Intermittent montelukast in children aged 10 months to 5 years with wheeze (WAIT trial): a multicentre, randomised, placebo-controlled trial

MALAT1 binds to miR-188-3p to regulate ALOX5 activity in the lung inflammatory response of neonatal bronchopulmonary dysplasia

Bronchopulmonary dysplasia (BPD) causes high morbidity and mortality in infants, but no effective preventive or therapeutic agents have been developed to combat BPD. In this study, we assessed the expression of MALAT1 and ALOX5 in peripheral blood mononuclear cells from BPD neonates, hyperoxia-induced rat models and lung epithelial cell lines. Interestingly, we found upregulated expression of MALAT1 and ALOX5 in the experimental groups, along with upregulated expression of proinflammatory cytokines. According to bioinformatics prediction, MALAT1 and ALOX5 simultaneously bind to miR-188-3p, which was downregulated in the experimental groups above. Silencing MALAT1 or ALOX5 and overexpressing miR-188-3p inhibited apoptosis and promoted the proliferation of hyperoxia-treated A549 cells. Suppressing MALAT1 or overexpressing miR-188-3p increased the expression levels of miR-188-3p but decreased the expression levels of ALOX5. Moreover, RNA immunoprecipitation (RIP) and luciferase assays showed that MALAT1 directly targeted miR-188-3p to regulate ALOX5 expression in BPD neonates. Collectively, our study demonstrates that MALAT1 regulates ALOX5 expression by binding to miR-188-3p, providing novel insights into potential therapeutics for BPD treatment.

Phenotype and endotype based treatment of preschool wheeze

INTRODUCTION

Preschool wheeze (PSW) is a significant public health issue, with a high presentation rate to emergency departments, recurrent symptoms, and severe exacerbations. A heterogenous condition, PSW comprises several phenotypes that may relate to a range of pathobiological mechanisms. However, treating PSW remains largely generalized to inhaled corticosteroids and a short acting beta agonist, guided by symptom-based labels that often do not reflect underlying pathways of disease.

AREAS COVERED

We review the observable features and characteristics used to ascribe phenotypes in children with PSW and available pathobiological evidence to identify possible endotypes. These are considered in the context of treatment options and future research directions. The role of machine learning (ML) and modern analytical techniques to identify patterns of disease that distinguish phenotypes is also explored.

EXPERT OPINION

Distinct clusters (phenotypes) of severe PSW are characterized by different underlying mechanisms, some shared and some unique. ML-based methodologies applied to clinical, biomarker, and environmental data can help design tools to differentiate children with PSW that continues into adulthood, from those in whom wheezing resolves, identifying mechanisms underpinning persistence and resolution. This may help identify novel therapeutic targets, inform mechanistic studies, and serve as a foundation for stratification in future interventional therapeutic trials.

Basic clinical management of preschool wheeze

Preschool wheeze is very common and often difficult to treat. Most children do not require any investigations; only a detailed history and physical examination to ensure an alternative diagnosis is not being missed; and the differential diagnosis, and hence investigation protocols for the child in whom a major illness is suspected, shows geographical variation. The pattern of symptoms may be divided into episodic viral and multiple trigger to guide treatment, but the pattern of symptoms must be re-assessed regularly. However, symptom patterns are a poor guide to underlying pathology. Attention to the proper use of spacers, and adverse environmental exposures such as tobacco smoke exposure, is essential. There are no disease-modifying therapies, so therapy is symptomatic. This paper reviews recent advances in treatment, including new data on the place of leukotriene receptor antagonists, prednisolone for acute attacks of wheeze, and antibiotics, based on new attempts to understand the underlying pathology in a way that is clinically practical.

Intermittent Tiotropium Bromide for Episodic Wheezing: A Randomized Trial

BACKGROUND AND OBJECTIVES

Options to treat and prevent episodic wheezing in children are scarce. Our objective was to assess the efficacy of intermittent tiotropium bromide treatment in early childhood episodic wheezing.

METHODS

This 48-week, randomized, open-label, controlled, parallel-group trial was conducted at 4 hospitals in Finland. Children aged 6 to 35 months with 2 to 4 physician-confirmed episodes of wheeze and/or shortness of breath were considered eligible. Study participants were randomly allocated to receive 1 of 3 treatments: once-daily tiotropium bromide 5 µg for 7 to 14 days during respiratory tract infections and as-needed albuterol sulfate 0.2 mg (n = 27), twice-daily fluticasone propionate 125 µg for 7 to 14 days during respiratory tract infections and as-needed albuterol sulfate 0.2 mg (n = 25), or as-needed albuterol sulfate 0.2 mg alone (n = 28). The primary outcome was efficacy, assessed as intention-to-treat by comparing the proportion of episode-free days (the days lacking symptoms or treatments) between the treatment groups.

RESULTS

The proportion of episode-free days was higher in those receiving intermittent tiotropium bromide (median 97% [interquartile range, 93% to 99%]) than in those receiving intermittent fluticasone propionate (87% [78% to 93%], P = .002), or with as-needed albuterol sulfate alone (88% [79% to 95%], P = .003). Adjustment with allergic sensitization, the baseline number of physician-confirmed episodes of wheeze and/or shortness of breath, or short-course glucocorticoid treatment in the 2 weeks before the enrollment, did not affect the result. Intervention-related adverse events were not seen.

CONCLUSIONS

Intermittent tiotropium bromide treatment may be an effective alternative to current therapies for episodic wheezing. Before implementation of use, further research on safety and efficacy is indicated.

Management of Preschool Wheezing: Guideline from the Emilia-Romagna Asthma (ERA) Study Group

Preschool wheezing should be considered an umbrella term for distinctive diseases with different observable and measurable phenotypes. Despite many efforts, there is a large gap in knowledge regarding management of preschool wheezing. In order to fill this lack of knowledge, the aim of these guidelines was to define management of wheezing disorders in preschool children (aged up to 5 years). A multidisciplinary panel of experts of the Emilia-Romagna Region, Italy, addressed twelve different key questions regarding the management of preschool wheezing. Clinical questions have been formulated by the expert panel using the PICO format (Patients, Intervention, Comparison, Outcomes) and systematic reviews have been conducted on PubMed to answer these specific questions, with the aim of formulating recommendations. The GRADE approach has been used for each selected paper, to assess the quality of the evidence and the degree of recommendations. These guidelines represent, in our opinion, the most complete and up-to-date collection of recommendations on preschool wheezing to guide pediatricians in the management of their patients, standardizing approaches. Undoubtedly, more research is needed to find objective biomarkers and understand underlying mechanisms to assess phenotype and endotype and to personalize targeted treatment.

