A pragmatic guide to choosing biologic therapies in severe asthma

Assessment of Treatment Response in Patients With Severe Asthma Using Visual and Quantitative Analysis of Chest CT

OBJECTIVE

To evaluate the role of visual and quantitative chest CT parameters in assessing treatment response in patients with severe asthma.

MATERIALS AND METHODS

Korean participants enrolled in a prospective multicenter study, named the Precision Medicine Intervention in Severe Asthma study, from May 2020 to August 2021, underwent baseline and follow-up chest CT scans (inspiration/expiration) 10-12 months apart, before and after biologic treatment. Two radiologists scored bronchiectasis severity and mucus plugging extent. Quantitative parameters were obtained from each CT scan as follows: normal lung area (normal), air trapping without emphysema (AT without emph), air trapping with emphysema (AT with emph), and airway (total branch count, Pi10). Clinical parameters, including pulmonary function tests (forced expiratory volume in 1 s [FEV1] and FEV1/forced vital capacity [FVC]), sputum and blood eosinophil count, were assessed at initial and follow-up stages. Changes in CT parameters were correlated with changes in clinical parameters using Pearson or Spearman correlation.

RESULTS

Thirty-four participants (female:male, 20:14; median age, 50.5 years) diagnosed with severe asthma from three centers were included. Changes in the bronchiectasis and mucus plugging extent scores were negatively correlated with changes in FEV1 and FEV1/FVC (ρ = from -0.544 to -0.368, all P < 0.05). Changes in quantitative CT parameters were correlated with changes in FEV1 (normal, r = 0.373 [P = 0.030], AT without emph, r = -0.351 [P = 0.042]), FEV1/FVC (normal, r = 0.390 [P = 0.022], AT without emph, r = -0.370 [P = 0.031]). Changes in total branch count were positively correlated with changes in FEV1 (r = 0.349 [P = 0.043]). There was no correlation between changes in Pi10 and the clinical parameters (P > 0.05).

CONCLUSION

Visual and quantitative CT parameters of normal, AT without emph, and total branch count may be effective for evaluating treatment response in patients with severe asthma.

Long-Term Effectiveness of Anti-IL-4R Therapy Following Suboptimal Response to Anti-IL-5/5R Therapy in Severe Eosinophilic Asthma

BACKGROUND

Dupilumab is an anti-IL-4R monoclonal antibody (mAb) with proven efficacy in severe eosinophilic asthma (SEA). A suboptimal response to anti-IL-5/5R mAbs is seen in some patients with ongoing evidence of type 2 (T2) inflammation.

OBJECTIVE

To understand whether targeting IL-13 pathways with dupilumab in these patients may lead to better clinical outcomes.

METHODS

We performed a retrospective analysis of the extended clinical effectiveness of dupilumab up to 2 years of treatment in patients with SEA who had not responded adequately to anti-IL-5/5R biologics. The ability to achieve clinical remission and the change in the remission domains of exacerbation rate (AER), maintenance oral corticosteroid dose (mOCS), lung function (forced expiratory volume in 1 second), and asthma control (Asthma Control Questionnaire 6) were recorded.

RESULTS

Thirty-seven patients (mean age 41 years, 70% female) were included in the analysis. The mean (standard deviation) AER fell by almost 90% from 3.16 (1.28) at dupilumab initiation to 0.35 (0.72) after 1 year. The median (interquartile range) mOCS dose (n = 20) fell from 10 (5-25) mg to 0 (0-5) mg at 1 year, with 14 of 20 (70%) able to stop prednisolone altogether. Clinical remission was achieved in 16 of 37 (43%). Patients who achieved remission had a higher pre-IL-5/5R fractional exhaled nitric oxide (FeNO) level (85 [39-198] parts per billion [ppb] vs 75 [42-96] ppb, P = .03).

