Aeroallergen Sensitization, Serum IgE, and Eosinophilia as Predictors of Response to Omalizumab Therapy During the Fall Season Among Children with Persistent Asthma

Updated review of omalizumab to treat uncontrolled pediatric allergic asthma

Asthma has been increasingly recognized as a heterogeneous disease; however, many patients with asthma have allergic asthma (AA). Inhaled corticosteroids and other inhalers have been integral in treating many symptoms of asthma, but these medications do not completely address the disease's underlying mechanism. Pediatric asthma imposes a substantial burden on patients and the health care system. Omalizumab is consistently recognized as an important consideration for add-on therapy in pediatric patients with AA in published guidelines from multiple international societies such as the Global Initiative for Asthma. Since our last report in 2017, the amount of information available regarding the safety and effectiveness of omalizumab in pediatric patients with AA has continued to accumulate and is supported by several observational and real-world data studies. A number of studies including real-world effectiveness studies, post hoc analyses of clinical trial data, and systematic literature reviews and meta-analyses have since expanded the published data on the efficacy and safety of omalizumab in pediatric patients. In this article, we present an updated review of this literature focused on omalizumab therapy in children with AA.

Therapeutic relevance of eosinophilic inflammation and airway viral interactions in severe asthma

The role of eosinophils in airway inflammation and asthma pathogenesis is well established, with raised eosinophil counts in blood and sputum associated with increased disease severity and risk of asthma exacerbation. Conversely, there is also preliminary evidence suggesting antiviral properties of eosinophils in the airways. These dual roles for eosinophils are particularly pertinent as respiratory virus infections contribute to asthma exacerbations. Biologic therapies targeting key molecules implicated in eosinophil-associated pathologies have been approved in patients with severe asthma and, therefore, the effects of depleting eosinophils in a clinical setting are of considerable interest. This review discusses the pathological and antiviral roles of eosinophils in asthma and exacerbations. We also highlight the significant reduction in asthma exacerbations seen with biologic therapies, even at the height of the respiratory virus season. Furthermore, we discuss the implications of these findings in relation to the role of eosinophils in inflammation and antiviral responses to respiratory virus infection in asthma.

Epigenetic patient stratification via contrastive machine learning refines hallmark biomarkers in minoritized children with asthma

Identifying and refining clinically significant patient stratification is a critical step toward realizing the promise of precision medicine in asthma. Several peripheral blood hallmarks, including total peripheral blood eosinophil count (BEC) and immunoglobulin E (IgE) levels, are routinely used in asthma clinical practice for endotype classification and predicting response to state-of-the-art targeted biologic drugs. However, these biomarkers appear ineffective in predicting treatment outcomes in some patients, and they differ in distribution between racially and ethnically diverse populations, potentially compromising medical care and hindering health equity due to biases in drug eligibility. Here, we propose constructing an unbiased patient stratification score based on DNA methylation (DNAm) and utilizing it to refine the efficacy of hallmark biomarkers for predicting drug response. We developed Phenotype Aware Component Analysis (PACA), a novel contrastive machine-learning method for learning combinations of DNAm sites reflecting biomedically meaningful patient stratifications. Leveraging whole-blood DNAm from Latino (discovery; n=1,016) and African American (replication; n=756) pediatric asthma case-control cohorts, we applied PACA to refine the prediction of bronchodilator response (BDR) to the short-acting β2-agonist albuterol, the most used drug to treat acute bronchospasm worldwide. While BEC and IgE correlate with BDR in the general patient population, our PACA-derived DNAm score renders these biomarkers predictive of drug response only in patients with high DNAm scores. BEC correlates with BDR in patients with upper-quartile DNAm scores (OR 1.12; 95% CI [1.04, 1.22]; P=7.9 e-4) but not in patients with lower-quartile scores (OR 1.05; 95% CI [0.95, 1.17]; P=0.21); and IgE correlates with BDR in above-median (OR for response 1.42; 95% CI [1.24, 1.63]; P=3.9e-7) but not in below-median patients (OR 1.05; 95% CI [0.92, 1.2]; P=0.57). These results hold within the commonly recognized type 2 (T2)-high asthma endotype but not in T2-low patients, suggesting that our DNAm score primarily represents an unknown variation of T2 asthma. Among T2-high patients with high DNAm scores, elevated BEC or IgE also corresponds to baseline clinical presentation that is known to benefit more from biologic treatment, including higher exacerbation scores, higher allergen sensitization, lower BMI, more recent oral corticosteroids prescription, and lower lung function. Our findings suggest that BEC and IgE, the traditional asthma biomarkers of T2-high asthma, are poor biomarkers for millions worldwide. Revisiting existing drug eligibility criteria relying on these biomarkers in asthma medical care may enhance precision and equity in treatment.