Pharmacogenomics of Leukotriene Modifiers: A Systematic Review and Meta-Analysis

Pharmacogenetics research on leukotriene modifiers (LTMs) for asthma has been developing rapidly, although pharmacogenetic testing for LTMs is not yet used in clinical practice. We performed a systematic review and meta-analysis on the impact of pharmacogenomics on LTMs response. Studies published until May 2022 were searched using PubMed, EMBASE, and Cochrane databases. Pharmacogenomics/genetics studies of patients with asthma using LTMs with or without other anti-asthmatic drugs were included. Statistical tests of the meta-analysis were performed with Review Manager (Revman, version 5.4, The Cochrane Collaboration, Copenhagen, Denmark) and R language and environment for statistical computing (version 4.1.0 for Windows, R Core Team, Vienna, Austria) software. In total, 31 studies with 8084 participants were included in the systematic review and five studies were also used to perform the meta-analysis. Two included studies were genome-wide association studies (GWAS), which showed different results. Furthermore, none of the SNPs investigated in candidate gene studies were identified in GWAS. In candidate gene studies, the most widely studied SNPs were ALOX5 (tandem repeats of the Sp1-binding domain and rs2115819), LTC4S-444A/C (rs730012), and SLCO2B1 (rs12422149), with relatively inconsistent conclusions. LTC4S-444A/C polymorphism did not show a significant effect in our meta-analysis (AA vs. AC (or AC + CC): −0.06, 95%CI: −0.16 to 0.05, p = 0.31). AA homozygotes had smaller improvements in parameters pertaining to lung functions (−0.14, 95%CI: −0.23 to −0.05, p = 0.002) in a subgroup of patients with non-selective CysLT receptor antagonists and patients without inhaled corticosteroids (ICS) (−0.11, 95%CI: −0.14 to −0.08, p < 0.00001), but not in other subgroups. Variability exists in the pharmacogenomics of LTMs treatment response. Our meta-analysis and systematic review found that LTC4S-444A/C may influence the treatment response of patients taking non-selective CysLT receptor antagonists for asthma, and patients taking LTMs not in combination with ICS for asthma. Future studies are needed to validate the pharmacogenomic influence on LTMs response.

Prevention and Outpatient Treatment of Asthma Exacerbations in Children

Acute exacerbations cause significant morbidity and mortality in children with asthma worldwide. Although exacerbations can be minor and transient, in some children they are recurrent and significantly adversely impact quality of life. Children with frequent exacerbations account for a disproportionate amount of unscheduled care in nonprimary health facilities. Frequent exacerbators are often prescribed controller medications, but poor adherence is common. Major predictors for asthma exacerbations include genetic, social, comorbid, biological, and environmental factors. Although virus infections are a key trigger for exacerbations, other environmental factors also significantly increase risk. A previous exacerbation is a major risk factor for future exacerbations and thus identifies children to target for prevention of future episodes. In this review, we discuss both modifiable and fixed factors associated with asthma exacerbations, how to assess children for risk, and which pharmacological and nonpharmacological interventions may be of benefit. Finally, we review the current evidence around treatment within the outpatient setting for an emerging exacerbation.

Effects of using montelukast during acute wheezing attack in hospitalized preschool children on the discharge rate and the clinical asthma score

BACKGROUND

In chronic asthma treatment, leukotriene receptor antagonists have been recommended, but it is not clear whether montelukast can be used in acute recurrent wheezing attacks in children.

OBJECTIVE

To investigate the safety and effectiveness of oral montelukast in addition to standard treatment in hospitalized children aged between 6 and 72 months with acute recurrent wheezing attacks.

METHOD

One hundred patients aged between 6 and 72 months who had wheezing attacks with clinical asthma scores (CAS) ≥3 and were hospitalized were included in this randomized, double-blind, placebo-controlled, parallel-group clinical trial. All the patients included in the study were given 0.15 mg/kg (maximum 5 mg) nebulized salbutamol (8 L/min and with 100% O₂ ) with 4 h of intervals, 1 mg/kg prednisolone (maximum 5 days), nebulized ipratropium bromide (total eight doses) with 6 h of intervals. In addition to this treatment, one group received 4 mg montelukast, and the other group received a placebo. The CAS of the patients were evaluated with 4-h intervals.

RESULTS

Total hospital length of stay (LOS) was not different between the montelukast and placebo groups (p = 0.981). There was no statistically significant difference between the two treatment groups in terms of discharge time, CAS, and oxygen saturation (p ≥ 0.05).

CONCLUSION

Adding montelukast to standard treatment in patients hospitalized for moderate-to-severe wheezing attacks did not affect hospital LOS and CAS.

Factors and mechanisms contributing to the development of preschool wheezing disorders

INTRODUCTION

Half of all children will experience an episode of wheezing by their sixth birthday and acute episodes of wheezing in preschool children account for the majority of all childhood hospital admissions for wheeze. Recurrent preschool wheezing associates with early loss of lung function and a life-long impact on lung health.

AREAS COVERED

We reviewed the literature on PubMed from August 2010-2020 focussing on factors associated with wheeze inception and persistence, paying specific attention to mechanistic studies that have investigated the impact of early life exposures in shaping immune responses in children with underlying susceptibility to wheezing. In particular, the role of early allergen sensitization, respiratory infections, and the impact of the environment on shaping the airway microbiome and resulting immune responses are discussed.

EXPERT OPINION

There is an abundance of associative data showing the role of in utero and postnatal factors influencing wheeze onset and persistence. However, mechanistic and stratified, biomarker-based interventional studies that confirm these associations are now needed if we are to impact the significant healthcare burden resulting from preschool wheezing disorders.

Predictors of response to medications for asthma in pediatric patients: A systematic review of the literature

OBJECTIVES

There has been no systematic review of studies aimed to predict differential responses to medication regimens for asthma controller therapies in pediatric patients. The aim of the present study was to summarize those identifying biomarkers for the different asthma controller therapies.

