Association of Sputum Eosinophilia With Easily Measured Type-2 Inflammatory Biomarkers in Untreated Mild Persistent Asthma

BACKGROUND

A multicenter clinical trial in patients with mild persistent asthma indicated that response to inhaled corticosteroids (ICS) is limited to those with sputum eosinophilia. However, testing for sputum eosinophilia is impractical in most clinical settings.

OBJECTIVE

We examined associations between sputum eosinophilia and type 2 inflammatory biomarkers in untreated mild persistent asthma.

METHODS

Induced sputum, blood eosinophil count (BEC), fractional exhaled nitric oxide (FeNO), and serum periostin were obtained twice during the 6-week run-in period in a clinical trial that enrolled patients 12 years and older with symptomatic, mild persistent asthma without controller therapy. The optimal threshold for each biomarker was based on achieving 80% or greater sensitivity. Performance of biomarkers (area under the receiver operating characteristics curve [AUC], range 0.0-1.0) in predicting sputum eosinophilia 2% or greater was determined; AUCs of 0.8 to 0.9 and more than 0.9 define excellent and outstanding discrimination, respectively.

RESULTS

Of 564 participants, 27% were sputum eosinophilic, 83% were atopic, 70% had BEC of 200/uL or higher or FeNO of 25 ppb or greater; 64% of participants without sputum eosinophilia had elevated BEC or FeNO. The AUCs for BEC, FeNO, and both together in predicting sputum eosinophilia were all below the threshold for excellent discrimination (AUC 0.75, 0.78, and 0.79, respectively). Periostin (in adults) had poor discrimination (AUC 0.59; P = .02).

CONCLUSIONS

In untreated mild persistent asthma, there is substantial discordance between sputum eosinophilia, BEC, and FeNO. Until prospective trials test the ability of alternative biomarkers to predict ICS response, BEC or FeNO phenotyping may be an option to consider ICS through a shared decision-making process with consideration of other clinical features.

Mepolizumab Reduces Systemic Corticosteroid Use in Chronic Rhinosinusitis With Nasal Polyps

BACKGROUND

Systemic corticosteroids (SCSs) are associated with short- and long-term adverse effects.

OBJECTIVE

To assess mepolizumab efficacy according to prior SCS use and characterize mepolizumab's SCS-sparing capabilities, in patients with severe chronic rhinosinusitis with nasal polyps.

METHODS

In the randomized, double-blind, phase III SYNAPSE trial (NCT03085797), adults with severe chronic rhinosinusitis with nasal polyps eligible for repeat sinus surgery despite standard of care treatment received mepolizumab (100 mg subcutaneously) or placebo every 4 weeks for 52 weeks. The impact of prior SCS courses (0/1/>1) on mepolizumab versus placebo treatment responses (changes from baseline in total endoscopic nasal polyp [week 52], nasal obstruction visual analog scale [weeks 49-52], and 22-item Sino-Nasal Outcome Test total [week 52] scores) was analyzed post hoc. To characterize mepolizumab's SCS-sparing capabilities, time-to-first SCS course for nasal polyps (prespecified) and total prednisolone-equivalent oral corticosteroid dose by patient baseline characteristics (post hoc, in patients with ≥1 SCS course during SYNAPSE) were assessed up to week 52.

RESULTS

Mepolizumab versus placebo improved treatment responses, irrespective of prior SCS use. By week 52, the probability of requiring SCSs for nasal polyps (Kaplan-Meier estimate [95% CI]) was lower with mepolizumab (25.4% [20.0-32.1]) versus placebo (37.5% [31.1-44.6]). In patients requiring 1 or more dose of SCSs, total (mean ± SD mg/y) prednisolone-equivalent oral corticosteroid dose was lower with mepolizumab (438.9 ± 350.40) versus placebo (505.2 ± 455.091), overall and irrespective of prior sinus surgeries, blood eosinophil count, or comorbidities.

CONCLUSIONS

Mepolizumab is associated with clinical benefits in patients with severe chronic rhinosinusitis with nasal polyps regardless of prior SCS use and has an SCS-sparing effect.

Dupilumab Efficacy in Patients with Type 2 Asthma with and without Elevated Blood Neutrophils

Introduction

Elevated neutrophil counts in blood, sputum, or lung have been associated with poor clinical outcomes and more severe disease in patients with type 2 asthma. In the phase 3 LIBERTY ASTHMA QUEST (NCT02414854), add-on dupilumab 200 and 300 mg every 2 weeks compared with matched placebo significantly reduced severe asthma exacerbations and improved forced expiratory volume in 1 s (FEV1) in patients with uncontrolled, moderate-to-severe asthma. This post hoc analysis explored the efficacy of dupilumab in patients with type 2 asthma enrolled in QUEST with or without elevated blood neutrophil counts.

Methods

Annualized severe exacerbation rates during the 52-week treatment period and least-squares mean change from baseline in FEV1 over time were evaluated for patients with elevated type 2 biomarkers at baseline (blood eosinophils ≥ 150 cells/µL or fractional exhaled nitric oxide (FeNO) ≥ 20 ppb; and eosinophils ≥ 300 cells/µL or FeNO ≥ 50 ppb) and low (<4,000 cells/µL) or high (≥4,000 cells/µL) neutrophil counts.

Results

Dupilumab significantly reduced annualized severe exacerbation rates compared with placebo during the 52-week treatment period in patients with elevated type 2 biomarkers, irrespective of baseline neutrophil count (P < 0.0001 for all comparisons). Significant improvements in FEV1 versus placebo were observed as early as Week 2 and over the 52-week treatment period, irrespective of baseline neutrophil count (P < 0.001 for all comparisons). Safety findings were similar across all subgroups, regardless of neutrophil counts at baseline.

Conclusions

Dupilumab treatment significantly reduced annualized severe exacerbation rates and improved lung function in patients with uncontrolled, moderate-to-severe, type 2 asthma, irrespective of baseline blood neutrophil count. This trial is registered with NCT02414854.

Patterns of rescue and maintenance therapy claims surrounding a clinical encounter for an asthma exacerbation

BACKGROUND

A "window of opportunity" has been proposed where anti-inflammatory therapy administration in response to symptoms could prevent exacerbation.

OBJECTIVE

To evaluate rescue and maintenance therapy claims surrounding a severe asthma exacerbation serious enough to require a face-to-face clinical encounter.

METHODS

Merative MarketScan research databases (US administrative claims 2011 to 2017) were analyzed for patients aged ≥4 years, with an asthma diagnosis code, who filled short-acting β2-agonist (SABA) and Global Initiative for Asthma Steps 3 to 5 maintenance therapies. Patients were indexed on a random SABA claim and had 12 months' continuous health plan eligibility pre- and post-index. Serious exacerbations were severe exacerbations requiring systemic corticosteroids prescribed from an outpatient clinic, urgent care or emergency department, or hospitalization for asthma. SABA and maintenance claims 30 days pre- and post-event were analyzed.

RESULTS

Of 319,342 patients (30% children 4 to 11 years; 70% adults or adolescents ≥12 years), 27.2% of children and 16.8% of adolescents or adults experienced ≥ 1 serious exacerbation (unadjusted odds ratio [OR], 1.85 [95% confidence interval, 1.81-1.88]). In the 30 days pre-event, 42.6% filled ≥1 SABA (children: 44.3%; adolescents or adults: 41.5%; OR, 1.12 [1.09-1.16]) and 57.4% filled maintenance (children: 59.0%; adolescents or adults: 56.3%; OR, 1.12 [1.08-1.15]). In the 30 days post-event, 61.4% filled SABA (children: 69.7%; adolescents or adults: 55.6%; OR, 1.84 [1.78-1.90]) and 94.8% filled maintenance (children: 98.6%; adolescents or adults: 92.2%; OR, 6.09 [5.45-6.81]).

CONCLUSION

Many patients treated as having moderate-to-severe asthma escalate SABA claims before a serious exacerbation, but approximately 40% have no anti-inflammatory maintenance fill, highlighting a "window of opportunity" to prevent exacerbations using inhaled corticosteroids concomitantly with SABA as rescue.

Mild asthma: Lessons learned and remaining questions

Patients living with mild disease represent the largest proportion of asthma patients. There are significant challenges in proposing a definition that would best describe these patients, while also accurately identifying at-risk individuals. Current literature suggests considerable inflammatory and clinical heterogeneity within this group. Research has shown that these patients are at risk of poor control, exacerbations, lung function decline, and death. Despite conflicting data on its prevalence, eosinophilic inflammation appears to be a predictor of poorer outcomes in mild asthma. There is an immediate need to better understand phenotypic clusters in mild asthma. It is also important to understand factors that influence disease progression and remission, as it is evident that both vary in mild asthma. Guided by robust literature that supports inhaled corticosteroid-based strategies over short-acting beta-agonist (SABA) reliant regimens, the management of these patients has evolved considerably. Unfortunately, SABA use remains high in clinical practice despite strong advocacy from the Global Initiative for Asthma. Future mild asthma research should explore the role of biomarkers, develop prediction tools based on composite risk scores, and explore targeted therapies at least for at-risk individuals.

