Tezepelumab and Mucus Plugs in Patients with Moderate-to-Severe Asthma

Tezepelumab can Restore Normal Lung Function in Patients with Severe, Uncontrolled Asthma: Pooled Results from the PATHWAY and NAVIGATOR Studies

INTRODUCTION

This post hoc analysis assessed the ability of tezepelumab treatment to restore normal lung function in patients with severe, uncontrolled asthma with abnormal lung function at baseline pooled from the PATHWAY and NAVIGATOR studies.

METHODS

PATHWAY and NAVIGATOR were multicentre, randomized, double-blind, placebo-controlled studies. Patients (12-80 years old) included in this analysis received tezepelumab 210 mg subcutaneously every 4 weeks or matched placebo for 52 weeks. Patients had a percent predicted pre-bronchodilator (BD) forced expiratory volume in 1 s (FEV1) of < 80% (< 90% for adolescents in NAVIGATOR) at screening. The change from baseline to week 52 in pre-BD FEV1 was assessed by baseline percent predicted pre-BD FEV1 subgroup [abnormal (< 80%) and normal (≥ 80%)]. The proportion of patients with abnormal lung function at baseline who achieved normal lung function at week 52 was assessed overall and by biomarker level and disease duration subgroups.

RESULTS

Of the 665 and 669 patients who received tezepelumab or placebo, respectively, 564 and 569 had abnormal lung function at baseline. Tezepelumab improved the pre-BD FEV1 from baseline to week 52 versus placebo by 0.14 L [95% confidence interval (CI) 0.09-0.19] and 0.13 L (95% CI 0.01-0.24) in patients with abnormal and normal lung function at baseline, respectively. A higher proportion of tezepelumab than placebo recipients with abnormal lung function at baseline achieved normal lung function at week 52 (17.2% vs. 9.9%, respectively). Among tezepelumab recipients, those with higher levels of type 2 inflammatory biomarkers and a shorter duration of disease at baseline were more likely to achieve normal lung function at week 52.

CONCLUSION

In patients with severe, uncontrolled asthma, a greater proportion of tezepelumab than placebo recipients with abnormal lung function at baseline achieved normal lung function at week 52.

TRIAL REGISTRATION

PATHWAY: NCT02054130; NAVIGATOR: NCT03347279.

Mucus Plug Score Predicts Clinical and Pulmonary Function Response to Biologic Therapy in Patients With Severe Asthma

BACKGROUND

Mucus plugging has been identified as an important feature of severe asthma contributing to airway obstruction and disease severity. Recently, improvement in mucus plugging has been found on treatment with several biologic therapies.

OBJECTIVES

To analyze associations of baseline characteristic with the mucus plugging score (MPS) and to determine whether the MPS at baseline predicts the clinical and functional response to biologic treatment in patients with severe asthma.

METHODS

We retrospectively analyzed biologic-naive patients with a suitable computed tomography scan available at baseline. We calculated the MPS and analyzed correlations with baseline parameters and improvements in biomarkers, pulmonary function, and clinical parameters after 4 months of biologic therapy.

RESULTS

We included 113 patients in the baseline cohort, 101 patients of whom had sufficient data after 4 months of biologic therapy for the follow-up analysis. Computed tomography showed mucus plugging in 77% of patients (median MPS, 4). Multivariate regression analysis showed a correlation of MPS with lower FEV1 (ρ = -0.24; P = .009) and diffusing capacity for carbon monoxide (ρ = -0.26; P = .01), and higher FeNO (ρ = .36; P = .0003) at baseline. Patients received treatment with anti-IgE (8.8%), anti-IL-5 (27.4%), anti-IL-5R (37.2%), anti-IL-4R (25.7%), and anti-thymic stromal lymphopoietin (0.9%) in clinical routine. Baseline MPS correlated with improvements in FEV1 (β = 0.72; P = .01) and Asthma Control Test (β = 0.24; P = .001) in multivariate regression analysis.

CONCLUSION

Our study suggests that a higher MPS correlates with worse pulmonary function at baseline but also predicts a larger clinical and pulmonary function response to biologic therapies in severe asthma.

Real-World Effectiveness of Biologic Therapy in Allergic Bronchopulmonary Aspergillosis

BACKGROUND

Allergic bronchopulmonary aspergillosis (ABPA) is characterized by a severe hypersensitivity reaction to Aspergillus species. Current treatment relies on oral corticosteroids (OCS) and triazole antifungal therapy, but there is increasing evidence of the benefits of biologic therapies targeting type 2 inflammatory pathways.

OBJECTIVE

To assess the real-world effectiveness of biologic therapies in patients with ABPA.

METHODS

We performed a large retrospective single-center analysis of patients with ABPA as defined by the modified International Society for Human and Animal Mycology (ISHAM) criteria between 2014 and 2022. Baseline characteristics were recorded. Clinical outcomes were assessed at 12 months after commencement of a biologic including symptom scores, exacerbation frequency, corticosteroid use, and multidisciplinary team consensus of effectiveness.

RESULTS

A total of 74 patients received a biologic, of whom 32% (n = 24) received anti-IgE therapy, 65% (n = 48) anti-IL5/5Rα therapy, and 3% (n = 2) anti-IL4-Rα therapy. Of the total, 65% (n = 48) patients were deemed to have a successful response at 12 months with a ≥50% reduction in OCS use and 35% (n = 26) stopped or changed biologic during the follow-up period because of failed clinical response (n = 21), side effects (n = 4), or medical comorbidities (n = 1). There was a significant reduction in the 6-item Asthma Control Questionnaire score (P < .0001), exacerbation rate over 12 months (P < .0001), and maintenance OCS use (P = .0173). Univariate analysis revealed that mucus plugging was associated with nonresponse to biologic therapy (P = .0189).

CONCLUSION

Biologic therapies are effective in a number of patients with ABPA. However, further prospective clinical trials are required to determine the effectiveness and which phenotypes likely to respond. These data nevertheless increase the evidence base for biologics in ABPA.

Three-dimensional bronchial tree visualization in exercise-induced severe asthma following tezepelumab treatment

Airway hyperresponsiveness, a key feature of asthma, is associated with exercise-induced asthma. Tezepelumab was reported to reduce airway hyperresponsiveness. Tezepelumab was confirmed through 3-dimensional bronchial tree visualization to be effective for exercise-induced asthma, reducing the need for a short-acting β2 agonist.