METHODS

Studies published by June 2019 that report phenotypic or genotypic characteristics or biomarkers that could potentially serve as response predictors to asthma controller therapies in pediatric patients were included. The quality of studies was assessed using the Cochrane Risk of Bias tool and the Newcastle-Ottawa Scale tool.

RESULTS

Of 385 trials identified, 30 studies were included. Children with asthma and a positive family history of asthma, with more severe disease, of the white race, with allergy biomarkers, nonobese, with lower lung function, high bronchial hyperresponsiveness to methacholine, or having variants in the FCER2 and CRHR1 gene respond better to inhaled corticosteroids (ICS). Younger age (<10 years), short disease duration (<4 years), high cotinine and urinary leukotriene E4 (LTE4) levels, and 5/5 ALOX5 were associated with a better response to leukotriene receptor antagonist (LTRA). For patients that remain symptomatic, white Hispanics were more likely to respond to LTRA, blacks to ICS, white non-Hispanics to LTRA or LABA, and children without a history of eczema, regardless of race or ethnicity to LABA set-up therapy. In severe persistent asthma, those with atopy and body mass index greater than or equal 25 were more likely to benefit from omalizumab.

CONCLUSION

Several phenotypic characteristics, biomarkers, or pharmacogenomics markers could be useful for predicting the best drug for asthma treatment.

Prevention and treatment of recurrent viral-induced wheezing in the preschool child

OBJECTIVE

To summarize the recent evidence in the treatment of viral-induced wheezing in the infant and preschool aged child.

DATA SOURCES

Published literature obtained through PubMed database searches.

STUDY SELECTIONS

Studies relevant to phenotypes and treatment of wheezing illnesses in infants and preschool children were included.

RESULTS

Recurrent wheezing in preschool children is common and is frequently triggered by viral respiratory tract infections. Certain phenotypes may respond to treatments differently, depending on the risk factors identified. Inhaled corticosteroids, administered continuously or intermittently, reduce the risk of virus-induced wheezing episodes. The use of leukotriene modifying agents may have a role in wheezing episodes in a select group of preschool children. Early administration of azithromycin reduces the risk of severe lower respiratory tract illnesses in children. The effect of oral corticosteroids on wheezing episodes in young children varies by degree of episode severity.

CONCLUSION

Recurrent viral-induced wheezing illnesses has been the focus of many clinical trials, which now provide an increasingly robust evidence base for management. Additional research is needed to define optimal strategies, to best match therapies to specific phenotypes and endotypes, and will eventually begin to include therapies directed specifically at the viral triggers.

Preschool Wheezing: Trajectories and Long-Term Treatment

Wheezing is very common in infancy affecting one in three children during the first 3 years of life. Several wheeze phenotypes have been identified and most rely on temporal pattern of symptoms. Assessing the risk of asthma development is difficult. Factors predisposing to onset and persistence of wheezing such as breastfeeding, atopy, indoor allergen exposure, environmental tobacco smoke and viral infections are analyzed. Inhaled corticosteroids are recommended as first choice of controller treatment in all preschool children irrespective of phenotype, but they are particularly beneficial in terms of fewer exacerbations in atopic children. Other therapeutic options include the addition of montelukast or the intermittent use of inhaled corticosteroids. Overuse of inhaled steroids must be avoided. Therefore, adherence to treatment and correct administration of the medications need to be checked at every visit.

Management of acute loss of asthma control: yellow zone strategies

PURPOSE OF REVIEW

Asthma exacerbations are associated with a significant burden to both the individual patient and to the healthcare system. Patients often step-up home therapies in response to increased asthma symptoms, and the asthma action plan was created to empower patients to self-manage their asthma care. The yellow (intermediate) zone of the asthma action plan is frequently poorly defined, and current Expert Panel Report 3 guideline recommendations are not effective for all patients. This article reviews the evidence behind various recommended yellow zone intervention strategies.

RECENT FINDINGS

There are many potential methods of delivering yellow zone therapy, and recent studies have assessed preventive efficacy of a scheduled increase in controller medication(s), reliever medication(s), or a symptom-driven combination of both. The literature suggests that, in certain asthma subpopulations, some methods may be more efficacious than others.

SUMMARY

Multiple yellow zone approaches may be beneficial, and the yellow zone is not a 'one size fits all' narrative.

Personalized Medicine and Pediatric Asthma

Asthma is a heterogeneous disorder described by a large number of clinical features. A growing body of literature on more specific asthma phenotypes provides evidence for a phenotype-based approach to management in which specific therapies are recommended based on patient and disease characteristics. This understanding, coupled with an increase in the number of available therapies for children with asthma, as well as emerging therapies and phenotypic markers, will allow for improved asthma management in the future.

Treatment strategies for the yellow zone

OBJECTIVE

To evaluate relevant studies and documents that address treatment strategies for acute loss of asthma control (yellow zone).

DATA SOURCES

Publications available on various treatment strategies for the yellow zone, Global Initiative for Asthma, and FDA Drug Safety Communication.

STUDY SELECTIONS

Studies that assessed the effectiveness of specific therapies as yellow zone strategies were included in this review.

RESULTS

Multiple yellow zone strategies exist, but only a few have been shown consistently effective. No specific evidence suggests that scheduled SABA can prevent exacerbation. Results for intermittent leukotriene receptor antagonist use have been mixed. Strong evidence supports intermittent inhaled corticosteroid (ICS) dosing for preschool-aged children with intermittent viral-induced wheeze, but data regarding this strategy for older children and adults are limited. As for short-term increase in scheduled ICS controller, doubling the dose seems to be ineffective, whereas results for a more substantial increase in ICS dose (quadrupling and quintupling) have been mixed. Dynamic dosing appears most promising, because symptom-driven ICS in tandem with rescue beta agonist use (whether short- or long-acting) is the strategy with the most robust data demonstrating reduction in exacerbations while minimizing ICS exposure.

CONCLUSION

Varying study designs and the heterogeneity of asthma itself likely account for the difference in outcomes seen with the various yellow zone intervention strategies studied. More studies are needed to determine the right yellow zone therapies for the right patients, but this is likely to be most effective through a personalized approach.

Does understanding endotypes translate to better asthma management options for all?

