Smoking cessation results in an improvement of symptoms and pulmonary functioning. Counselling and first-line medications for smoking cessation (nicotine replacement therapy, bupropion and varenicline) significantly increase quitting rates. The role of electronic cigarettes in this group of patients has only begun to be studied. The treatment of asthmatics that smoke has characteristics that need must be well understood by clinicians, especially the poor response to corticosteroids. This condition is not universal and physicians should always consider its inclusion in the treatment of these patients. The association of inhaled corticosteroids (ICS) plus a long-acting beta2 adrenegic (LABA) by smoking asthmatics results in more pronounced improvement in several asthma outcomes compared with the use of corticosteroid alone. Inhaled corticosteroids in extra-fine particles associated with LABA may be a new perspective of treatment. Also the use of leukotriene antagonists may become another therapeutic alternative. The purpose of this narrative review is to discuss the challenges faced by clinicians to control asthma in smokers and to present methods of coping with smoking treatment and avoiding relapses.

Smoking asthma phenotype: diagnostic and management challenges

PURPOSE OF REVIEW

The prevalence of active smoking in adults with asthma is similar to the general population. Smoking asthma is associated with poorer disease control, impaired response to corticosteroid therapy, accelerated decline in lung function, and increased rate of healthcare utilization. Current asthma guidelines do not provide specific treatment advice for smoking asthmatic patients. There is an urgent need for better understanding of the underlying mechanisms and effective treatment for smoking asthmatic patients.

RECENT FINDINGS

An association between both active and passive smoking and adult-onset asthma is supported by many studies.The asthma-COPD overlap syndrome (ACOS) has recently gained particular interest and smoking asthmatic patients should be evaluated for ACOS.Treatment regimens for smoking asthma include higher doses of inhaled corticosteroids (ICS), extrafine particle ICS formulations, antileukotrienes, and combinations of these options.Asthma is associated with increased risk of cardiovascular comorbidities whereas smoking is an additional strong independent risk factor for pulmonary and cardiovascular diseases. Tobacco smoking and not asthma per se seems to be the reason of poor prognosis, especially with regard to lung cancer, cardiovascular diseases, and mortality in asthmatic patients.

SUMMARY

Smoking asthma represents a common challenge to the clinician both in terms of diagnosis and management. These aspects have not been thoroughly evaluated and deserve further investigation.

Addressing corticosteroid insensitivity in adults with asthma

Corticosteroids are the most effective treatment for asthma, but the therapeutic response varies markedly between individuals, with up to one third of patients showing evidence of insensitivity to corticosteroids. This article summarizes information on genetic, environmental and asthma-related factors as well as demographic and pharmacokinetic variables associated with corticosteroid insensitivity in asthma. Molecular mechanisms proposed to explain corticosteroid insensitivity are reviewed including alterations in glucocorticoid receptor subtype, binding and nuclear translocation, increased proinflammatory transcription factors and defective histone acetylation. Current therapies and future interventions that may restore corticosteroid sensitivity in asthma are discussed, including small molecule drugs and biological agents. In the future, biomarkers may be used in the clinic to predict corticosteroid sensitivity in patients with poorly controlled asthma.

Leukotriene-receptor antagonists versus placebo in the treatment of asthma in adults and adolescents: a systematic review and meta-analysis

BACKGROUND

Leukotriene-receptor antagonists (LTRAs) are recommended as an alternative treatment in patients with mild asthma, but their effect compared with placebo is unclear.

PURPOSE

To determine the benefits and harms of LTRAs as monotherapy or in combination with inhaled corticosteroids compared with placebo in adults and adolescents with asthma.

DATA SOURCES

MEDLINE and the Cochrane Central Register of Controlled Trials from inception through June 2015.

STUDY SELECTION

Peer-reviewed, English-language, randomized, controlled trials in patients with asthma that reported the effect of LTRAs versus placebo on measures of asthma control.

DATA EXTRACTION

Three researchers extracted data on study population, interventions, outcome measures, and adverse events. One researcher assessed risk of bias.

DATA SYNTHESIS

Of the 2008 abstracts that were screened, 50 trials met eligibility criteria. Random-effects meta-analyses of 6 trials of LTRA monotherapy showed that LTRAs reduced the risk for an exacerbation (summary risk ratio [RR], 0.60 [95% CI, 0.44 to 0.81]). In 4 trials of LTRAs as add-on therapy to inhaled corticosteroids, the summary RR for exacerbation was 0.80 (CI, 0.60 to 1.07). Leukotriene-receptor antagonists either as monotherapy or as add-on therapy to inhaled corticosteroids increased FEV1, whereas FEV1 percentage of predicted values was improved only in trials of LTRA monotherapy. Adverse event rates were similar in the intervention and comparator groups.