Questions in Mild Asthma: An Official American Thoracic Society Research Statement

Background: Patients with mild asthma are believed to represent the majority of patients with asthma. Disease-associated risks such as exacerbations, lung function decline, and death have been understudied in this patient population. There have been no prior efforts from major societies to describe research needs in mild asthma. Methods: A multidisciplinary, diverse group of 24 international experts reviewed the literature, identified knowledge gaps, and provided research recommendations relating to mild asthma definition, pathophysiology, and management across all age groups. Research needs were also investigated from a patient perspective, generated in conjunction with patients with asthma, caregivers, and stakeholders. Of note, this project is not a systematic review of the evidence and is not a clinical practice guideline. Results: There are multiple unmet needs in research on mild asthma driven by large knowledge gaps in all areas. Specifically, there is an immediate need for a robust mild asthma definition and an improved understanding of its pathophysiology and management strategies across all age groups. Future research must factor in patient perspectives. Conclusions: Despite significant advances in severe asthma, there remain innumerable research areas requiring urgent attention in mild asthma. An important first step is to determine a better definition that will accurately reflect the heterogeneity and risks noted in this group. This research statement highlights the topics of research that are of the highest priority. Furthermore, it firmly advocates the need for engagement with patient groups and for more support for research in this field.

Severe Asthma Standard-of-Care Background Medication Reduction With Benralizumab: ANDHI in Practice Substudy

BACKGROUND

The phase IIIb, randomized, parallel-group, placebo-controlled ANDHI double-blind (DB) study extended understanding of the efficacy of benralizumab for patients with severe eosinophilic asthma. Patients from ANDHI DB could join the 56-week ANDHI in Practice (IP) single-arm, open-label extension substudy.

OBJECTIVE

Assess potential for standard-of-care background medication reductions while maintaining asthma control with benralizumab.

METHODS

Following ANDHI DB completion, eligible adults were enrolled in ANDHI IP. After an 8-week run-in with benralizumab, there were 5 visits to potentially reduce background asthma medications for patients achieving and maintaining protocol-defined asthma control with benralizumab. Main outcome measures for non-oral corticosteroid (OCS)-dependent patients were the proportions with at least 1 background medication reduction (ie, lower inhaled corticosteroid dose, background medication discontinuation) and the number of adapted Global Initiative for Asthma (GINA) step reductions at end of treatment (EOT). Main outcomes for OCS-dependent patients were reductions in daily OCS dosage and proportion achieving OCS dosage of 5 mg or lower at EOT.

RESULTS

For non-OCS-dependent patients, 53.3% (n = 208 of 390) achieved at least 1 background medication reduction, increasing to 72.6% (n = 130 of 179) for patients who maintained protocol-defined asthma control at EOT. A total of 41.9% (n = 163 of 389) achieved at least 1 adapted GINA step reduction, increasing to 61.8% (n = 110 of 178) for patients with protocol-defined EOT asthma control. At ANDHI IP baseline, OCS dosages were 5 mg or lower for 40.4% (n = 40 of 99) of OCS-dependent patients. Of OCS-dependent patients, 50.5% (n = 50 of 99) eliminated OCS and 74.7% (n = 74 of 99) achieved dosages of 5 mg or lower at EOT.

CONCLUSIONS

These findings demonstrate benralizumab's ability to improve asthma control, thereby allowing background medication reduction.

Impact of mepolizumab in patients with high-burden severe asthma within a managed care population

OBJECTIVE

To evaluate the real-world impact of mepolizumab on the incidence of asthma exacerbations, oral corticosteroid (OCS) use and asthma exacerbation-related costs in patients with high-burden severe asthma.

METHODS

This was a retrospective study of the MarketScan Commercial and Medicare Databases in patients with high-burden severe asthma (≥80th percentile of total healthcare expenditure and/or significant comorbidity burden). Patients were ≥12 years of age upon mepolizumab initiation (index date November 1, 2015-December 31, 2018) and had ≥2 mepolizumab administrations during the 6 months post-index. Asthma exacerbation frequency (primary outcome), use of OCS (secondary outcome), and asthma exacerbation-related costs (exploratory outcome) were assessed during the 12 months pre-index (baseline) and post-index (follow-up).

RESULTS

In total, 281 patients were analyzed. Mepolizumab significantly reduced the proportion of patients with any asthma exacerbation (P < 0.001) or exacerbations requiring hospitalization (P = 0.004) in the follow-up versus baseline period. The mean number of exacerbations decreased from 2.5 to 1.5 events/patient/year (relative reduction: 40.0%; P < 0.001). The proportion of patients with ≥1 OCS claim also decreased significantly from 94.0% to 81.9% (relative reduction: 12.9%; P < 0.001), corresponding to a decrease from 6.6 to 4.7 claims/person/year (P < 0.001). Of the 264 patients with ≥1 OCS claim during baseline, 191 (72.3%) showed a decrease in mean daily OCS use by ≥50% in 117 patients (61.3%). Total asthma exacerbation-related costs were significantly lower after mepolizumab was initiated (P < 0.001).

CONCLUSIONS

Mepolizumab reduced exacerbation frequency, OCS use and asthma exacerbation-related costs in patients with high-cost severe asthma. Mepolizumab provides real-world benefits to patients, healthcare systems and payers.

A Predictive Machine Learning Tool for Asthma Exacerbations: Results from a 12-Week, Open-Label Study Using an Electronic Multi-Dose Dry Powder Inhaler with Integrated Sensors

PURPOSE

Machine learning models informed by sensor data inputs have the potential to provide individualized predictions of asthma deterioration. This study aimed to determine if data from an integrated digital inhaler could be used to develop a machine learning model capable of predicting impending exacerbations.

PATIENTS AND METHODS

Adult patients with poorly controlled asthma were enrolled in a 12-week, open-label study using ProAir® Digihaler®, an electronic multi-dose dry powder inhaler (eMDPI) with integrated sensors, as reliever medication (albuterol, 90 µg/dose; 1-2 inhalations every 4 hours, as needed). Throughout the study, the eMDPI recorded inhaler use, peak inspiratory flow (PIF), inhalation volume, inhalation duration, and time to PIF. A model predictive of impending exacerbations was generated by applying machine learning techniques to data downloaded from the inhalers, together with clinical and demographic information. The generated model was evaluated by receiver operating characteristic area under curve (ROC AUC) analysis.

RESULTS

Of 360 patients included in the predictive analysis, 64 experienced a total of 78 exacerbations. Increased albuterol use preceded exacerbations; the mean number of inhalations in the 24-hours preceding an exacerbation was 7.3 (standard deviation 17.3). The machine learning model, using gradient-boosting trees with data from the eMDPI and baseline patient characteristics, predicted an impending exacerbation over the following 5 days with an ROC AUC of 0.83 (95% confidence interval: 0.77-0.90). The feature of the model with the highest weight was the mean number of daily inhalations during the 4 days prior to the day the prediction was made.

CONCLUSION

A machine learning model to predict impending asthma exacerbations using data from the eMDPI was successfully developed. This approach may support a shift from reactive care to proactive, preventative, and personalized management of chronic respiratory diseases.

Phenotyping, Precision Medicine, and Asthma

The traditional one-size-fits all approach based on asthma severity is archaic. Asthma is a heterogenous syndrome rather than a single disease entity. Studies evaluating observable characteristics called phenotypes have elucidated this heterogeneity. Asthma clusters demonstrate overlapping features, are generally stable over time and are reproducible. What the identification of clusters may have failed to do, is move the needle of precision medicine meaningfully in asthma. This may be related to the lack of a straightforward and clinically meaningful way to apply what we have learned about asthma clusters. Clusters are based on both clinical factors and biomarkers. The use of biomarkers is slowly gaining popularity, but phenotyping based on biomarkers is generally greatly underutilized even in subspecialty care. Biomarkers are more often used to evaluate type 2 (T2) inflammatory signatures and eosinophils (sputum and blood), fractional exhaled nitric oxide (FeNO) and serum total and specific immunoglobulin (Ig) E reliably characterize the underlying inflammatory pathways. Biomarkers perform variably and clinicians must be familiar with their advantages and disadvantages to accurately apply them in clinical care. In addition, it is increasingly clear that clinical features are critical in understanding not only phenotypic characterization but in predicting response to therapy and future risk of poor outcomes. Strategies for asthma management will need to leverage our knowledge of biomarkers and clinical features to create composite scores and risk prediction tools that are clinically applicable. Despite significant progress, many questions remain, and more work is required to accurately identify non-T2 biomarkers. Adoption of phenotyping and more consistent use of biomarkers is needed, and we should continue to encourage this incorporation into practice.