Despite the development of novel treatments, improvement in the design of delivery devices, and new technologies for monitoring and improving adherence, the burden of asthma is not decreasing. Predicting an individual patient's response to asthma drugs remains challenging, and the provision of personalized treatment remains elusive. Although biomarkers, such as allergic sensitization and blood eosinophilia, might be important predictors of response to inhaled corticosteroids in preschool children, these relatively cheap and available investigations are seldom used in clinical practice to select patients for corticosteroid prescription. However, for the majority of patients, response to different treatments cannot be accurately predicted. One of the key factors preventing further advances is the reductionist view of asthma as a single disease, which is forcing patients with different asthma subtypes into a single group for empiric treatment. This inevitably results in treatment failures and, for some, an unacceptable risk/benefit ratio. The approach to asthma today is an example of the traditional symptom (diagnosis)-based, one-size-fits-all approach rather than a stratified approach, and our guidelines-driven management based on a unitary diagnosis might not be the optimal way to deliver care. The only way to deliver stratified medicine and find a cure is through the understanding of asthma endotypes. We propose that the way to discover endotypes, biomarkers, and personalized treatments is through the iterative process based on interpretation of big data analytics from birth and patient cohorts, responses to treatments in randomized controlled trials, and in vitro mechanistic studies using human samples and experimental animal models, with technological and methodological advances at its core.

Advances in the aetiology, management, and prevention of acute asthma attacks in children

Acute attacks of wheeze or asthma are among the most common reasons for paediatric hospital attendance, and the incidence of severe attacks in the UK is among the highest in Europe. Although most attacks are driven by infection, there are important differences in the underlying pathophysiology of asthma and wheeze between preschool and school-aged children. Allergen sensitisation, airway eosinophilia, and type 2 inflammation predominate in older children, whereas phenotypes in preschool children are variable, often including non-atopic episodes driven by neutrophilic infection. Currently, a universal approach is adopted towards management, but there is a need to make objective assessments of airway function, inflammation, and infection, both during the attack and during stable periods, to identify treatable traits and to target therapy if outcomes are to be improved. An assessment of the risk factors that led to the attack and early, focused follow-up are essential to ensure attacks never occur again.

Asthma in the Preschool Age Child

Wheeze in preschool children (5 years of age and younger) is common. The majority of severe episodes are triggered by viral colds. Unlike atopic asthma in adults and young people, the underlying pathology of this condition is poorly understood, and the label of “preschool wheeze” should therefore not be regarded as a diagnosis but a description of symptoms. It is important to consider other causes of wheeze, but, for the most part, serious conditions such as cystic fibrosis and foreign body aspiration are associated with atypical features on careful history and examination. There remain significant uncertainties about the optimal management of children with this condition. Short-acting bronchodilators are indicated for the acute treatment of wheeze, and current evidence suggests that daily inhaled corticosteroid therapy is an effective preventive therapy, at least in a subgroup of children. Some trials suggest that preemptive therapy with inhaled corticosteroids may be as effective as regular inhaled corticosteroids. Since wheeze is intermittent for the majority of children, preemptive therapy is a logical approach. However, more studies are needed to confirm whether preemptive inhaled corticosteroids are as, or more, effective than regular preventer therapy.

Matched cohort study of therapeutic strategies to prevent preschool wheezing/asthma attacks

Background

An inhaled corticosteroid (ICS) or leukotriene receptor antagonist (LTRA) may prevent wheezing/asthma attacks in preschoolers with recurrent wheeze when added to short-acting β-agonist (SABA).

Objective

The aim of this historical matched cohort study was to assess the effectiveness of these treatments for preventing wheezing/asthma attacks.

Methods

Electronic medical records from the Optimum Patient Care Research Database were used to characterize a UK preschool population (1–5 years old) with two or more episodes of wheezing during 1 baseline year before first prescription (index date) of ICS or LTRA, or repeat prescription of SABA. Children initiating ICS or LTRA on the index date were matched 1:4 to those prescribed only SABA for age, sex, year of index prescription, mean baseline SABA dose, baseline attacks, baseline antibiotic prescriptions, and eczema diagnosis. Wheezing/asthma attacks (defined as asthma-related emergency attendance, hospital admission, or acute oral corticosteroid prescription) during 1 outcome year were compared using conditional logistic regression.

Results

Matched ICS and SABA cohorts included 990 and 3,960 children, respectively (61% male; mean [SD] age 3.2 [1.3] years), and matched LTRA and SABA cohorts included 259 and 1,036 children, respectively (65% male; mean [SD] age 2.6 [1.2] years). We observed no significant difference between matched cohorts in the odds of a wheezing/asthma attack: ICS vs SABA, OR (95% CI) 1.01 (0.85–1.19) and LTRA vs SABA, OR (95% CI) 1.28 (0.96–1.72).

Conclusion

We found no evidence that initiation of ICS or LTRA therapy is associated with fewer attacks during 1 outcome year than SABA alone for a heterogeneous group of preschool children with recurrent wheeze in the real-life clinical setting.

Daily inhaled corticosteroids or montelukast for preschoolers with asthma or recurrent wheezing: A systematic review

BACKGROUND

Most international asthma guidelines recommend that children ≤5 years with asthma or recurrent wheezing be treated with daily low- moderate dose inhaled corticosteroids (ICS) as the preferred controller and leukotriene receptor antagonists (LTRA) as alternative therapy. There is no systematic review comparing the efficacy of ICS versus LTRA monotherapy in this age group.

OBJECTIVE

To compare the efficacy of daily ICS versus LTRA in preschoolers with asthma or recurrent wheezing.

METHODS

Randomized, prospective, controlled trials published by December 2017, with a minimum of 3-month therapy with daily ICS versus LTRA were identified. The co-primary outcomes were the number of wheezing episodes and daily symptom score. Secondary outcomes included unscheduled emergency visits, need of rescue systemic corticosteroids (SC), hospitalization for exacerbations, lung function, and adverse effects.

RESULTS

Of 29 trials identified, six studies (n = 3204 patients, 62% males, age range: 6-54 months) met the inclusion criteria; two were at low risk of bias. Five pertained to children with asthma; one to those with recurrent wheezing. No outcomes were similarly reported in the six studies, preventing meta-analysis. Based on trials at lowest risk of bias and the largest open-labelled studies, ICS was associated with better control of symptoms and less exacerbations than LTRA. And also less need for rescue SC. Insufficient data of high quality prevented firm conclusions on other secondary outcomes.

CONCLUSIONS

In preschoolers with asthma or recurrent wheezing, daily ICS appears more effective than daily LTRA for improving symptom control and decreasing exacerbations, particularly those requiring rescue SC, although the magnitude of benefit remains to be quantified.

