Eosinophils in bronchial mucosa of asthmatics after allergen challenge: effect of anti-IgE treatment

Changes in Small Airway Physiology Measured by Impulse Oscillometry in Subjects with Allergic Asthma Following Methacholine and Inhaled Allergen Challenge

Background: Small airway dysfunction (SAD) is associated with impaired asthma control, but small airway physiology is not routinely assessed in clinical practice. Previously, we demonstrated impulse oscillometry (IOS)-defined small airway dysfunction (SAD) in dual responders (DRs) upon bronchoprovocation with various allergens. Aim: To compare lung physiology using spirometry and IOS following bronchoprovocation with methacholine (M) and inhaled house dust mite (HDM) extract in corticosteroid-naïve asthmatic subjects. Methods: Non-smoking, clinically stable HDM-allergic asthmatic subjects (18-55 years, FEV1 > 70% of pred.) underwent an M and inhaled HDM challenge on two separate days. Airway response was measured by IOS and spirometry, until a drop in FEV1 ≥ 20% (PC20) from post-diluent baseline (M), and up to 8 h post-allergen (HDM). Early (EAR) and late asthmatic response (LAR) to HDM were defined as ≥20% and ≥15% fall in FEV1 from post-diluent baseline during 0-3 h and 3-8 h post-challenge, respectively. IOS parameters (Rrs5, Rrs20, Rrs5-20, Xrs5, AX, Fres) were compared between mono-responders (MRs: EAR only) and dual responders (EAR + LAR). Correlations between maximal % change from baseline after the two airway challenges were calculated for both FEV1 and IOS parameters. Results: A total of 47 subjects were included (11 MRs; 36 DRs). FEV1 % predicted did not differ between MR and DR at baseline, but DR had lower median PC20M (0.84 (range 0.07-7.51) vs. MR (2.15 (0.53-11.29)); p = 0.036). During the LAR, DRs had higher IOS values than MRs. For IOS parameters (but not for FEV1), the maximal % change from baseline following M and HDM challenge were correlated. PC20M was inversely correlated with the % change in FEV1 and the % change in Xrs5 during the LAR (r= -0.443; p = 0.0018 and r= -0.389; p = 0.0075, respectively). Conclusions: During HDM-induced LAR, changes in small airway physiology can be non-invasively detected with IOS and are associated with increased airway hyperresponsiveness and changes in small airway physiology during methacholine challenge. DRs have a small airways phenotype, which reflects a more advanced airway disease.

Asthma Biologics Across the T2 Spectrum of Inflammation in Severe Asthma: Biomarkers and Mechanism of Action

Airway inflammation, a hallmark feature of asthma, drives many canonical features of the disease, including airflow limitation, mucus plugging, airway remodeling, and hyperresponsiveness. The T2 inflammatory paradigm is firmly established as the dominant mechanism of asthma pathogenesis, largely due to the success of inhaled corticosteroids and biologic therapies targeting components of the T2 pathway, including IL-4, IL-5, IL-13, and thymic stromal lymphopoietin (TSLP). However, up to 30% of patients may lack signatures of meaningful T2 inflammation (ie, T2 low). In T2-low asthma patients, T2 inflammation may be masked due to anti-inflammatory treatments or may be highly variable depending on exposure to common asthma triggers such as allergens, respiratory infections, and smoke or pollution. The epithelium and epithelial cytokines (TSLP, IL-33) are increasingly recognized as upstream drivers of canonical T2 pathways and as modulators of various effector cells, including mast cells, eosinophils, and neutrophils, which impact the pathological manifestations of airway smooth muscle hypertrophy, hypercontractility, and airway hyperresponsiveness. Approved biologics for severe asthma target several distinct mechanisms of action, leading to differential effects on the spectrum of T2 inflammation, inflammatory biomarkers, and treatment efficacy (reducing asthma exacerbations, improving lung function, and diminishing symptoms). The approved anti-asthma biologics primarily target T2 immune pathways, with little evidence suggesting a benefit of targeting non-T2 asthma-associated mediators. Indeed, many negative results challenge current assumptions about the etiology of non-T2 asthma and raise doubts about the viability of targeting popular alternative inflammatory pathways, such as T17. Novel data have emerged from the use of biologics to treat various inflammatory mediators and have furthered our understanding of pathogenic mechanisms that drive asthma. This review discusses inflammatory pathways that contribute to asthma, quantitatively outlines effects of available biologics on biomarkers, and summarizes data and challenges from clinical trials that address non-T2 mechanisms of asthma.

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.

Airway hyperresponsiveness in asthma: The role of the epithelium

Airway hyperresponsiveness (AHR) is a key clinical feature of asthma. The presence of AHR in people with asthma provides the substrate for bronchoconstriction in response to numerous diverse stimuli, contributing to airflow limitation and symptoms including breathlessness, wheeze, and chest tightness. Dysfunctional airway smooth muscle significantly contributes to AHR and is displayed as increased sensitivity to direct pharmacologic bronchoconstrictor stimuli, such as inhaled histamine and methacholine (direct AHR), or to endogenous mediators released by activated airway cells such as mast cells (indirect AHR). Research in in vivo human models has shown that the disrupted airway epithelium plays an important role in driving inflammation that mediates indirect AHR in asthma through the release of cytokines such as thymic stromal lymphopoietin and IL-33. These cytokines upregulate type 2 cytokines promoting airway eosinophilia and induce the release of bronchoconstrictor mediators from mast cells such as histamine, prostaglandin D2, and cysteinyl leukotrienes. While bronchoconstriction is largely due to airway smooth muscle contraction, airway structural changes known as remodeling, likely mediated in part by epithelial-derived mediators, also lead to airflow obstruction and may enhance AHR. In this review, we outline the current knowledge of the role of the airway epithelium in AHR in asthma and its implications on the wider disease. Increased understanding of airway epithelial biology may contribute to better treatment options, particularly in precision medicine.

IgE directly affects eosinophil migration in chronic rhinosinusitis with nasal polyps through CCR3 and predicts the efficacy of omalizumab

BACKGROUND

Whether IgE affects eosinophil migration in chronic rhinosinusitis with nasal polyps (CRSwNP) remains largely unclear. Moreover, our understanding of local IgE, eosinophils, and omalizumab efficacy in CRSwNP remains limited.

OBJECTIVE

We investigated whether IgE acts directly on eosinophils and determined its role in omalizumab therapy.

METHODS

Eosinophils and their surface receptors were detected by hematoxylin and eosin staining and flow cytometry. IgE and its receptors, eosinophil peroxidase (EPX), eosinophilic cationic protein, and CCR3 were detected by immunohistochemistry and immunofluorescence. Functional analyses were performed on blood eosinophils and polyp tissues. Logistic regression was performed to screen for risk factors. Receiver operating characteristic curve was generated to evaluate the accuracy.

RESULTS

Both FcεRI and CD23 were expressed on eosinophils. The expression of FcεRI and CD23 on eosinophil in nasal polyp tissue was higher than in peripheral blood (both P < .001). IgE and EPX colocalized in CRSwNP. IgE directly promoted eosinophil migration by upregulating CCR3 in CRSwNP but not in healthy controls. Omalizumab and lumiliximab were found to be effective in restraining this migration, indicating CD23 was involved in IgE-induced eosinophil migration. Both IgE+ and EPX+ cells were significantly reduced after omalizumab treatment in those who experienced response (IgE+ cells, P = .001; EPX+ cells, P = .016) but not in those with no response (IgE+ cells, P = .060; EPX+ cells, P = .151). Baseline IgE+ cell levels were higher in those with response compared to those without response (P = .024). The baseline local IgE+ cell count predicted omalizumab efficacy with an accuracy of 0.811.

CONCLUSIONS

IgE directly promotes eosinophil migration, and baseline local IgE+ cell counts are predictive of omalizumab efficacy in CRSwNP.

Effect of Biologic Therapies on Airway Hyperresponsiveness and Allergic Response: A Systematic Literature Review

Background

Airway hyperresponsiveness (AHR) is a key feature of asthma. Biologic therapies used to treat asthma target specific components of the inflammatory pathway, and their effects on AHR can provide valuable information about the underlying disease pathophysiology. This review summarizes the available evidence regarding the effects of biologics on allergen-specific and non-allergen-specific airway responses in patients with asthma.

Methods

We conducted a systematic review in accordance with Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) guidelines, including risk-of-bias assessment. PubMed and Ovid were searched for studies published between January 1997 and December 2021. Eligible studies were randomized, placebo-controlled trials that assessed the effects of biologics on AHR, early allergic response (EAR) and/or late allergic response (LAR) in patients with asthma.

Results

Thirty studies were identified for inclusion. Bronchoprovocation testing was allergen-specific in 18 studies and non-allergen-specific in 12 studies. Omalizumab reduced AHR to methacholine, acetylcholine or adenosine monophosphate (3/9 studies), and reduced EAR (4/5 studies) and LAR (2/3 studies). Mepolizumab had no effect on AHR (3/3 studies), EAR or LAR (1/1 study). Tezepelumab reduced AHR to methacholine or mannitol (3/3 studies), and reduced EAR and LAR (1/1 study). Pitrakinra reduced LAR, with no effect on AHR (1/1 study). Etanercept reduced AHR to methacholine (1/2 studies). No effects were observed for lebrikizumab, tocilizumab, efalizumab, IMA-638 and anti-OX40 ligand on AHR, EAR or LAR; benralizumab on LAR; tralokinumab on AHR; and Ro-24-7472 on AHR or LAR (all 1/1 study each). No dupilumab or reslizumab studies were identified.

Conclusion

Omalizumab and tezepelumab reduced EAR and LAR to allergens. Tezepelumab consistently reduced AHR to methacholine or mannitol. These findings provide insights into AHR mechanisms and the precise effects of asthma biologics. Furthermore, findings suggest that tezepelumab broadly targets allergen-specific and non-allergic forms of AHR, and the underlying cells and mediators involved in asthma.