A real-world study on tezepelumab effectiveness in severe asthma focusing on small airway dysfunction

BACKGROUND

Severe asthma (SA) is a complex condition often involving small airway dysfunction (SAD). Tezepelumab has demonstrated efficacy in clinical trials, but real-world evidence is scarce, and its impact on SAD remains unexplored.

OBJECTIVE

This prospective study evaluated the effectiveness of tezepelumab in patients with SA, stratified by the SAD presence and asthma phenotype (type 2-high vs type 2-low).

METHODS

Seventeen SA patients received tezepelumab. A range of clinical and laboratory outcomes were assessed, including annualized asthma exacerbation rate (AAER), lung function, and oral corticosteroids (OCS) use. Respiratory parameters were assessed using spirometry, body plethysmography, and forced oscillation technique (FOT).

RESULTS

After 6 months of treatment, tezepelumab significantly reduced median AAER (from 5.0 to 0.0, p = 0.001) and OCS dose (from 14.6 mg/day to 0.0 mg/day, p < 0.001), alongside a marked reduction in median blood eosinophil count (from 130 to 60 cells/mm3, p = 0.032). Among respiratory parameters, total resistance, measured by body plethysmography, improved significantly in the overall population (median values from 0.49 to 0.37 KPa L s-1, p = 0.005). Spirometry and FOT measures, including total reactance (p = 0.018) and tidal expiratory flow limitation (p = 0.043), improved only in patients with SAD.

CONCLUSION

Tezepelumab significantly reduced exacerbations and improved asthma control, positively impacting respiratory parameters and small airway function in patients with SAD. These findings support SAD as a treatable trait, highlighting the importance of integrating advanced diagnostic tools, such as body plethysmography and FOT, into routine clinical practice.

Recent advances in asthma mucus biology and emerging treatment strategies

PURPOSE OF REVIEW

To describe the recent advances in the pathobiology and treatment of mucus hypersecretion in asthma, a critical factor contributing to airway obstruction, inflammation, and impaired lung function.

RECENT FINDINGS

Significant progress has been made in understanding how mucin protein regulation, mucus viscosity, and adhesion are affected by cytokine-driven inflammation, especially interleukin-13, and defects in ion transport mechanisms. Advances in imaging techniques, such as multidetector computed tomography (MDCT) and hyperpolarized gas MRI, allow for a more precise assessment of mucus plugging and associated ventilation defects. Emerging therapies, including biologicals targeting type-2 (T2) inflammation, and novel mucolytics aimed at modifying mucus properties and secretion, offer promising effects in reducing mucus in severe asthmatics.

SUMMARY

The growing understanding of mucus biology and the development of advanced imaging and therapeutic strategies could significantly improve the management of mucus-related complications in asthma. By targeting mucus characteristics, these findings support future approaches to reduce airway obstruction, enhance lung function, and improve clinical outcomes in patients with severe asthma. A deeper understanding of the glycobiology of mucus is critical to develop new therapies.

Airway epithelial cells as drivers of severe asthma pathogenesis

Our understanding of the airway epithelium's role in driving asthma pathogenesis has evolved over time. From being regarded primarily as a physical barrier that could be damaged via inflammation, the epithelium is now known to actively contribute to asthma development through interactions with the immune system. The airway epithelium contains multiple cell types with specialized functions spanning barrier action, mucociliary clearance, immune cell recruitment, and maintenance of tissue homeostasis. Environmental insults may cause direct or indirect injury to the epithelium leading to impaired barrier function, epithelial remodelling, and increased release of inflammatory mediators. In severe asthma, the epithelial barrier repair process is inhibited and the response to insults is exaggerated, driving downstream inflammation. Genetic and epigenetic mechanisms also maintain dysregulation of the epithelial barrier, adding to disease chronicity. Here, we review the role of the airway epithelium in severe asthma and how targeting the epithelium can contribute to asthma treatment.

Effect of dupilumab on exhaled nitric oxide, mucus plugs, and functional respiratory imaging in patients with type 2 asthma (VESTIGE): a randomised, double-blind, placebo-controlled, phase 4 trial

BACKGROUND

Asthma is a respiratory disease characterised by chronic airway inflammation and mucus hypersecretion. VESTIGE used functional respiratory imaging to assess changes in airway structure and function, including mucus plugging, in response to dupilumab.

METHODS

VESTIGE was a randomised, double-blind, placebo-controlled, phase 4 trial done at 72 research sites or academic centres in 14 countries. We recruited adult patients (aged 18-70 years) with physician-diagnosed, uncontrolled, moderate-to-severe type 2 asthma (blood eosinophil count ≥300 cells/μL and fractional exhaled nitric oxide [FeNO] ≥25 parts per billion [ppb]) being treated with medium-dose to high-dose inhaled corticosteroids combined with other controller medications. Patients were randomly assigned (2:1; block size of 6) via interactive voice-web response technology to receive add-on dupilumab 300 mg subcutaneously once every 2 weeks or volume-matched placebo up to week 24. Randomisation was stratified by inhaled corticosteroids dose level and region (eastern Europe vs the rest of the world). Participants and investigators, including those assessing outcomes, were masked to group assignment. The primary endpoints were the proportion of patients with a FeNO concentration below 25 ppb at week 24, and percentage change from baseline to week 24 in airway volumes (specific regional airway volumes corrected for lung volume, [s]iVaw) at total lung capacity (TLC), both assessed in the intention-to-treat population. Safety was assessed in all patients who received at least one dose of study drug or placebo. The trial is registered with ClinicalTrials.gov, NCT04400318, and is completed.