CONCLUSIONS

Significant improvements in clinical outcomes are possible after a switch to dupilumab in patients experiencing a suboptimal response to anti-IL-5/5R therapies. A higher FeNO in poor responders to anti-IL-5/5R who achieve remission with dupilumab is suggestive of an IL-13-driven subphenotype of T2-high asthma in which the eosinophil appears unlikely to play a key role in the disease pathogenesis.

Quality of Life Improvements with Biologic Initiation Among Subspecialist-Treated US Patients with Severe Asthma

Purpose

Patients living with severe asthma (SA) experience multiple health-related quality of life (HRQoL) impairments. This study examined HRQoL changes after biologic treatment initiation among a large, real-world cohort of patients with SA.

Patients and methods

CHRONICLE is an ongoing observational study of subspecialist-treated adults with SA who receive biologics or maintenance systemic corticosteroids or are uncontrolled on high-dosage inhaled corticosteroids with additional controllers. Patients enrolled February 2018-February 2023 were asked to complete the St. George's Respiratory Questionnaire (SGRQ) every 6 months (total score range of 0-100 [0=best possible health], meaningful change threshold is a 4-unit reduction in the total score). Changes in SGRQ responses from 6 months before initiation to 12 to 18 months after initiation were summarized.

Results

A total of 76 patients completed the SGRQ 0 to 6 months before and 12 to 18 months after biologic initiation. The mean (SD) SGRQ total score decreased from 52.2 (20.6) to 41.9 (23.8), with improvement across the symptoms (-14.5), activity (-11.0), and impacts (-8.3) components. For specific impairments reported by ≥50% of patients before biologic initiation, fewer reported each impairment after biologic initiation; the largest reductions were for "Questions about what activities usually make you feel short of breath these days [Walking outside on level ground]" (67% to 43%), "Questions about other effects that your respiratory problems may have on you these days [I feel that I am not in control of my respiratory problems]" (55% to 34%), and "Questions about your cough and shortness of breath these days [My coughing or breathing disturbs my sleep]" (63% to 45%).

Conclusion

In this real-world cohort of adults with SA, biologic initiation was associated with meaningful improvements in asthma-related HRQoL. These data provide further insight into the burden SA places on patients and the benefits of biologic treatment.

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

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

Reliability of blood eosinophil count in steady-state bronchiectasis

RATIONALE

The baseline value of eosinophils in peripheral blood (BEC) has been associated with different degrees of severity, prognosis and response to treatment in patients with bronchiectasis. It is not known, however, if this basal value remains constant over time.

OBJECTIVES

The aim of this study was to assess whether the BEC remains stable in the long term in patients with bronchiectasis.

METHODS AND MEASUREMENTS

Patients from the RIBRON registry of bronchiectasis diagnosed by computed tomography with at least 2 BEC measurements one year apart were included in the study. Patients with asthma and those taking anti-eosinophilic drugs were excluded. Reliability was assessed using the intra-class correlation coefficient (ICC). A patient with a BEC of at least 300 cells/uL or less than 100 cells/uL was considered eosinophilic or eosinopenic, respectively. Group changes over time were also calculated.

MAIN RESULTS

Seven hundred and thirteen patients were finally included, with a mean age of 66.5 (13.2) years (65.8 % women). A total of 2701 BEC measurements were performed, with a median number of measurements per patient of 4 (IQR: 2-5) separated by a median of 12.1 (IQR: 10.5-14.3) months between two consecutive measurements. The ICC was good (>0.75) when calculated between two consecutive measurements (approximately one year apart) but had dropped significantly by the time of the next annual measurements. Similarly, the change from an eosinophilic or eosinopenic patient to a non-eosinophilic or non-eosinopenic patient, respectively, was less than 30 % during the first year with respect to the baseline value but was close to 50 % in later measurements.

CONCLUSIONS

Given the significant changes observed in the baseline value of the BEC over time, its monitoring is necessary in patients with bronchiectasis in order to more reliably assess its usefulness.