Cytokine-targeted therapies for asthma and COPD

Asthma affects over 300 million people worldwide and its prevalence is increasing. COPD is the third leading cause of death globally. Asthma and COPD are complex inflammatory diseases of the airways in which impaired host defences lead to increased susceptibility to pathogens, pollutants and allergens. There is a constant interplay between host and the environment. Environmental exposures can alter the lung microbiome and influence the development of sensitisation by disrupting normal immunoregulation. The underlying airway inflammation in severe asthma is heterogeneous, with upregulation of type 2 cytokines in most cases but increased neutrophilic inflammation and activated T-helper 17 mediated immunity in others. COPD may also comprise several different phentoypes that are driven by different molecular mechanisms or endotypes. This disease heterogeneity is affected by comorbidities, treatments and environmental exposures. Recent intervention trials have shed light on the pathways beyond type 2 inflammation that can lead to beneficial outcomes versus potentially deleterious effects. We have made a great deal of progress over the last 10 years in terms of immunology and the pathophysiology of asthma and this has led to the development of novel treatments and major improvements in severe asthma outcomes. In COPD, however, no targeted treatments have demonstrated great improvements. This article reviews the mechanism of action and efficacy of the available biologics in asthma and COPD.

Emerging therapies targeting eosinophil-mediated inflammation in chronic allergic conjunctivitis

Ocular allergy remains a significant burden to the population while the treatment for the severe, chronic forms of allergic conjunctivitis remains largely limited to non-specific immunosuppressants. Eosinophils are central to the pathophysiology and sustaining the immunologic response found in the chronic forms of ocular allergy such as vernal keratoconjunctivitis and atopic keratoconjunctivitis. Several mediators of eosinophil recruitment, chemotaxis, adhesion, activation, and survival have been identified that offer potential therapeutic targets for ocular allergy. Based on preclinical and clinical data available in both ocular and non-ocular allergy studies, these emerging therapies warrant further investigation in reducing the severity of disease in patients with chronic ocular allergy.

Anti-IL-5 therapies for asthma

BACKGROUND

This is the second update of previously published reviews in the Cochrane Library (2015, first update 2017). Interleukin-5 (IL-5) is the main cytokine involved in the proliferation, maturation, activation and survival of eosinophils, which cause airway inflammation and are a classic feature of asthma. Studies of monoclonal antibodies targeting IL-5 or its receptor (IL-5R) suggest they reduce asthma exacerbations, improve health-related quality of life (HRQoL) and lung function in appropriately selected patients, justifying their inclusion in the latest guidelines.

OBJECTIVES

To compare the effects of therapies targeting IL-5 signalling (anti-IL-5 or anti-IL-5Rα) with placebo on exacerbations, health-related quality-of-life (HRQoL) measures and lung function in adults and children with chronic asthma, and specifically in those with eosinophilic asthma refractory to existing treatments.

SEARCH METHODS

We searched CENTRAL, MEDLINE, Embase, and two trials registers, manufacturers' websites, and reference lists of included studies. The most recent search was 7 February 2022.

SELECTION CRITERIA

We included randomised controlled trials comparing mepolizumab, reslizumab and benralizumab versus placebo in adults and children with asthma.

DATA COLLECTION AND ANALYSIS

Two review authors independently extracted data and analysed outcomes using a random-effects model. We used standard methods expected by Cochrane.

MAIN RESULTS

Seventeen studies on about 7600 participants met the inclusion criteria. Six used mepolizumab, five used reslizumab, and six used benralizumab. One study using benralizumab was terminated early due to sponsor decision and contributed no data. The studies were predominantly on people with severe eosinophilic asthma, which was similarly but variably defined. One was in children aged 6 to 17 years; nine others included children over 12 years but did not report results by age group separately. We deemed the overall risk of bias to be low, with all studies contributing data of robust methodology. We considered the certainty of the evidence for all comparisons to be high overall using the GRADE scheme, except for intravenous (IV) mepolizumab and subcutaneous (SC) reslizumab because these are not currently licensed delivery routes. The anti-IL-5 treatments assessed reduced rates of 'clinically significant' asthma exacerbation (defined by treatment with systemic corticosteroids for three days or more) by approximately half in participants with severe eosinophilic asthma on standard care (at least medium-dose inhaled corticosteroids (ICS)) with poorly controlled disease (either two or more exacerbations in the preceding year or Asthma Control Questionnaire (ACQ) score of 1.5 or more), except for reslizumab SC. The rate ratios for these effects were 0.45 (95% confidence interval (CI) 0.36 to 0.55; high-certainty evidence) for mepolizumab SC, 0.53 (95% CI 0.44 to 0.64; moderate-certainty evidence) for mepolizumab IV, 0.43 (95% CI 0.33 to 0.55; high-certainty evidence) for reslizumab IV, and 0.59 (95% CI 0.52 to 0.66; high-certainty evidence) for benralizumab SC. Non-eosinophilic participants treated with benralizumab also showed a significant reduction in exacerbation rates, an effect not seen with reslizumab IV, albeit in only one study. No data were available for non-eosinophilic participants treated with mepolizumab. There were improvements in validated HRQoL scores with all anti-IL-5 agents in severe eosinophilic asthma. This met the minimum clinically important difference (MCID) for the broader St. George's Respiratory Questionnaire (SGRQ; 4-point change) for benralizumab only, but the improvement in the ACQ and Asthma Quality of Life Questionnaire (AQLQ), which focus on asthma symptoms, fell short of the MCID (0.5 point change for both ACQ and AQLQ) for all of the interventions. The evidence for an improvement in HRQoL scores in non-eosinophilic participants treated with benralizumab and reslizumab was weak, but the tests for subgroup difference were negative. All anti-IL-5 treatments produced small improvements in mean pre-bronchodilator forced expiratory flow in one second (FEV1) of between 0.08 L and 0.15 L in eosinophilic participants, which may not be sufficient to be detected by patients. There were no excess serious adverse events with any anti-IL-5 treatment; in fact, there was a reduction in such events with benralizumab, likely arising from fewer asthma-related hospital admissions. There was no difference compared to placebo in adverse events leading to discontinuation with mepolizumab or reslizumab, but significantly more discontinued benralizumab than placebo, although the absolute numbers were small (42/2026 (2.1%) benralizumab versus 11/1227 (0.9%) placebo). The implications for efficacy or adverse events are unclear.

AUTHORS' CONCLUSIONS

Overall this analysis supports the use of anti-IL-5 treatments as an adjunct to standard care in people with severe eosinophilic asthma and poor symptom control. These treatments roughly halve the rate of asthma exacerbations in this population. There is limited evidence for improved HRQoL scores and lung function, which may not meet clinically detectable levels. The studies did not report safety concerns for mepolizumab or reslizumab, or any excess serious adverse events with benralizumab, although there remains a question over adverse events significant enough to prompt discontinuation. Further research is needed on biomarkers for assessing treatment response, optimal duration and long-term effects of treatment, risk of relapse on withdrawal, non-eosinophilic patients, children (particularly under 12 years), comparing anti-IL-5 treatments to each other and, in patients meeting relevant eligibility criteria, to other biological (monoclonal antibody) therapies. For benralizumab, future studies should closely monitor rates of adverse events prompting discontinuation.

Omalizumab Restores Response to Corticosteroids in Patients with Eosinophilic Chronic Rhinosinusitis and Severe Asthma

Eosinophilic chronic rhinosinusitis (ECRS), which is a subgroup of chronic rhinosinusitis with nasal polyps, is characterized by eosinophilic airway inflammation extending across both the upper and lower airways. Some severe cases are refractory even after endoscopic sinus surgery, likely because of local steroid insensitivity. Although real-life studies indicate that treatment with omalizumab for severe allergic asthma improves the outcome of coexistent ECRS, the underlying mechanisms of omalizumab in eosinophilic airway inflammation have not been fully elucidated. Twenty-five patients with ECRS and severe asthma who were refractory to conventional treatments and who received omalizumab were evaluated. Nineteen of twenty-five patients were responsive to omalizumab according to physician-assessed global evaluation of treatment effectiveness. In the responders, the levels of peripheral blood eosinophils and fractionated exhaled nitric oxide (a marker of eosinophilic inflammation) and of CCL4 and soluble CD69 (markers of eosinophil activation) were reduced concomitantly with the restoration of corticosteroid sensitivity. Omalizumab restored the eosinophil-peroxidase-mediated PP2A inactivation and steroid insensitivity in BEAS-2B. In addition, the local inflammation simulant model using BEAS-2B cells incubated with diluted serum from each patient confirmed omalizumab’s effects on restoration of corticosteroid sensitivity via PP2A activation; thus, omalizumab could be a promising therapeutic option for refractory eosinophilic airway inflammation with corticosteroid resistance.

The effect of tezepelumab on airway hyperresponsiveness to mannitol in asthma (UPSTREAM)

RATIONALE AND OBJECTIVES

Thymic stromal lymphopoietin (TSLP), an epithelial upstream cytokine, initiates production of type-2 (T2) cytokines with eosinophilia and possibly airway hyperresponsiveness (AHR) in asthma.This study aimed to determine whether tezepelumab (a human monoclonal antibody targeting TSLP) decreases AHR and airway inflammation in patients with symptomatic asthma on maintenance treatment with inhaled corticosteroids.

METHODS AND MEASUREMENTS

In this double-blind, placebo-controlled randomised trial adult patients with asthma and AHR to mannitol received either 700 mg tezepelumab or placebo intravenously at 4-week intervals for 12 weeks. AHR to mannitol was assessed, and a bronchoscopy was performed at baseline and after 12 weeks. The primary outcome was the change in AHR from baseline to week-12 and secondary outcomes were changes in airway inflammation.