A critical role for the RNA binding protein HuR in CD4+ T cell-mediated airway inflammation in mouse and human

The RNA-binding protein HuR (elavl1) positively regulates the expression of its targets by increasing mRNA stability and translation. Th2 and Th17 related genes play critical roles in airway inflammation in both mouse and human. Using in vitro and in vivo studies, we have previously shown that these proinflammatory genes are regulated by HuR. Here, we generated a conditional ablation of HuR in T cells (distal Lck-cre HuRfl/fl). We found significant decreases in Th2 differentiation, cytokine production, and lung inflammation in an alum-emulsified ovalbumin (ova-alum) model of allergic airway inflammation using this novel mouse model. We hypothesized that HuR might similarly regulate lung inflammation in human asthma. Using peripheral CD4+ T cells from 45 asthmatic patients, we found the inhibitory effect of the HuR-specific inhibitor CMLD-2, as well as an AMPK activator (acadesine aka AICAR), on both Th2/Th17 signature cytokines in both protein and mRNA levels. Our asthmatics were classified into type 2 high or non-type 2 high based on their blood eosinophil and FeNO levels. Interestingly, there were significant positive correlations between Th2 cytokine levels in CD4+ cells with levels of eosinophils and FeNO from asthmatics. Surprisingly, IFNγ (protein and mRNA) were also markedly decreased by HuR inhibition. Our bioinformatic studies also revealed proteins with high interaction with HuR including MAPK14/p38α and PTEN, common in the pathways with IFNγ, are affected by HuR inhibitor. Taken together, our mouse and human data suggest that HuR plays a crucial permissive role in both allergen- and nonallergen-driven airway inflammation by regulating key genes and that interfering with its function may be a novel way to treat asthma.

Supported by R01: AI080870, R21: AI079341

Allergic and eosinophilic asthma in the era of biomarkers and biologics: similarities, differences and misconceptions

OBJECTIVE

Severe asthma is associated with substantial personal and economic burden; maintaining disease control is the key management goal. Increased understanding of asthma heterogeneity and development of type 2 (T2)-targeting biologics has substantially advanced disease management and outcomes; however, despite both being driven by T2 inflammation, allergic and eosinophilic asthma have different treatment recommendations. We sought to better understand the similarities and differences between allergic and eosinophilic asthma and highlight where misconceptions may arise.

DATA SOURCES

Published articles, pivotal trials, post hoc analyses, and asthma clinical guidelines sourced from PubMed.

STUDY SELECTIONS

Sources reporting allergic and eosinophilic asthma classifications, disease mechanisms, and biomarkers associated with treatment response.

RESULTS

This review highlights that severe allergic and eosinophilic asthma are both driven by T2 inflammation with eosinophils playing a cardinal role. Despite this overlap, treatment recommendations differ based on asthma classification. T2 cytokine gene expression is a reasonably well-established research tool, but not a well-established biomarker in clinical practice, unlike blood eosinophil counts, fractional exhaled nitric oxide, and immunoglobulin E; the clinical relevance of immunoglobulin E as a predictive biomarker remains unclear.

CONCLUSION

Asthma classifications that can be easily characterized at patient level to ensure accurate diagnosis, predict disease trajectory, and treatment response are required. The current dichotomy of allergic and eosinophilic asthma classifications is likely too simplistic, given the similar eosinophil-mediated disease pathophysiology in both classifications. Our results provide future directions to guide clinically meaningful interpretation of asthma endophenotypes, which may improve understanding of severe asthma characterization and aid future advances in defining responders more precisely with personalized medicine approaches.

Real World Biologic Use and Switch Patterns in Severe Asthma: Data from the International Severe Asthma Registry and the US CHRONICLE Study

Introduction

International registries provide opportunities to describe use of biologics for treating severe asthma in current clinical practice. Our aims were to describe real-life global patterns of biologic use (continuation, switches, and discontinuations) for severe asthma, elucidate reasons underlying these patterns, and examine associated patient-level factors.

Methods

This was a historical cohort study including adults with severe asthma enrolled into the International Severe Asthma Registry (ISAR; http://isaregistries.org, 2015–2020) or the CHRONICLE Study (2018–2020) and treated with a biologic. Eleven countries were included (Bulgaria, Canada, Denmark, Greece, Italy, Japan, Kuwait, South Korea, Spain, UK, and USA). Biologic utilization patterns were defined: 1) continuing initial biologic; 2) stopping biologic treatment; or 3) switching to another biologic. Reasons for discontinuation/switching were recorded and comparisons drawn between groups.

Results

A total of 3531 patients were included. Omalizumab was the most common initial biologic in 2015 (88.2%) and benralizumab in 2019 (29.6%). Most patients (79%; 2791/3531) continued their first biologic; 10.2% (356/3531) stopped; 10.8% (384/3531) switched. The most frequent first switch was from omalizumab to an anti–IL-5/5R (49.6%; 187/377). The most common subsequent switch was from one anti–IL-5/5R to another (44.4%; 20/45). Insufficient efficacy and/or adverse effects were the most frequent reasons for stopping/switching. Patients who stopped/switched were more likely to have a higher baseline blood eosinophil count and exacerbation rate, lower lung function, and greater health care resource utilization.

Conclusion

The description of real-life patterns of continuing, stopping, or switching biologics enhances our understanding of global biologic use. Prospective studies involving structured switching criteria could ascertain optimal strategies to identify patients who may benefit from switching.

HuR-Targeted Inhibition Impairs Th2 Proinflammatory Responses in Asthmatic CD4+ T Cells

RNA-binding protein HuR (ELAVL1) is a master regulator of gene expression in human pathophysiology. Its dysregulation plays an important role in many diseases. We hypothesized that HuR plays an important role in Th2 inflammation in asthma in both mouse and human. To address this, we used a model of airway inflammation in a T cell-specific knockout mouse model, distal lck-Cre HuR^fl/fl, as well as small molecule inhibitors in human peripheral blood-derived CD4⁺ T cells. Peripheral CD4⁺ T cells were isolated from 26 healthy control subjects and 45 asthmatics (36 type 2 high and 9 non-type 2 high, determined by blood eosinophil levels and fraction of exhaled NO). Our mouse data showed conditional ablation of HuR in T cell-abrogated Th2 differentiation, cytokine production, and lung inflammation. Studies using human T cells showed that HuR protein levels in CD4⁺ T cells were significantly higher in asthmatics compared with healthy control subjects. The expression and secretion of Th2 cytokines were significantly higher in asthmatics compared with control subjects. AMP-activated protein kinase activator treatment reduced the expression of several cytokines in both type 2 high and non-type 2 high asthma groups. However, the effects of CMLD-2 (a HuR-specific inhibitor) were more specific to endotype-defining cytokines in type 2 high asthmatics. Taken together, these data suggest that HuR plays a permissive role in both allergen and non-allergen-driven airway inflammation by regulating key genes, and that interfering with its function may be a novel method of asthma treatment.

Benralizumab improves symptoms of patients with severe, eosinophilic asthma with a diagnosis of nasal polyposis

BACKGROUND

Clinically meaningful improvement in the Sino-Nasal Outcome Test-22 (SNOT-22) was observed in patients with severe, eosinophilic asthma, and nasal polyposis (NP) treated with benralizumab in the ANDHI trial. A post hoc assessment of the effects of benralizumab on SNOT-22 response and asthma efficacy measures in these patients was conducted for further characterization of the efficacy and safety of benralizumab for patients with severe asthma and NP.

METHODS

Adults with severe, eosinophilic asthma who had experienced ≥2 prior-year exacerbations despite high-dosage inhaled corticosteroid plus additional controller[s] were randomized to 24 weeks of benralizumab or placebo. Patients with physician-diagnosed chronic rhinosinusitis with NP of any severity ongoing at baseline who consented to participate were included in the current ANDHI NP substudy population. Effect on NP symptoms was assessed by the SNOT-22, with an improvement of at least 8.9 defined as clinically significant (responder). Effects on chronic asthma outcomes were assessed by means of annualized asthma exacerbation rate (AER), St. George's Respiratory Questionnaire (SGRQ) total score, forced expiratory volume in one second (FEV₁ ), and Asthma Control Questionnaire-6 (ACQ-6). All p-values were nominal.