FINDINGS

Patient recruitment occurred from July 18, 2020, to Jan 6, 2023. Patients (mean age 50·4 years [SD 12·6]; 68 [62%] female and 41 [38%] male) were randomly assigned to receive dupilumab 300 mg (n=72) or placebo (n=37). At week 24, patients in the dupilumab group were significantly more likely than those in the placebo group to have a FeNO concentration below 25 ppb (41 [57%] of 72 patients vs four [11%] of 37; odds ratio: 9·8 [95% CI 3·1 to 30·8]; p<0·001). Treatment with dupilumab versus placebo led to a numerical increase in (s)iVaw at TLC from baseline to week 24, although the difference was not significant (least squares [LS] mean percentage change from baseline to week 24: 19·7% [SE 8·1] for dupilumab and -2·0% [11·5] for placebo; LS mean difference vs placebo: 21·8% [95% CI -7·7 to 51·3]; p=0·14). Safety was consistent with the reported safety profile for dupilumab. Treatment-emergent adverse events related to study intervention were reported in 11 (15%) of 72 patients who received dupilumab and four (11%) of 37 who received placebo; no deaths occurred during the intervention period.

INTERPRETATION

The full results of this study indicate that dupilumab reduced airway inflammation and mucus plugging, and improved airway volume and flow, corresponding to improved lung function and asthma control. This study highlights the potential of imaging technology to assess disease burden, monitor progression, and evaluate therapeutic responses, which can provide valuable insights to guide clinical decision making for patients with uncontrolled, moderate-to-severe type 2 asthma.

FUNDING

Sanofi and Regeneron Pharmaceuticals.

Innate Immunity and Asthma Exacerbations: Insights From Human Models

Asthma is a common chronic respiratory disease characterized by the presence of airway inflammation, airway hyperresponsiveness, and mucus hypersecretion. Repeated asthma exacerbations can lead to progressive airway remodeling and irreversible airflow obstruction. Thus, understanding and preventing asthma exacerbations are of paramount importance. Although multiple endotypes exist, asthma is most often driven by type 2 airway inflammation. New therapies that target specific type 2 mediators have been shown to reduce the frequency of asthma exacerbations but are incompletely effective in a significant number of asthmatics. Furthermore, it remains unknown whether current treatments lead to sustained changes in the airway or if targeting additional pathways may be necessary to achieve asthma remission. Activation of innate immunity is the initial event in the inflammatory sequence that occurs during an asthma exacerbation. However, there continue to be critical gaps in our understanding of the innate immune response to asthma exacerbating factors. In this review, we summarize the current understanding of the role of innate immunity in asthma exacerbations and the methods used to study them. We also identify potential novel therapeutic targets for asthma and future areas for investigation.

Biologics and airway remodeling in asthma: early, late, and potential preventive effects

Although airway remodeling in severe and/or fatal asthma is still considered irreversible, its individual components as a cause of clinical symptoms and/or lung function changes remain largely unknown. While inhaled glucocorticoids have not consistently been shown to affect airway remodeling, biologics targeting specific pathways of airway inflammation have been shown to improve lung function, mucus plugging, and airway structural changes that can exceed those seen with glucocorticoids. This superiority of biologic treatment, which cannot be solely explained by insufficient doses or limited durations of glucocorticoid therapies, needs to be further explored. For this field of research, we propose a novel classification of the potential effects of biologics on airway remodeling into three temporal effects: early effects (days to weeks, primarily modulating inflammatory processes), late effects (months to years, predominantly affecting structural changes), and potential preventive effects (outcomes of early treatment with biologics). For the identification of potential preventive effects of biologics, we call for studies exploring the impact of early biological treatment on airway remodeling in patients with moderate-to-severe asthma, which should be accompanied by a long-term evaluation of clinical parameters, biomarkers, treatment burden, and socioeconomic implications.

Development and qualification of an LC-MS/MS method for quantification of MUC5AC and MUC5B mucins in spontaneous sputum

AIM

Airway mucins in sputum are promising respiratory disease biomarkers, despite posing substantial analytical challenges due to their physicochemical properties and rare and heterogenous nature of the matrix. We aimed to identify a suitable sputum collection and processing method, and qualify a bioanalytical method for MUC5AC and MUC5B quantification in clinical samples.

METHOD

Mucins were quantified in induced and spontaneous sputum collected from the same COPD patients, following various sample processing procedures. LC-MS/MS method used truncated recombinant mucins as surrogate analytes in surrogate matrix.

RESULTS

Frozen spontaneous sputum was found to be a suitable and convenient matrix for mucin quantification and fit-for-purpose method qualification was performed.

CONCLUSION

Our methodology provides accurate and reliable MUC5AC and MUC5B quantification and facilitates multi-site clinical sputum collection.

New frontiers in asthma chest imaging

Modern pulmonary imaging can reveal underlying pathologic and pathophysiologic changes in the lungs of people with asthma, with important clinical implications. A multitude of imaging modalities, including computed tomography, magnetic resonance imaging, optical coherence tomography, and endobronchial ultrasound, are now being used to examine underlying structure-function relationships. Imaging-based biomarkers from these techniques, including airway dimensions, blood vessel volumes, mucus scores, extent of ventilation defect, and extent of air trapping, often have increased sensitivity compared with that of traditional lung function measurements and are increasingly being used as end points in clinical trials. Imaging has been crucial to recent improvements in our understanding of the relationships between type 2 inflammation, eosinophilia, and mucus extent. With the advent of effective anti-type 2 biologic therapies, computed tomography and magnetic resonance imaging techniques can identify not just which patients benefit from therapy but why they benefit. Clinical trials have begun to assess the utility of imaging to prospectively plan airway therapy targets in bronchial thermoplasty and have potential to direct future bronchoscopic therapies. Together, imaging techniques provide a diverse set of tools to investigate how spatially distributed airway, blood, and parenchymal abnormalities shape disease heterogeneity in patients with asthma.

Effect of mepolizumab in airway remodeling in patients with late-onset severe asthma with an eosinophilic phenotype

BACKGROUND

Clinical trials and real-world experience have provided evidence for the clinical benefits of mepolizumab, an anti-IL-5 biologic, in severe asthma. However, limited data exist regarding the impact of mepolizumab on airway remodeling.

OBJECTIVE

We sought to investigate the effect of mepolizumab on airway structural remodeling in patients treated for severe asthma in routine clinical care.

METHODS

The MESILICO (Efficacy of Mepolizumab in patients with latE-onset Severe eosInophiLic asthma and fIxed obstruCtiOn) study is a multicenter study involving 8 pulmonology departments in Greece. This study focused on patients who initiated mepolizumab for severe asthma with an eosinophilic phenotype and had late-onset disease with obstructive patterns (impaired reversibility). Forty-seven patients were recruited, of whom 41 were enrolled in the bronchoscopy substudy. The findings were related to clinical outcome.