What Is the Role of Increasing Inhaled Corticosteroid Therapy in Worsening Asthma in Children?

The treatment of "yellow zone," or worsening, asthma in children remains controversial. The 2018 Global Initiative for Asthma strategy recommends increasing the dose of inhaled corticosteroid (ICS) for the short (1-2 weeks) or longer (3 months) term in children older than 5 years with worsening asthma. In contrast, the National Heart, Lung, and Blood Institute's Expert Panel Report 3 guideline for the diagnosis and management of asthma notes that doubling the dose of ICS therapy is "not sufficient" in worsening asthma, as does the Canadian Thoracic Society guideline on asthma management in children. Both guidelines do comment that higher than double dosing may be effective. In particular, the Expert Panel Report 3 guideline specifies that more than doubling the dose of ICS therapy may be useful in the emergency department management of worsening asthma, because it may prevent oral corticosteroid requirement. The Canadian Thoracic Society suggests that adolescents (older than 12 years) quadruple ICS maintenance dosing by 4- or 5-fold for 7 to 14 days with worsening asthma if there is a history of a severe exacerbation in the past year. All these recommendations were published before a recent, large randomized double-blind controlled trial by Jackson et al that further calls into question the efficacy of increased ICS dosing in worsening asthma in children. The goal of this Rostrum was to review available data and consider the role of increasing doses of ICS and potential alternative approaches to this common practice.

Preschool wheeze, genes and treatment

Preschool wheeze is a common but poorly understood cause of respiratory morbidity that is both distinct from and overlaps with infantile bronchiolitis and school age asthma. Attempts at classification by epidemiology, pathophysiology, therapeutic response and clinical phenotype are imperfect and yet fundamental to both treatment choice and research design. The four main therapeutic classes for preschool wheeze, namely beta₂ agonists, anticholinergics, corticosteroids and leukotriene modifiers are employed with variable and often scanty evidence base, with evidence for a genetic influence on response variations. The article will discuss the pharmacogenetics of the various options, summarise current treatment recommendations, and explore future research directions.

Management of asthma in children

This manuscript takes a challenging look at the management of asthma in childhood, in particular in the light of the recent Lancet commission. One of the central pillars of the Commission is the need to deliver personalized medicine for airway disease by deconstructing the airway into components of fixed and variable airflow obstruction, inflammation and infection. Before any treatment for asthma, a diagnostic workup is essential to exclude other conditions. A diagnosis of asthma needs to be based on objective evidence of bronchodilator sensitive variable airflow obstruction, eosinophilic airway inflammation and atopy. Most children with atopic asthma respond to low dose inhaled corticosteroids, sometimes requiring a long acting β-agonist. If the response is unsatisfactory, then, rather than escalate treatment, an approach for which there is little evidence, a full review of the child should be undertaken, including extrapulmonary comorbidities, adherence and adverse environmental influences. If these cannot or will not be addressed by the family, then further treatment including biologicals may be indicated. Asthma attacks are an important warning sign and should always be taken seriously, including a focused reassessment of all aspects of the management of the child. Finally, preschool children with wheeze can also be evaluated for eosinophilic airway inflammation using peripheral blood eosinophil count as a surrogate. It is essential that we start to deliver personalized medicine to children with airway disease.

Fifteen-minute consultation: An evidence-based approach to the child with preschool wheeze

Preschool wheeze is very common and its prevalence is increasing. It consumes considerable healthcare resources and has a major impact on children and their families due to significant morbidity associated with acute episodes.History taking is the main diagnostic instrument in the assessment of preschool wheeze. Diagnosis and management is complicated by a broad differential and associations with many other diseases and conditions that give rise to noisy breathing, which could be misinterpreted as wheeze. Several clinical phenotypes have been described but they have limitations and do not clearly inform therapeutic decisions. New insights in aetiopathogenesis modify treatment options and lay foundation for further research. An understanding of the approach and available evidence to assess and manage wheeze informs best patient care and use of resources.Our objective is to demonstrate a focused history, examination and management options in a preschool child with wheeze.

Early control treatment with montelukast in preschool children with asthma: A randomized controlled trial

BACKGROUND

While Japanese guideline recommends initial control treatment for preschool children with asthma symptoms more than once a month, Western guidelines do not. To determine whether control treatment with montelukast was more effective than as-needed β₂-agonists in this population, we conducted a randomized controlled trial.

METHODS

Eligible patients were children aged 1-5 years who had asthma symptoms more than once a month but less than once a week. Patients were randomly assigned in a 1:1 ratio to receive montelukast 4 mg daily for 48 weeks or as-needed β₂-agonists. The primary endpoint was the number of acute asthma exacerbations before starting step-up treatment with inhaled corticosteroids. This study is registered with the University Hospital Medical Information Network clinical trials registry, number UMIN000002219.

RESULTS

From September 2009 to November 2012, 93 patients (47 in the montelukast group and 46 in the no-controller group) were enrolled into the study. All patients were included in the analysis. During the study, 13 patients (28%) in the montelukast group and 23 patients (50%) in the no-controller group had acute exacerbations with the mean numbers of 0.9 and 1.9/year, respectively (P = 0.027). In addition, 10 (21%) and 19 (41%) patients received step-up treatment, respectively. Cumulative incidence of step-up treatment was significantly lower in the montelukast group (hazard ratio 0.45, 95% confidence interval 0.21 to 0.92; P = 0.033).

CONCLUSIONS

Montelukast is an effective control treatment for preschool children who had asthma symptoms more than once a month but less than once a week.

Management of preschool recurrent wheezing and asthma: a phenotype-based approach

PURPOSE OF REVIEW

The purpose of this review is to summarize the recent evidence on the management of preschool children with wheezing and asthma, and to propose a phenotype-based approach to the management of these children.