RESULTS

Of the ANDHI population (n = 656), 23% (n = 153) participated in the NP substudy (n = 96 benralizumab; n = 57 placebo). Patients were 50% female, with mean age of 53 years, had prior-year AER = 3.3; mean pre-bronchodilator FEV₁  = 55% predicted; and median blood eosinophil count ​= 510 cells/µl. For patients with high baseline SNOT-22 scores (>30), benralizumab treatment improved symptoms of NP as measured by SNOT-22 from baseline to Week 24 compared with placebo (Week 24: -10.44 [p = .0176]). Percentage of responders to SNOT-22 was greater for benralizumab vs. placebo (71.3% vs. 45.5%; p = .0036), and effect was enhanced for patients with high baseline SNOT-22 scores (>30). A 69% reduction vs. placebo in annualized AER (0.77 vs. 2.47; p < .0001) and greater clinically meaningful improvements from baseline in SGRQ total score (-16.7), FEV₁ (+0.32 L), and ACQ-6 (-0.88) were observed (p < .0001). Benralizumab was well-tolerated. Frequency of adverse events (AEs) was similar for benralizumab (76.0%) and placebo (73.7%) groups. Most common AEs (frequency ≥5%) reported at a greater frequency in benralizumab vs. placebo included headache, sinusitis, pyrexia, and influenza.

CONCLUSIONS

These substudy data from ANDHI demonstrated the efficacy profile of benralizumab for patients with severe, eosinophilic asthma and NP, with improvement in SNOT-22 and asthma outcomes.

Demographics, Treatment Patterns, and Morbidity in Patients with Exercise-Induced Bronchoconstriction: An Administrative Claims Data Analysis

PURPOSE

Exercise-induced bronchoconstriction (EIB) is generally treated with short-acting β2-agonists (SABA) before exercising, to prevent symptoms. Real-world data on treatments and outcomes for patients with EIB alone (EIBalone), or with asthma (EIBasthma), in the USA are limited. This study compared demographics, treatment patterns, morbidity, and costs of treating EIB between these two groups of patients.

PATIENTS AND METHODS

Administrative claims from US IBM® MarketScan® Research databases were analyzed retrospectively. Patients aged ≥4 years filling a SABA claim between 1/1/2011 and 12/31/2016 were evaluated. Patients were indexed on a random SABA claim and required to have 12 months' continuous eligibility pre- and post-index, ≥1 maintenance medication and/or SABA fill post-index, and were designated EIBalone or EIBasthma according to diagnostic codes (EIB only or EIB plus asthma, respectively). Descriptive statistics were used.

RESULTS

In total, 13,480 patients had EIBalone and 14,862 had EIBasthma. Compared with EIBasthma, the EIBalone group was older (mean[SD] 20.4[13.6] vs 17.8[13.6] years), had more females (60.7% vs 54.7%), and filled fewer SABA claims (1.9[1.4] vs 2.5[2.2]) (all p<0.001). A smaller proportion of patients in the EIBalone than EIBasthma group had maintenance therapy claims (79.9% vs 90.6%, p<0.001). The EIBalone group also had a lower proportion of patients with oral or injectable corticosteroid claims (29.4% vs 32.0%) and asthma and/or EIB-related emergency department (1.0% vs 13.0%) or outpatient visits (65.1% vs 72.3%; all p<0.0001). Annual days' supply of oral corticosteroids was similar between groups (mean[SD] EIBalone: 20.7[30.8] vs EIBasthma: 19.8[28] days).

CONCLUSION

Individuals with EIBalone or EIBasthma demonstrate considerable morbidity. New treatment paradigms may be needed to optimize outcomes for both patient groups.

Onset of effect and impact on health-related quality of life, exacerbation rate, lung function, and nasal polyposis symptoms for patients with severe eosinophilic asthma treated with benralizumab (ANDHI): a randomised, controlled, phase 3b trial

BACKGROUND

ANDHI was done to assess the efficacy of benralizumab, including onset of effect and impact on health-related quality of life (HRQOL), exacerbation rate, lung function, and nasal polyposis symptoms.

METHODS

This phase 3b, randomised, double-blind, parallel-group, placebo-controlled ANDHI study was completed in adults (aged 18-75 years) with severe eosinophilic asthma with at least 2 exacerbations in the previous year, despite high-dose inhaled corticosteroid plus additional controllers, screening blood eosinophil counts of at least 150 cells per μL, and an Asthma Control Questionnaire 6 (ACQ-6) score of 1·5 or more. Patients who met eligibility criteria were randomly assigned (2:1; stratified by previous exacerbation count [two, or three or more], maintenance oral corticosteroid use, and region), using an integrated web-based response system, to receive benralizumab at 30 mg every 8 weeks (first three doses given 4 weeks apart) or matched placebo for 24 weeks. Primary efficacy measure was annualised asthma exacerbation rate, with rate ratio (RR) calculated over the approximate 24-week follow-up. Secondary efficacy measures included change from baseline to end of treatment (week 24) in St George's Respiratory Questionnaire (SGRQ) total score (key secondary endpoint), FEV₁, peak expiratory flow (PEF), ACQ-6, Predominant Symptom and Impairment Assessment (PSIA), Clinician Global Impression of Change (CGI-C), Patient Global Impression of Change (PGI-C), and Sino-Nasal Outcome Test-22 (SNOT-22). All efficacy analyses, except for SNOT-22, were summarised and analysed using the full analysis set on an intention-to-treat population (all randomly assigned patients receiving investigational product, regardless of protocol adherence or continued participation in the study). SNOT-22 was summarised for the subgroup of patients with physician-diagnosed nasal polyposis with informed consent. This study is registered with ClinicalTrials.gov, NCT03170271.

FINDINGS

Between July 7, 2017, and Sept 25, 2019, 656 patients received benralizumab (n=427) or placebo (n=229). Baseline characteristics were consistent with severe eosinophilic asthma. Benralizumab significantly reduced exacerbation risk by 49% compared with placebo (RR estimate 0·51, 95% CI 0·39-0·65; p<0·0001) over the 24-week treatment period and provided clinically meaningful and statistically significant improvement from baseline to week 24 in SGRQ total score versus placebo (least squares mean change from baseline -8·11 (95% CI -11·41 to -4·82; p<0·0001), with similar differences at earlier timepoints. Benralizumab improved FEV₁, PEF, ACQ-6, CGI-C, PGI-C, PSIA, and SNOT-22 at week 24 versus placebo, with differences observed early (within weeks 1 to 4). Adverse events were reported for 271 (63%) of 427 patients on benralizumab versus 143 (62%) of 229 patients on placebo. The most commonly reported adverse events for the 427 patients receiving benralizumab (frequency >5%) were nasopharyngitis (30 [7%]), headache (37 [9%]), sinusitis (28 [7%]), bronchitis (22 [5%]), and pyrexia (26 [6%]). Fewer serious adverse events were reported for benralizumab (23 [5%]) versus placebo (25 [11%]), and the only common serious adverse event (experienced by >1% of patients) was worsening of asthma, which was reported for nine (2%) patients in the benralizumab group and nine (4%) patients in the placebo group.

INTERPRETATION

Our results extend the efficacy profile of benralizumab for patients with severe eosinophilic asthma, showing early clinical benefits in patient-reported outcomes, HRQOL, lung function, and nasal polyposis symptoms.

FUNDING

AstraZeneca.

Prothrombotic autoantibodies in serum from patients hospitalized with COVID-19

Patients with COVID-19 are at high risk for thrombotic arterial and venous occlusions. Lung histopathology often reveals fibrin-based blockages in the small blood vessels of patients who succumb to the disease. Antiphospholipid syndrome is an acquired and potentially life-threatening thrombophilia in which patients develop pathogenic autoantibodies targeting phospholipids and phospholipid-binding proteins (aPL antibodies). Case series have recently detected aPL antibodies in patients with COVID-19. Here, we measured eight types of aPL antibodies in serum samples from 172 patients hospitalized with COVID-19. These aPL antibodies included anticardiolipin IgG, IgM, and IgA; anti-β2 glycoprotein I IgG, IgM, and IgA; and anti-phosphatidylserine/prothrombin (aPS/PT) IgG and IgM. We detected aPS/PT IgG in 24% of serum samples, anticardiolipin IgM in 23% of samples, and aPS/PT IgM in 18% of samples. Antiphospholipid autoantibodies were present in 52% of serum samples using the manufacturer's threshold and in 30% using a more stringent cutoff (≥40 ELISA-specific units). Higher titers of aPL antibodies were associated with neutrophil hyperactivity, including the release of neutrophil extracellular traps (NETs), higher platelet counts, more severe respiratory disease, and lower clinical estimated glomerular filtration rate. Similar to IgG from patients with antiphospholipid syndrome, IgG fractions isolated from patients with COVID-19 promoted NET release from neutrophils isolated from healthy individuals. Furthermore, injection of IgG purified from COVID-19 patient serum into mice accelerated venous thrombosis in two mouse models. These findings suggest that half of patients hospitalized with COVID-19 become at least transiently positive for aPL antibodies and that these autoantibodies are potentially pathogenic.

