Severe Asthma in Children

Challenges in managing difficult-to-treat asthma in children: Stop, look, and listen

It is recognized that asthma places a significant economic burden on the United States, with a total cost of $81.9 billion total costs including costs incurred by absenteeism and mortality. Severe asthma places a large burden of morbidity on children and their caregivers, including severe exacerbations, medication side effects, increased missed school days leading to impaired school performance, and lower caregiver quality of life. Therefore, we need to take a careful look at how we can make asthma care more efficient and cost effective, especially for those children with severe asthma. The 2019 American Thoracic Society symposium reported in this theme issue presented four aspects of managing severe asthma in children that merit attention including patient variables that affect severe asthma, understanding patient behaviors around medications, the appropriate use of bronchoscopy in diagnosis and management of severe asthma, and also the rational use of biologic therapy. This editorial will summarize key points in each of these reviews and prompt a more careful reading of each contribution.

WITHDRAWN: Mometasone furoate for children with asthma: A meta-analysis

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Eosinophilic Asthma

Asthma endotypes are constantly evolving. Currently, there are no universally accepted criteria to define endotypes. The T_H2-high endotype can have either allergic or nonallergic underpinnings and is typically characterized by some degree of eosinophilic airway inflammation. Unbiased clustering analyses have led to the identification of pediatric and adult phenotypes characterized by T_H2 inflammation and associated endotypes with eosinophilic inflammation. Aspirin-exacerbated respiratory disease has also long been recognized as a unique asthma phenotype. An approach to identify these groups with biomarkers and subsequently choose a targeted therapeutic modality, particularly in severe disease requiring biologic agents, is outlined.

The Tempest: Difficult to Control Asthma in Adolescence

Severe asthma is associated with significant morbidity and is a highly heterogeneous disorder. Severe asthma in adolescence has some unique elements compared with the features of severe asthma a medical provider would see in younger children or adults. A specific focus on psychological issues and adherence highlights some of the challenges in the management of asthma in adolescents. Treatment of adolescents with severe asthma now includes 3 approved biologic phenotype-directed therapies. Therapies available to adults may be beneficial to adolescents with severe asthma. Research into predictors of specific treatment response by phenotypes is ongoing. Optimal treatment strategies are not yet defined and warrant further investigation.

Targeted Therapy for Severe Asthma in Children and Adolescents: Current and Future Perspectives

Severe asthma in children remains a significant issue. It places a heavy burden on affected individuals and society as a whole in terms of high morbidity, mortality, consumption of healthcare resources, and side effects from high-dose corticosteroid therapy. New, targeted biologic therapies for asthma have emerged as effective add-on options, complementing our expanding understanding of asthma phenotypes/endotypes and the underlying immunopathology of the disease spectrum. They include omalizumab, mepolizumab, reslizumab, benralizumab, and dupilumab. Omalizumab represents the first available therapeutic option for allergic asthma in patients as young as 6 years of age. Its efficacy and safety have been established by several randomized controlled trials specifically conducted in pediatric patients, leading to its final registration > 10 years ago. Three new interleukin (IL)-5 targeted agents, mepolizumab, reslizumab, and benralizumab, have been approved for the treatment of severe eosinophilic asthma starting from 6 years of age, and varying by country. More recently, dupilumab, a targeted agent against the IL-4 receptor α-chain, was approved for patients ≥12 years of age in the United States after pivotal trials were completed. The late-stage clinical testing of these targeted agents has mostly involved patients aged 12 years and up, and the application of those data to younger children can be inappropriate and carry risk. The efficacy and safety of these newer biologics in children should be supported by adequate research within this targeted age group. In this review, we will present the most recent evidence on these five biological therapies for severe asthma and will discuss dosage and administration, their efficacy, safety, and future prospects, with a focus on the pediatric age group, defined as age < 18 years.

Proportion of Severe Asthma Patients Eligible for Mepolizumab Therapy by Age and Age of Onset of Asthma

BACKGROUND

Mepolizumab is an anti-IL-5 antibody approved for the treatment of severe eosinophilic asthma. However, the prevalence of patients with severe asthma eligible for mepolizumab remains unknown, especially among children.

OBJECTIVE

To determine, in a population of patients with severe asthma from a tertiary referral center, the proportion of patients with an eosinophilic phenotype who would be eligible for mepolizumab, when stratified for the age of onset of asthma, and the prevalence of phenotypic features that favor mepolizumab therapy.