RECENT FINDINGS

Recent studies have begun to identify populations of preschool children that are likely to benefit from inhaled corticosteroids (ICS) therapy and defined ICS regimens: daily ICS in preschool children with persistent asthma, and pre-emptive high-dose intermittent ICS among preschool children with intermittent disease reduce the risk of exacerbation. In addition, among preschool children with mild persistent asthma, the presence of aeroallergen sensitivity and/or blood eosinophil counts of 300/μL or greater are predictors of good response to daily ICS therapy. Other studies identified intermittent azithromycin as a therapy to prevent, and potentially to treat, acute exacerbations.The uncertainty of the role of oral corticosteroids (OCS) as a therapy for acute exacerbations continues, as a recent meta-analysis showed that OCS did not prevent hospitalizations or urgent visits, and did not reduce the need for additional courses of OCS. Whereas previous epidemiologic studies suggested acetaminophen may increase risk of exacerbations, a clinical trial clearly demonstrated acetaminophen use, compared to ibuprofen use,does not increase exacerbation risk among preschool children with mild-persistent asthma.

SUMMARY

Recent studies have shown potential for phenotypic-driven therapies for the management of preschool children with asthma. Targeting airway bacteria has emerged as a promising therapeutic approach, but its effect on antibiotic resistance still needs to be investigated. Finally, more studies are required to evaluate if oral corticosteroids provide any benefits for acute episodic wheeze.

Understanding the applicability of results from primary care trials: lessons learned from applying PRECIS-2

OBJECTIVE

To compare two approaches for trial teams to apply PRECIS-2 to pragmatic trials: independent scoring and scoring following a group discussion.

STUDY DESIGN AND SETTING

We recruited multidisciplinary teams who were conducting or had conducted trials in primary care in collaboration with the Pragmatic Clinical Trials Unit, Queen Mary University of London. Each team carried out two rounds of scoring on the nine PRECIS-2 domains: first independently using an online version of PRECIS-2 and second following a discussion.

RESULTS

Seven teams took part in the study. Before the discussion, within-team agreement in scores was generally poor and not all raters were able to score all domains; agreement improved after the discussion. The PRECIS-2 wheels suggested that the trials were pragmatic, although some domains were more pragmatic than others.

CONCLUSION

PRECIS-2 can facilitate information exchange within trial teams. To apply PRECIS-2 successfully, we recommend a discussion between those with detailed understanding of what usual care is for the intervention, the trial's design including operational and technical aspects, and the PRECIS-2 domains. For some cluster-randomized trials, greater insight may be gained by plotting two PRECIS-2 wheels, one at the individual participant level and another at the cluster level.

Infantile wheeze: rethinking dogma

Wheeze is a common symptom in young children and is usually associated with viral illnesses. It is a major source of morbidity and is responsible for a high consumption of healthcare and economic resources worldwide. A few children have a condition resembling classical asthma. Rarer specific conditions may have a wheezy component and should be considered in the differential diagnosis. Over the last half century, there have been many circular discussions about the best way of managing preschool wheeze. In general, intermittent wheezing should be treated with intermittent bronchodilator therapy, and a controller therapy should be prescribed for a young child with recurrent wheezing only if positively indicated, and only then if carefully monitored for efficacy. Good multidisciplinary support, attention to environmental exposition and education are essential in managing this common condition. This article analyses the pathophysiological basis of wheezing in infancy and critically discusses the evolution of the scientific progress over time in this unique field of respiratory medicine.

A meta-analysis of montelukast for recurrent wheeze in preschool children

There is conflicting evidence of the effectiveness of montelukast in preschool wheeze. A recent Cochrane review focused on its use in viral-induced wheeze; however, such subgroups are unlikely to exist in real life and change with time, recently highlighted in an international consensus report. We have therefore sought to investigate the effectiveness of montelukast in all children with preschool wheeze (viral-induced and multiple-trigger wheeze). The PubMed, Cochrane Library, Ovid Medline and Ovid EMBASE were screened for randomised controlled trials (RCTs), examining the efficacy of montelukast compared with placebo in children with the recurrent preschool wheeze. The primary endpoint examined was frequency of wheezing episodes. Five trials containing 3960 patients with a preschool wheezing disorder were analysed. Meta-analyses of studies of intermittent montelukast showed no benefit in preventing episodes of wheeze (mean difference (MD) 0.07, 95% confidence interval (CI) -0.14 to 0.29; mean for montelukast 2.68 vs placebo 2.54 (p = 0.5)), reducing unscheduled medical attendances (MD -0.13, 95% CI -0.33 to 0.07; mean for montelukast 1.62 vs placebo 1.78 (p = 0.21)) and reducing oral corticosteroids (MD -0.06, 95% CI -0.16 to 0.02; mean for montelukast 0.35 vs placebo 0.36 (p = 0.25)). The pooled results of the continuous regimen showed no significant difference in the number of wheezing episodes between the montelukast and placebo groups (MD -0.40, 95% CI -1.00 to 0.19; mean for montelukast 2.05 vs placebo 2.37 (p = 0.18)).

CONCLUSIONS

This review highlights that the currently available evidence does not support the use of montelukast in preschool children with recurrent wheeze. We recommend further studies to investigate if a 'montelukast responder' phenotype exists, and how these can be easily identified in the clinical setting. What is Known: • Current guidelines recommend montelukast use in preschool children with recurrent wheeze. • A recent Cochrane review has found montelukast to be ineffective at reducing courses of oral corticosteroids for viral-induced wheeze. What is New: • This meta-analysis has examined all children with preschool wheeze and found that montelukast was not effective at preventing wheezing episodes or reducing unscheduled medical attendances. • A specific montelukast responder phenotype may exist, but such patients should be sought in larger multicentre RCTs.

Gu-Ben-Fang-Xiao decoction attenuates sustained airway inflammation by suppressing ER stress response in a murine asthma remission model of respiratory syncytial virus infection

ETHNOPHARMACOLOGICAL RELEVANCE

In recent years, asthma has increased dramatically in prevalence with a considerable economic burden all over the world. Long-term remission should be regarded as the promising and meaningful therapeutic goal in asthma management. However, the precise definition criteria and rational therapies for asthma remission have not been well-established. In academia, there is a consensus that even in those who develop asymptomatic remission of asthma, persistent airway inflammation is ubiquitous. Gubenfangxiao decoction (GBFXD) has been widely used in treating asthma remission stage for decades in the Jiangsu Province Hospital of Chinese Medicine, China. We previously demonstrated that GBFXD could downregulate the asthma susceptibility gene ORMDL3, a trigger of Endoplasmic reticulum (ER) stress and unfolded protein response (UPR).

AIM THIS STUDY

To investigate the involvement of ER stress and UPR in the anti-inflammatory effects of GBFXD in Respiratory Syncytial Virus (RSV)-OVA-induced asthma remission mice.