Ratio of plasma IL-13/TNF- ∝ and CXCL10/CCL17 predicts mepolizumab and omalizumab response in asthma better than eosinophil count or immunoglobulin E level

To date, most studies to identify biomarkers associated with response to the anti-interleukin 5 agent, mepolizumab, and to the anti-immunoglobulin E agent, omalizumab have focused on clinically available biomarkers, such as the peripheral blood eosinophil counts (BEC) and total immunoglobulin E (IgE). However, these biomarkers often have low predictive accuracy, with many patients with eosinophilic or allergic asthma failing to demonstrate clinical response to mepolizumab or omalizumab respectively. In this study, we evaluated the association of baseline pre-biologic plasma levels of 26 cytokines and chemokines, including T-helper 1 (Th1)-, Th2-, Th17-related cytokines, and their ratios with subsequent clinical response to mepolizumab or omalizumab. We defined clinical response as a reduction in the baseline annual exacerbation rate by half or more over the one-year period following initiation of the biologic. Baseline levels of plasma IL-13 were differentially elevated in responders versus non-responders to mepolizumab and plasma CXCL10 levels were differentially elevated in responders to omalizumab. The ratio of IL-13/TNF-α had the best sensitivity and specificity in predicting response to mepolizumab and CXCL10/CCL17 to omalizumab, and these performed better as predictive biomarkers of response than BEC and IgE. Cytokines and chemokines associated with airway eosinophilia, allergic inflammation, or Th2 inflammation, such as IL-13 and CXCL10, may be better predictors of clinical response to mepolizumab and omalizumab, than IL-5 or IgE, the targets of mepolizumab and omalizumab.

The Evolution of Scientific Knowledge in Childhood Asthma over Time: A Surprising History

Asthma is a disease that has been described since the times of Hammurabi. However, it is only since the 1960s that effective therapeutic strategies have been available. Pathogenic mechanisms underlying the disease have been deeply studied, contributing to creating a "patient-specific asthma" definition. Biological drugs have been approved over the last twenty years, improving disease management in patients with severe asthma via a "precision medicine-driven approach". This article aims to describe the evolution of scientific knowledge in childhood asthma, focusing on the most recent biological therapies and their indications for patients with severe asthma.

Unanswered questions on the use of biologics in pediatric asthma

The emergence of biologic therapies for the management of asthma has been a revolutionary change in our capacity to manage this disease. Since the launch of omalizumab, several other biologics have been marketed or are close to being marketed, suggesting that a plethora of monoclonal antibodies can be expected in the coming years. This will facilitate the transition to the paradigm of personalized medicine, but on the other hand will decisively further complicate the choice of the most appropriate treatment, in the absence of reliable enough biological markers. For these reasons, along with the relatively short time of use with these treatments, there are recurrently arising questions for which there are not even moderately documented answers, and for which the only solution must be based, with all reservations, on the combination of indirect evidence and expertise. In this paper, we attempt to address such questions, providing relevant commentaries and considering the whole width of the evidence base.