LIMITATION

Variation in definitions and reporting of outcomes, high risk of bias in some studies, heterogeneity of findings, possible selective outcome reporting bias, and inability to assess the effect of asthma severity on summary estimates.

CONCLUSION

Leukotriene-receptor antagonists as monotherapy improved asthma control compared with placebo, but which patients are most likely to respond to treatment with LTRAs remains unclear.

PRIMARY FUNDING SOURCE

National Institutes of Health.

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.

Phenotype of asthma-chronic obstructive pulmonary disease overlap syndrome

Many patients with asthma or chronic obstructive pulmonary disease (COPD) have overlapping characteristics of both diseases. By spirometric definition, patients with both fixed airflow obstruction (AO) and bronchodilator reversibility or fixed AO and bronchial hyperresponsiveness can be considered to have asthma-COPD overlap syndrome (ACOS). However, patients regarded to have ACOS by spirometric criteria alone are heterogeneous and can be classified by phenotype. Eosinophilic inflammation, a history of allergic disease, and smoke exposure are important components in the classification of ACOS. Each phenotype has a different underlying pathophysiology, set of characteristics, and prognosis. Medical treatment for ACOS should be tailored according to phenotype. A narrower definition of ACOS that includes both spirometric and clinical criteria is needed.

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.

Complementing the randomized controlled trial evidence base. Evolution not revolution

Observational studies and pragmatic trials can complement classical randomized controlled trials (RCTs) by providing data more relevant to the circumstances under which medicine is routinely practiced, thereby providing practical guidance for clinicians. The bearing of RCT findings on day-to-day practice can be weighted and the data more meaningfully interpreted by practicing clinicians if evidence is integrated from a variety of different study designs and methodologies. The advent of observational studies and pragmatic trials, often referred to as "real-life studies," has met with a degree of cynicism, but their role and value is gaining widespread recognition and support among clinicians. This article discusses where observational studies and pragmatic trials have utility, namely: in addressing clinical questions that are unanswered and/or unanswerable by RCTs; in testing new hypotheses and possible license extensions; and in helping to differentiate between available therapies for a given indication. Moreover, it seeks to highlight how the different approaches fit within a conceptual framework of evidence relevant to clinical practice, a step-change in the traditional view of medical evidence.

Montelukast for the high impact of asthma exacerbations in Venezuela: a practical and valid approach for Latin America?

Background

Asthma affects mainly Venezuela’s urban and poor majority. Exacerbations bring about a high demand in health services, thus becoming a significant public health problem. In general, asthma control programs (GINA) with use of inhaled steroid medications have proven effective, although their implementation in real life remains cumbersome. Montelukast could be a useful and practical tool for these deprived socioeconomic sectors.

Methods

This real-life pilot study was conducted in a prospective, double blinded, placebo-controlled manner with randomized and parallel groups. Asthmatics that had never used leukotriene modifiers were recruited and followed-up every three months. The main outcome was the number of exacerbations meriting use of nebulized bronchodilators administered by the health care system.

Results

Eighty-eight asthmatic patients were enrolled, between children and adults. Groups were comparable in: demographic data, previous use of other medications, ACT scores, pulmonary functions (Wright Peak Flow meter), allergy status (Skin Prick Test) as well as adherence to the prescribed Montelukast treatment. By an intention to treat (ITT), a total of 64 patients were included for analysis. For the three and six months time points the difference between placebo and Montelukast was found to be significant (p < 0.03 and p < 0.04, respectively). Such trends continued for the rest of the year, but without statistical significance, due to patient attrition.

Conclusions

This real-life pilot study shows that a simplified strategy with oral Montelukast was practical and effective in controlling exacerbations in an asthmatic population of a vulnerable community from Caracas. Such an approach reinforces the role of primary care in asthma treatment.