RESULTS

Forty patients were randomised to receive either tezepelumab (n=20) or placebo (n=20). The mean change in PD15 with tezepelumab was 1.9 DD (95% CI 1.2 to 2.5) versus 1·0 (95% CI 0.3 to 1.6) with placebo; p=0.06. Nine (45%) tezepelumab and three (16%) placebo patients had a negative PD₁₅ test at week-12, p=0.04. Airway tissue and BAL eosinophils decreased by 74% (95% CI -53 to -86) and 75% (95% CI -53 to -86) respectively with tezepelumab compared with an increase of 28% (95% CI -39 to 270) and a decrease of 7% (95% CI -49 to 72) respectively with placebo, p=0.004 and p=0.01.

CONCLUSIONS

Inhibiting TSLP-signalling with tezepelumab reduced the proportion of patients with AHR and decreased eosinophilic inflammation in BAL and airway tissue.

EAACI Biologicals Guidelines-Recommendations for severe asthma

Severe asthma imposes a significant burden on patients, families and healthcare systems. Management is difficult, due to disease heterogeneity, co-morbidities, complexity in care pathways and differences between national or regional healthcare systems. Better understanding of the mechanisms has enabled a stratified approach to the management of severe asthma, supporting the use of targeted treatments with biologicals. However, there are still many issues that require further clarification. These include selection of a certain biological (as they all target overlapping disease phenotypes), the definition of response, strategies to enhance the responder rate, the duration of treatment and its regimen (in the clinic or home-based) and its cost-effectiveness. The EAACI Guidelines on the use of biologicals in severe asthma follow the GRADE approach in formulating recommendations for each biological and each outcome. In addition, a management algorithm for the use of biologicals in the clinic is proposed, together with future approaches and research priorities.

Chronic Rhinosinusitis with Nasal Polyps: Targeting IgE with Anti-IgE Omalizumab Therapy

Chronic rhinosinusitis with nasal polyps (CRSwNP) is a complex, clinically heterogeneous and persistent inflammatory disorder of the upper airway. Detailed mechanistic insights into disease pathogenesis are lacking, but it is now accepted that local tissue IgE driven T2-high inflammatory pathways are critical to disease. The recent CRSwNP Phase 3 POLYP1 and POLYP2 replicate studies of blocking IgE with omalizumab confirmed rapid improvements in all clinical parameters of sinonasal disease, confirming a pivotal role for IgE driven inflammatory pathways in CRSwNP. This review summarises the biology of IgE in relation to CRSwNP. Insight into how IgE may drive CRSwNP is evaluated in the context of clinical improvements seen with omalizumab. The need for further studies using a broader patient and biomarker specific groups to aid more precise drug-patient selection alongside more detailed mechanistic studies of omalizumab in CRSwNP is highlighted.

CASCADE: a phase 2, randomized, double-blind, placebo-controlled, parallel-group trial to evaluate the effect of tezepelumab on airway inflammation in patients with uncontrolled asthma

BACKGROUND

Patients with severe, uncontrolled asthma, particularly those with a non-eosinophilic phenotype, have a great unmet need for new treatments that act on a broad range of inflammatory pathways in the airway. Tezepelumab is a human monoclonal antibody that blocks the activity of thymic stromal lymphopoietin, an epithelial cytokine. In the PATHWAY phase 2b study (NCT02054130), tezepelumab reduced exacerbations by up to 71% in adults with severe, uncontrolled asthma, irrespective of baseline eosinophilic inflammatory status. This article reports the design and objectives of the phase 2 CASCADE study.

METHODS

CASCADE is an ongoing exploratory, phase 2, randomized, double-blind, placebo-controlled, parallel-group study aiming to assess the anti-inflammatory effects of tezepelumab 210 mg administered subcutaneously every 4 weeks for 28 weeks in adults aged 18-75 years with uncontrolled, moderate-to-severe asthma. The primary endpoint is the change from baseline to week 28 in airway submucosal inflammatory cells (eosinophils, neutrophils, T cells and mast cells) from bronchoscopic biopsies. Epithelial molecular phenotyping, comprising the three-gene-mean technique, will be used to assess participants' type 2 (T2) status to enable evaluation of the anti-inflammatory effect of tezepelumab across the continuum of T2 activation. Other exploratory analyses include assessments of the impact of tezepelumab on airway remodelling, including reticular basement membrane thickening and airway epithelial integrity. At the onset of the COVID-19 pandemic, the protocol was amended to address the possibility that site visits would be limited. The amendment allowed for: at-home dosing of study drug by a healthcare professional, extension of the treatment period by up to 6 months so patients are able to attend an onsite visit to undergo the end-of-treatment bronchoscopy, and replacement of final follow-up visits with a virtual or telephone visit.

DISCUSSION

CASCADE aims to determine the mechanisms by which tezepelumab improves clinical asthma outcomes by evaluating the effect of tezepelumab on airway inflammatory cells and remodelling in patients with moderate-to-severe, uncontrolled asthma. An important aspect of this study is the evaluation of the anti-inflammatory effect of tezepelumab across patients with differing levels of eosinophilic and T2 inflammation.

TRIAL REGISTRATION

NCT03688074 (ClinicalTrials.gov). Registered 28 September 2018.

Effect of monoclonal antibody drug therapy on mucosal biomarkers in airway disease: A systematic review

BACKGROUND

Monoclonal antibody therapies have a growing role in treating refractory airway disease.

OBJECTIVE

The review aimed to summarize the response of respiratory mucosa to monoclonal antibody treatments in inflammatory airway conditions.

DESIGN

We conducted a systematic review including risk of bias assessment.

DATA SOURCES

MEDLINE, EMBASE and PubMed from 1 January 2000 to 16 November 2019 were searched.

ELIGIBILITY CRITERIA

Eligible studies assessed the immunological and histological response of airway mucosa to monoclonal antibody therapy compared with baseline or a comparison group in patients with respiratory diseases (asthma, chronic rhinosinusitis and allergic rhinitis). Any prospective interventional studies, including randomized controlled trials (RCTs) and single-arm trials, were eligible.

RESULTS

There were 4195 articles screened, and full-text analysis produced n = 11 studies with extractable data. Nine were RCTs, and two were single-arm trials. These studies focused on asthma (n = 9 articles), chronic rhinosinusitis (n = 1) and allergic rhinitis (n = 1). Five monoclonal antibody drugs were assessed (omalizumab, mepolizumab, dupilumab, benralizumab and tralokinumab). Risk of bias was low (n = 6) or unclear (n = 3) in the RCTs and moderate in the single-arm trials. Omalizumab reduced the mucosal concentration of its target, IgE. Dupilumab reduced the concentration of one of its targets, IL-13, but not IL-4. Omalizumab, mepolizumab and benralizumab reduced tissue eosinophil cell density. Dupilumab decreased mucosal eosinophil granule proteins. Tralokinumab did not affect airway mucosa.

CONCLUSIONS

Knowledge of the expected biological response of monoclonal antibody therapy on biomarkers in disease tissue provides an important supplement to data about clinical outcomes. An understanding of the biological effect is essential to identify likely responders, reasons for treatment failure and necessary adjustments to monoclonal antibody treatment. Further investigation into the effect of monoclonal antibody therapy on disease mucosa and more precise endotyping are required to move closer to achieving personalized medicine.

How do biologicals and other novel therapies effect clinically used biomarkers in severe asthma?

While there has been much interest in using biomarkers to select patients for particular targeted therapies, there has been much less attention paid to how these biomarkers change in patients once treatment begins. This is an area of great interest to practising clinicians, especially respiratory physicians and allergists who manage severe asthma. In this article, we review monoclonal antibodies and related targeted therapies, especially those that are currently available or in late stage clinical trials, focussing on the differential effects such agents have on biomarkers in widespread clinical practice such as eosinophils, FeNO and total IgE. Serial measurements of biomarkers can be useful in determining whether a particular targeted therapy is having its expected biological effect and invaluable in assessing the reasons for treatment failure should that occur.

Dupilumab: Clinical Efficacy of Blocking IL-4/IL-13 Signalling in Chronic Rhinosinusitis with Nasal Polyps

In September 2019, The Lancet published details of two large Phase III double-blind placebo-controlled studies (LIBERTY NP SINUS-24 and LIBERTY NP SINUS-52) confirming the clinical efficacy of the biologic dupilumab in simultaneously blocking both IL-4/IL-13 signalling in chronic rhinosinusitis with nasal polyps (CRSwNP). The studies demonstrated that dupilumab (Dupixent^®, Sanofi and Regeneron) 300mg subcutaneously administered was clinically effective when added for patients with moderate to severe CRSwNP already maintained on the standard intranasal steroid mometasone furoate. Duration of treatment ranged from injections either 2 weekly for 24 weeks (SINUS-24) or every 2 weeks for 52 weeks or finally every 2 weeks for 24 weeks stepping down thereafter to every 4 weeks for a further 28 weeks (SINUS-52). Rapid improvements in all important parameters of disease burden were seen with such improvement maintained even where the frequency of injections was decreased. In patients with co-existent asthma, lung function and asthma control scores improved. This is consistent with the one airway hypothesis of shared T2 inflammatory programmes driving both disease syndromes. The studies formed the basis for FDA registration and clinical launch in the US, and EMA approval in Europe. Dupilumab presents a significant new treatment option in an area of urgent unmet therapeutic need in CRSwNP. Should dupilumab prove to be as effective in the real-life clinical environment as it has been in the studies, then a paradigm shift from sinonasal surgery to medical treatment of CRSwNP may need to occur in the ENT community. Questions in relation to best patient selection, combined upper and lower airway therapeutic pathways, long-term safety along with health economics and cost constraints ought now to be addressed.