RESULTS

After 12 months, mepolizumab treatment was associated with significant improvements in lung function and Asthma Control Test score, along with a significant decrease in severe exacerbation events (P < .001). Thirty-four of the 41 participants (83%) had paired biopsies for comparative analysis. There was a significant reduction from baseline in sub-basement membrane thickness, airway smooth muscle area, airway smooth muscle layer thickness, extent of epithelial damage, and number of tissue eosinophils (all P < .001). The extent of reduction in airway smooth muscle layer thickness positively correlated with the submucosal eosinophil reduction (r = 0.599; P < .001).

CONCLUSIONS

This study identified that 12 months of mepolizumab treatment in patients with late-onset severe asthma, who are also characterized by eosinophilic and impaired reversibility phenotypes, not only leads to clinical improvement but also reduces indices of airway tissue remodeling suggestive of a disease-modifying effect.

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.

Airway Remodeling in Asthma: Mechanisms, Diagnosis, Treatment, and Future Directions

Airway remodeling (AR) with chronic inflammation, are key features in asthma pathogenesis. AR characterized by structural changes in the bronchial wall is associated with a specific asthma phenotype with poor clinical outcomes, impaired lung function and reduced treatment response. Most studies focus on the role of inflammation, while understanding the mechanisms driving AR is crucial for developing disease-modifying therapeutic strategies. This review paper summarizes current knowledge on the mechanisms underlying AR, diagnostic tools, and therapeutic approaches. Mechanisms explored include the role of the resident cells and the inflammatory cascade in AR. Diagnostic methods such as bronchial biopsy, lung function testing, imaging, and possible biomarkers are described. The effectiveness on AR of different treatments of asthma including corticosteroids, leukotriene modifiers, bronchodilators, macrolides, biologics, and bronchial thermoplasty is discussed, as well as other possible therapeutic options. AR poses a significant challenge in asthma management, contributing to disease severity and treatment resistance. Current therapeutic approaches target mostly airway inflammation rather than smooth muscle cell dysfunction and showed limited benefits on AR. Future research should focus more on investigating the mechanisms involved in AR to identify novel therapeutic targets and to develop new effective treatments able to prevent irreversible structural changes and improve long-term asthma outcomes.

Biologics in severe asthma: a state-of-the-art review

Asthma is considered severe if it remains uncontrolled despite optimal conventional therapy, characterised by poor symptom control, frequent exacerbations and increased exposure to systemic corticosteroids. This has a significant impact on morbidity, mortality and healthcare resource utilisation. Recent advances in the understanding of asthma heterogeneity and immunopathogenesis have helped delineate precise disease pathways. The discovery of these pivotal pathways has led to the development of highly effective biologic therapies. Currently available asthma biologics target immunoglobulin E, interleukin (IL)-5/IL-5Rα, IL-4Rα and thymic stromal lymphopoietin. Identification of specific asthma phenotypes, utilising easily measurable biomarkers, has paved the way towards personalised and precision asthma management. Biologic therapies play a significant role in reducing exacerbations, hospitalisations and the need for maintenance systemic steroids, while also improving the quality of life in patients with severe asthma. The evidence for their clinical efficacy comes from randomised controlled trials (RCTs), extension studies, metanalyses and real-world data. This review synthesises findings from early, pivotal RCTs and subsequent studies following the approval of biologics for severe asthma. The safety and efficacy data from these studies, completed in a variety of settings, provide practical perspectives on their application and enhance their generalisability.

Molecular mechanisms and clinical impact of biologic therapies in severe asthma

Severe asthma is a critical condition for patients with asthma, characterized by frequent exacerbations, decreased pulmonary function, and unstable symptoms related to asthma. Consequently, the administration of systemic corticosteroids, which cause secondary damage because of their adverse effects, is considered. Recently, several types of molecular-targeted biological therapies have become available for patients with severe asthma, and they have a capacity to improve the pathophysiology of severe asthma. However, several clinical reports indicate that the effects differ depending on the biological targets of asthma in individual patients. In this review, the molecular mechanisms and clinical impact of biologic therapies in severe asthma are described. In addition, molecules targeted by possible future biologics are also addressed. Better understanding of the mechanistic basis for the role of biologics in severe asthma could lead to new therapeutic options for these patients.

Identifying super-responders: A review of the road to asthma remission

Asthma is a chronic respiratory disease marked by heterogeneity and variable clinical outcomes. Recent therapeutic advances have highlighted patients achieving optimal outcomes, termed "remission" or "super-response." This review evaluates the various definitions of these terms and explores how disease burden impedes the attainment of remission. We assessed multiple studies, including a recent systematic review and meta-analysis, on biologic treatments for asthma remission. Our review highlights that type 2 inflammation may be the strongest predictor of biologic response. Key comorbidities (eg, obesity and mood disorders) and behavioral factors (eg, poor adherence, improper inhalation technique, and smoking) were identified as dominant traits limiting remission. In addition, asthma burden and longer disease duration significantly restrict the potential for remission in patients with severe asthma under the current treatment paradigm. We review the potential for a "predict-and-prevent" approach, which focuses on early identification of high-risk patients with type 2 inflammation and aggressive treatment to improve long-term asthma outcomes. In conclusion, this scoping review highlights the following unmet needs in asthma remission: (1) a harmonized global definition, with better defined lung function parameters; (2) integration of nonbiologic therapies into remission strategies; and (3) a clinical trial of early biologic intervention in patients with remission-prone, very type 2-high, moderately severe asthma with clinical remission as a predefined primary end point.

Possible Biological Heterogeneity of Airway Mucus Plugs in a Patient with Asthma

Background

The presence of mucus plugs in the airway is a severe phenotype in patients with asthma; however, the mechanisms and specific treatments are not fully understood.

Purpose

To clarify the efficacy of biologics and the mechanisms for mucus plug in patients with asthma.

