Baseline FeNO as a prognostic biomarker for subsequent severe asthma exacerbations in patients with uncontrolled, moderate-to-severe asthma receiving placebo in the LIBERTY ASTHMA QUEST study: a post-hoc analysis

Clinical utilization of airway inflammatory biomarkers in the prediction and monitoring of clinical outcomes in patients with chronic obstructive pulmonary disease

INTRODUCTION

Chronic obstructive pulmonary disease (COPD) accounts for 545 million people living with chronic respiratory disorders and is the third leading cause of morbidity and mortality around the world. COPD is a progressive disease, characterized by episodes of acute worsening of symptoms such as cough, dyspnea, and sputum production.

AREAS COVERED

Airway inflammation is a prominent feature of COPD. Chronic airway inflammation results in airway structural remodeling and emphysema. Persistent airway inflammation is a treatable trait of COPD and plays a significant role in disease development and progression. In this review, the authors summarize the current and emerging biomarkers that reveal the heterogeneity of airway inflammation subtypes, clinical outcomes, and therapeutic response in COPD.

EXPERT OPINION

Airway inflammation can be broadly categorized as eosinophilic (type 2 inflammation) and non-eosinophilic (non-type 2 inflammation) in COPD. Currently, blood eosinophil counts are incorporated in clinical practice guidelines to identify COPD patients who are at a higher risk of exacerbations and lung function decline, and who are likely to respond to inhaled corticosteroids. As new therapeutics are being developed for the chronic management of COPD, it is essential to identify biomarkers that will predict treatment response.

Burden of Uncontrolled Severe Asthma With and Without Elevated Type-2 Inflammatory Biomarkers

BACKGROUND

Many patients with asthma have type-2 airway inflammation, identified by the presence of biomarkers, including history of allergy, high blood eosinophil (EOS) count, and high fractional exhaled nitric oxide levels.

OBJECTIVE

To assess disease burden in relation to type-2 inflammatory biomarker status (history of allergy, blood EOS count, and fractional exhaled nitric oxide level) in patients with uncontrolled and controlled severe asthma in the NOVEL observational longiTudinal studY (NOVELTY) (NCT02760329).

METHODS

Asthma diagnosis and severity were physician-reported. Control was defined using Asthma Control Test score (uncontrolled <20, controlled ≥20) and/or 1 or more severe physician-reported exacerbation in the previous year. Biomarker distribution (history of allergy, blood EOS count, and fractional exhaled nitric oxide level), symptom burden (Asthma Control Test score, modified Medical Research Council dyspnea scale), health status (St George's Respiratory Questionnaire score), exacerbations, and health care resource utilization were assessed.

RESULTS

Of 647 patients with severe asthma, 446 had uncontrolled and 123 had controlled asthma. Among those with uncontrolled asthma, 196 (44%) had 2 or more positive biomarkers, 187 (42%) had 1 positive biomarker, 325 (73%) had low blood EOS, and 63 (14%) were triple-negative. Disease burden was similarly high across uncontrolled subgroups, irrespective of biomarker status, with poor symptom control (Asthma Control Test score 14.9-16.6), impaired health status (St George's Respiratory Questionnaire total score 46.7-49.4), clinically important breathlessness (modified Medical Research Council grade ≥2 in 47.3%-57.1%), and 1 or more severe exacerbation (70.6%-76.2%).

CONCLUSIONS

Type-2 inflammatory biomarkers did not differentiate disease burden in patients with severe asthma. Patients with low type-2 inflammatory biomarker levels have few biologic therapy options; their needs should be addressed.