The Effects of Benralizumab on Lung Volumes and Airway Resistance in Severe Eosinophilic Asthma: A Real-World Study

INTRODUCTION

Add-on biological monoclonal antibodies such as benralizumab (anti-IL-5Ra) are recommended by international guidelines to reduce exacerbations in severe eosinophilic asthma (SEA). However, few studies have assessed the impact of these therapies on lung function-related outcomes. Our goal was to evaluate the effectiveness of benralizumab on lung function, including lung volumes and airway resistance, in SEA patients in Portugal.

METHODS

This was a real-world, observational, prospective, multicentric study including adult patients diagnosed with SEA (January-June 2023). Spirometry and plethysmography were performed at baseline (T0) and after six months of treatment (T6) with benralizumab to assess: total lung capacity (TLC), residual volume (RV), forced expiratory volume in one second (FEV1), forced vital capacity (FVC), mean forced expiratory flow between 25% and 75% of FVC (mFEF-25/75), intrathoracic gas volume (ITGV), and respiratory airway resistance (Raw). Descriptive statistics (with categorical variables described as frequencies and continuous values as mean and standard deviation (SD)) and paired t-test and Cohen's d effect size were calculated (analyses performed in StataCorp v.15.1; StataCorp LLC, TX, USA).

RESULTS

Overall, 30 SEA patients were evaluated, mostly women (n=18, 60.0%), with atopy (n=22, 73.3%), a mean age of 58.4 years (SD 11.7), and assisted by pulmonology (n=19, 63.3%) or immunology-allergology (n=11, 36.7%) services. Mean eosinophilia at baseline was 1103.57 cells/mcL (SD 604.88; minimum-maximum 460-2400); after the use of benralizumab, the count dropped to zero. After six months of treatment, a significant increase (p<0.0001) in FVC (15.3%), FEV1 (22.6%), and mFEF-25/75 (17.7%) were observed from baseline (Cohen's d between 0.78 and 1.11). ITGV, RV, RV/TLC, and Raw significantly decreased (p<0.0001) during the study period (-17.3%, -29.7%, -8.9%, and -100.6%, respectively) (Cohen's d between -0.79 and -1.06). No differences in TLC were obtained (p=0.173). No differences between sexes were observed for any measure. Patients with more significant eosinophilia (>900 cells/mcL count; n=15) presented better responses in FEV1 (p=0.001) and mFEF-25/75 (p=0.007).

CONCLUSIONS

A notable eosinophil depletion with add-on benralizumab led to significant improvements in SEA patients' respiratory function (static lung volumes and airway resistance) in real-world settings after six months. The significant deflating effect of benralizumab on patients' hyperinflated lungs led to enhanced expiratory flow (increased FEV1 and mFEF-25/75) and air trapping (decreased RV/TLC), suggesting this antibody improves bronchial obstruction, lung hyperinflation, and airway resistance. Further studies in a larger population are required to confirm these findings.

The Neutralization of the Eosinophil Peroxidase Antibody Accelerates Eosinophilic Mucin Decomposition

Eosinophilic airway inflammation, complicated by bronchial asthma and eosinophilic chronic rhinosinusitis (ECRS), is difficult to treat. The disease may become refractory when eosinophilic mucin associated with eosinophil peroxidase (EPX) and autoantibodies fills in the paranasal sinus and small airway. This study investigated the functional role of an anti-EPX antibody in eosinophilic mucin of ECRS in eosinophilic airway inflammation. Eosinophilic mucin was obtained from patients with ECRS. The effects of the anti-EPX antibody on dsDNA release from eosinophils and eosinophilic mucin decomposition were evaluated. Immunofluorescence or enzyme-linked immunosorbent assays were performed to detect the anti-EPX antibody and its supernatant and serum levels in eosinophilic mucin, respectively. The serum levels of the anti-EPX antibody were positively correlated with sinus computed tomography score and fractionated exhaled nitrogen oxide. Patients with refractory ECRS had higher serum levels of the anti-EPX antibody than those without. However, dupilumab treatment decreased the serum levels of the anti-EPX antibody. Immunoglobulins (Igs) in the immunoprecipitate of mucin supernatants enhanced dsDNA release from eosinophils, whereas the neutralization of Igs against EPX stopped dsDNA release. Furthermore, EPX antibody neutralization accelerated mucin decomposition and restored corticosteroid sensitivity. Taken together, the anti-EPX antibody may be involved in the formulation of eosinophilic mucin and be used as a clinical marker and therapeutic target for intractable eosinophilic airway inflammation.