Prothrombotic antiphospholipid antibodies in COVID-19

Patients with coronavirus disease 19 (COVID-19) are at high risk for thrombotic arterial and venous occlusions. At the same time, lung histopathology often reveals fibrin-based occlusion in the small vessels of patients who succumb to the disease. Antiphospholipid syndrome (APS) is an acquired and potentially life-threatening thrombophilia in which patients develop pathogenic autoantibodies (aPL) targeting phospholipids and phospholipid-binding proteins. Case series have recently detected aPL in patients with COVID-19. Here, we measured eight types of aPL [anticardiolipin IgG/IgM/IgA, anti-beta-2 glycoprotein I IgG/IgM/IgA, and anti- phosphatidylserine/prothrombin (aPS/PT) IgG/IgM] in the sera of 172 patients hospitalized with COVID-19. We detected aPS/PT IgG in 24%, anticardiolipin IgM in 23%, and aPS/PT IgM in 18%. Any aPL was present in 52% of patients using the manufacturer's threshold and in 30% using a more stringent cutoff (≥40 units). Higher levels of aPL were associated with neutrophil hyperactivity (including the release of neutrophil extracellular traps/NETs), higher platelet count, more severe respiratory disease, and lower glomerular filtration rate. Similar to patients with longstanding APS, IgG fractions isolated from patients with COVID-19 promoted NET release from control neutrophils. Furthermore, injection of these COVID-19 IgG fractions into mice accelerated venous thrombosis. Taken together, these studies suggest that a significant percentage of patients with COVID-19 become at least transiently positive for aPL and that these aPL are potentially pathogenic.

Neutrophil calprotectin identifies severe pulmonary disease in COVID-19

Severe cases of coronavirus disease 2019 (COVID-19) are regularly complicated by respiratory failure. Although it has been suggested that elevated levels of blood neutrophils associate with worsening oxygenation in COVID-19, it is unknown whether neutrophils are drivers of the thrombo-inflammatory storm or simple bystanders. To better understand the potential role of neutrophils in COVID-19, we measured levels of the neutrophil activation marker S100A8/A9 (calprotectin) in hospitalized patients and determined its relationship to severity of illness and respiratory status. Patients with COVID-19 (n = 172) had markedly elevated levels of calprotectin in their blood. Calprotectin tracked with other acute phase reactants including C-reactive protein, ferritin, lactate dehydrogenase, and absolute neutrophil count, but was superior in identifying patients requiring mechanical ventilation. In longitudinal samples, calprotectin rose as oxygenation worsened. When tested on day 1 or 2 of hospitalization (n = 94 patients), calprotectin levels were significantly higher in patients who progressed to severe COVID-19 requiring mechanical ventilation (8039 ± 7031 ng/ml, n = 32) as compared to those who remained free of intubation (3365 ± 3146, P < 0.0001). In summary, serum calprotectin levels track closely with current and future COVID-19 severity, implicating neutrophils as potential perpetuators of inflammation and respiratory compromise in COVID-19.

Neutrophil extracellular traps and thrombosis in COVID-19

BACKGROUND

Early studies of patients with COVID-19 have demonstrated markedly dysregulated coagulation and a high risk of morbid arterial and venous thrombotic events. While elevated levels of blood neutrophils and neutrophil extracellular traps (NETs) have been described in patients with COVID-19, their potential role in COVID-19-associated thrombosis remains unknown.

OBJECTIVES

To elucidate the potential role of hyperactive neutrophils and NET release in COVID-19-associated thrombosis.

PATIENTS/METHODS

This is a retrospective, case-control study of patients hospitalized with COVID-19 who developed thrombosis (n=11), as compared with gender- and age-matched COVID-19 patients without clinical thrombosis (n=33). In addition to capturing clinical data, we measured remnants of NETs (cell-free DNA, myeloperoxidase-DNA complexes, and citrullinated histone H3) and neutrophil-derived S100A8/A9 (calprotectin) in patient sera.

RESULTS

The majority of patients (9/11) were receiving at least prophylactic doses of heparinoids at the time thrombosis was diagnosed. As compared with controls, patients with COVID-19-associated thrombosis had significantly higher blood levels of markers of NETs (cell-free DNA, myeloperoxidase-DNA complexes, citrullinated histone H3) and neutrophil activation (calprotectin). The thrombosis group also had higher levels of D-dimer, CRP, ferritin, and platelets, but not troponin or neutrophils. Finally, there were strong associations between markers of hyperactive neutrophils (calprotectin and cell-free DNA) and D-dimer.

CONCLUSION

Elevated levels of neutrophil activation and NET formation in patients hospitalized with COVID-19 are associated with higher risk of morbid thrombotic complications. These observations underscore the need for urgent investigation into the potential relationship between NETs and unrelenting thrombosis in COVID-19.

Blood eosinophil count group shifts and kinetics in severe eosinophilic asthma

BACKGROUND

Blood eosinophil count (BEC) measurements are a noninvasive, relatively reliable surrogate marker for eosinophilic airway inflammation. Single measurements of peripheral BEC greater than or equal to 150 cells/μL predict the response to anti-eosinophil therapies for patients with characteristics of severe eosinophilic asthma.

OBJECTIVE

To describe how BECs shift over time for patients with severe, uncontrolled asthma receiving placebo in 2 large, randomized, placebo-controlled clinical trials of benralizumab (SIROCCO and CALIMA).

METHODS

Our analysis included all adult patients who were randomized to placebo in the SIROCCO and CALIMA phase III benralizumab studies. Patients were categorized into baseline BEC groups of less than 150 cells/μL, greater than or equal to 150 cells/μL but less than 300 cells/μL, and greater than or equal to 300 cells/μL. The timing of the initial shift from baseline to a different group was evaluated at weeks 4, 8, 24, and 40 and at the end of treatment. Baseline characteristics, including oral corticosteroid use, were described based on the presence or absence of a BEC group shift.

RESULTS

Of the 734 evaluable patients, 65% (n = 474) shifted BEC groups during the study, and most patients (86% [n = 410]) shifted by week 24. Patients who started in the less than 150 cells/μL group tended to shift groups earlier, with 59% shifting by week 4 compared with 38% to 55% for other groups in the same time frame. Patients who shifted BEC groups vs those who did not tend to have lower BECs, more oral corticosteroid use, and less incidence of nasal polyps or past polypectomy.

CONCLUSION

A single BEC measurement, particularly when low, may be inadequate to help establish a phenotype of severe eosinophilic asthma.

TRIAL REGISTRATION

ClinicalTrials.gov Identifiers NCT01928771 (SIROCCO trial) and NCT01914757 (CALIMA trial).

Rapid onset of effect of benralizumab on morning peak expiratory flow in severe, uncontrolled asthma

BACKGROUND

Benralizumab is a unique eosinophil-depleting monoclonal antibody that significantly reduces asthma exacerbations, improves lung function and asthma symptoms, and permits the reduction of maintenance oral corticosteroid dosage for patients with severe, uncontrolled eosinophilic asthma.

OBJECTIVE

To assess benralizumab's onset of action and efficacy by examining change in morning peak expiratory flow (PEF) after initiation of treatment in the phase 3 clinical trials SIROCCO, CALIMA, and ZONDA.

METHODS

Mixed-model repeated-measures analysis was used to calculate PEF using daily least squares mean changes from baseline in morning PEF as well as differences between the benralizumab every 8 weeks (first 3 doses every 4 weeks) and placebo groups. A Bayesian nonlinear mixed-effects approach with an exponential relationship was used to model trial data to determine time to clinically meaningful improvement in morning PEF (defined as ≥25 L/min).

RESULTS

Least squares mean morning PEF improvement from baseline was numerically greater by Day 2 after initiation of benralizumab therapy in all 3 trials. The Bayesian nonlinear mixed-effects model indicated that PEF improvement reached the clinically meaningful threshold within 3 weeks in SIROCCO and CALIMA and 2 weeks in ZONDA.