Efficacy and safety of treatment with biologicals (benralizumab, dupilumab and omalizumab) for severe allergic asthma: A systematic review for the EAACI Guidelines - recommendations on the use of biologicals in severe asthma

Allergic asthma is a frequent asthma phenotype. Both IgE and type 2 cytokines are increased, with some degree of overlap with other phenotypes. Systematic reviews assessed the efficacy and safety of benralizumab, dupilumab and omalizumab (alphabetical order) vs standard of care for patients with uncontrolled severe allergic asthma. PubMed, Embase and Cochrane Library were searched to identify RCTs and health economic evaluations, published in English. Critical and important asthma-related outcomes were evaluated. The risk of bias and the certainty of the evidence were assessed using GRADE. All three biologicals reduced with high certainty the annualized asthma exacerbation rate: benralizumab incidence rate ratios (IRR) 0.63 (95% CI 0.50 - 0.81); dupilumab IRR 0.58 (95%CI 0.47 - 0.73); and omalizumab IRR 0.56 (95%CI 0.42 - 0.73). Benralizumab and dupilumab improved asthma control with high certainty and omalizumab with moderate certainty; however, none reached the minimal important difference (MID). Both benralizumab and omalizumab improved QoL with high certainty, but only omalizumab reached the MID. Omalizumab enabled ICS dose reduction with high certainty. Benralizumab and omalizumab showed an increase in drug-related adverse events (AEs) with low to moderate certainty. All three biologicals had moderate certainty for an ICER/QALY value above the willingness to pay threshold. There was high certainty that in children 6-12 years old omalizumab decreased the annualized exacerbation rate [IRR 0.57 (95%CI 0.45-0.72)], improved QoL [relative risk 1.43 (95%CI 1.12 -1.83)], reduced ICS [mean difference (MD) -0.45 (95% CI -0.58 to -0.32)] and rescue medication use [ MD -0.41 (95%CI -0.66 to -0.15)].

Chronic rhinosinusitis with nasal polyps: insights into mechanisms of disease from emerging biological therapies

Introduction: Chronic rhinosinusitis with nasal polyps (CRSwNP) is a complex disease of the upper airway, with long-term morbidity. With detailed mechanistic studies currently lacking, understanding of the immunopathogenesis is still limited. However, outcomes from CRSwNP clinical studies using biologics that block key mediators or cells may provide some insights into how immune signaling pathways potentially integrate and modulate each other and contribute to disease. Current treatments are often ineffective and there is an urgent unmet clinical need for effective therapeutic strategies. Emerging biologics hold promise. Areas covered: This review covers the biology of CRSwNP in terms of the clinical outcomes reported from blocking immune cascades with available biologics. Immune amplification mechanisms and how biologics can potentially modulate such 'master' cytokines and signaling proteins that drive inflammation and contribute to tissue remodeling in CRSwNP are discussed. Expert commentary: Biologics have the potential to transform CRSwNP treatment. The ability to predict clinical response in a complex disease as CRSwNP to a biologic cannot necessarily be predicted by measuring a single protein or cell as a biomarker of disease. Further studies with biologics must be carefully undertaken to fully evaluate wider biomarker associated pheno-endotype responses along with any associated asthma outcome measures.

Response to omalizumab using patient enrichment criteria from trials of novel biologics in asthma

Background

Recent efficacy studies of asthma biologics have included highly enriched patient populations. Using a similar approach, we examined factors that predict response to omalizumab to facilitate selection of patients most likely to derive the greatest clinical benefit from therapy.

Methods

Data from two phase III clinical trials of omalizumab in patients with allergic asthma were examined. Differences in rates of asthma exacerbations between omalizumab and placebo groups during the 16‐week inhaled corticosteroid (ICS) dose‐stable phase were evaluated with respect to baseline blood eosinophil counts (eosinophils <300/μL [low] vs ≥300/μL [high]) and baseline markers of asthma severity (emergency asthma treatment in prior year, asthma hospitalization in prior year, forced expiratory volume in 1 second [FEV₁; FEV₁ <65% vs ≥65% predicted], inhaled beclomethasone dipropionate dose [<600 vs ≥600 μg/day], and long‐acting beta‐agonist [LABA] use [yes/no]).

Results

Adults/adolescents (N = 1071) were randomized to receive either omalizumab (n = 542) or placebo (n = 529). In the 16‐week ICS dose‐stable phase, rates of exacerbations requiring ≥3 days of systemic corticosteroid treatment were 0.066 and 0.147 with omalizumab and placebo, respectively, representing a relative rate reduction in omalizumab‐treated patients of 55% (95% CI, 32%‐70%; P = .002). For patients with eosinophils ≥300/μL or with more severe asthma, this rate reduction was significantly more pronounced.

Conclusion

In patients with allergic asthma, baseline blood eosinophil levels and/or clinical markers of asthma severity predict response to omalizumab.

Effects of Omalizumab on Rhinovirus Infections, Illnesses, and Exacerbations of Asthma

RATIONALE

Allergic inflammation has been linked to increased susceptibility to viral illnesses, but it is unclear whether this association is causal.

OBJECTIVES

To test whether omalizumab treatment to reduce IgE would shorten the frequency and duration of rhinovirus (RV) illnesses in children with allergic asthma.

METHODS

In the PROSE (Preventative Omalizumab or Step-up Therapy for Severe Fall Exacerbations) study, we examined children with allergic asthma (aged 6-17 yr; n = 478) from low-income census tracts in eight U.S. cities, and we analyzed virology for the groups randomized to treatment with guidelines-based asthma care (n = 89) or add-on omalizumab (n = 259). Weekly nasal mucus samples were analyzed for RVs, and respiratory symptoms and asthma exacerbations were recorded over a 90-day period during the fall seasons of 2012 or 2013. Adjusted illness rates (illnesses per sample) by treatment arm were calculated using Poisson regression.

MEASUREMENTS AND MAIN RESULTS

RVs were detected in 97 (57%) of 171 exacerbation samples and 2,150 (36%) of 5,959 nonexacerbation samples (OR, 2.32; P < 0.001). Exacerbations were significantly associated with detection of rhinovirus C (OR, 2.85; P < 0.001) and rhinovirus A (OR, 2.92; P < 0.001), as well as, to a lesser extent, rhinovirus B (OR, 1.98; P = 0.019). Omalizumab decreased the duration of RV infection (11.2 d vs. 12.4 d; P = 0.03) and reduced peak RV shedding by 0.4 log units (95% confidence interval, -0.77 to -0.02; P = 0.04). Finally, omalizumab decreased the frequency of RV illnesses (risk ratio, 0.64; 95% confidence interval, 0.49-0.84).

CONCLUSIONS

In children with allergic asthma, treatment with omalizumab decreased the duration of RV infections, viral shedding, and the risk of RV illnesses. These findings provide direct evidence that blocking IgE decreases susceptibility to RV infections and illness. Clinical trial registered with www.clinicaltrials.gov (NCT01430403).

Anti-IgE Treatment for Disorders Other Than Asthma

Immunoglobulin E (IgE) plays a key role in the pathogenesis of many allergic diseases. Thus, IgE-mediated immunologic pathways are an attractive target for intervention in allergic diseases. Omalizumab is a recombinant humanized monoclonal antibody that binds IgE and has been used treat allergic asthma for over a decade. Currently, omalizumab is approved for the treatment of both allergic asthma and chronic spontaneous urticaria. Since IgE plays a critical role in other allergic diseases, anti-IgE therapy has been evaluated in other allergic diseases in small clinical trials and case reports. Omalizumab has demonstrated efficacy in treating allergic rhinitis, atopic dermatitis, physical urticarias, mast cell disorders, food allergy, and other allergic diseases. In addition, the use of omalizumab with conventional allergen immunotherapy improves both safety and effectiveness.

Anti-IL5 therapies for asthma

BACKGROUND

This review is the first update of a previously published review in The Cochrane Library (Issue 7, 2015). Interleukin-5 (IL-5) is the main cytokine involved in the activation of eosinophils, which cause airway inflammation and are a classic feature of asthma. Monoclonal antibodies targeting IL-5 or its receptor (IL-5R) have been developed, with recent studies suggesting that they reduce asthma exacerbations, improve health-related quality of life (HRQoL) and lung function. These are being incorporated into asthma guidelines.

OBJECTIVES

To compare the effects of therapies targeting IL-5 signalling (anti-IL-5 or anti-IL-5Rα) with placebo on exacerbations, health-related qualify of life (HRQoL) measures, and lung function in adults and children with chronic asthma, and specifically in those with eosinophilic asthma refractory to existing treatments.

SEARCH METHODS

We searched the Cochrane Airways Trials Register, clinical trials registries, manufacturers' websites, and reference lists of included studies. The most recent search was March 2017.

SELECTION CRITERIA

We included randomised controlled trials comparing mepolizumab, reslizumab and benralizumab versus placebo in adults and children with asthma.

DATA COLLECTION AND ANALYSIS

Two authors independently extracted data and analysed outcomes using a random-effects model. We used standard methods expected by Cochrane.

MAIN RESULTS

Thirteen studies on 6000 participants met the inclusion criteria. Four used mepolizumab, four used reslizumab, and five used benralizumab. One study in benralizumab was terminated early due to sponsor decision and contributed no data. The studies were predominantly on people with severe eosinophilic asthma, which was similarly but variably defined. Eight included children over 12 years but these results were not reported separately. We deemed the risk of bias to be low, with all studies contributing data being of robust methodology. We considered the quality of the evidence for all comparisons to be high overall using the GRADE scheme, with the exception of intravenous mepolizumab because this is not currently a licensed delivery route.All of the anti-IL-5 treatments assessed reduced rates of 'clinically significant' asthma exacerbation (defined by treatment with systemic corticosteroids for three days or more) by approximately half in participants with severe eosinophilic asthma on standard of care (at least medium-dose inhaled corticosteroids (ICS)) with poorly controlled disease (either two or more exacerbations in the preceding year or Asthma Control Questionnaire (ACQ) 1.5 or more). Non-eosinophilic participants treated with benralizumab also showed a significant reduction in exacerbation rates, but no data were available for non-eosinophilic participants, and mepolizumab or reslizumab.We saw modest improvements in validated HRQoL scores with all anti-IL-5 agents in severe eosinophilic asthma. However these did not exceed the minimum clinically important difference for ACQ and Asthma Quality of Life Questionnaire (AQLQ), with St. George's Respiratory Questionnaire (SGRQ) only assessed in two studies. The improvement in HRQoL scores in non-eosinophilic participants treated with benralizumab, the only intervention for which data were available in this subset, was not statistically significant, but the test for subgroup difference was negative.All anti-IL-5 treatments produced a small but statistically significant improvement in mean pre-bronchodilator forced expiratory flow in one second (FEV1) of between 0.08 L and 0.11 L.There were no excess serious adverse events with any anti-IL-5 treatment, and indeed a reduction in favour of mepolizumab that could be due to a beneficial effect on asthma-related serious adverse events. There was no difference compared to placebo in adverse events leading to discontinuation with mepolizumab or reslizumab, but significantly more discontinued benralizumab than placebo, although the absolute numbers were small (36/1599 benralizumab versus 9/998 placebo).Mepolizumab, reslizumab and benralizumab all markedly reduced blood eosinophils, but benralizumab resulted in almost complete depletion, whereas a small number remained with mepolizumab and reslizumab. The implications for efficacy and/or adverse events are unclear.