Case Report: Off-label treatment of idiopathic hypereosinophilic syndrome with Omalizumab

Idiopathic hypereosinophilic syndrome (IHES) is a rare disease characterized by causeless persistent hypereosinophilia and eosinophilia-associated end-organ damage. Current treatment modalities don't meet the needs due to adverse events of steroids as first-line therapy and the limited efficacy of second-line treatments, underscoring the need for new therapeutic strategies. Here we presented two cases of IHES with different clinical manifestations that were both refractory to corticosteroids. Patient #1 experienced rashes, cough, pneumonia, and steroid-induced side effects. Patient #2 had severe gastrointestinal symptoms attributed to hypereosinophilia. They both had high levels of serum IgE, didn't respond well to second-line treatments of interferon-α (IFN-α) and imatinib, and Mepolizumab was not accessible. We then innovatively switched to Omalizumab, an anti-IgE monoclonal antibody approved for allergic asthma and chronic idiopathic urticaria. Patient #1 was treated with Omalizumab 600 mg per month for 20 months; his absolute eosinophil count (AEC) decreased significantly and has stabilized at around 1.0×10⁹/L for 17 months, with complete relief from erythra and cough. Patient #2 recovered promptly from severe diarrhea with a sharp drop in AEC after 3 months of treatment with omalizumab at 600 mg per month. Therefore, we concluded that Omalizumab may be a seminal therapeutic strategy for IHES patients who are refractory to corticosteroids, whether as long-term management of AEC or as an urgent intervention to address severe symptoms caused by eosinophilia.

Influence of Genetics on the Response to Omalizumab in Patients with Severe Uncontrolled Asthma with an Allergic Phenotype

Omalizumab is a monoclonal antibody indicated for the treatment of severe uncontrolled asthma with an allergic phenotype. Its effectiveness could be influenced by clinical variables and single nucleotide polymorphisms (SNPs) in one or more of the genes involved in the mechanism of action and process of response to omalizumab, and these could be used as predictive biomarkers of response. We conducted an observational retrospective cohort study that included patients with severe uncontrolled allergic asthma treated with omalizumab in a tertiary hospital. Satisfactory response after 12 months of treatment was defined as (1) Reduction ≥ 50% of exacerbations or no exacerbations, (2) Improvement of lung function ≥ 10% FEV1, and (3) Reduction ≥ 50% of OCS courses or no OCS. Polymorphisms in the FCER1A (rs2251746, rs2427837), FCER1B (rs1441586, rs573790, rs1054485, rs569108), C3 (rs2230199), FCGR2A (rs1801274), FCGR2B (rs3219018, rs1050501), FCGR3A (rs10127939, rs396991), IL1RL1 (rs1420101, rs17026974, rs1921622), and GATA2 (rs4857855) genes were analyzed by real-time polymerase chain reaction (PCR) using TaqMan probes. A total of 110 patients under treatment with omalizumab were recruited. After 12 months of treatment, the variables associated with a reduction in exacerbations were the absence of polyposis (odds ratio [OR] = 4.22; 95% confidence interval [CI] = 0.95-19.63), IL1RL1 rs17026974-AG (OR = 19.07; 95% CI = 1.27-547), and IL1RL1 rs17026974-GG (OR = 16.76; 95% CI = 1.22-438.76). Reduction in oral corticosteroids (OCS) was associated with age of starting omalizumab treatment (OR = 0.95; 95% CI = 0.91-0.99) and blood eosinophil levels > 300 cells/µL (OR = 2.93; 95% CI = 1.01-9.29). Improved lung function showed a relationship to the absence of chronic obstructive pulmonary disease (COPD) (OR = 12.16; 95% CI = 2.45-79.49), FCGR2B rs3219018-C (OR = 8.6; 95% CI = 1.12-117.15), GATA2 rs4857855-T (OR = 15.98; 95% CI = 1.52-519.57) and FCGR2A rs1801274-G (OR = 13.75; 95% CI = 2.14-142.68; AG vs. AA and OR = 7.46; 95% CI = 0.94-89.12; GG vs. AA). Meeting one response criterion was related to FCER1A rs2251746-TT (OR = 24; 95% CI = 0.77-804.57), meeting two to age of asthma diagnosis (OR = 0.93; 95% CI = 0.88-0.99), and meeting all three to body mass index (BMI) < 25 (OR = 14.23; 95% CI = 3.31-100.77) and C3 rs2230199-C (OR = 3; 95% CI = 1.01-9.92). The results of this study show the possible influence of the polymorphisms studied on the response to omalizumab and the clinical benefit that could be obtained by defining predictive biomarkers of treatment response.