MATERIALS AND METHODS

Mice were orally administered GBFXD at three doses for 30 days after an RSV-OVA challenge. The levels of inflammation mediators in serum were measured using a Luminex assay and the amount of IFN-γ in lung homogenates was detected using ELISA. The splenic CD4+ and CD8+ T lymphocytes were counted using flow cytometric analysis. The mRNA and protein levels of asthma susceptibility gene ORMDL3, ER stress markers (BIP, CHOP), and three canonical UPR branches (PERK-eIF2a-ATF4, IRE1α-XBP1/IRE1α-JNK-AP1 and ATF6-SERCA2b signal pathways) were detected using real-time RT-PCR and western blot.

RESULTS

Histopathological analysis showed that the model group mice still exhibited a sustained airway inflammation even after suspending the OVA-challenge and RSV infections for 30 days. H&E staining results indicated that GBFXD could attenuate sustained airway inflammation. Decreased serum CXCL1 level and increased IFN-γ level in lung homogenate were observed after GBFXD treatment. Reductions in the number of splenic CD4+/CD8+ T lymphocytes were found after DEX treatment. We further confirmed the previous finding that GBFXD could downregulate the expression of ORMDL3. As a result of suppressed UPR, decreased ER stress markers and inhibited UPR branches (PERK and IRE1α signal pathway) were also observed through the significant reduction of signature mRNA and protein expressions after GBFXD treatment.

CONCLUSION

GBFXD can significantly attenuate RSV-OVA-induced persistent airway inflammation in murine asthma remission model. These effects may be mediated, at least partially, by inhibiting the activation of ER stress responses.

Asma infantil

El asma es la enfermedad crónica infantil más frecuente. El diagnóstico es fácil en la mayoría de las ocasiones por la aparición de episodios de disnea espiratoria con sibilancias reversibles espontáneamente o por el efecto de broncodilatadores. En el momento del diagnóstico, se requieren tres pruebas complementarias: las radiografías de tórax, las pruebas funcionales respiratorias y un estudio alergológico. El tratamiento de las exacerbaciones se basa en los beta2-adrenérgicos inhalados y, si es preciso, en la corticoterapia oral. El objetivo del tratamiento de fondo es mantener el control, prevenir las exacerbaciones y restaurar o mantener las funciones pulmonares normales. Se debe adaptar al nivel de control del asma y en él tiene un lugar destacado la corticoterapia inhalada y los broncodilatadores de acción prolongada. En los menores de tres años, el asma se diagnostica a partir de tres episodios de sibilancias. Se debe buscar la presencia de antecedentes particulares, de manifestaciones atípicas o persistentes y de anomalías en la radiografía de tórax para descartar las demás causas de manifestaciones sibilantes recidivantes. Cuando es necesario un tratamiento de fondo, se basa en la corticoterapia inhalada. Las cohortes prospectivas han permitido demostrar que la atopia, la gravedad clínica y la persistencia de una obstrucción clínica son los factores principales tanto de la persistencia como de la gravedad del asma durante la vida.

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.

Treatment of asthma in young children: evidence-based recommendations

In the present review, we focus on evidence-based data for the use of inhaled corticosteroids (ICS), leukotriene receptor antagonist (LTRA), long-acting beta2-agonits (LABA) and oral corticosteroids (OCS), with a special emphasis on well-performed randomized clinical trials (RCTs) and meta-analyses of such trials for the chronic management of asthma/wheeze in infants and preschoolers. Results: Seven meta-analyses and 14 RCTs were reviewed. Daily ICS should be the preferred drug for infants/preschoolers with recurrent wheezing, especially in asthmatics. For those with moderate or severe episodes of EVW, the use of high intermittent ICS doses significantly reduce the use of OCS. There is no evidence of effect of intermittent ICS at low-moderate dose in preschoolers with mild EVW episodes. In preschoolers with asthma, there were no significant differences between daily vs. intermittent ICS in terms of asthma exacerbations with insufficient power to conclude to equivalence; however, for other asthma control outcomes, daily ICS works significantly better than intermittent ICS for older children. Daily ICS is superior to daily or intermittent LRTA for reducing symptoms, preventing exacerbations, and improving lung function. No RCTs testing combination therapy with ICS and LABA (or LTRA) were published in infant/preschoolers. Parent-initiation of OCS at the first sign of symptoms is not effective in children with recurrent wheezing episode. In terms of ICS safety, growth suppression is dose and molecule-dependent but it’s effect is not cumulative beyond the first year of therapy and may be associated with some catch-up growth while on or off therapy. Linear growth must be monitored as individual susceptibility to ICS drugs may vary considerably.

Biomarkers to predict asthma in wheezing preschool children

Wheezing in preschool children is a very common symptom. An adequate prediction of asthma in these children is difficult and cannot be reliably assessed with conventional clinical tools. The study of potential predictive biomarkers in various media, ranging from invasive sampling (e.g. bronchoscopy) to non-invasive sampling (lung function testing and exhaled breath analysis), was comprehensively reviewed. The evolution in biomarker discovery has resulted in an 'omics' approach, in which hundreds of biomarkers in the field of genomics, proteomics, metabolomics, and 'breath-omics' can be simultaneously studied. First, results on gene expression and exhaled breath profiles in predicting an early asthma diagnosis are promising. However, many hurdles need to be overcome before clinical implementation is possible. To reliably predict asthma in a wheezing child, probably a holistic approach is needed, combining clinical information with blood sampling, lung function tests, and potentially exhaled breath analysis. The further development of predictive, non-invasive biomarkers may eventually improve an early asthma diagnosis in wheezing preschool children and assist clinicians in early treatment decision-making.

Recent advances in paediatric respiratory medicine

This review highlights important advances in paediatric respiratory medicine since 2014, excluding cystic fibrosis. It focuses mainly on the more common conditions, bronchopulmonary dysplasia, bronchiolitis and preschool wheezing, asthma, pneumonia and sleep, and highlights some of the rarer conditions such as primary ciliary dyskinesia and interstitial lung disease (ILD).