AUTHORS' CONCLUSIONS

Overall our study supports the use of anti-IL-5 treatments as an adjunct to standard of care in people with severe eosinophilic asthma and poor control. These treatments roughly halve the rate of asthma exacerbations in this population. There is limited evidence for improved HRQoL scores and lung function, which may not meet clinically detectable levels. There were no safety concerns regarding mepolizumab or reslizumab, and no excess serious adverse events with benralizumab, although there remains a question over adverse events significant enough to prompt discontinuation.Further research is needed on biomarkers for assessing treatment response, optimal duration and long-term effects of treatment, risk of relapse on withdrawal, non-eosinophilic patients, children (particularly under 12 years), and comparing anti-IL-5 treatments to each other and, in people eligible for both, to anti-immunoglobulin E. For benralizumab, future studies should closely monitor rates of adverse events prompting discontinuation.

Bidirectional Mast Cell-Eosinophil Interactions in Inflammatory Disorders and Cancer

Human mast cells (MCs) and eosinophils were first described and named by Paul Ehrlich. These cells have distinct myeloid progenitors and differ morphologically, ultrastructurally, immunologically, biochemically, and pharmacologically. However, MCs and eosinophils play a pivotal role in several allergic disorders. In addition, these cells are involved in autoimmune disorders, cardiovascular diseases, and cancer. MCs are distributed throughout all normal human tissues, whereas eosinophils are present only in gastrointestinal tract, secondary lymphoid tissues, and adipose tissue, thymus, mammary gland, and uterus. However, in allergic disorders, MCs and eosinophils can form the "allergic effector unit." Moreover, in several tumors, MCs and eosinophils can be found in close proximity. Therefore, it is likely that MCs have the capacity to modulate eosinophil functions and vice versa. For example, interleukin 5, stem cell factor, histamine, platelet-activating factor (PAF), prostaglandin D2 (PGD2), cysteinyl leukotrienes, and vascular endothelial growth factors (VEGFs), produced by activated MCs, can modulate eosinophil functions through the engagement of specific receptors. In contrast, eosinophil cationic proteins such as eosinophil cationic protein and major basic protein (MBP), nerve growth factor, and VEGFs released by activated eosinophils can modulate MC functions. These bidirectional interactions between MCs and eosinophils might be relevant not only in allergic diseases but also in several inflammatory and neoplastic disorders.

Association of Mycoplasma pneumoniae infection with increased risk of asthma in children

The present study was conducted to investigate the relationship between Mycoplasma pneumoniae (MP) infection and the risk of asthma among children by detecting the rate of MP immunoglobulin M (MP-IgM) and the eosinophil (EOS) count. A total of 139 asthmatic children were enrolled as the case group and assigned into three groups: Group A (aged <3 years, n=42), group B (aged 3–8 years, n=45) and group C (aged >8 years, n=52). Additionally, 115 healthy children were enrolled in the control group. Enzyme-linked immunosorbent assay was used to measure the MP-IgM-positive rate. EOS count was detected in the experimental and control groups by using a hemocytometer analyzer. A meta-analysis was performed by using the Comprehensive Meta-Analysis version 2.0 software. The positive rates of the MP-IgM and EOS count in the experimental group were significantly higher than those in control group (both P<0.001). Furthermore, the asthmatic children in group C had a higher MP-IgM-positive rate and EOS count as compared to those in groups A and B, respectively (all P<0.05). Results from groups A and B were not statistically significant (all P>0.05). The meta-analysis further confirmed that asthmatic children had a higher MP-IgM-positive rate as compared to the healthy controls (P<0.001). Age-stratified analysis revealed that the MP-IgM-positive rate in asthmatic children aged ≥8 and <8 years was significantly higher than that in the healthy controls (P=0.003 and P<0.001). Asthmatic children had a higher MP-IgM-positive rate and EOS count as compared with controls, suggesting that the MP infection may be closely associated with the risk of asthma. Additionally, the positive rate of MP-IgM may indicate an important biological marker in predicting the development of asthma.

[Omalizumab: Beyond anti-IgE properties]

INTRODUCTION

Omalizumab is used as a treatment for severe allergic asthma. Its intended mechanism of action is based on its anti-IgE proprieties. However, recent studies have highlighted other mechanisms of action.

STATE OF THE ART

Omalizumab treatment is associated with a decrease in the number of dendritic cells, T and B lymphocytes and eosinophils. This anti-inflammatory activity is characterized by a decrease in the levels of several cytokines involved in the recruitment, activation and survival of eosinophils and mastocytes, and in a Th2 orientation of the immune response. A modulation of bronchial remodeling by omalizumab has recently been shown. A decrease in the production of extracellular matrix components and in the proliferation of smooth muscle cells could be involved in this modulation. These mechanisms of action could explain in part the clinical efficiency of omalizumab in non-allergic conditions such as non-allergic asthma, non-allergic urticaria or nasal polyposis.

CONCLUSION

A precise knowledge of the mechanisms of action of omalizumab could allow the identification of biomarkers predictive of efficacy of this treatment. These could be useful tools in the phenotyping of severe asthma.

Biological Modulators in Eosinophilic Diseases

Eosinophils can regulate local and systemic inflammation, and their presence in higher numbers appears to play an important role in the pathology of various atopic and inflammatory diseases. Eosinophil maturation, recruitment, and survival depend on several cytokine regulators, including interleukin (IL)-5, IL-4, and IL-13 as well as growth factors such as GM-CSF. Over the last decade, the approach to treating eosinophilic diseases has changed greatly. A number of biologic modulators have been developed to target eosinophilic inflammatory pathways, and their usage has resulted in variable clinical improvement in the treatment of eosinophilic-associated conditions. Novel targeted therapies that are safe and effective for treating these disorders are being investigated. This review summarizes the clinical use of biologic agents that have been studied in clinical trials or approved for treating eosinophilic diseases.

Anti-IgE treatment, airway inflammation and remodelling in severe allergic asthma: current knowledge and future perspectives

Asthma is a disorder of the airways involving various inflammatory cells and mediators and characterised by bronchial hyperresponsiveness, chronic inflammation and structural alterations in the airways, also known as remodelling. IgE is an important mediator of allergic reactions and has a central role in allergic asthma pathophysiology, as it is implicated in both the early and late phase allergic response. Moreover, clinical and mechanistic evidence has lately emerged, implicating IgE in the development of airway remodelling. The use of monoclonal antibodies targeting IgE, such as omalizumab, has proven very effective in improving respiratory symptoms and quality of life, while reducing asthma exacerbations, emergency room visits and the use of systemic corticosteroids in allergic severe asthma. These effects are believed to be mainly mediated by omalizumab's inhibitory effect on the initiation and further propagation of the allergic inflammation cascade. However, there is evidence to suggest that anti-IgE treatment remains effective long after it has been discontinued. In part, these findings could be attributed to the possible ameliorating effects of anti-IgE treatment on airway remodelling. In this review, we discuss recent findings supporting the notion that anti-IgE treatment modulates the complex immune responses that manifest clinically as asthma and ameliorates airway remodelling changes often observed in allergic severe asthma phenotypes.

Anti-IgE treatment, airway inflammation and remodelling in severe allergic asthma: current knowledge and future perspectives

Asthma is a disorder of the airways involving various inflammatory cells and mediators and characterised by bronchial hyperresponsiveness, chronic inflammation and structural alterations in the airways, also known as remodelling. IgE is an important mediator of allergic reactions and has a central role in allergic asthma pathophysiology, as it is implicated in both the early and late phase allergic response. Moreover, clinical and mechanistic evidence has lately emerged, implicating IgE in the development of airway remodelling. The use of monoclonal antibodies targeting IgE, such as omalizumab, has proven very effective in improving respiratory symptoms and quality of life, while reducing asthma exacerbations, emergency room visits and the use of systemic corticosteroids in allergic severe asthma. These effects are believed to be mainly mediated by omalizumab's inhibitory effect on the initiation and further propagation of the allergic inflammation cascade. However, there is evidence to suggest that anti-IgE treatment remains effective long after it has been discontinued. In part, these findings could be attributed to the possible ameliorating effects of anti-IgE treatment on airway remodelling. In this review, we discuss recent findings supporting the notion that anti-IgE treatment modulates the complex immune responses that manifest clinically as asthma and ameliorates airway remodelling changes often observed in allergic severe asthma phenotypes.