Patients and Methods

A 79-year-old Japanese asthmatic woman with high blood eosinophil and fractional exhaled nitric oxide (FeNO) was pointed massive mucus plugs in airway on chest CT imaging. She was treated with mepolizumab for 3 months; however, those were augmented without improvement of pulmonary function and FeNO. She was switched to dupilumab and, three months later, the mucus plugs were completely disappeared with improvement in pulmonary function, FeNO and asthma-related symptoms. She continues treatment with dupilumab, and her asthma symptoms are stable.

Conclusion

Biologics including mepolizumab and dupilumab have been reported to improve mucus plugs in patients with asthma; however, their efficacy might be different depending on the clinical characteristics of patients. Present data remind us of the possibility that, if FeNO levels remain high after treatment with anti-IL-5 antibody in asthma patients with mucus plugs, switching to other biologics, including anti-IL-4Rα antibody, might be considered.

Thymic Stromal Lymphopoietin (TSLP): Evidence in Respiratory Epithelial-driven Diseases Including Chronic Rhinosinusitis with Nasal Polyps

PURPOSE OF THE REVIEW

Thymic stromal lymphopoietin (TSLP) is increasingly recognized for its pivotal role in the pathogenesis of various epithelial-driven chronic inflammatory diseases. This review navigates the existing evidence on TSLP, with a particular focus on asthma, before delving into the current understanding of its role in chronic rhinosinusitis with nasal polyps (CRSwNP). We explore the role of TSLP in the pathogenesis of asthma and CRSwNP, two conditions often interconnected and collectively referred to as"Global Airway Disease". Additionally, this review assesses the therapeutic potential of TSLP inhibition as a treatment option for both CRSwNP and asthma. A systematic literature search was conducted; selected publications were used to describe the biology of TSLP, including its expression and diverse effects on inflammation.

RECENT FINDINGS

The role of TSLP in asthma is well established and supported by the efficacy of tezepelumab, the first anti-TSLP monoclonal antibody approved for both type 2 (T2)-high and T2-low severe asthma. TSLP may be a key contributor to CRSwNP pathogenesis as evidenced by genetic and mechanistic studies in which TSLP has been shown to regulate T2 inflammation and influence non-T2 responses. Preliminary data from the NAVIGATOR trial indicate that tezepelumab may reduce CRSwNP symptoms in patients with comorbid asthma. While further research is required to clarify the extent of TSLP contribution in CRSwNP, this review highlights the potential of anti-TSLP therapies as a novel approach for managing severe, uncontrolled CRSwNP. If these preliminary findings are confirmed, targeting TSLP could become a promising strategy to treat CRSwNP with or without comorbid asthma.

Clinical response and on-treatment clinical remission with tezepelumab in a broad population of patients with severe, uncontrolled asthma: results over 2 years from the NAVIGATOR and DESTINATION studies

BACKGROUND

In asthma, clinical response is characterised by disease improvement with treatment, whereas clinical remission is characterised by long-term disease stabilisation with or without ongoing treatment. The proportions of patients receiving tezepelumab who responded to treatment and who achieved on-treatment clinical remission were assessed in the NAVIGATOR (ClinicalTrials.gov identifier NCT03347279) and DESTINATION (ClinicalTrials.gov identifier NCT03706079) studies of severe, uncontrolled asthma.

METHODS

NAVIGATOR and DESTINATION were phase 3, randomised, double-blind, placebo-controlled studies; DESTINATION was an extension of NAVIGATOR. Complete clinical response was defined as achieving all of the following: ≥50% reduction in exacerbations versus the previous year, improvements in pre-bronchodilator (BD) forced expiratory volume in 1 s (FEV1) of ≥100 mL or ≥5%, improvements in Asthma Control Questionnaire (ACQ)-6 score of ≥0.5 and physician's assessment of asthma improvement. On-treatment clinical remission was defined as an ACQ-6 total score ≤1.5, stable lung function (pre-BD FEV1 >95% of baseline) and no exacerbations or use of oral corticosteroids during the time periods assessed.

RESULTS

Higher proportions of tezepelumab than placebo recipients achieved complete clinical response over weeks 0-52 (46% versus 24%; OR 2.83, 95% CI 2.10-3.82) and on-treatment clinical remission over weeks 0-52 (28.5% versus 21.9%; OR 1.44, 95% CI 0.95-2.19) and weeks >52-104 (33.5% versus 26.7%; OR 1.44, 95% CI 0.97-2.14). Tezepelumab recipients who achieved on-treatment clinical remission versus complete clinical response at week 52 had better preserved lung function and lower inflammatory biomarker levels at baseline, and fewer exacerbations in the 12 months before the study.

CONCLUSIONS

Among patients with severe, uncontrolled asthma, tezepelumab treatment was associated with an increased likelihood of achieving complete clinical response and on-treatment clinical remission compared with placebo. Both are clinically important outcomes, but may be driven by different patient characteristics.

Positioning tezepelumab for patients with severe asthma: from evidence to unmet needs

Several endotypes of severe asthma with predominantly type 2 inflammation can be distinguished by the immune pathways driving the inflammatory processes. However, in the absence of type 2 inflammation, asthma is less clearly defined and is generally associated with poor responses to conventional anti-asthmatic therapies. Studies have shown that disruption of the epithelial barrier triggers inflammatory responses and increases epithelial permeability. A key aspect of this process is that epithelial cells release alarmin cytokines, including interleukin (IL)-25, IL-33, and thymic stromal lymphopoietin (TSLP), in response to allergens and infections. Among these cytokines, TSLP has been identified as a potential therapeutic target for severe asthma, leading to the development of a new biologic, tezepelumab (TZP). By blocking TSLP, TZP may produce wide-ranging effects. Based on positive clinical trial results, TZP appears to offer a promising, safe, and effective treatment approach. This narrative review examines the evidence for treating severe asthma with TZP, analyses clinical trial findings, and provides clinicians with practical insights into identifying patients who may respond best to this novel biologic therapy.