Preschool Wheezing Phenotypes

Wheezing in preschool children is very common, with a wide differential diagnosis. It is essential to be sure of the exact sound that parents are describing; the term ‘wheeze‘ is often applied to non-specific sounds. Structural airway disease such as vascular ring should be considered. Thereafter we propose that umbrella terms for preschool wheeze should be abandoned in favour of ‘Hargreave phenotyping’, in which the presence and extent of the components of infection, inflammation, variable airflow obstruction, and fixed airflow obstruction are determined as far as is possible, rather than using a general umbrella term such as ‘asthma’. The justification for this approach is that it leads to a logical approach to treatment in the disparate airway diseases presenting in the preschool years, and should hopefully prevent over-treatment with inhaled corticosteroids. If, despite this approach, doubt remains as to the nature of the airway disease, then a therapeutic trial of treatment is permissible, but it should be for a short defined period only. In any event, such children should be reviewed regularly to see if treatments need to be changed.

Diagnosis and management of asthma in preschoolers: A Canadian Thoracic Society and Canadian Paediatric Society position paper

Asthma often starts before six years of age. However, there remains uncertainty as to when and how a preschool-age child with symptoms suggestive of asthma can be diagnosed with this condition. This delays treatment and contributes to both short- and long-term morbidity. Members of the Canadian Thoracic Society Asthma Clinical Assembly partnered with the Canadian Paediatric Society to develop a joint working group with the mandate to develop a position paper on the diagnosis and management of asthma in preschoolers. In the absence of lung function tests, the diagnosis of asthma should be considered in children one to five years of age with frequent (≥8 days/month) asthma-like symptoms or recurrent (≥2) exacerbations (episodes with asthma-like signs). The diagnosis requires the objective document of signs or convincing parent-reported symptoms of airflow obstruction (improvement in these signs or symptoms with asthma therapy), and no clinical suspicion of an alternative diagnosis. The characteristic feature of airflow obstruction is wheezing, commonly accompanied by difficulty breathing and cough. Reversibility with asthma medications is defined as direct observation of improvement with short-acting ß2-agonists (SABA) (with or without oral corticosteroids) by a trained health care practitioner during an acute exacerbation (preferred method). However, in children with no wheezing (or other signs of airflow obstruction) on presentation, reversibility may be determined by convincing parental report of a symptomatic response to a three-month therapeutic trial of a medium dose of inhaled corticosteroids with as-needed SABA (alternative method), or as-needed SABA alone (weaker alternative method). The authors provide key messages regarding in whom to consider the diagnosis, terms to be abandoned, when to refer to an asthma specialist and the initial management strategy. Finally, dissemination plans and priority areas for research are identified.

Leukotriene receptor antagonists as maintenance and intermittent therapy for episodic viral wheeze in children

BACKGROUND

Episodic viral wheeze (EVW) associated with viral respiratory tract infections is a common reason for pre-school children to utilise health care resources and for carers to take time away from employment. About a third of children experience a wheezing episode before the age of five years. EVW therefore represents a significant public health problem. Many pre-school children only wheeze in association with viral infections and in such cases EVW appears to be a separate entity from atopic asthma. Some trials have explored the effectiveness of leukotriene receptor antagonists (LTRAs) as regular (maintenance) or episodic (intermittent) treatment in this context.

OBJECTIVES

To evaluate the evidence for the efficacy and safety of maintenance and intermittent LTRAs in the management of EVW in children aged one to six years.

SEARCH METHODS

We searched the Cochrane Airways Group register of trials with pre-specified terms. We performed additional searches by consulting the authors of identified trials, online trial registries of manufacturers' web sites, and reference lists of identified primary papers and reviews. Search results are current to June 2015.

SELECTION CRITERIA

We included randomised controlled trials with a parallel-group or cross-over (for intermittent LTRA only) design. Maintenance was considered as treatment for more than two months and intermittent as less than 14 days. EVW was defined as a history of at least one previous episode of wheezing in association with a viral respiratory tract infection in the absence of symptoms between episodes. As far as possible, relevant specific data were obtained from authors of studies that included children of a wider age group or phenotype.  

DATA COLLECTION AND ANALYSIS

Two authors independently assessed studies for inclusion in the review and assessed risk of bias. The primary outcome was number of children with one or more viral-induced episodes requiring one or more treatments with rescue oral corticosteroids. We analysed combined continuous data outcomes with the mean difference and dichotomous data outcomes with an odds ratio (OR).

MAIN RESULTS

We identified five studies eligible for inclusion in the review (one investigated maintenance treatment, three intermittent therapy and one had both maintenance and intermittent treatment arms) these included 3741 participants. Each study involved oral montelukast and was of good methodological quality, but differed in choice of outcome measures thus limiting our ability to aggregate data across studies. Only primary outcome and adverse event data are reported in this abstract.For maintenance treatment, specific data obtained from a single study, pertaining to children with only an EVW phenotype, showed no statistically significant group reduction in the number of episodes requiring rescue oral corticosteroids associated with daily montelukast versus placebo (OR 1.20, 95% CI 0.70 to 2.06, moderate quality evidence).For intermittent LTRA, pooled data showed no statistically significant reduction in the number of episodes requiring rescue oral steroids in children treated with LTRA versus placebo (OR 0.77, 95% CI 0.48 to 1.25, moderate quality evidence). Specific data for children with an EVW phenotype obtained from a single study of intermittent montelukast treatment showed a small, but statistically significant reduction in unscheduled medical attendances due to wheeze (RR 0.83, 95% CI 0.71 to 0.98).For maintenance compared to intermittent LTRA treatment no data relating to the primary outcome of the review were identified.There were no other significant group differences identified in other secondary efficacy outcomes for maintenance or intermittent LTRA treatment versus placebo, or maintenance versus intermittent LTRA treatment. We collected descriptive data on adverse events as reported by four of the five included studies, and rates were similar between treatment and placebo groups.Potential heterogeneity in the phenotype of participants within and across trials is a limitation of the evidence.

AUTHORS' CONCLUSIONS

In pre-school children with EVW, there is no evidence of benefit associated with maintenance or intermittent LTRA treatment, compared to placebo, for reducing the number of children with one or more viral-induced episodes requiring rescue oral corticosteroids, and little evidence of significant clinical benefit for other secondary outcomes. Therefore until further data are available, LTRA should be used with caution in individual children. When used, we suggest a therapeutic trial is undertaken, during which efficacy should be carefully monitored. It is likely that children with an apparent EVW phenotype are not a homogeneous group and that subgroups may respond to LTRA treatment depending on the exact patho-physiological mechanisms involved.