Targeting the interleukin pathway in the treatment of asthma

Asthma is a common heterogeneous disease with a complex pathophysiology. Current therapies based on inhaled corticosteroids and longacting β2 agonists are effective in controlling asthma in most, but not all patients, with a few patients falling into the severe asthma category. Severe asthma is characterised by poor asthma control, recurrent exacerbations, and chronic airflow obstruction despite adequate and, in many cases, high-dose treatments. There is strong evidence supporting the role for interleukins derived from T-helper-2 (Th2) cells and innate lymphoid cells, such as interleukins 4, 5, and 13, as underlying the eosinophilic and allergic inflammatory processes in nearly half of these patients. An anti-IgE antibody, omalizumab, which binds to circulating IgE, a product of B cells from the actions of interleukin 4 and interleukin 13, is used as treatment for severe allergic asthma. Studies examining cytokine blockers such as anti-interleukin-5, anti-interleukin-4Rα, and anti-interleukin-13 monoclonal antibodies in patients with severe asthma with recurrent exacerbations and high blood eosinophil counts despite use of inhaled corticosteroids have reported improved outcomes in terms of exacerbations, asthma control, and forced expiratory volume in 1 s. The US Food and Drug Administration's recommendation to use an anti-interleukin-5 antibody for the treatment of severe eosinophilic asthma suggests that there will be a therapeutic place for these anti-Th2 agents. Biomarkers should be used to identify the right patients for such targeted approaches. More guidance will be needed as to which patients should receive each of these classes of selective antibody-based treatments. Currently, there is no treatment that targets the cytokines driving asthma associated with non-eosinophilic inflammation and low Th2 expression.

Mepolizumab versus placebo for asthma

BACKGROUND

Mepolizumab is a human monoclonal antibody against interleukin-5 (IL-5), the main cytokine involved in the activation of eosinophils, which in turn causes airway inflammation. Recent studies have suggested these agents may have a role in reducing exacerbations and improving health-related quality of life (HRQoL). There are no recommendations for the use of mepolizumab in adults or children in the recent update of the BTS/SIGN guidelines (BTS/SIGN 2014).

OBJECTIVES

To compare the effects of mepolizumab with placebo on exacerbations and HRQoL in adults and children with chronic asthma.

SEARCH METHODS

We searched the Cochrane Airways Group Register (CAGR) of trials, clinical trial registries, manufacturers' websites and the reference lists of included studies. Searches were conducted in November 2013 and updated in November 2014.

SELECTION CRITERIA

We included randomised controlled trials comparing mepolizumab versus placebo in adults and children with asthma.

DATA COLLECTION AND ANALYSIS

Two authors independently extracted data and analysed outcomes using a random-effects model. We used standard methods expected by The Cochrane Collaboration.

MAIN RESULTS

Eight studies on 1707 participants met the inclusion criteria. Only two studies included children (over 12 years of age), but they did not report separate findings for the adolescents. Seven studies involved intravenous mepolizumab alone; one included a subcutaneous arm. There was heterogeneity in the severity and clinical pattern of asthma among the participants in the eight studies, varying from mild to moderate atopic asthma, to persistent asthma and eosinophilic asthma with recurrent exacerbations. Selection bias was a concern in several of the studies included in this review.Four trials compared intravenous mepolizumab to placebo in relation to HRQoL. Two studies measured scores from the Asthma Quality of Life Questionnaire (AQLQ), which showed a non-significant difference between mepolizumab and placebo (mean difference (MD) 0.21, 95% confidence interval (CI) - 0.01 to 0.44; participants = 682), in the direction favouring mepolizumab. The third study used the St. George's Respiratory Questionnaire (SGRQ) and found a significant difference between mepolizumab and placebo (MD 6.40, 95% CI 3.15 to 9.65; participants = 576), which indicated a clinically important benefit favouring mepolizumab. A fourth study noted that there was no significant difference but did not provide any data. The two studies in people with eosinophilic asthma showed a reduction in clinically significant exacerbation rates (Risk Ratio 0.52, 95% CI 0.43 to 0.64; participants = 690). However, an analysis of four studies that were not confined to people with eosinophilic asthma indicated considerable heterogeneity and no significant difference in people with one or more exacerbations between mepolizumab and placebo using a random-effects model (Risk Ratio 0.67, 95% CI 0.34 to 1.31; participants = 468; I(2) = 59%).The analysis of serious adverse events indicated a significant difference favouring mepolizumab (Risk ratio 0.49, 95% CI 0.30 to 0.80; participants = 1441; studies = 5; I(2) = 0%). It was not possible to combine the results for adverse events, and we deemed the quality of this evidence to be low.A single study compared subcutaneous mepolizumab to placebo in 385 adults with severe eosinophilic asthma and found an improvement in HRQoL scores and a reduction in asthma exacerbations, including exacerbations requiring admission to hospital.

AUTHORS' CONCLUSIONS

It is not possible to draw firm conclusions from this review with respect to the role of mepolizumab in patients with asthma. Our confidence in the results of this review are limited by the fact that the intravenous route is not currently licensed for mepolizumab, and the evidence for the currently licenced subcutaneous route is limited to a single study in participants with severe eosinophilic asthma.The currently available studies provide evidence that mepolizumab can lead to an improvement in health-related quality of life scores and reduce asthma exacerbations in people with severe eosinophilic asthma.Further research is needed to clarify which subgroups of patients with asthma could potentially benefit from this treatment. Dosage, ideal dosing regimens and duration of treatment need to be clarified, as the studies included in this review differed in their protocols. There are no studies reporting results from children, so we cannot comment on treatment for this age group. At the present time, larger studies using licenced treatment regimens are required to establish the role of mepolizumab in the treatment of severe asthma.

[Intolerance of specific immunotherapy with Hymenoptera venom: jumping the hurdle with omalizumab]

Specific immunotherapy is a very effective and well-tolerated therapeutic option in patients with Hymenoptera venom allergy. Many patients can be successfully treated, and severe side-effects are rarely seen. In most cases local swelling of the injection site is noticed, whereas systemic reactions are uncommon. No reliable biomarkers to prove the positive response to the specific immunotherapy have been validated. But on the other hand the failure of the venom immunotherapy can be verified by performing a sting challenge test; in this case the maintenance dose of the venom immunotherapy has to be increased and the sting challenge test has to be repeated. This approach works well most of the patients. In rare cases severe anaphylactic reactions occur during the initiation of the venom immunotherapy due to individual risk factors. While in the past this necessitated discontinuation of the specific immunotherapy, the current situation has remarkably changed. Since the IgE-antibody omalizumab has been licensed for different indications, a new therapeutic option is available. We have employed this approach since 2005. We share our own practical experience as well as recent data, presenting a management approach for Hymenoptera venom allergy in high-risk patients.

Asthma phenotypes and the use of biologic medications in asthma and allergic disease: the next steps toward personalized care

Traditionally, asthma and allergic diseases have been defined by broad definitions and treated with nonspecific medications, including corticosteroids and bronchodilators. There is an increasing appreciation of heterogeneity within asthma and allergic diseases based primarily on recent cluster analyses, molecular phenotyping, biomarkers, and differential responses to targeted and nontargeted therapies. These pioneering studies have led to successful therapeutic trials of molecularly targeted therapies in defined phenotypes. This review analyzed randomized double-blind, placebo-controlled trials of molecularly targeted therapies in defined allergic disease and asthma phenotypes. IgE was the first successful biological target used in patients with allergic disease and asthma. This review shows that therapies targeting the canonical type 2 cytokines IL-4, IL-5, and IL-13 have shown consistent efficacy, especially in asthmatic patients with evidence of TH2/type 2 inflammation ("type 2 high"). As of yet, there are no successful trials of targeted therapies in asthmatic patients without evidence for type 2 inflammation. We conclude that further refinement of type 2 therapies to specific type 2 phenotypes and novel approaches for patients without type 2 inflammation are needed for asthma and allergic disease treatment.

Is there still hope for single therapies: how do we set up experimental systems to efficiently test combination therapies?

Severe asthma, chronic obstructive pulmonary disease (COPD) and idiopathic pulmonary fibrosis (IPF) are chronic lung diseases with a clear need for development of new and more efficient therapy. In preclinical research, the mouse model has been instrumental in advancing our knowledge of the biology and immunology. However, it has been proven rather difficult and time consuming to develop new treatments that can impact on the clinical course of these diseases. Many challenges need to be overcome for upgrading the quality of currently available experimental disease models in order to enhance the translation rate of basic research to clinical practice. Establishment of transgenic mouse overexpressing disease-causing genes may provide tools to discover new pathological pathways and to evaluate the possibility of molecular targeted therapy in chronic lung diseases. Personalized medicine, if developed, might be the solution for 'disease heterogeneity' and for improving clinical outcome.

An overview of integrative therapies in asthma treatment

Treatment of asthma lends itself to an integrative medicine approach due to the multifactorial nature of the disease. It is well established that asthma has a neuromuscular component (bronchospasm), an immunological component (inflammation), and a psychological component. This encourages the use of diverse approaches to address all avenues of pathophysiology, aiming for the most effective blend of treatment approaches possible. Integrative medicine is defined by NIH NCCAM ( http://nccam.nih.gov ) as medicine that blends the use of evidence-based complementary therapies with conventional medicine. Statistics from the 2007 National Health Interview Survey (NHIS), conducted by the Centers for Disease Control and Prevention's (CDC) National Center for Health Statistics (NCHS), showed that approximately four out of 10 adults and approximately one in nine children and more than 50 % of children living with chronic illness, including asthma, used complementary therapies in the USA in 2007. Asthma and allergies rank among the top 15 most common medical conditions in which integrative therapies are used in both children and adults. To date, integrative treatment approaches with some evidence for benefit in asthma treatment include the following: nutrition modification, mind-body medicine, physical activity, and certain dietary supplement interventions.

The effects of lebrikizumab in patients with mild asthma following whole lung allergen challenge

Background

Interleukin 13 (IL13) is a T-helper type 2 (Th2) cytokine associated with inflammation and pathology in allergic diseases such as bronchial asthma. We have shown that treatment with lebrikizumab, an anti-IL13 monoclonal antibody, significantly improves prebronchodilator forced expiratory volume in 1 s (FEV₁) in a subset of subjects with uncontrolled asthma.

Objective

To evaluate efficacy and safety of lebrikizumab in subjects with mild asthma who underwent bronchial allergen challenge.