METHODS

An extensive database of 245 adults and children referred for severe asthma was used. The prevalence of severe asthma was estimated by using the European Respiratory Society/American Thoracic Society criteria. Patients with an eosinophilic uncontrolled phenotype qualified for mepolizumab.

RESULTS

In our cohort, 216 (88%) had severe asthma. Based on blood eosinophils of either greater than or equal to 150 cells/μL or greater than or equal to 300 cells/μL, 61%/41% had an eosinophilic phenotype, while 49%/34% were eligible for mepolizumab therapy. A greater percentage of adults (60%/47% of adults with asthma onset in adulthood [AoA] and 48%/26% adults with childhood-onset asthma [<18 years, CoA]) were eligible compared with children (33%/24%), for eosinophil counts of ≥150 and ≥300 cells/μL, respectively; P < .05. Compared with adults, children had a similar number of exacerbations while having better lung function (P < .05). Among adults, those with AoA were older, were more likely to have nasal polyps (28% vs 5%; P < .05), and had higher blood eosinophil counts (272 vs 150 cells/μL; P < .05) compared with those with CoA, with no difference in lung function noted between the 2 groups. Subjects showing greater than or equal to 500 eosinophils/μL, a strong indicator for mepolizumab therapy, had more nasal polyps, higher inhaled steroid dose, lower lung function, and AoA predominance than did those with less than 500 eosinophils/μL (P < .05).

CONCLUSIONS

A smaller percentage of children with severe asthma were eligible for mepolizumab compared with their adult peers. Severe AoA has distinct phenotypic features that favor treatment with mepolizumab, including greater eosinophilia and nasal polyposis, in contrast to CoA, which appears to have fewer features of type 2 mucosal inflammation.

Severe asthma in children-a review of definitions, epidemiology, and treatment options in 2019

Severe asthma is a relatively uncommon condition in children but one which causes morbidity, occasionally mortality, and is a challenging condition to manage. There are several definitions of severe asthma, which have a common theme of poor control despite high dose inhaled corticosteroid treatment. Depending on the definition chosen, the prevalence of severe childhood asthma may be up to 5% within populations with asthma. Collectively, there is some evidence that the treatments used in severe asthma are beneficial, but a solid evidence-base is lacking for many treatments and some treatments have recognized side effects. Evidence supporting the use of maintenance oral prednisolone and intramuscular triamcinolone is weak. Response to systemic corticosteroids is heterogeneous and recognizing phenotypes or endotypes may identify those most likely to gain maximal benefit from treatment. For children aged 6 to 11 years, the anti-IgE biologic omalizumab is effective and anti-IL-5 agent (mepolizumab) has recently been licenced in Europe (but not the US). Biologics, which are licenced for >11 year olds include omalizumab, mepolizumab, benralizumab, reslizumab, and dupilumab. There is plenty that the clinician can offer to the child and adolescent with severe asthma in 2019, including nontherapeutic and therapeutic interventions. To manage severe asthma, practitioners from broad specialities must establish and maintain a close therapeutic relationship with patients. Looking beyond 2019, more treatment options will emerge for severe childhood asthma, and clinical teams will need to continue weighing up benefits and harms.

Obese- and allergic-related asthma phenotypes among children across the United States

OBJECTIVES

Pediatric asthma is heterogeneous with phenotypes that reflect differing underlying inflammation and pathophysiology. Little is known about the national prevalence of certain obesity- and allergy-related asthma phenotypes or associated characteristics. We therefore assessed the national prevalence, risk factors, and caregiver-reported severity of four asthma phenotypes: not-allergic-not-obese, allergic-not-obese, obese-not-allergic, and allergic-and-obese.

METHODS

We analyzed data from the 2007-2008 National Survey of Children's Health (NSCH) of 10-17 year-olds with caregiver-reported asthma. We described sociodemographic and health risk factors of each phenotype and then applied logistic and ordinal regression models to identify associated risk factors and level of severity of the phenotypes.