Cockroach allergy: Understanding complex immune responses to develop novel therapies

Cockroach allergy is associated with the development of asthma. The identification of cockroach allergens, which began in the 1990 s, is an ongoing process that has led to the current listing of 20 official allergen groups in the WHO/IUIS Allergen Nomenclature database. The function and structure of some of these allergens has been determined and define their natural delivery into the environment and their allergenicity. Analysis of antigenic determinants by X-ray crystallography and rational design of site-directed mutagenesis led to the identification of IgE binding sites for the design of molecules with reduced IgE reactivity and T cell modulatory capacity. New developments in recent years include component analyses of B and T cell reactivity and a recent cockroach immunotherapy trial, CRITICAL, that will contribute to understand the immune response to cockroach and to define future directions for cockroach allergy diagnosis and immunotherapy.

Impact of Omalizumab in Patients with Severe Uncontrolled Asthma and Possible Predictive Biomarkers of Response: A Real-Life Study

Most patients with asthma can control their symptoms with a basic standard of medical care and with maintenance and rescue medication. However, between 5% and 10% of asthmatics worldwide do not achieve control of their symptoms and have recurrent exacerbations and respiratory difficulties. The objective of the study was the real-life evaluation of the clinical improvement of patients with severe eosinophilic asthma treated with omalizumab, together with the search for biomarkers associated with the response. An observational retrospective cohort study was conducted that included patients with severe uncontrolled allergic asthma being treated with omalizumab. Three types of response were evaluated: lower use of oral corticosteroids, improvement in lung function, and reduction in exacerbations. A total of 110 patients under treatment with omalizumab were included, with a mean age of 48 ± 16 years. After 12 months had elapsed, significant reductions were found in the number of exacerbations, use of oral cortico-steroids and doses of inhaled corticosteroids (p < 0.001). Lung function and asthma control improved significantly (p < 0.001; p = 0.004) and eosinophil levels were significantly reduced (p = 0.004). Low scores in the Asthma Control Test were associated with the oral corticosteroid-saving effect; lower previous FEV1 levels and absence of chronic obstructive pulmonary disease (COPD) were related to improvement in lung function, and prior FEV1 values higher than 80% and absence of gastroesophageal reflux disease (GERD) with a reduction in exacerbations. The results of this study confirm the clinical benefit obtained after the introduction of omalizumab and the possible predictive biomarkers of response to the treatment.

Pediatric obesity and severe asthma: Targeting pathways driving inflammation

Asthma affects more than 300 million people of all ages worldwide, including about 10-15% of school-aged children, and its prevalence is increasing. Severe asthma (SA) is a particular and rare phenotype requiring treatment with high-dose inhaled corticosteroids plus a second controller and/or systemic glucocorticoid courses to achieve symptom control or remaining "uncontrolled" despite this therapy. In SA, other diagnoses have been excluded, and potential exacerbating factors have been addressed. Notably, obese asthmatics are at higher risk of developing SA. Obesity is both a major risk factor and a disease modifier of asthma in children and adults: two main "obese asthma" phenotypes have been described in childhood with high or low levels of Type 2 inflammation biomarkers, respectively, the former characterized by early onset and eosinophilic inflammation and the latter by neutrophilic inflammation and late-onset. Nevertheless, the interplay between obesity and asthma is far more complex and includes obese tissue-driven inflammatory pathways, mechanical factors, comorbidities, and poor response to corticosteroids. This review outlines the most recent findings on SA in obese children, particularly focusing on inflammatory pathways, which are becoming of pivotal importance in order to identify selective targets for specific treatments, such as biological agents.