CONCLUSION

In 3 phase 3 randomized clinical trials, benralizumab provided notable improvement in morning PEF 2 days after initiation and clinically meaningful improvements within 3 weeks for patients with severe, uncontrolled eosinophilic asthma. The rapid improvement in PEF demonstrated in these trials suggests that benralizumab's unique mechanism of action rapidly improves lung function for patients with severe, eosinophilic asthma.

TRIAL REGISTRATION

ClinicalTrials.gov Identifiers: NCT01928771 (SIROCCO), NCT01914757 (CALIMA), and NCT02075255 (ZONDA).

Medication Regimens for Managing Stable Asthma

Guideline-based management of asthma was developed as a means of standardizing asthma therapies and of improving outcomes. The National Asthma Education and Prevention Program and the Global Initiative for Asthma guidelines provide recommendations to care providers about the routine management of asthma. There has been rapid development of new therapies for asthma, specifically with the advent of new drug delivery devices and biologic therapies for severe asthma. We are increasingly recognizing that asthma is a heterogenous disease with a diverse underlying pathophysiology, and therefore, it is imperative for care providers to begin to understand asthma phenotypes and endotypes, and the implications of these classifications on management, especially of severe refractory asthma. This article serves as a review of guideline-based therapy for asthma and includes updates on alternative therapies, new approaches that use previously recognized therapies, and special populations with asthma.

Effect of the S-nitrosoglutathione reductase inhibitor N6022 on bronchial hyperreactivity in asthma

RATIONALE

Patients with asthma demonstrate depletion of the endogenous bronchodilator GSNO and upregulation of GSNOR.

OBJECTIVES

An exploratory proof of concept clinical study of N6022 in mild asthma to determine the potential bronchoprotective effects of GSNOR inhibition. Mechanistic studies aimed to provide translational evidence of effect.

METHODS

Fourteen mild asthma patients were treated with intravenous N6022 (5 mg) or placebo and observed for 7 days, with repeated assessments of the provocative dose of methacholine causing a 20% fall in FEV1 (methacholine PC₂₀ FEV1), followed by a washout period and crossover treatment and observation. In vitro studies in isolated eosinophils investigated the effect of GSNO and N6022 on apoptosis.

MEASUREMENTS AND MAIN RESULTS

This was a negative trial as it failed to reach its primary endpoint, which was change from baseline in methacholine PC₂₀ FEV1 at 24 h. However, our exploratory analysis demonstrated significantly more two dose-doubling increases in PC₂₀ FEV1 for N6022 compared with placebo (21% vs 6%, P < 0.05) over the 7-day observation period. Furthermore, a significant treatment effect was observed in the change in PC₂₀ FEV1 from baseline averaged over the 7-day observation period (mean change: +0.82 mg/ml [N6022] from 1.34 mg/ml [baseline] vs -0.18 mg/ml [placebo] from 1.16 mg/ml [baseline], P = 0.023). N6022 was well tolerated in mild asthmatics. In vitro studies demonstrated enhanced eosinophilic apoptosis with N6022.

CONCLUSIONS

In this early phase exploratory proof of concept trial in asthma, N6022 did not significantly alter methacholine PC₂₀ FEV1 at 24 h, but did have a treatment effect at 7 days compared to baseline. Further investigation of the efficacy of S-nitrosoglutathione reductase inhibition in a patient population with eosinophilic asthma is warranted.

Oral Glucocorticoid-Sparing Effect of Benralizumab in Severe Asthma

BACKGROUND

Many patients with severe asthma rely on oral glucocorticoids to manage their disease. We investigated whether benralizumab, a monoclonal antibody directed against the alpha subunit of the interleukin-5 receptor that significantly reduces the incidence of asthma exacerbations, was also effective as an oral glucocorticoid-sparing therapy in patients relying on oral glucocorticoids to manage severe asthma associated with eosinophilia.

METHODS

In a 28-week randomized, controlled trial, we assessed the effects of benralizumab (at a dose of 30 mg administered subcutaneously either every 4 weeks or every 8 weeks [with the first three doses administered every 4 weeks]) versus placebo on the reduction in the oral glucocorticoid dose while asthma control was maintained in adult patients with severe asthma. The primary end point was the percentage change in the oral glucocorticoid dose from baseline to week 28. Annual asthma exacerbation rates, lung function, symptoms, and safety were assessed.

RESULTS

Of 369 patients enrolled, 220 underwent randomization and started receiving benralizumab or placebo. The two benralizumab dosing regimens significantly reduced the median final oral glucocorticoid doses from baseline by 75%, as compared with a reduction of 25% in the oral glucocorticoid doses in the placebo group (P<0.001 for both comparisons). The odds of a reduction in the oral glucocorticoid dose were more than 4 times as high with benralizumab as with placebo. Among the secondary outcomes, benralizumab administered every 4 weeks resulted in an annual exacerbation rate that was 55% lower than the rate with placebo (marginal rate, 0.83 vs. 1.83, P=0.003), and benralizumab administered every 8 weeks resulted in an annual exacerbation rate that was 70% lower than the rate with placebo (marginal rate, 0.54 vs. 1.83, P<0.001). At 28 weeks, there was no significant effect of either benralizumab regimen on the forced expiratory volume in 1 second (FEV₁), as compared with placebo. The effects on various measures of asthma symptoms were mixed, with some showing significant changes in favor of benralizumab and others not showing significant changes. Frequencies of adverse events were similar between each benralizumab group and the placebo group.

CONCLUSIONS

Benralizumab showed significant, clinically relevant benefits, as compared with placebo, on oral glucocorticoid use and exacerbation rates. These effects occurred without a sustained effect on the FEV₁. (Funded by AstraZeneca; ZONDA ClinicalTrials.gov number, NCT02075255 .).

Related or not? Development of spontaneous Creutzfeldt-Jakob disease in a patient with chronic, well-controlled HIV: A case report and review of the literature

Background:

We report a novel case of a rare disease: spontaneous Creutzfeldt–Jakob disease in a patient with well-controlled HIV. We explore the relationship between spontaneous Creutzfeldt–Jakob disease and HIV.

Case report:

A 66-year-old man with long-standing, well-controlled HIV infection presented with 3 months of progressive, subacute neurocognitive decline. His symptoms included conceptual apraxia, apathy, memory impairment, and gait disturbance, and were initially attributed to depressive “pseudo-dementia.” Unfortunately, the patient’s symptoms rapidly progressed and he ultimately succumbed to his illness. Autopsy confirmed the clinical diagnosis of spontaneous Creutzfeldt–Jakob disease.

Discussion:

This case highlights spontaneous Creutzfeldt–Jakob disease as a rare terminal illness in the setting of well-controlled chronic HIV. To our knowledge, this is the first report of a patient with chronic and previously well-controlled HIV infection dying from a prion disease. Despite the very different epidemiology and pathophysiology of HIV and spontaneous Creutzfeldt–Jakob disease, this case does raise questions of whether certain host genetic factors could predispose to both conditions, albeit currently, there is no clear causal link between HIV and spontaneous Creutzfeldt–Jakob disease.

Role of Matrix Metalloproteinases-1 and -2 in Interleukin-13-Suppressed Elastin in Airway Fibroblasts in Asthma

Elastin synthesis and degradation in the airway and lung parenchyma contribute to airway mechanics, including airway patency and elastic recoil. IL-13 mediates many features of asthma pathobiology, including airway remodeling, but the effects of IL-13 on elastin architecture in the airway wall are not known. We hypothesized that IL-13 modulates elastin expression in airway fibroblasts from subjects with allergic asthma. Twenty-five subjects with mild asthma (FEV1, 89 ± 3% predicted) and 30 normal control subjects (FEV1, 102 ± 2% predicted) underwent bronchoscopy with endobronchial biopsy. Elastic fibers were visualized in airway biopsy specimens using Weigert's resorcin-fuchsin elastic stain. Airway fibroblasts were exposed to IL-13; a pan-matrix metalloproteinase (MMP) inhibitor (GM6001); specific inhibitors to MMP-1, -2, -3, and -8; and combinations of IL-13 with MMP inhibitors in separate conditions in serum-free media for 48 hours. Elastin (ELN) expression as well as MMP secretion and activity were quantified. Results of this study show that elastic fiber staining of airway biopsy tissue was significantly associated with methacholine PC20 (i.e., the provocative concentration of methacholine resulting in a 20% fall in FEV1 levels) in patients with asthma. IL-13 significantly suppressed ELN expression in asthmatic airway fibroblasts as compared with normal control fibroblasts. The effect of IL-13 on ELN expression was significantly correlated with postbronchodilator FEV1/FVC in patients with asthma. MMP inhibition significantly stimulated ELN expression in patients with asthma as compared with normal control subjects. Specific inhibition of MMP-1 and MMP-2, but not MMP-3 or MMP-8, reversed the IL-13-induced suppression of ELN expression. In asthma, MMP-1 and MMP-2 mediate IL-13-induced suppression of ELN expression in airway fibroblasts.