Methods

Twenty-nine subjects were randomized 1: 1–5 mg/kg lebrikizumab (n = 13) or placebo (n = 16) administered subcutaneously every 4 weeks over 12 weeks, a total of four doses. Primary efficacy outcome was late asthmatic response (LAR) at Week 13, defined as area under the curve of FEV₁ measured 2–8 h following inhaled allergen challenge. Serum biomarkers were measured to verify IL13 pathway inhibition and identify patients with an increased response to lebrikizumab.

Results

At Week 13, the LAR in lebrikizumab subjects was reduced by 48% compared with placebo subjects, although this was not statistically significant (95% confidence interval, −19%, 90%). Exploratory analysis indicated that lebrikizumab-treated subjects with elevated baseline levels of peripheral blood eosinophils, serum IgE, or periostin exhibited a greater reduction in LAR compared with subjects with lower baseline levels of these biomarkers. Lebrikizumab exerted systemic effects on markers of Th2 inflammation, reducing serum immunoglobulin E (IgE), chemokine ligands 13 and 17 by approximately 25% (P < 0.01). Lebrikizumab was well tolerated.

Conclusion and Clinical Relevance

Lebrikizumab reduced the LAR in subjects with mild asthma. Clinical trial number NCT00781443.

New strategies with anti-IgE in allergic diseases

IgE has long been known as a therapeutic target for allergic disease, but the difficulty has been in selecting agents that don't trigger cross linkage of IgE when bound to its high affinity receptor (FceR1) on mast cells and basophils. By "designing" a monoclonal antibody (mAb) which targets that part of IgE that binds to that binds to the a-chain of FceR1, the allergic cascade can be effectively interrupted and diseases such as asthma greatly improved, providing a substantial part of their phenotype engages IgE. Clinical trials and real life studies confirm this. Beyond asthma, a whole range of other diseases dependent upon IgE initiation and triggering are being identified. These diseases are now being explored as being amenable to anti-IgE therapy some of which are comorbidities of asthma and others not. The advent of an even more potent anti-IgE mAb - QGE031 - is creating further opportunities for anti-IgE therapy to improve the lives of so many people with IgE-related diseases.

Biologic therapy in asthma: entering the new age of personalized medicine

OBJECTIVE

Asthma is a common chronic disease with various phenotypes and therapeutic responses. Unlike other diseases, current anti-inflammatory treatment with corticosteroids does not include any reference to biological measures which may vary among different asthma phenotypes. Morbidity from uncontrolled asthma suggests a need for specific targeted treatment approaches such as biologic medications. In half of asthmatics, chronic airway inflammation may be driven by T helper (Th)-2 cells, which release pro-inflammatory cytokines, such as interleukin (IL)-4, IL-5 and IL-13, contributing to eosinophil inflammation and IgE production. Earlier studies of cytokine-targeted biologic therapy on non-phenotyped asthma patients were generally not clinically effective.

METHODS

Literature published from 1958-2013 was identified through PubMed using the search terms which included asthma and therapy. A total of 32 studies were reviewed covering both pediatric and adult asthmatics and included double-blind randomized placebo-controlled trials testing efficacy of biologic agents to treat asthma.

RESULTS

More recent approaches to personalized medicine with expression profiling studies, genetic analysis and clinical biomarkers of Th2 inflammation have allowed identification of asthma phenotypes including a Th2 "high" phenotype. Studies targeting IgE, IL-5, IL-13 and the IL4 receptor alpha chain have shown some efficacy in phenotyped patients. For those without evidence of Th2 inflammation, no specific therapies have been identified.

CONCLUSIONS

In recent years, the identification of Type-2 cytokine "high" asthma in numerous studies has predicted the clinical response to the Th2 associated therapies. It is not yet clear whether all Type 2 high asthma will respond similarly to IL-4, 5 and 13 approaches.

Development of assay for determining free IgE levels in serum from patients treated with omalizumab

BACKGROUND

Omalizumab, a monoclonal anti-IgE antibody, is currently indicated for the treatment of moderate-to-severe allergic asthma. To measure active IgE levels in sera from patients treated with omalizumab, the IgE subfraction in complex with omalizumab should be eliminated from total IgE, and free IgE levels can then be determined. With the aim of therapeutic monitoring for anti-IgE therapy, we developed a new ELISA for free IgE.

METHODS

We used recombinant human soluble FcεRIα as a capture antigen and a biotinylated polyclonal anti-IgE antibody for detection. Using the newly developed ELISA, we measured the serum free IgE levels weekly in four asthmatic patients after their first omalizumab injection. We also measured the serum free IgE levels in 54 patients treated with omalizumab for over 4 weeks.

RESULTS

This assay was technically robust, the mean recovery rate in serum was 93.16% ± 5.34%. For all patients, omalizumab treatment significantly reduced serum free IgE levels prior to the second omalizumab injection. To maintain the benefit of omalizumab, serum free IgE concentrations should be <50 ng/ml. However, in 14 of 54 patients treated with omalizumab for over 4 weeks, serum free IgE concentrations measured by our ELISA were >50 ng/ml.

CONCLUSIONS

Our data suggest that the measurement of free IgE levels using our newly developed ELISA would be useful for monitoring serum free IgE levels during omalizumab therapy.

Omalizumab: a review of its use in patients with severe persistent allergic asthma

Omalizumab (Xolair(®)) is a subcutaneously administered monoclonal antibody that targets circulating free IgE and prevents its interaction with the high-affinity IgE receptor (FCεRI), thereby interrupting the allergic cascade. In the EU, the drug is approved as add-on therapy in adults, adolescents and children aged ≥6 years with severe persistent allergic asthma. In well designed clinical trials, add-on omalizumab significantly reduced the asthma exacerbation rate (primary endpoint) compared with placebo in adults, adolescents and children with severe persistent allergic asthma. Furthermore, add-on omalizumab reduced the need for inhaled corticosteroids in adults and adolescents, and improved asthma control and symptoms, and asthma-related quality of life in all age groups. The efficacy of omalizumab was also demonstrated in the real-world setting, with add-on therapy leading to reduced rates of hospitalizations, emergency room visits and unscheduled doctor's visits, as well as improvements in asthma symptom scores and the physician's overall assessment of treatment response. More data are needed to determine the optimum duration of treatment, and currently the duration is at the discretion of the treating physician. Omalizumab was generally well tolerated in clinical trials; the most common adverse event was transient injection-site reactions. In cost-utility analyses modelled over a life-time horizon, add-on omalizumab was cost effective compared with standard therapy, with incremental cost-effectiveness ratios falling within generally accepted willingness-to-pay thresholds. Thus, in difficult-to-treat patients with severe persistent allergic asthma, omalizumab provides a valuable treatment option.

Omalizumab for asthma in adults and children

BACKGROUND

Asthma is a respiratory (airway) condition that affects an estimated 300 million people worldwide and is associated with significant morbidity and mortality. Omalizumab is a monoclonal antibody that binds and inhibits free serum immunoglobulin E (IgE). It is called an 'anti-IgE' drug. IgE is an immune mediator involved in clinical manifestations of asthma. A recent update of National Institute for Health and Care Excellence (NICE) guidance in 2013 recommends omalizumab for use as add-on therapy in adults and children over six years of age with inadequately controlled severe persistent allergic IgE-mediated asthma who require continuous or frequent treatment with oral corticosteroids.

OBJECTIVES

To assess the effects of omalizumab versus placebo or conventional therapy for asthma in adults and children.

SEARCH METHODS

We searched the Cochrane Airways Group Specialised Register of trials for potentially relevant studies. The most recent search was performed in June 2013. We also checked the reference lists of included trials and searched online trial registries and drug company websites.

SELECTION CRITERIA

Randomised controlled trials examining anti-IgE administered in any manner for any duration. Trials with co-interventions were included, as long as they were the same in each arm.

DATA COLLECTION AND ANALYSIS

Two review authors independently assessed study quality and extracted and entered data. Three modes of administration were identified from the published literature: inhaled, intravenous and subcutaneous injection. The main focus of the updated review is subcutaneous administration, as this route is currently used in clinical practice. Subgroup analysis was performed by asthma severity. Data were extracted from published and unpublished sources.

MAIN RESULTS

In all, 25 trials were included in the review, including 11 new studies since the last update, for a total of 19 that considered the efficacy of subcutaneous anti-IgE treatment as an adjunct to treatment with corticosteroids.For participants with moderate or severe asthma who were receiving background inhaled corticosteroid steroid (ICS) therapy, a significant advantage favoured subcutaneous omalizumab with regard to experiencing an asthma exacerbation (odds ratio (OR) 0.55, 95% confidence interval (CI) 0.42 to 0.60; ten studies, 3261 participants). This represents an absolute reduction from 26% for participants suffering an exacerbation on placebo to 16% on omalizumab, over 16 to 60 weeks. A significant benefit was noted for subcutaneous omalizumab versus placebo with regard to reducing hospitalisations (OR 0.16, 95% CI 0.06 to 0.42; four studies, 1824 participants), representing an absolute reduction in risk from 3% with placebo to 0.5% with omalizumab over 28 to 60 weeks. No separate data on hospitalisations were available for the severe asthma subgroup, and all of these data were reported for participants with the diagnosis of moderate to severe asthma. Participants treated with subcutaneous omalizumab were also significantly more likely to be able to withdraw their ICS completely than those treated with placebo (OR 2.50, 95% CI 2.00 to 3.13), and a small but statistically significant reduction in daily inhaled steroid dose was reported for omalizumab-treated participants compared with those given placebo (weighted mean difference (WMD) -118 mcg beclomethasone dipropionate (BDP) equivalent per day, 95% CI -154 to -84). However, no significant difference between omalizumab and placebo treatment groups was seen in the number of participants who were able to withdraw from oral corticosteroid (OCS) therapy (OR 1.18, 95% CI 0.53 to 2.63).Participants treated with subcutaneous omalizumab as an adjunct to treatment with corticosteroids required a small but significant reduction in rescue beta2-agonist medication compared with placebo (mean difference (MD) -0.39 puffs per day, 95% CI -0.55 to -0.24; nine studies, 3524 participants). This benefit was observed in both the moderate to severe (MD -0.58, 95% CI -0.84 to -0.31) and severe (MD -0.30, 95% CI -0.49 to -0.10) asthma subgroups on a background therapy of inhaled corticosteroids; however, no significant difference between subcutaneous omalizumab and placebo was noted for this outcome in participants with severe asthma who were receiving a background therapy of inhaled plus oral corticosteroids. Significantly fewer serious adverse events were reported in participants assigned to subcutaneous omalizumab than in those receiving placebo (OR 0.72, 95% CI 0.57 to 0.91; 15 studies, 5713 participants), but more injection site reactions were observed (from 5.6% with placebo to 9.1% with omalizumab).To reflect current clinical practice, discussion of the results is limited to subcutaneous use, and trials involving intravenous and inhaled routes have been archived.