A Pragmatic Primary Practice Approach to Using Specific IgE in Allergy Testing in Asthma Diagnosis, Management, and Referral

Asthma afflicts an estimated 339 million people globally and is associated with ill health, disability, and early death. Strong risk factors for developing asthma are genetic predisposition and environmental exposure to inhaled substances that may provoke allergic reactions. Asthma guidelines recommend identifying causal or trigger allergens with specific IgE (sIgE) testing after a diagnosis of asthma has been made. Allergy testing with sIgE targets subpopulations of patients considered at high risk, such as those with frequent exacerbations, emergency visits or hospitalizations, or uncontrolled symptoms. Specific recommendations apply to preschool children, school-age children, patients with persistent or difficult-to-control asthma, patients needing oral corticosteroids or high-dose inhaled steroids, patients seeking understanding and guidance about their disease, and candidates for advanced therapies (biologics, allergen immunotherapy). Allergen skin testing is common in specialized settings but less available in primary care. Blood tests for total and sIgE are accessible and yield quantifiable results for tested allergens, useful for detecting sensitization. Results are interpreted in the context of the patient’s clinical presentation, age, and relevant allergen exposures. Incorporating sIgE testing into asthma management adds objective information to identify specific allergies and can guide personalized treatment plans, which reinforce patient-doctor communication. Test results can also be used to predict exacerbations and response to therapies. Additional diagnostic information can be gleaned from (i) eosinophil count ≥300 μL, which significantly increases the odds of having exacerbations, and emerging eosinophil biomarkers (eg, eosinophil-derived neurotoxin), which can be measured in plasma or serum samples, and (ii) fractional exhaled nitric oxide (FeNO), with values ≥25 ppb regarded as the cutoff for diagnosis, evaluating inhaled corticosteroid response, and of probable response to anti-IgE, anti-IL4 and anti-IL5 receptor biologics. Referral to asthma/allergy specialists is warranted when the initial diagnosis is uncertain, and when asthma symptoms, impairment, or exacerbations are repeated or severe.

Prevention of omalizumab for seasonal allergic rhinoconjunctivitis: a retrospective cohort study

Background

Allergic rhinoconjunctivitis (ARC) is an allergic disease that is characterized by conjunctival and nasal symptoms such as edema and congestion of conjunctiva, rhinorrhea, sneezing, and blocked nose. Seasonal ARC (SARC) is usually induced by seasonal allergens and often occurs at specific times during the year. Traditional treatments of SARC include nasal corticosteroids, antihistamines, and mast cell membrane stabilizers. Biological agents such as omalizumab have also been proved effective in the treatment of SARC.

Objectives

We aim to certify the preventative efficacy of omalizumab for SARC and explore its influence factors.

Methods

Medical records of 64 SARC patients were retrospectively analyzed, and generalized linear models were used to analyze influence factors of efficacy of omalizumab.

Results

Compared with forepassed pollen season without omalizumab treatment, the combined symptom and medication score (CSMS) of ARC with pre-seasonal omalizumab was significantly lower (with omalizumab: 0.67[0.00,1.83], without omalizumab: 4.00[2.83,4.96], p<0.001, max score=6). Subgroup analysis was conducted to explore the influence factor of preventative efficacy of omalizumab. The CSMS with omalizumab treatment were not significantly different among different age, gender, dosage, number of injections, and injection date subgroups (p>0.05).

Conclusion

Pre-seasonal omalizumab treatment could significantly relieve SARC related symptoms and reduce medication use. This preventative efficacy would not be influenced by the dosage and number of injections of omalizumab. A single dose of 150mg omalizumab could achieve a satisfactory outcome.

Predictive biomarkers for response to omalizumab in patients with severe allergic asthma: a meta-analysis

BACKGROUND

Predicting omalizumab treatment response has been a challenge and significant aspect for selecting suitable severe allergic asthma patients for omalizumab use.

OBJECTIVE

To determine which domains of pretreatment baseline characteristics predict omalizumab treatment response among asthmatic patients.