Impact of Age and Sex on Response to Asthma Therapy

RATIONALE

Age and sex are associated with differences in asthma prevalence and morbidity.

OBJECTIVES

To determine if age and sex associate with distinct phenotypes and a variable response to therapy in subjects with mild to moderate asthma.

METHODS

We used Asthma Clinical Research Network data to determine the impact of age and sex on phenotypes and treatment failures among subjects participating in 10 trials from 1993 to 2003.

MEASUREMENTS AND MAIN RESULTS

A total of 1,200 subjects were identified (median age, 30.4 yr; male, 520 [43.3%]; female, 680 [56.7%]) and analyzed. A higher proportion of subjects greater than or equal to 30 years old experienced treatment failures (17.3% vs. 10.3%; odds ratio [OR], 1.82; confidence interval [CI], 1.30-2.54; P < 0.001), and rates increased proportionally with increasing age older than 30 across the cohort (OR per yr, 1.02 [CI, 1.01-1.04]; OR per 5 yr, 1.13 [CI, 1.04-1.22]; P < 0.001). Lower lung function and longer duration of asthma were associated with a higher risk of treatment failures. A higher proportion of subjects greater than or equal to 30 years old receiving controller therapy experienced treatment failures. When stratified by specific therapy, treatment failures increased consistently for every year older than age 30 in subjects on inhaled corticosteroids (OR per year, 1.03; CI, 1.01-1.07). Females had a slightly higher FEV1 % predicted (84.5% vs. 81.1%; P < 0.001) but similar asthma control measures. There was not a statistically significant difference in treatment failures between females and males (15.2% vs. 11.7%; P = 0.088).

CONCLUSIONS

Older age is associated with an increased risk of treatment failure, particularly in subjects taking inhaled corticosteroids. There was no significant difference in treatment failures between sexes.

Alveolar macrophages from overweight/obese subjects with asthma demonstrate a proinflammatory phenotype

RATIONALE

Obesity is associated with increased prevalence and severity of asthma. Adipose tissue macrophages can contribute to the systemic proinflammatory state associated with obesity. However, it remains unknown whether alveolar macrophages have a unique phenotype in overweight/obese patients with asthma.

OBJECTIVES

We hypothesized that leptin levels would be increased in the bronchoalveolar lavage fluid from overweight/obese subjects and, furthermore, that leptin would alter the response of alveolar macrophages to bacterial LPS.

METHODS

Forty-two subjects with asthma and 46 healthy control subjects underwent research bronchoscopy. Bronchoalveolar lavage fluid from 66 was analyzed for the level of cellular inflammation, cytokines, and soluble leptin. Cultured primary macrophages from 22 subjects were exposed to LPS, leptin, or leptin plus LPS. Cytokines were measured in the supernatants.

MEASUREMENTS AND MAIN RESULTS

Leptin levels were increased in overweight/obese subjects, regardless of asthma status (P = 0.013), but were significantly higher in overweight/obese subjects with asthma. Observed levels of tumor necrosis factor-α were highest in overweight/obese subjects with asthma. Ex vivo studies of primary alveolar macrophages indicated that the response to LPS was most robust in alveolar macrophages from overweight/obese subjects with asthma and that preexposure to high-dose leptin enhanced the proinflammatory response. Leptin alone was sufficient to induce production of proinflammatory cytokines from macrophages derived from overweight/obese subjects with asthma.

CONCLUSIONS

Ex vivo studies indicate that alveolar macrophages derived from overweight/obese subjects with asthma are uniquely sensitive to leptin. This macrophage phenotype, in the context of higher levels of soluble leptin, may contribute to the pathogenesis of airway disease associated with obesity.

Mast cell TNF receptors regulate responses to Mycoplasma pneumoniae in surfactant protein A (SP-A)-/- mice

BACKGROUND

Mycoplasma pneumoniae (Mp) frequently colonizes the airways of patients with chronic asthma and likely contributes to asthma exacerbations. We previously reported that mice lacking surfactant protein A (SP-A) have increased airway hyperresponsiveness (AHR) during M pneumoniae infection versus wild-type mice mediated by TNF-α. Mast cells (MCs) have been implicated in AHR in asthma models and produce and respond to TNF-α.

OBJECTIVE

Determine the contribution of MC/TNF interactions to AHR in airways lacking functional SP-A during Mp infection.

METHODS

Bronchoalveolar lavage fluid was collected from healthy and asthmatic subjects to examine TNF-α levels and M pneumoniae positivity. To determine how SP-A interactions with MCs regulate airway homeostasis, we generated mice lacking both SP-A and MCs (SP-A(-/-)Kit(W-sh/W-sh)) and infected them with M pneumoniae.

RESULTS

Our findings indicate that high TNF-α levels correlate with M pneumoniae positivity in human asthmatic patients and that human SP-A inhibits M pneumoniae-stimulated transcription and release of TNF-α by MCs, implicating a protective role for SP-A. MC numbers increase in M pneumoniae-infected lungs, and airway reactivity is dramatically attenuated when MCs are absent. Using SP-A(-/-)Kit(W-sh/W-sh) mice engrafted with TNF-α(-/-) or TNF receptor (TNF-R)(-/-) MCs, we found that TNF-α activation of MCs through the TNF-R, but not MC-derived TNF-α, leads to augmented AHR during M pneumoniae infection when SP-A is absent. Additionally, M pneumoniae-infected SP-A(-/-)Kit(W-sh/W-sh) mice engrafted with TNF-α(-/-) or TNF-R(-/-) MCs have decreased mucus production compared with that seen in mice engrafted with wild-type MCs, whereas burden was unaffected.

CONCLUSION

Our data highlight a previously unappreciated but vital role for MCs as secondary responders to TNF-α during the host response to pathogen infection.

SHP-1 as a critical regulator of Mycoplasma pneumoniae-induced inflammation in human asthmatic airway epithelial cells

Asthma is a chronic inflammatory disease in which airway epithelial cells are the first line of defense against exposure of the airway to infectious agents. Src homology protein (SHP)-1, a protein tyrosine phosphatase, is a negative regulator of signaling pathways that are critical to the development of asthma and host defense. We hypothesize that SHP-1 function is defective in asthma, contributing to the increased inflammatory response induced by Mycoplasma pneumoniae, a pathogen known to exacerbate asthma. M. pneumoniae significantly activated SHP-1 in airway epithelial cells collected from nonasthmatic subjects by bronchoscopy with airway brushing but not in cells from asthmatic subjects. In asthmatic airway epithelial cells, M. pneumoniae induced significant PI3K/Akt phosphorylation, NF-κB activation, and IL-8 production compared with nonasthmatic cells, which were reversed by SHP-1 overexpression. Conversely, SHP-1 knockdown significantly increased IL-8 production and PI3K/Akt and NF-κB activation in the setting of M. pneumoniae infection in nonasthmatic cells, but it did not exacerbate these three parameters already activated in asthmatic cells. Thus, SHP-1 plays a critical role in abrogating M. pneumoniae-induced IL-8 production in nonasthmatic airway epithelial cells through inhibition of PI3K/Akt and NF-κB activity, but it is defective in asthma, resulting in an enhanced inflammatory response to infection.

Obesity, metabolic dysregulation and oxidative stress in asthma

BACKGROUND

Epidemiological data demonstrate an increased risk of developing incident asthma with increasing adiposity. While the vast majority of studies support the interaction between obesity and asthma, the causality is unclear.

SCOPE OF REVIEW

This article will review the current literature supporting the presence of an obese asthma phenotype and the possible mechanisms mediating the effects of obesity on asthma.

MAJOR CONCLUSIONS

Obesity is associated with poor asthma control, altered responsiveness to medications and increased morbidity. Obesity is characterized by systemic inflammation that may result in increased airway inflammation. However, this assertion is not supported by current studies that demonstrate a lack of significant airway inflammation in obese asthmatics. In spite this observation one must consider limitations of these studies including the fact that most subjects were treated with inhaled corticosteroids that would likely alter inflammation in the lung. Thus, it remains unclear if obesity is associated with alterations in inflammation in the airways of subjects with asthma. Hormones such as leptin and adiponectin are affected by obesity and may play a role in mediating innate immune responses and allergic responses, respectively. The role of oxidative stress remains controversial and the current evidence suggests that while oxidative stress is important in asthma, it does not fully explain the characteristics associated with this unique phenotype.