Lung imaging in COPD and asthma

Chronic obstructive pulmonary disease (COPD) and asthma are common lung diseases with heterogeneous clinical presentations. Lung imaging allows evaluations of underlying pathophysiological changes and provides additional personalized approaches for disease management. This narrative review provides an overview of recent advances in chest imaging analysis using various modalities, such as computed tomography (CT), dynamic chest radiography, and magnetic resonance imaging (MRI). Visual CT assessment localizes emphysema subtypes and mucus plugging in the airways. Dedicated software quantifies the severity and spatial distribution of emphysema and the airway tree structure, including the central airway wall thickness, branch count and fractal dimension of the tree, and airway-to-lung size ratio. Nonrigid registration of inspiratory and expiratory CT scans quantifies small airway dysfunction, local volume changes and shape deformations in specific regions. Lung ventilation and diaphragm movement are also evaluated on dynamic chest radiography. Functional MRI detects regional oxygen transfer across the alveolus using inhaled oxygen and ventilation defects and gas diffusion into the alveolar-capillary barrier tissue and red blood cells using inhaled hyperpolarized 129Xe gas. These methods have the potential to determine local functional properties in the lungs that cannot be detected by lung function tests in patients with COPD and asthma. Further studies are needed to apply these technologies in clinical practice, particularly for early disease detection and tailor-made interventions, such as the efficient selection of patients likely to respond to biologics. Moreover, research should focus on the extension of healthy life expectancy in patients at higher risk and with established diseases.

Picture this: The future of imaging biomarkers in COPD

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Efficacy of tezepelumab in patients with severe asthma and persistent airflow obstruction

Background

Persistent airflow obstruction (PAO) in patients with asthma can be difficult to treat. Tezepelumab blocks thymic stromal lymphopoietin, an epithelial cytokine implicated in asthma pathogenesis. This analysis evaluated the efficacy of tezepelumab in patients with severe, uncontrolled asthma and PAO.

Methods

PATHWAY (phase 2b) and NAVIGATOR (phase 3) were multicentre, randomised, double-blind, placebo-controlled studies. This post hoc analysis included PATHWAY and NAVIGATOR patients who received tezepelumab 210 mg or placebo every 4 weeks for 52 weeks. Change from baseline to week 52 in pre-bronchodilator forced expiratory volume in 1 s (FEV1) and the annualised asthma exacerbation rate (AAER) over 52 weeks were assessed in patients with and without PAO (post-bronchodilator FEV1/forced vital capacity ratio <0.7) at baseline.

Results

Of the 1334 included patients, 782 (58.6%) had PAO at baseline. At week 52, greater improvements in pre-bronchodilator FEV1 from baseline were observed in tezepelumab versus placebo recipients with PAO (least-squares (LS) mean 0.24 versus 0.07 L; difference 0.17 L, 95% confidence interval (CI): 0.11-0.23) and without PAO (LS mean 0.20 versus 0.12 L; difference 0.08 L, 95% CI: 0.01-0.15). Tezepelumab reduced the AAER versus placebo by 61% (95% CI: 51-69) and 56% (95% CI: 42-67) in patients with and without PAO, respectively. For patients with PAO at baseline, the proportion without PAO at week 52 was higher with tezepelumab (12.1%) than placebo (6.6%) (odds ratio 1.96, 95% CI: 1.30-2.94).

Conclusion

Tezepelumab improved lung function and reduced exacerbations versus placebo in patients with severe, uncontrolled asthma with and without PAO.

Airway Mucus Plugs on Chest Computed Tomography Are Associated with Exacerbations in COPD

Rationale/Objective: Acute exacerbations (AEs) of chronic obstructive pulmonary disease (COPD) are associated with significant morbidity and mortality. Whether mucus plugs are associated with prospective exacerbations has not been examined extensively.

METHODS

Mucus plugs were visually-identified on baseline chest computed tomography (CT) scans from smokers with Global Initiative for Chronic Obstructive Lung Disease (GOLD) grades 2-4 COPD enrolled in two multicenter cohort studies: Evaluation of COPD Longitudinally to Identify Predictive Surrogate Endpoints (ECLIPSE) and COPDGene. Associations between ordinal mucus plug score categories (0/1-2/≥3) and prospectively-ascertained AEs, defined as worsening respiratory symptoms requiring systemic steroids and/or antibiotics (moderate-to-severe) and/or ER/hospitalization (severe), were assessed using multivariable-adjusted zero-inflated Poisson regression; subjects were exacerbation-free at enrollment.

RESULTS

Among 3,250 participants in COPDGene (mean±SD age 63.7±8.4 years, FEV1 50.6%±17.8% predicted, 45.1% female) and 1,716 participants in ECLIPSE (age 63.3±7.1 years, FEV1 48.3%±15.8% predicted, 36.2% female), 44.4% and 46.0% had mucus plugs, respectively. The incidence rates of AEs were 61.0 (COPDGene) and 125.7 (ECLIPSE) per 100 person-years. Relative to those without mucus plugs, the presence of 1-2 and ≥3 mucus plugs was associated with increased risk (adjusted rate ratio, aRR [95%CI]=1.07[1.05-1.09] and 1.15[1.1-1.2] in COPDGene; aRR=1.06[1.02-1.09] and 1.12[1.04-1.2] in ECLIPSE, respectively) for prospective moderate-to-severe AEs. The presence of 1-2 and ≥3 mucus plugs was also associated with increased risk for severe AEs during follow-up (aRR=1.05[1.01-1.08] and 1.09[1.02-1.18] in COPDGene; aRR=1.17[1.07-1.27] and 1.37[1.15-1.62] in ECLIPSE, respectively).

CONCLUSION

CT-based mucus plugs are associated with an increased risk for future COPD AEs.

The epithelial era of asthma research: knowledge gaps and future direction for patient care

The Epithelial Science Expert Group convened on 18-19 October 2023, in Naples, Italy, to discuss the current understanding of the fundamental role of the airway epithelium in asthma and other respiratory diseases and to explore the future direction of patient care. This review summarises the key concepts and research questions that were raised. As an introduction to the epithelial era of research, the evolution of asthma management throughout the ages was discussed and the role of the epithelium as an immune-functioning organ was elucidated. The role of the bronchial epithelial cells in lower airway diseases beyond severe asthma was considered, as well as the role of the epithelium in upper airway diseases such as chronic rhinosinusitis. The biology and application of biomarkers in patient care was also discussed. The Epithelial Science Expert Group also explored future research needs by identifying the current knowledge and research gaps in asthma management and ranking them by priority. It was identified that there is a need to define and support early assessment of asthma to characterise patients at high risk of severe asthma. Furthermore, a better understanding of asthma progression is required. The development of new treatments and diagnostic tests as well as the identification of new biomarkers will also be required to address the current unmet needs. Finally, an increased understanding of epithelial dysfunction will determine if we can alter disease progression and achieve clinical remission.