AUTHORS' CONCLUSIONS

Omalizumab was effective in reducing asthma exacerbations and hospitalisations as an adjunctive therapy to inhaled steroids and during steroid tapering phases of clinical trials. Omalizumab was significantly more effective than placebo in increasing the numbers of participants who were able to reduce or withdraw their inhaled steroids. Omalizumab was generally well tolerated, although more injection site reactions were seen with omalizumab. Further assessment in paediatric populations is necessary, as is direct double-dummy comparison with ICS. Although subgroup analyses suggest that participants receiving prednisolone had better asthma control when they received omalizumab, it remains to be tested prospectively whether the addition of omalizumab has a prednisolone-sparing effect. It is also not clear whether there is a threshold level of baseline serum IgE for optimum efficacy of omalizumab. Given the high cost of the drug, identification of biomarkers predictive of response is of major importance for future research.

Stratified approaches to the treatment of asthma

While asthma is a chronic inflammatory disorder that is managed with inhaled controller and reliever drugs, there remains a large unmet need at the severe end of the disease spectrum. Here, a novel stratified approach to its treatment is reviewed, based upon identification of causal pathways, with a focus on biologics. A systematic search of the literature was made using Medline, and publications were selected on the basis of their relevance to the topic. Despite strong preclinical data for many of the more recently identified asthma targets, especially those relating to the T-helper 2 allergic pathway, clinical trials with specific biologics in moderate to severe asthma as a group have been disappointing. However, subgroup analyses based upon pathway-specific biomarkers suggest specific endotypes that are responsive. Application of hypothesis-free analytical approaches (the 'omics') to well-defined phenotypes is leading to the stratification of asthma along causal pathways. Refinement of this approach is likely to be the future for diagnosing and treating this group of diseases, as well as helping to define new causal pathways. The identification of responders and nonresponders to targeted asthma treatments provides a new way of looking at asthma diagnosis and management, especially with biologics that are costly. The identification of novel biomarkers linked to well-phenotyped patients provides a stratified approach to disease management beyond simple disease severity and involving causal pathways. In order to achieve this effectively, a closer interaction will be required between industry (therapeutic and diagnostic), academia and health workers.

Phenotyping airways disease: an A to E approach

The airway diseases asthma and chronic obstructive pulmonary disease (COPD) are heterogeneous conditions with overlapping pathophysiological and clinical features. It has previously been proposed that this heterogeneity may be characterized in terms of five relatively independent domains labelled from A to E, namely airway hyperresponsiveness (AHR), bronchitis, cough reflex hypersensitivity, damage to the airways and surrounding lung parenchyma, and extrapulmonary factors. Airway hyperresponsiveness occurs in both asthma and COPD, accounting for variable day to day symptoms, although the mechanisms most likely differ between the two conditions. Bronchitis, or airway inflammation, may be predominantly eosinophilic or neutrophilic, with different treatments required for each. Cough reflex hypersensitivity is thought to underlie the chronic dry cough out of proportion to other symptoms that can occur in association with airways disease. Structural changes associated with airway disease (damage) include bronchial wall thickening, airway smooth muscle hypertrophy, bronchiectasis and emphysema. Finally, a variety of extrapulmonary factors may impact upon airway disease, including rhinosinusitis, gastroesophageal reflux disease, obesity and dysfunctional breathing. This article discusses the A to E concept in detail and describes how this framework may be used to assess and treat patients with airway diseases in the clinic.

Omalizumab attenuates airway inflammation and interleukin-5 production by mononuclear cells in patients with severe allergic asthma

BACKGROUND

Omalizumab, an anti-immunoglobulin E monoclonal antibody, has shown an inhibitory effect on airway inflammation, which may be associated with clinical improvement of severe asthma. This study evaluated changes in airway inflammation and cytokine release by the peripheral blood mononuclear cells (PBMCs) of Japanese patients with severe asthma after administration of omalizumab.

METHODS

Sixteen Japanese patients with severe asthma who were allergic to house-dust mites were enrolled in this study. Eight received omalizumab every 2 or 4 weeks for 16 weeks, and 8 control subjects were treated with conventional drug treatment. Changes in clinical scores for sputum eosinophils and levels of fraction of exhaled nitric oxide (FeNO) were measured at the time of enrollment and at week 16. Cytokines from PBMCs stimulated by house-dust mite (Dermatophagoides farinae) or ionomycin/phorbol myristate acetate (PMA) were measured at baseline and at week 16.

RESULTS

In the omalizumab-treated group, decreases in sputum eosinophils and FeNO were observed following treatment. Furthermore, the ex vivo production of interleukin (IL)-5 by PBMCs in response to both mite allergen and ionomycin/PMA decreased significantly. In contrast, interferon (IFN)-γ production was unchanged. There were no changes in any of the parameters observed in the control group.

CONCLUSION

Omalizumab exerts inhibitory effects on airway inflammation in Japanese patients with severe allergic asthma. This treatment attenuates production of IL-5 by PBMCs stimulated with both a specific allergen and a nonspecific activator. Reduction of the Th2 inflammatory cascade likely contributes to clinical benefits; however, further studies are required to clarify these results due to the small sample size in this study.

Flavonone treatment reverses airway inflammation and remodelling in an asthma murine model

BACKGROUND AND PURPOSE

Asthma is an inflammatory disease that involves airway hyperresponsiveness and remodelling. Flavonoids have been associated to anti-inflammatory and antioxidant activities and may represent a potential therapeutic treatment of asthma. Our aim was to evaluate the effects of the sakuranetin treatment in several aspects of experimental asthma model in mice.

EXPERIMENTAL APPROACH

Male BALB/c mice received ovalbumin (i.p.) on days 0 and 14, and were challenged with aerolized ovalbumin 1% on days 24, 26 and 28. Ovalbumin-sensitized animals received vehicle (saline and dimethyl sulfoxide, DMSO), sakuranetin (20 mg kg(-1) per mice) or dexamethasone (5 mg kg(-1) per mice) daily beginning from 24th to 29th day. Control group received saline inhalation and nasal drop vehicle. On day 29, we determined the airway hyperresponsiveness, inflammation and remodelling as well as specific IgE antibody. RANTES, IL-5, IL-4, Eotaxin, IL-10, TNF-α, IFN-γ and GMC-SF content in lung homogenate was performed by Bioplex assay, and 8-isoprostane and NF-kB activations were visualized in inflammatory cells by immunohistochemistry.

KEY RESULTS

We have demonstrated that sakuranetin treatment attenuated airway hyperresponsiveness, inflammation and remodelling; and these effects could be attributed to Th2 pro-inflammatory cytokines and oxidative stress reduction as well as control of NF-kB activation.

CONCLUSIONS AND IMPLICATIONS

These results highlighted the importance of counteracting oxidative stress by flavonoids in this asthma model and suggest sakuranetin as a potential candidate for studies of treatment of asthma.

Novel targeted therapies for eosinophilic disorders

Hypereosinophilic syndromes (HESs) are a diverse group of conditions characterized by clinical manifestations attributable to eosinophilia and eosinophilic infiltration of tissues. HESs are chronic disorders with significant morbidity and mortality. Although the availability of targeted chemotherapeutic agents, including imatinib, has improved quality of life and survival in some patients with HESs, additional agents with increased efficacy and decreased toxicity are sorely needed. The purpose of this review is to provide an overview of eosinophil biology with an emphasis on potential targets of pharmacotherapy and to provide a summary of potential eosinophil-targeting agents, including those in development, in clinical trials, or approved for other disorders.

Airway responses and inflammation in subjects with asthma after four days of repeated high-single-dose allergen challenge

BACKGROUND

Both standard and low-dose allergen provocations are an established tool in asthma research to improve our understanding of the pathophysiological mechanism of allergic asthma. However, clinical symptoms are less likely to be induced. Therefore, we designed a protocol for repetitive high-dose bronchial allergen challenges to generate clinical symptoms and airway inflammation.

METHODS

A total of 27 patients aged 18 to 40 years with positive skin-prick tests and mild asthma underwent repetitive high-dose allergen challenges with household dust mites for four consecutive days. Pulmonary function and exhaled NO were measured at every visit. Induced sputum was analysed before and after the allergen challenges for cell counts, ECP, IL-5, INF-γ, IL-8, and the transcription factor Foxp3.

RESULTS

We found a significant decrease in pulmonary function, an increased use of salbutamol and the development of a late asthmatic response and bronchial hyperresponsiveness, as well as a significant induction of eNO, eosinophils, and Th-2 cytokines. Repeated provocation was feasible in the majority of patients. Two subjects had severe adverse events requiring prednisolone to cope with nocturnal asthma symptoms.

CONCLUSIONS

Repeated high-dose bronchial allergen challenges resulted in severe asthma symptoms and marked Th-2-mediated allergic airway inflammation. The high-dose challenge model is suitable only in an attenuated form in diseased volunteers for proof-of-concept studies and in clinical settings to reduce the risk of severe asthma exacerbations.

TRIAL REGISTRATION

ClinicalTrials.govNCT00677209.