Advances in environmental and occupational disorders in 2013

In this review of articles published in the Journal in 2013, we report on the significant advances in environmental and occupational disorders. Research advances have led to the identification and defined the structure and function of several major allergens. A meta-analysis confirmed the importance of mold exposure in patients with allergic rhinitis, and a new immunologic classification of aspergillosis emerged. Insights into the role of diesel exhaust particles in patients with severe asthma were clarified. Improvements in stinging insect allergy diagnostics were reported. Genetic, immunologic, and biomarker studies advanced the understanding of adverse drug reactions. New practice parameters for cockroach allergen control were presented. The pathologic role of viruses and bacterial agents in patients with asthma and chronic obstructive pulmonary disease were further defined. An excellent review of allergen bronchoprovocation testing was reported. The roles of bronchoprovocation and bronchodilator responsiveness in asthma diagnosis were further clarified. A biomarker for neutrophilic asthma was identified. Therapeutic advances in asthma research include the inhibition of IL-13 by lebrikizumab, use of montelukast in asthmatic smokers, and a thorough review of bronchial thermoplasty in patients with severe asthma. Lastly, maternal asthma was linked to a number of adverse neonatal outcomes.

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.

Clinical effectiveness and safety of montelukast in asthma. What are the conclusions from clinical trials and meta-analyses?

Asthma is a common childhood atopic disease associated with chronicity and impaired quality of life. As there is no cure for this disease, treatment relies on avoidance of triggers such as food and aeroallergens, the use of inhaled bronchodilators/corticosteroids and antiallergic or immunomodulating therapies. Inhaled corticosteroids (ICSs) and bronchodilators have been the mainstay. However, in Asia, myths and fallacies regarding Western medicine and corticosteroids are prevalent and lead to nonadherence to treatment. Also, use of traditional and proprietary herbal medicines is popular. In the past decades, a novel class of nonsteroidal immunomodulating montelukasts has become available. This article reviews the evidence for the effectiveness and clinical efficacy of these medications. A number of randomized and controlled trials have been performed over the years. The majority of studies confirm the usefulness of montelukast as monotherapy and add-on therapy to ICS in mild to moderate childhood asthma across all age groups. ICSs are generally superior to montelukasts for asthma management. However, montelukast has a place in the treatment of young children with viral-triggered wheezing diseases, exercise-induced asthma, and in children whose parents are steroid-phobic and find ICS unacceptable.

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.

Arachidonic acid metabolites and enzyme transcripts in asthma are altered by cigarette smoking

BACKGROUND

Arachidonic acid metabolites are implicated in the pathogenesis of asthma although only limited information is available on the impact of current smoking history on these metabolites. The aim of the study was to examine the effect of smoking status on urinary, sputum, and plasma eicosanoid concentrations and relevant enzyme transcripts in asthma.

METHODS

In 108 smokers and never smokers with asthma and 45 healthy controls [smokers and never smokers], we measured urinary tetranor prostaglandin (PG)D2 (PGDM) and leukotriene (LT)E4 , induced sputum fluid LTB4 , LTE4 , PGD2 , and PGE2 , plasma secretory phospholipase A2 (sPLA2 ), and 11β prostaglandin F2α (11βPGF2α ), and, in a subgroup with severe asthma, airway leukocyte and epithelial cell mRNA expression levels of arachidonic acid metabolic enzymes.

RESULTS

Smokers with asthma had higher urinary LTE4 ; 83 (59, 130) vs 59 (40, 90) pg/mg creatinine, P = 0.008, and PGDM; 60 (35, 100) vs 41 (28, 59) ng/mg creatinine, P = 0.012 concentrations, respectively, and lower sputum PGE2 concentrations 80 (46, 157) vs 192 (91, 301) pg/ml, P = 0.001 than never smokers with asthma. Sputum LTB4 (P = 0.013), and plasma 11βPGF2α (P = 0.032), concentrations, respectively, were increased in smokers with asthma compared with healthy smokers. Asthma-specific and smoking-related increases (>1.5-fold expression) in arachidonate 15-lipoxygenase and gamma-glutamyltransferase transcripts were demonstrated.

CONCLUSIONS

Several arachidonic acid metabolites and enzyme transcripts involving both lipoxygenase and cyclooxygenase pathways are increased in smokers with asthma and differ from never smokers with asthma. Possibly targeting specific lipoxygenase and cyclooxygenase pathways that are activated by asthma and cigarette smoking may optimize therapeutic responses.

Advances in adult asthma diagnosis and treatment in 2013

In 2013, several themes emerged: (1) a dedicated search for new therapies using new mechanisms; (2) the importance of the plasticity of the immune system (eg, that molecules that mediate inflammation in one setting can promote its resolution and return to homeostasis in other circumstances); (3) the complex role of viruses in asthma exacerbations; (4) the similarities and differences among asthma, asthma in smokers, and chronic obstructive pulmonary disease; and (5) the importance of understanding asthma phenotypes and their stability over time. Once new therapeutics pass the initial clinical trials, patient-oriented and real-world research will be needed.