METHODS

Electronic bases were searched for eligible studies that reported potential biomarkers that could predict omalizumab responsiveness and efficacy. Patients who accepted omalizumab treatment were stratified into responders and non-responders. WMD, OR, and their 95%CI were used to access the differences between those omalizumab receivers. Sensitivity analysis and subgroup analysis were conducted for potential heterogeneity.

RESULTS

A total of 41 studies evaluating efficacy predictors of omalizumab were included in this meta-analysis. The pooled results showed that omalizumab responders had significantly younger age in the adult subgroup, higher pretreatment total serum IgE level, percent predicted FEV₁ and FeNO than that non-responder. We further confirmed that higher blood eosinophil counts and total serum IgE levels are useful markers for selecting asthma patients who may benefit more from omalizumab.

CONCLUSIONS

Pre-treatment blood eosinophil counts and total serum IgE level can be a useful efficacy predictor in selecting allergic asthma patients for omalizumab treatment.

Longitudinal asthma exacerbation phenotypes in the Korean childhood asthma study cohort

BACKGROUND

Asthma exacerbation (AE) leads to social and economic costs and long-term adverse outcomes. We aimed to predict exacerbation-prone asthma (EPA) in children.

METHODS

The Korean childhood Asthma Study (KAS) is a prospective nationwide pediatric asthma cohort of children aged 5-15 years followed every 6 months. Patients with AE during the 6 months prior to all three visits, with AE prior to one or two visits, and without AE prior to any visit were defined as having EPA, exacerbation-intermittent asthma (EIA), and exacerbation-resistant asthma (ERA), respectively. Risk factors and prediction models of EPA were explored.

RESULTS

Of the 497 patients who completed three visits, 42%, 18%, and 15% had exacerbations prior to visits 1, 2, and 3 and 5%, 47%, and 48% had EPA, EIA, and ERA, respectively. Univariate and multivariable logistic regression revealed forced expiratory volume in 1 s (FEV1) z-score, forced vital capacity (FVC) z-score, white blood cell (WBC) count, and asthma control test (ACT) score as relevant EPA risk factors. The EPA prediction model comprised FVC z-score, WBC count, ACT score, sex, and parental education level (area under the receiver operating characteristic curve [AUROC] 0.841 [95% confidence interval (CI): 0.728-0.954]).

CONCLUSION

With appropriate management, AE decreases over time, but persistent AEs may occur. Apart from asthma control level, baseline lung function and WBC count predicted EPA.

Effectiveness and Safety Studies of Omalizumab in Children and Adolescents With Moderate-To-Severe Asthma

BACKGROUND

Omalizumab is currently approved for the treatment of moderate-to-severe allergic asthma in patients 6 years and older.

OBJECTIVE

To assess the effectiveness and safety of subcutaneous omalizumab as an add-on therapy option for moderate-severe allergic asthma in patients aged 6-20 years old.

METHODS

The studies published from July, 1970 to May, 2021 were searched from the electronic databases which followed keywords: ("anti-IgE" OR "anti-immunoglobulin E" OR "anti-IgE antibody" OR "omalizumab" OR "rhuMAb-E25" OR "Xolair") AND "asthma" AND ("child" OR "children" OR "adolescents" OR "youth" OR "teenager" OR "kids" OR "pediatric"). Thirteen studies were pooled to determine the effectiveness and safety of omalizumab. Efficacy endpoints were evaluated using a fixed-effects model or a random-effects model depending on heterogeneity. Safety endpoints were evaluated by odds ratio.

RESULTS

Thirteen studies were included. In this meta-analysis, our results showed that fractional exhaled nitric oxide and asthma control test scores were significantly improved with omalizumab treatment. Serum immunoglobulin E was also decreased in children with moderate-to-severe asthma after treatment with omalizumab. The analysis found that there was no significant difference between pre-and post-treatment in forced expiratory volume in one second/ forced vital capacity ratio, forced expiratory flow between 25 and 75% of vital capacity, or FEV1. Overall, more adverse events occurred with omalizumab compared to placebo. However, the degree was mild to moderate.

CONCLUSION

This meta-analysis indicates that omalizumab is safe and effective to treat children and adolescents with moderate-to-severe asthma.