Parasitic infections related to anti-type 2 immunity monoclonal antibodies: a disproportionality analysis in the food and drug administration's adverse event reporting system (FAERS)

Introduction: Monoclonal antibodies (mAbs) targeting immunoglobulin E (IgE) [omalizumab], type 2 (T2) cytokine interleukin (IL) 5 [mepolizumab, reslizumab], IL-4 Receptor (R) α [dupilumab], and IL-5R [benralizumab]), improve quality of life in patients with T2-driven inflammatory diseases. However, there is a concern for an increased risk of helminth infections. The aim was to explore safety signals of parasitic infections for omalizumab, mepolizumab, reslizumab, dupilumab, and benralizumab. Methods: Spontaneous reports were used from the Food and Drug Administration's Adverse Event Reporting System (FAERS) database from 2004 to 2021. Parasitic infections were defined as any type of parasitic infection term obtained from the Standardised Medical Dictionary for Regulatory Activities® (MedDRA®). Safety signal strength was assessed by the Reporting Odds Ratio (ROR). Results: 15,502,908 reports were eligible for analysis. Amongst 175,888 reports for omalizumab, mepolizumab, reslizumab, dupilumab, and benralizumab, there were 79 reports on parasitic infections. Median age was 55 years (interquartile range 24-63 years) and 59.5% were female. Indications were known in 26 (32.9%) reports; 14 (53.8%) biologicals were reportedly prescribed for asthma, 8 (30.7%) for various types of dermatitis, and 2 (7.6%) for urticaria. A safety signal was observed for each biological, except for reslizumab (due to lack of power), with the strongest signal attributed to benralizumab (ROR = 15.7, 95% Confidence Interval: 8.4-29.3). Conclusion: Parasitic infections were disproportionately reported for mAbs targeting IgE, T2 cytokines, or T2 cytokine receptors. While the number of adverse event reports on parasitic infections in the database was relatively low, resulting safety signals were disproportionate and warrant further investigation.

Dupilumab efficacy in high sleep disturbance management among patients with type 2 asthma

BACKGROUND

Patients with asthma often experience sleep disturbances. We assessed the 5-item Asthma Control Questionnaire (ACQ-5) score ≥2.5 as a useful threshold to identify patients with moderate-to-severe type 2 asthma and high sleep disturbance (HSD) and investigated dupilumab efficacy on clinical and sleep-related outcomes among patients with HSD.

METHODS

QUEST (NCT02414854) data were used in this post hoc analysis. A composite endpoint from validated patient-reported outcomes was developed to identify patients with HSD using sleep-related items from the ACQ-5, Asthma-Related Quality-of-Life Questionnaire, Rhino-Conjunctivitis Quality-of-Life Questionnaire, and Sino-Nasal Outcome Test-22. Impairment in at least 1 item was considered an indication of HSD. Change from baseline to Week 52 in nighttime symptoms, ACQ-5 score, lung function, annualized severe exacerbation rates (AER), and short-acting β-agonists use during treatment was used to assess dupilumab efficacy.

RESULTS

In type 2 asthma patients, 64% had HSD at baseline; of those with ACQ-5 ≥2.5 at baseline, 82% had HSD. In this population, dupilumab reduced nighttime symptoms and ACQ-5 score by 0.31 and 0.56 points, respectively, by Week 52 versus placebo, and led to a 66% reduction in AER during QUEST and 0.34 L improvement in pre-bronchodilator (pre-BD) forced expiratory volume in 1 s (FEV1) at Week 52.