RESULTS

Among 4427 children with asthma in this NSCH cohort, the association between race and phenotype was statistically significant (p < 0.0001); white children with asthma were most likely to have allergic-not-obese asthma while black and Hispanic children with asthma were most likely to have the obese-nonallergic phenotype (p < 0.001). Attention-deficit disorder/attention-deficit hyperactivity disorder was more likely to be present in allergic-not-obese children (odds ratio (OR) 1.50, confidence interval (CI) 1.14-1.98, p = 0.004). The phenotype with the highest risk for more severe compared to mild asthma was the obese-and-allergic asthma phenotype (OR 3.34, CI 2.23-5.01, p < 0.001).

CONCLUSIONS

Allergic-not-obese asthma comprised half of our studied asthma phenotypes, while obesity-related asthma (with or without allergic components) comprised one-fifth of asthma phenotypes in this cohort representative of the US population. Children with both obese and allergic asthma are most likely to have severe asthma. Future management of childhood asthma might consider more tailoring of treatment and management plans based upon different childhood asthma phenotypes.

Severe asthma in children: Evaluation and management

Severe asthma in children is associated with significant morbidity. Children with severe asthma are at increased risk for adverse outcomes including medication-related side effects, life-threatening exacerbations, and impaired quality of life. It is important to differentiate between severe therapy resistant asthma and difficult-to-treat asthma due to comorbidities. The most common problems that need to be excluded before a diagnosis of severe asthma can be made are poor medication adherence, poor medication technique or incorrect diagnosis of asthma. Difficult to treat asthma is a much more common reason for persistent symptoms and exacerbations and can be managed if comorbidities are clearly addressed. Children with persistent symptoms and exacerbations despite correct inhaler technique and good medical adherence to standard Step 4 asthma therapies according to the guidelines^1,2, should be referred to an asthma specialist with expertise in severe asthma.

Academic achievement of adolescents with asthma or atopic disease

Background

Over a fifth of children and adolescents suffer with asthma or atopic disease. It is unclear whether asthma impacts academic performance in children and adolescents, and little is known about the association of eczema, food allergy or hayfever and academic performance.

Objective

To examine whether asthma, eczema, food allergy or hayfever impacts on adolescent academic performance and to assess the role of unmeasured confounding.

Methods

This study used the Childhood and Adolescent Twin Study of Sweden cohort born 1992‐1998. At age 9‐12 years, parents reported on their child's ever or current asthma, eczema, food allergy and hayfever status (n = 10 963). At age 15, linked national patient and medication register information was used to create current and ever asthma definitions including severe and uncontrolled asthma for the same children. Academic outcomes in Grade 9 (age 15‐16 years) included: eligibility for high school (Grades 10‐12), and total mark of the best 16 subject units, retrieved from the Grade 9 academic register. Whole cohort analyses adjusted for known covariates were performed, and co‐twin control analyses to assess unmeasured confounders.

Results

There were no associations found for asthma or food allergy at 9‐12 years and academic outcomes in adolescence. In addition, at age 15, there were no statistically significant associations with current, ever, severe or uncontrolled asthma and academic outcomes. Eczema and hayfever at age 9‐12 years were found to be positively associated with academic outcomes; however, co‐twin control analyses did not support these findings, suggesting the main analyses may be subject to unmeasured confounding.

Conclusion and clinical relevance

Having asthma or an atopic disease during childhood or adolescence does not negatively impact on academic performance. This information can be used by clinicians when talking with children and parents about the implications of living with asthma or atopic disease.

Omalizumab and unmet needs in severe asthma and allergic comorbidities in Japanese children

Childhood asthma is one condition within a family of allergic diseases, which includes allergic rhinitis, atopic dermatitis, and food allergy, among others. Omalizumab is an anti-IgE antibody therapy that was approved in Japan for children with asthma and added to the Japanese pediatric asthma guidelines in 2017. This review highlights the Japanese clinical perspectives in pediatric allergic asthma, and consideration for allergic comorbidities, and reflects on omalizumab clinical trials in progress to present comprehensive future opportunities.