Exploring the therapeutic potential of monoclonal antibodies targeting TSLP and IgE in asthma management

BACKGROUND

In recent years, there has been a growing interest in the utilization of biologic therapies for the management of asthma. Both TSLP and IgE are important immune molecules in the development of asthma, and they are involved in the occurrence and regulation of inflammatory response.

METHODS

A comprehensive search of PubMed and Web of Science was conducted to gather information on anti-TSLP antibody and anti-IgE antibody.

RESULTS

This investigation elucidates the distinct mechanistic roles of Thymic Stromal Lymphopoietin (TSLP) and Immunoglobulin E (IgE) in the pathogenesis of asthma, with a particular emphasis on delineating the therapeutic mechanisms and pharmacological properties of monoclonal antibodies targeting IgE and TSLP. Through a meticulous examination of clinical trials involving paradigmatic agents such as omalizumab and tezepelumab, we offer valuable insights into the potential treatment modalities for diseases with shared immunopathogenic pathways involving IgE and TSLP.

CONCLUSION

The overarching objective of this comprehensive study is to delve into the latest advancements in asthma therapeutics and to provide guidance for future investigations in this domain.

What every clinician should know about inflammation in COPD

Inflammation drives COPD pathogenesis and exacerbations. Although the conceptual framework and major players in the inflammatory milieu of COPD have been long established, the nuances of cellular interactions and the etiological differences that create heterogeneity in inflammatory profiles and treatment response continue to be revealed. This wealth of data and understanding is not only a boon to the researcher but also provides guidance to the clinician, moving the field closer to precision medicine. It is through this lens that this review seeks to describe the inflammatory processes at play in COPD, relating inflammation to pathological and functional changes, identifying patient-specific and disease-related factors that may influence clinical observations, and providing current insights on existing and emerging anti-inflammatory treatments and treatment targets, including biological therapies and phosphodiesterase (PDE) inhibitors.

Imagining the severe asthma decision trees of the future

INTRODUCTION

There are no validated decision-making algorithms concerning severe asthma (SA) management. Future risks are crucial factors and can be derived from SA trajectories.

AREAS COVERED

The future severe asthma-decision trees should revisit current knowledge and gaps. A focused literature search has been conducted.

EXPERT OPINION

Asthma severity is currently defined a priori, thereby precluding a role for early interventions aiming to prevent outcomes such as exacerbations (systemic corticosteroids exposure) and lung function decline. Asthma 'at-risk' might represent the ultimate paradigm but merits longitudinal studies considering modern interventions. Real exacerbations, severe airway hyperresponsiveness, excessive T2-related biomarkers, noxious environments and patient behaviors, harms of OCS and high-doses inhaled corticosteroids (ICS), and low adherence-to-effectiveness ratios of ICS-containing inhalers are predictors of future risks. New tools such as imaging, genetic, and epigenetic signatures should be used. Logical and numerical artificial intelligence may be used to generate a consistent risk score. A pragmatic definition of response to treatments will allow development of a validated and applicable algorithm. Biologics have the best potential to minimize the risks, but cost remains an issue. We propose a simplified six-step algorithm for decision-making that is ultimately aiming to achieve asthma remission.

Associations of fractional exhaled nitric oxide with airway dimension and mucus plugs on ultra-high-resolution computed tomography in former smokers and nonsmokers with asthma

BACKGROUND

Associations of fractional exhaled nitric oxide (FeNO) with airway wall remodeling and mucus plugs remain to be explored in smokers and nonsmokers with asthma. Ultra-high-resolution computed tomography (U-HRCT), which allows accurate structural quantification of airways >1 mm in diameter, was used in this study to examine whether higher FeNO was associated with thicker walls of the 3rd to 6th generation airways and mucus plugging in patients with asthma.

METHODS

The retrospective analyses included consecutive former smokers and nonsmokers with asthma who underwent U-HRCT in a hospital. The ratio of wall area to summed lumen and wall area was calculated as the wall area percent (WA%). Mucus plugging was visually scored.

RESULTS

Ninety-seven patients with asthma (including 59 former smokers) were classified into low (<20 ppb), middle (20-35 ppb), and high (>35 ppb) FeNO groups (n = 24, 26, and 47). In analysis including all patients and subanalysis including nonsmokers or former smokers, WA% in the 6th generation airways was consistently higher in the high FeNO group than in the low FeNO group, whereas WA% in the 3rd to 5th generation airways was not. In multivariable models, WA% in the 6th generation airways and the rate of mucus plugging were higher in the high FeNO group than in the low FeNO group after adjusting for age, sex, body mass index, smoking status, lung volume, and allergic rhinitis presence.

CONCLUSIONS

Higher FeNO may reflect the inflammation and remodeling of relatively peripheral airways in asthma in both former smokers and nonsmokers.

Eosinophil-mucus interplay in severe asthma: Implications for treatment with biologicals

Airway mucus is a hydrogel with unique biophysical properties due to its primary water composition and a small proportion of large anionic glycoproteins or mucins. The predominant mucins in human mucus, MUC5AC and MUC5B, are secreted by specialized cells within the airway epithelium both in normal conditions and in response to various stimuli. Their relative proportions are correlated with specific inflammatory responses and disease mechanisms. The dysregulation of mucin expression is implicated in numerous respiratory diseases, including asthma, COPD, and cystic fibrosis, where the pathogenic role of mucus has been extensively described yet often overlooked. In airway diseases, excessive mucus production or impaired mucus clearance leads to mucus plugging, with secondary airway occlusion that contribute to airflow obstruction, asthma severity and poor control. Eosinophils and Charcot Leyden crystals in sputum contribute to the mucus burden and tenacity. Mucin may also contribute to eosinophil survival. Other mechanisms, including eosinophil-independent IL-13 release, mast-cell activation and non-type-2 (T2) cytokines, are also likely to participate in mucus pathobiology. An accurate assessment of mucus and its clinical and functional consequences require a thorough approach that includes evaluation of cellular predominance in sputum, airway cytokines and other inflammatory markers, mucus characteristics and composition and structural and functional impact measured by advanced lung imaging. This review, illustrated with clinical scenarios, provides an overview of current methods to assess mucus and its relevance to the choice of biologics to treat patients with severe asthma.