CONCLUSION

A majority of patients with moderate-to-severe type 2 asthma with ACQ-5 ≥2.5 at baseline had HSD. Dupilumab reduced nighttime symptoms and exacerbations, and improved lung function, overall asthma control, and quality of life. Further studies are needed to confirm the association between ACQ-5 score ≥2.5 and higher sleep disturbance rates.

Biological therapy for severe asthma - Indian perspectives and challenges

Asthma is a complex and heterogeneous disease. Severe asthma makes up only a minority of asthma patients encountered in clinical settings but accounts for substantial healthcare utilisation in terms of manpower as well as economic allocation. The availability of monoclonal antibodies has a major impact on severe asthmatics and has provided excellent clinical results in properly selected patients. The discovery of new molecules might present uncertainties to clinicians as to the best agent to institute in an individual patient. The practice scenario in India is unique when it comes to the commercial availability of monoclonal antibodies, patient attitudes, and allocation of the healthcare budget. The present review dissects and summarises the available monoclonal antibodies for asthma treatment in India, the perspectives of Indian patients on biological therapy, and the challenges encountered by patients and physicians in this regard. We provide practical suggestions for utilising monoclonal antibodies and deciding on the optimal agent for a given patient.

Eosinophilic Airway Diseases: From Pathophysiological Mechanisms to Clinical Practice

Eosinophils play a key role in airway inflammation in many diseases, such as allergic and non-allergic asthma, chronic rhinosinusitis with nasal polyps, and chronic obstructive pulmonary disease. In these chronic disabling conditions, eosinophils contribute to tissue damage, repair, remodeling, and disease persistence through the production a variety of mediators. With the introduction of biological drugs for the treatment of these respiratory diseases, the classification of patients based on clinical characteristics (phenotype) and pathobiological mechanisms (endotype) has become mandatory. This need is particularly evident in severe asthma, where, despite the great scientific efforts to understand the immunological pathways underlying clinical phenotypes, the identification of specific biomarkers defining endotypes or predicting pharmacological response remains unsatisfied. In addition, a significant heterogeneity also exists among patients with other airway diseases. In this review, we describe some of the immunological differences in eosinophilic airway inflammation associated with severe asthma and other airway diseases and how these factors might influence the clinical presentation, with the aim of clarifying when eosinophils play a key pathogenic role and, therefore, represent the preferred therapeutic target.

Applying the new guidelines to asthma management in children

PURPOSE OF REVIEW

This review aims to provide paediatricians with novel concepts from scientific evidence applicable to treating children with asthma. The latest guideline updates on paediatric asthma are discussed here, with a focus on the 2022 update of the GINA document.

RECENT FINDINGS

Mild asthma remains to be an important challenge for the paediatrician, and the introduction of new evidence-based treatment strategies, particularly those symptom-driven, could have a significant impact on the paediatric population. The identification of predictive biomarkers, the definition of biological treatment response, the possible duration of these therapies in this age group, as well as their potential action on airway remodelling are desirable in the short term. As the number of available biological treatment options expands, paediatricians should be supported by further evidence in decision-making.

SUMMARY

There is an urgent need to implement at multiple levels the latest therapeutic strategies proposed for asthma at all severities.

Baseline Characteristics of Patients Enrolled in Clinical Trials of Biologics for Severe Asthma as Potential Predictors of Outcomes

(1) Background: Over the past 20 years, monoclonal antibodies have been developed for the treatment of severe asthma, with numerous randomised controlled trials (RCTs) conducted to define their safety and efficacy. The growing availability of biologics, which until now have only been available for T2-high asthma, has been further enriched by the arrival of tezepelumab. (2) Methods: This review aims to evaluate the baseline characteristics of patients enrolled in RCTs of biologics for severe asthma to understand how they could potentially predict outcomes and how they can help differentiate between available options. (3) Results: The studies reviewed demonstrated that all biologic agents are effective in improving asthma control, especially with regard to reducing exacerbation rates and OCS use. As we have seen, in this regard, there are few data on omalizumab and none yet on tezepelumab. In analysing exacerbations and average doses of OCSs, pivotal studies on benralizumab have enrolled more seriously ill patients. Secondary outcomes, such as improvement in lung function and quality of life, showed better results-especially for dupilumab and tezepelumab. (4) Conclusion: Biologics are all effective, albeit with important differences. What fundamentally guides the choice is the patient's clinical history, the endotype represented by biomarkers (especially blood eosinophils), and comorbidities (especially nasal polyposis).