Epidemiology of Asthma in Children and Adults

Asthma is a globally significant non-communicable disease with major public health consequences for both children and adults, including high morbidity, and mortality in severe cases. We have summarized the evidence on asthma trends, environmental determinants, and long-term impacts while comparing these epidemiological features across childhood asthma and adult asthma. While asthma incidence and prevalence are higher in children, morbidity, and mortality are higher in adults. Childhood asthma is more common in boys while adult asthma is more common in women, and the reversal of this sex difference in prevalence occurs around puberty suggesting sex hormones may play a role in the etiology of asthma. The global epidemic of asthma that has been observed in both children and adults is still continuing, especially in low to middle income countries, although it has subsided in some developed countries. As a heterogeneous disease, distinct asthma phenotypes, and endotypes need to be adequately characterized to develop more accurate and meaningful definitions for use in research and clinical settings. This may be facilitated by new clustering techniques such as latent class analysis, and computational phenotyping methods are being developed to retrieve information from electronic health records using natural language processing (NLP) algorithms to assist in the early diagnosis of asthma. While some important environmental determinants that trigger asthma are well-established, more work is needed to define the role of environmental exposures in the development of asthma in both children and adults. There is increasing evidence that investigation into possible gene-by-environment and environment-by-environment interactions may help to better uncover the determinants of asthma. Therefore, there is an urgent need to further investigate the interrelationship between environmental and genetic determinants to identify high risk groups and key modifiable exposures. For children, asthma may impair airway development and reduce maximally attained lung function, and these lung function deficits may persist into adulthood without additional progressive loss. Adult asthma may accelerate lung function decline and increase the risk of fixed airflow obstruction, with the effect of early onset asthma being greater than late onset asthma. Therefore, in managing asthma, our focus going forward should be firmly on improving not only short-term symptoms, but also the long-term respiratory and other health outcomes.

Does allergy explain why some children have severe asthma?

Asthma is a common disease in childhood with a minority of affected children having severe therapy-resistant asthma (STRA). Children with STRA can be differentiated from those with mild-moderate disease by greater allergic sensitization, increased eosinophilic airway inflammation, increased airway remodelling and reduced corticosteroid responsiveness. The aetiology of STRA in children is multifactorial but allergy seems to play a key role. Many children with asthma have coexisting allergic disease, and severe rhinitis seems to be an important driver of STRA in children. Allergies to foods, moulds, pollen and pets have also been associated with severe asthma exacerbations. Identifying allergens that are driving asthma symptoms in children with STRA may provide additional strategies for improving their disease control. Avoidance strategies may be possible. Additional monoclonal antibody therapy with Omalizumab or Mepolizumab may be helpful in children with clinically important polysensitization.

Severe Asthma: Challenges and Pitfalls in Management

A small but significant subset of asthmatic children show a lack of response to standard management, resulting in further intensification of therapy to optimise symptom control and may remain symptomatic despite maximal therapy. Severe asthma results in increased risk of adverse outcomes whilst contributing significantly to the economic burden on the nation's health resources. The ERS / ATS guidelines were published in 2014 and form the basis of identifying, evaluating and managing severe asthmatic children. However, much of this evidence is extrapolated from adult studies and may be inappropriate in children as unlike adults, children have a more atopic phenotype. Severe asthma is an umbrella term and may represent several overlapping heterogeneous wheezing entities. This chapter aims at discussing the strategies employed in managing severe asthmatic children with particular focus on diagnostic challenges and management pitfalls. Particular emphasis is put into the logical and systematic approach to a child with severe asthma and describes the multidisciplinary approach to manage these children. Finally, this chapter describes the novel therapies available in children and in adults in managing this challenging condition.

Prospects for Monoclonal Antibody Therapy in Pediatric Asthma

PURPOSE OF REVIEW

The profile of biologic therapies for asthma is growing rapidly. We discuss how to match the proper pediatric patient with the most effective therapy.

RECENT FINDINGS

Currently available biologic therapies are most effective in patients with T2 high asthma. Newer drugs are currently being studied which target TSLP and interleukin 33. These newer drugs may provide options for asthmatics who do not respond to the current anti-IgE, anti-IL5, and anti-IL4/13 therapies. Asthma is a heterogeneous disease which can be driven by different inflammatory mediators in different patients. To select the most effective biologic therapy for a pediatric patient, the asthma phenotype must first be determined. The steep cost of biologics limits their use, which makes proper pairing of patient to therapy even more crucial. Presently, several therapies exist for T2 high asthma, but it is hoped in the future that development of drugs effective for T2 low asthmatics will be available as well.