Type 2 severe asthma: pathophysiology and treatment with biologics

INTRODUCTION

The hallmark of most patients with severe asthma is type 2 inflammation, driven by innate and adaptive immune responses leading to either allergic or non-allergic eosinophilic infiltration of airways. The cellular and molecular pathways underlying severe type 2 asthma can be successfully targeted by specific monoclonal antibodies.

AREAS COVERED

This review article provides a concise overview of the pathophysiology of type 2 asthma, followed by an updated appraisal of the mechanisms of action and therapeutic efficacy of currently available biologic treatments used for management of severe type 2 asthma. Therefore, all reported information arises from a wide literature search performed on PubMed.

EXPERT OPINION

The main result of the recent advances in the field of anti-asthma biologic therapies is the implementation of a personalized medicine approach, aimed to achieve clinical remission of severe asthma. Today this accomplishment is made possible by the right choice of the most beneficial biologic drug for the pathologic traits characterizing each patient, including type 2 severe asthma and its comorbidities.

Tezepelumab in patients with allergic and eosinophilic asthma

Asthma is a heterogeneous disease commonly driven by allergic and/or eosinophilic inflammation, both of which may be present in severe disease. Most approved biologics for severe asthma are indicated for specific phenotypes and target individual downstream type 2 components of the inflammatory cascade. Tezepelumab, a human monoclonal antibody (immunoglobulin G2λ), binds specifically to thymic stromal lymphopoietin (TSLP), an epithelial cytokine that initiates and sustains allergic and eosinophilic inflammation in asthma. By blocking TSLP, tezepelumab has demonstrated efficacy across known asthma phenotypes and acts upstream of all current clinically used biomarkers. In a pooled analysis of the phase 2b PATHWAY (NCT02054130) and phase 3 NAVIGATOR (NCT03347279) studies, compared with placebo, tezepelumab reduced the annualized asthma exacerbation rate over 52 weeks by 62% (95% confidence interval [CI]: 53, 70) in patients with perennial aeroallergen sensitization (allergic asthma); by 71% (95% CI: 62, 78) in patients with a baseline blood eosinophil count ≥300 cells/μL; and by 71% (95% CI: 59, 79) in patients with allergic asthma and a baseline blood eosinophil count ≥300 cells/μL. This review examines the efficacy and mode of action of tezepelumab in patients with allergic asthma, eosinophilic asthma and coexisting allergic and eosinophilic phenotypes.

Airway remodelling in asthma and the epithelium: on the edge of a new era

Asthma is a chronic, heterogeneous disease of the airways, often characterised by structural changes known collectively as airway remodelling. In response to environmental insults, including pathogens, allergens and pollutants, the epithelium can initiate remodelling via an inflammatory cascade involving a variety of mediators that have downstream effects on both structural and immune cells. These mediators include the epithelial cytokines thymic stromal lymphopoietin, interleukin (IL)-33 and IL-25, which facilitate airway remodelling through cross-talk between epithelial cells and fibroblasts, and between mast cells and airway smooth muscle cells, as well as through signalling with immune cells such as macrophages. The epithelium can also initiate airway remodelling independently of inflammation in response to the mechanical stress present during bronchoconstriction. Furthermore, genetic and epigenetic alterations to epithelial components are believed to influence remodelling. Here, we review recent advances in our understanding of the roles of the epithelium and epithelial cytokines in driving airway remodelling, facilitated by developments in genetic sequencing and imaging techniques. We also explore how new and existing therapeutics that target the epithelium and epithelial cytokines could modify airway remodelling.

Tezepelumab for Severe Asthma: One Drug Targeting Multiple Disease Pathways and Patient Types

Asthma is a heterogeneous inflammatory disease of the airways, affecting many children, adolescents, and adults worldwide. Up to 10% of people with asthma have severe disease, associated with a higher risk of hospitalizations, greater healthcare costs, and poorer outcomes. Patients with severe asthma generally require high-dose inhaled corticosteroids and additional controller medications to achieve disease control; however, many patients remain uncontrolled despite this intensive treatment. The treatment of severe uncontrolled asthma has improved with greater understanding of asthma pathways and phenotypes as well as the advent of targeted biologic therapies. Tezepelumab, a monoclonal antibody, blocks thymic stromal lymphopoietin, an epithelial cytokine that has multifaceted effects on the initiation and persistence of asthma inflammation and pathophysiology. Unlike other biologic treatments, tezepelumab has demonstrated efficacy across severe asthma phenotypes, with the magnitude of effects varying by phenotype. Here we describe the anti-inflammatory effects and efficacy of tezepelumab across the most relevant phenotypes of severe asthma. Across clinical studies, tezepelumab reduced annualized asthma exacerbation rates versus placebo by 63-71% in eosinophilic severe asthma, by 58-68% in allergic severe asthma, by 67-71% in allergic and eosinophilic severe asthma, by 34-49% in type 2-low asthma, and by 31-41% in oral corticosteroid-dependent asthma. Furthermore, in all these asthma phenotypes, tezepelumab demonstrated higher efficacy in reducing exacerbations requiring hospitalizations or emergency department visits versus placebo. In patients with severe uncontrolled asthma, who commonly have multiple drivers of inflammation and disease, tezepelumab may modulate airway inflammation more extensively, as other available biologics block only specific downstream components of the inflammatory cascade.

Do Biologic Therapies Decrease Mucus Plugging in Asthma?

Asthma researchers have long recognized that abnormal mucus production and clearance play a role in the pathophysiology of asthma.1 Mucus plugs are known to be common in patients with severe asthma, and mucus plug scores, for which higher scores indicate more severe plugging, are directly correlated with airflow obstruction and markers of eosinophilic airway inflammation (i.e., higher scores or marker levels are associated with more severe obstruction). Other work has shown that mucus plugs were associated with distal deficits in regional ventilation as delineated by hyperpolarized gas magnetic resonance imaging.2,3.