GENERAL SIGNIFICANCE

Obesity related asthma is associated with increased morbidity and differential response to asthma therapies. Understanding the mechanisms mediating this phenotype would have significant implications for millions of people suffering with asthma. This article is part of a Special Issue entitled Biochemistry of Asthma.

Surfactant protein A is defective in abrogating inflammation in asthma

Surfactant protein A (SP-A) regulates a variety of immune cell functions. We determined the ability of SP-A derived from normal and asthmatic subjects to modulate the inflammatory response elicited by Mycoplasma pneumoniae, a pathogen known to exacerbate asthma. Fourteen asthmatic and 10 normal control subjects underwent bronchoscopy with airway brushing and bronchoalveolar lavage (BAL). Total SP-A was extracted from BAL. The ratio of SP-A1 to total SP-A (SP-A1/SP-A) and the binding of total SP-A to M. pneumoniae membranes were determined. Airway epithelial cells from subjects were exposed to either normal or asthmatic SP-A before exposure to M. pneumoniae. IL-8 protein and MUC5AC mRNA were measured. Total BAL SP-A concentration did not differ between groups, but the percentage SP-A1 was significantly increased in BAL of asthmatic compared with normal subjects. SP-A1/SP-A significantly correlated with maximum binding of total SP-A to M. pneumoniae, but only in asthma. SP-A derived from asthmatic subjects did not significantly attenuate IL-8 and MUC5AC in the setting of M. pneumoniae infection compared with SP-A derived from normal subjects. We conclude that SP-A derived from asthmatic subjects does not abrogate inflammation effectively, and this dysfunction may be modulated by SP-A1/SP-A.

Airway fibroblasts in asthma manifest an invasive phenotype

RATIONALE

Invasive cell phenotypes have been demonstrated in malignant transformation, but not in other diseases, such as asthma. Cellular invasiveness is thought to be mediated by transforming growth factor (TGF)-β1 and matrix metalloproteinases (MMPs). IL-13 is a key T(H)2 cytokine that directs many features of airway remodeling through TGF-β1 and MMPs.

OBJECTIVES

We hypothesized that, in human asthma, IL-13 stimulates increased airway fibroblast invasiveness via TGF-β1 and MMPs in asthma compared with normal controls.

METHODS

Fibroblasts were cultured from endobronchial biopsies in 20 subjects with mild asthma (FEV(1): 90 ± 3.6% pred) and 17 normal control subjects (FEV(1): 102 ± 2.9% pred) who underwent bronchoscopy. Airway fibroblast invasiveness was investigated using Matrigel chambers. IL-13 or IL-13 with TGF-β1 neutralizing antibody or pan-MMP inhibitor (GM6001) was added to the lower chamber as a chemoattractant. Flow cytometry and immunohistochemistry were performed in a subset of subjects to evaluate IL-13 receptor levels.

MEASUREMENTS AND MAIN RESULTS

IL-13 significantly stimulated invasion in asthmatic airway fibroblasts, compared with normal control subjects. Inhibitors of both TGF-β1 and MMPs blocked IL-13-induced invasion in asthma, but had no effect in normal control subjects. At baseline, in airway tissue, IL-13 receptors were expressed in significantly higher levels in asthma, compared with normal control subjects. In airway fibroblasts, baseline IL-13Rα2 was reduced in asthma compared with normal control subjects.

CONCLUSIONS

IL-13 potentiates airway fibroblast invasion through a mechanism involving TGF-β1 and MMPs. IL-13 receptor subunits are differentially expressed in asthma. These effects may result in IL-13-directed airway remodeling in asthma.

Does obesity produce a distinct asthma phenotype?

Obesity and asthma prevalence have been increasing over the past decade. Epidemiological evidence demonstrates that obesity results in an increased risk of developing incident asthma. Even modest levels of increased weight increase asthma risk. Recently published data suggest that obese asthma patients may represent a distinct phenotype of asthma. Obese asthma patients demonstrate increased asthma severity, as indicated by increased exacerbations and decreased asthma control; however, they do not appear to have increased airway cellular inflammation. It seems likely that obesity does not contribute to asthma through conventional Th type 2-mediated inflammatory pathways but, rather, through separate mechanisms that are specific to the obese state. This may explain the variable responses of obese asthma patients to conventional asthma therapies, specifically, relative corticosteroid resistance. Small studies suggest improvements in the disease with weight loss in obese asthma patients, and other interventions to target asthma in obese individuals need to be investigated. Several postulated mechanisms for the occurrence of this distinct phenotype have been postulated: 1) the presence of comorbidities, such as gastroesophageal reflux disease and sleep disordered breathing, 2) systemic inflammation associated with obesity (with elevated levels of circulating cytokines, such as IL-6 and TNF-alpha), 3) increased oxidative stress, and 4) hormones of obesity, such as adiponectin, leptin, and resistin. Although the mechanisms underlying obesity in asthma require further investigation, obesity plays a major role in the asthma epidemic and likely results in a distinct phenotype of the disease.

S-nitrosoglutathione reductase: an important regulator in human asthma

RATIONALE

Nitric oxide bioactivity, mediated through the formation of S-nitrosothiols (SNOs), has a significant effect on bronchomotor tone. S-Nitrosoglutathione is an endogenous bronchodilator that is decreased in children with asthmatic respiratory failure and in adults with asthma undergoing segmental airway challenge. Recently we showed that S-nitrosoglutathione reductase (GSNOR) regulates endogenous SNOs. Mice with genetic deletion of GSNOR are protected from airway hyperresponsivity in an allergic asthma model.

OBJECTIVES

We hypothesized that GSNOR is increased in human asthma and correlates with lung SNO content and airway reactivity.

METHODS

We recruited 36 subjects with mild asthma with FEV(1) 88.5 +/- 2.3% predicted and 34 healthy control subjects with FEV(1) 100.7 +/- 2.5% predicted. Bronchoalveolar lavage (BAL) was performed in all subjects. Cell counts, differentials, GSNOR activity, and SNO levels were determined in BAL.

MEASUREMENTS AND MAIN RESULTS

SNO content was decreased in asthmatic BAL compared with control BAL and correlated inversely with GSNOR expression in BAL cell lysates. Furthermore, GSNOR activity measured from BAL samples was significantly increased in subjects with asthma compared with control subjects and correlated inversely with the provocative concentration of methacholine causing a 20% decrease in FEV(1).

CONCLUSIONS

These findings suggest that GSNOR is an important regulator of airway SNO content and airways hyperresponsiveness in human asthma.

Life-threatening asthma: pathophysiology and management

Asthma prevalence and mortality have been increasing over the past 2 decades, despite advances in medical therapy. In 2003 the National Health Interview Survey reported over 4,000 asthma-related deaths. A small proportion of people with severe asthma use a large proportion of health-care resources and bear the burden of asthma-related morbidity and mortality. The management of acute asthma is complex and evolving. Understanding the phenotypes and pathophysiology of acute asthma will lead to increased recognition and characterization of populations at risk for fatal asthma. The early identification and appropriate management of acute asthma is critical in decreasing asthma morbidity and mortality. This paper reviews current pharmacologic and nonpharmacologic management of severe acute asthma.

Genetic profiling and tailored therapy in asthma: are we there yet?

Asthma is characterized by reversible bronchial hyper-responsiveness and airway inflammation, and encompasses a wide variety of patients with different clinical phenotypes that display variable responses to therapy. The definition of genomic variation presented in the Human Genome Project has facilitated the development of genetic-guided therapy in various diseases, including asthma. Tailored therapy is a reality in many types of malignancies where specific gene mutations or molecular profiles are identified and used to make critical therapeutic decisions. Despite the identification of beta-adrenergic receptor polymorphisms by Liggett and colleagues during the 1990s, the pharmacogenetics of asthma is still in its infancy. There have been great advances in asthma pharmacogenetics and pharmacotherapy with the completion of several large trials highlighting the effects of genotype on response to asthma therapy. This review focuses on research articles that serve to emphasize the potential role of using genotyping as a tool to develop individualized patient treatment regimens for asthma, thus improving outcomes and limiting adverse effects of certain therapies.

Epidemiology of asthma

The epidemiology of asthma is complex but essential in enhancing the understanding of a disease that affects millions of patients. Asthma is associated with significant morbidity and mortality. Asthma prevalence rates in the United States reached a plateau after 1998 with an estimated overall prevalence of 3.8% in 2003. Racial disparities exist and there are staggering differences in morbidity and mortality. The analysis of data collected from epidemiologic studies continues to be a critical part of enhancing the understanding of the pathophysiology of asthma, which will lead to improved patient outcomes.