Difficult vs. Severe Asthma: Definition and Limits of Asthma Control in the Pediatric Population

Evaluating the degree of disease control is pivotal when assessing a patient with asthma. Asthma control is defined as the degree to which manifestations of the disease are reduced or removed by therapy. Two domains of asthma control are identified in the guidelines: symptom control and future risk of poor asthma outcomes, including asthma attacks, accelerated decline in lung function, or treatment-related side effects. Over the past decade, the definition and the tools of asthma control have been substantially implemented so that the majority of children with asthma have their disease well controlled with standard therapies. However, a small subset of asthmatic children still requires maximal therapy to achieve or maintain symptom control and experience considerable morbidity. Childhood uncontrolled asthma is a heterogeneous group and represents a clinical and therapeutic challenge requiring a multidisciplinary systematic assessment. The identification of the factors that may contribute to the gain or loss of control in asthma is essential in differentiating children with difficult-to-treat asthma from those with severe asthma that is resistant to traditional therapies. The aim of this review is to focus on current concept of asthma control, describing monitoring tools currently used to assess asthma control in clinical practice and research, and evaluating comorbidities and modifiable and non-modifiable factors associated with uncontrolled asthma in children, with particular reference to severe asthma.

The pediatric asthma yardstick: Practical recommendations for a sustained step-up in asthma therapy for children with inadequately controlled asthma

Current asthma guidelines recommend a control-based approach to management involving assessment of impairment and risk followed by implementation of treatment strategies individualized according to the patient's needs and preferences. However, for children with asthma, achieving control can be elusive. Although tools are available to help children (and families) track and manage day-to-day symptoms, when and how to implement a longer-term step-up in care is less clear. Furthermore, treatment is challenged by the 3 age groups of childhood-adolescence (12-18 years old), school age (6-11 years old), and young children (≤5 years old)-and what works for 1 age group might not be the best approach for another. The Pediatric Asthma Yardstick provides an in-depth assessment of when and how to step-up therapy for the child with not well or poorly controlled asthma. Development of this tool follows others in the Yardstick series, presenting patient profiles and step-up strategies based on current guidance documents, but modified according to newer data and the authors' combined clinical experience. The objective is to provide clinicians who treat children with asthma practical and clinically relevant recommendations for each step-up and each intervention, with the intent of helping practitioners better treat their pediatric patients with asthma, particularly those who do not always respond to recommended therapies.

The Journal of Allergy and Clinical Immunology: In Practice 2017 Year in Review

An impressive number of clinically impactful studies and reviews were published in The Journal of Allergy and Clinical Immunology: In Practice in 2017. As a service to our readers, the editors provide this Year in Review article to highlight and contextualize the advances published over the past year. We include information from articles on asthma, allergic rhinitis, rhinosinusitis, immunotherapy, atopic dermatitis, contact dermatitis, food allergy, anaphylaxis, drug hypersensitivity, urticarial/angioedema, eosinophilic disorders, and immunodeficiency. Within each topic, epidemiologic findings are presented, relevant aspects of prevention are described, and diagnostic and therapeutic advances are enumerated. Treatments discussed include behavioral therapy, allergen avoidance therapy, positive and negative effects of pharmacologic therapy, and various forms of immunologic and desensitization management. We hope this review will help readers consolidate and use this extensive and practical knowledge for the benefit of patients.

New approaches for identifying and testing potential new anti-asthma agents

INTRODUCTION

Asthma is a chronic disease with significant heterogeneity in clinical features, disease severity, pattern of underlying disease mechanisms, and responsiveness to specific treatments. While the majority of asthmatic patients are controlled by standard pharmacological strategies, a significant subgroup has limited therapeutic options representing a major unmet need. Ongoing asthma research aims to better characterize distinct clinical phenotypes, molecular endotypes, associated reliable biomarkers, and also to develop a series of new effective targeted treatment modalities. Areas covered: The expanding knowledge on the pathogenetic mechanisms of asthma has allowed researchers to investigate a range of new treatment options matched to patient profiles. The aim of this review is to provide a comprehensive and updated overview of the currently available, new and developing approaches for identifying and testing potential treatment options for asthma management. Expert opinion: Future therapeutic strategies for asthma require the identification of reliable biomarkers that can help with diagnosis and endotyping, in order to determine the most effective drug for the right patient phenotype. Furthermore, in addition to the identification of clinical and inflammatory phenotypes, it is expected that a better understanding of the mechanisms of airway remodeling will likely optimize asthma targeted treatment.