Integrating evidence for managing asthma in patients who smoke

Cigarette smoking among asthma patients is associated with worsening symptoms and accelerated decline in lung function. Smoking asthma is also characterized by increased levels of neutrophils and macrophages, and greater small airway remodeling, resulting in increased airflow obstruction and impaired response to corticosteroid therapy. As a result, smokers are typically excluded from asthma randomized controlled trials (RCTs). The strict inclusion/exclusion criteria used by asthma RCTs limits the extent to which their findings can be extrapolated to the routine care asthma population and to reflect the likely effectiveness of therapies in subgroups of particular clinical interest, such as smoking asthmatics. The inclusion of smokers in observational asthma studies and pragmatic trials in asthma provides a way of assessing the relative effectiveness of different treatment options for the management of this interesting clinical subgroup. Exploratory studies of possible treatment options for smoking asthma suggest potential utility in: prescribing higher-dose ICS; targeting the small airways of the lungs with extra-fine particle ICS formulations; targeting leukotreines, and possibly also combinations of these options. However, further studies are required. With the paucity of RCT data available, complementary streams of evidence (those from RCTs, pragmatic trials and observational studies) need to be combined to help guide judicious prescribing decisions in smokers with asthma.

Leukotriene receptor antagonists pranlukast and montelukast for treating asthma

INTRODUCTION

The prevalence of bronchial asthma, which is a chronic inflammatory disorder of the airway, is increasing worldwide. Although inhaled corticosteroids (ICS) play a central role in the treatment of asthma, they cannot achieve good control for all asthmatics, and medications such as leukotriene receptor antagonists (LTRAs) with bronchodilatory and anti-inflammatory effects often serve as alternatives or add-on drugs.

AREAS COVERED

Clinical trials as well as basic studies of montelukast and pranlukast in animal models are ongoing. This review report clarifies the current status of these two LTRAs in the treatment of asthma and their future direction.

EXPERT OPINION

LTRAs could replace ICS as first-line medications for asthmatics who are refractory to ICS or cannot use inhalant devices. Further, LTRAs are recommended for asthmatics under specific circumstances that are closely associated with cysteinyl leukotrienes (cysLTs). Considering the low incidence of both severe adverse effects and the induction of tachyphylaxis, oral LTRAs should be more carefully considered for treating asthma in the clinical environment. Several issues such as predicted responses, effects of peripheral airway and airway remodeling and alternative administration routes remain to be clarified before LTRAs could serve a more effective role in the treatment of asthma.

Inhaled corticosteroids for asthma: on-demand or continuous use

Continuous inhaled corticosteroid treatment is highly effective in children and adults with mild persistent asthma, although some therapeutic benefits are not lost if treatment is delayed. Many patients do not adhere to continuous treatment with inhaled corticosteroids, but rather take them intermittently, usually at the time of increased symptoms. Based on these observations it has been proposed that for patients with mild persistent asthma inhaled corticosteroids should be used on-demand when symptoms are troublesome, rather than on a continuous basis. The article reviews the pharmacological properties of inhaled corticosteroids used in clinical trials of on-demand treatment, as well as the evidence for the efficacy and safety of on-demand compared with continuous inhaled corticosteroid treatment of mild persistent asthma in adults and children. The place of on-demand treatment with inhaled corticosteroids in the management of asthma is discussed, as well as future directions for different management strategies for this group.

'SIMPLES': a structured primary care approach to adults with difficult asthma

The substantial majority of patients with asthma can expect minimal breakthrough symptoms on standard doses of inhaled corticosteroids with or without additional add-on therapies. SIMPLES is a structured primary care approach to the review of a person with uncontrolled asthma which encompasses patient education monitoring, lifestyle and pharmacological management and addressing support needs which will achieve control in most patients. The small group of patients presenting with persistent asthma symptoms despite being prescribed high levels of treatment are often referred to as having 'difficult asthma'. Some will have difficult, 'therapy resistant' asthma, some will have psychosocial problems which make it difficult for them to achieve asthma control and some may prove to have an alternative diagnosis driving their symptoms. A few patients will benefit from referral to a 'difficult asthma' clinic. The SIMPLES approach, aligned with close co-operation between primary and specialist care, can identify this patient group, avoid inappropriate escalation of treatment, and streamline clinical assessment and management.