Uncontrolled severe T2 asthma: Which biological to choose? A biomarker-based approach

In recent years, advances in knowledge of molecular mechanisms involved in asthma have changed uncontrolled severe asthma (USA) treatment, with the appearance of biological treatment. USA is a heterogeneous entity with different endotypes and phenotypes. Nowadays, the biological drugs approved with asthma indication are omalizumab, mepolizumab, reslizumab, benralizumab and dupilumab. Tezepelumab is approved by the Food and Drug Administration (FDA) in the United States and, recently, by the European Medicines Agency (EMA). All these biological drugs have shown their efficacy in clinical trials, especially in reducing exacerbations, improving asthma control, quality of life, pulmonary function, and withdrawing systemic corticosteroids or at least reducing their daily dose, with some differences between them. Except for mepolizumab and reslizumab, biological drugs have different targets and thus different therapeutic indications should be expected; however, in some patients, more than one drug could be indicated, making the election more difficult. Because there are no direct comparisons between biological drugs, some biomarkers are used to choose between them, but they are not unbeatable. In this article, an algorithm to choose the first biological drug in a specific patient is proposed based on different study results and patient' characteristics.

Therapeutical Targets in Allergic Inflammation

From the discovery of IgE to the in-depth characterization of Th2 cells and ILC2, allergic inflammation has been extensively addressed to find potential therapeutical targets. To date, omalizumab, an anti-IgE monoclonal antibody, and dupilumab, an anti-IL-4 receptor α monoclonal antibody, represent two pillars of biologic therapy of allergic inflammation. Their increasing indications and long-term follow-up studies are shaping the many different faces of allergy. At the same time, their limitations are showing the intricate pathogenesis of allergic diseases.

Real-Life Performance of Mepolizumab in T2-High Severe Refractory Asthma with the Overlapping Eosinophilic-Allergic Phenotype

Severe asthma (SA) is categorized into multiple overlapping phenotypes and clinical characteristics driven by complex mechanistic inflammatory pathways. Mepolizumab is a human monoclonal antibody effectively targeting interleukin-5 in severe eosinophilic asthma. However, the eligibility of biologics in coincident SA phenotypes is still unclear. We assessed the efficacy and safety of mepolizumab in real-life patients with the overlapping T2-high SA endotype. This was a phase IV, single-centre observational cohort study including patients with severe refractory T2-high asthma in treatment with mepolizumab. After 12 months of treatment with mepolizumab, significant improvements (p < 0.0001) in asthma control and lung function were recorded. Rates of clinically significant annual asthma exacerbation were also decreased by 71.22% after 52-week therapy with mepolizumab (p < 0.001) associated with a reduction in the mean daily dose of oral corticosteroids. Two patients (3.27%) had to discontinue mepolizumab due to musculoskeletal disorders with no severe safety issues reported. The use of mepolizumab as an add-on therapy in routine clinical practice was safely associated with significant clinical and functional in the overlapping eosinophilic-and-allergic SA phenotype. The current data should support clinical and therapeutic decision-making in this T2-high SA endotype.

Biologic therapy practices in severe asthma; outcomes from the UK Severe Asthma Registry and survey of specialist opinion

BACKGROUND

several biological treatments have become available for management of severe asthma. There is a significant overlap in the indication of these treatments with lack of consensus on the first-line biologic choice and switching practice in event of treatment failure.

AIMS

to evaluate outcomes of biologic treatments through analysis of the UK Severe Asthma Registry (UKSAR), and survey of the UK severe asthma specialists' opinion.

METHODS

patients registered in the UKSAR database and treated with biologics for severe asthma in the period between January 2014 and August 2021, were studied to explore biologic treatments practice. This was complemented by survey of opinion of severe asthma specialists.

RESULTS

a total of 2,490 patients from 10 severe asthma centres were included in the study (mean age 51.3 years, 61.1% female, mean BMI 30.9kg/m2 ). Biologics use included mepolizumab 1,115 (44.8%), benralizumab 925 (37.1%), omalizumab 432 (17.3%), dupilumab 13 (0.5%), and reslizumab 5 (0.2%). Patients on omalizumab were younger and had earlier age of onset asthma than those prescribed mepolizumab or benralizumab. Patients prescribed mepolizumab and benralizumab had similar clinical characteristics. Those on benralizumab were more likely to continue treatment at approximately one year follow up (93.9%), than those on mepolizumab (80%), or omalizumab (69.6%). The first choice biologic differed between centres and changed over the study time period. Experts' opinion also diverged in terms of biologic initiation choice and switching practice.

CONCLUSION

We observed significant variation and divergence in the prescribing practices of biologics in severe asthma that necessitates further research and standardisation.

CCL4 Functions as a Biomarker of Type 2 Airway Inflammation

Eosinophilic airway inflammatory disease is associated with bronchial asthma, with eosinophilic chronic rhinosinusitis (ECRS) typical of refractory type 2 airway inflammation. CCL4 produced at local inflammatory sites is involved in them via the accumulation and activation of type 2 inflammatory cells, including eosinophils. The detailed mechanism of CCL4 production remains unclear, and also the possibility it could function as a biomarker of type 2 airway inflammation remains unresolved. In this study, we evaluated CCL4 mRNA expression and production via the TSLP receptor (TSLPR) and toll-like receptors (TLRs) or proteinase-activated receptor-2 (PAR2) in BEAS-2B bronchial epithelial cells co-incubated with purified eosinophils or eosinophil peroxidase (EPX). We examined serum chemokine (CCL4, CCL11, CCL26, and CCL17) and total IgE serum levels, fractionated exhaled nitrogen oxide (FENO), and CCL4 expression in nasal polyps in patients with severe ECRS and asthma. CCL4 was induced by TSLP under eosinophilic inflammation. Furthermore, CCL4 was released via TLR3 signaling, which was enhanced by TSLP. CCL4 was mainly located in nasal polyp epithelial cells, while serum CCL4 levels were reduced after dupilumab treatment. Serum CCL4 levels were positively correlated with FENO, serum IgE, and CCL17 levels. Thus, CCL4 released from epithelial cells via the innate immune system during type 2 airway inflammation may function as a useful biomarker for the condition.

Dupilumab and tezepelumab in severe refractory asthma: new opportunities

Bronchial asthma is a chronic inflammatory condition with increasing prevalence worldwide that may present as heterogeneous phenotypes defined by the T2-mediated pattern of airway inflammation T2-high and T2-low asthma. Severe refractory asthma includes a subset of asthmatic patients who fail to control their disease despite maximal therapy and represent a group of patients needing marked resource utilization and hence may be eligible to add-on biological therapies. Among the new biologics, we focused our attention on two monoclonal antibodies: dupilumab, exerting a dual blockade of cytokine (interleukin (IL)-4 and IL-13) signaling; and tezepelumab, acting at a higher level preventing the binding of thymic stromal lymphopoietin (TSLP) to its receptor, thus blocking TSLP, IL-25, and IL-33 signaling, hence modulating airway T2 immune responses. With their different mechanisms of action, these two biologics represent important options to provide an enhanced personalized treatment regimen. Several clinical trials have been conducted testing the efficacy and safety of dupilumab in severe refractory asthmatic patients showing improvements in lung function, asthma control, and reducing exacerbations. Similar results were reported with tezepelumab that, differently from dupilumab, acts irrespectively on eosinophilic or non-eosinophilic phenotype. In this review, we provide an overview of the most important highlights regarding dupilumab and tezepelumab characteristics and mechanism of action with a critical review of the principal results of clinical (Phase II and III) studies concluded and those still in progress.