Phenotyping of Severe Asthma in the Era of Broad-Acting Anti-Asthma Biologics

Severe asthma is associated with significant morbidity and mortality despite the maximal use of inhaled corticosteroids and additional controller medications, and has a high economic burden. Biologic therapies are recommended for the management of severe, uncontrolled asthma to help to prevent exacerbations and to improve symptoms and health-related quality of life. The effective management of severe asthma requires consideration of clinical heterogeneity that is driven by varying clinical and inflammatory phenotypes, which are reflective of distinct underlying disease mechanisms. Phenotyping patients using a combination of clinical characteristics such as the age of onset or comorbidities and biomarker profiles, including blood eosinophil counts and levels of fractional exhaled nitric oxide and serum total immunoglobulin E, is important for the differential diagnosis of asthma. In addition, phenotyping is beneficial for risk assessment, selection of treatment, and monitoring of the treatment response in patients with asthma. This review describes the clinical and inflammatory phenotypes of asthma, provides an overview of biomarkers routinely used in clinical practice and those that have recently been explored for phenotyping, and aims to assess the value of phenotyping in severe asthma management in the current era of biologics.

Treatable Traits in Pregnant Women with Asthma

BACKGROUND

Asthma is the most common chronic respiratory disease in pregnancy, affecting approximately 8-10% of pregnant women. Uncontrolled asthma is associated with adverse perinatal outcomes, including low birth weight, preterm birth, and maternal complications such as pre-eclampsia.

SUMMARY

A current approach to the management of chronic airway diseases is based on targeting treatable traits. The aim of this review was to define treatable traits in pregnant women with asthma based on recent literature and to determine personalized treatment options according to these traits. Traits addressed in this review that may improve asthma control and pregnancy outcomes are fractional exhaled nitric oxide-based asthma monitoring and treatment, medication adherence and inhalation technique, impaired lung function, smoking cessation and comorbidity including psychological conditions (depression and anxiety), obesity, rhinitis, gastroesophageal reflux disease, chronic rhinosinusitis with or without nasal polyps, and sleep apnea.

KEY MESSAGES

All the treatable traits discussed have the potential to improve asthma control and pregnancy outcomes in pregnant women with asthma. Further research is needed to determine which management approaches are best to improve asthma control during pregnancy, to identify other relevant treatable traits, and to determine whether the treatable trait approach is feasible and beneficial in pregnant women with asthma.

Biomarkers of immediate drug hypersensitivity

Immediate drug hypersensitivity reactions (IDHRs) are a burden for patients and the health systems. This problem increases when taking into account that only a small proportion of patients initially labelled as allergic are finally confirmed after an allergological workup. The diverse nature of drugs involved will imply different interactions with the immunological system. Therefore, IDHRs can be produced by a wide array of mechanisms mediated by the drug interaction with specific antibodies or directly on effector target cells. These heterogeneous mechanisms imply an enhanced complexity for an accurate diagnosis and the identification of the phenotype and endotype at early stages of the reaction is of vital importance. Currently, several endophenotypic categories (type I IgE/non-IgE, cytokine release, Mast-related G-protein coupled receptor X2 (MRGPRX2) or Cyclooxygenase-1 (COX-1) inhibition and their associated biomarkers have been proposed. A precise knowledge of endotypes will permit to discriminate patients within the same phenotype, which is crucial in order to personalise diagnosis, future treatment and prevention to improve the patient's quality of life.

Asthma prediction via affinity graph enhanced classifier: a machine learning approach based on routine blood biomarkers

BACKGROUND

Asthma is a chronic respiratory disease affecting millions of people worldwide, but early detection can be challenging due to the time-consuming nature of the traditional technique. Machine learning has shown great potential in the prompt prediction of asthma. However, because of the inherent complexity of asthma-related patterns, current models often fail to capture the correlation between data samples, limiting their accuracy. Our objective was to use our novel model to address the above problem via an Affinity Graph Enhanced Classifier (AGEC) to improve predictive accuracy.

METHODS

The clinical dataset used in this study consisted of 152 samples, where 24 routine blood markers were extracted as features to participate in the classification due to their ease of sourcing and relevance to asthma. Specifically, our model begins by constructing a projection matrix to reduce the dimensionality of the feature space while preserving the most discriminative features. Simultaneously, an affinity graph is learned through the resulting subspace to capture the internal relationship between samples better. Leveraging domain knowledge from the affinity graph, a new classifier (AGEC) is introduced for asthma prediction. AGEC's performance was compared with five state-of-the-art predictive models.

RESULTS

Experimental findings reveal the superior predictive capabilities of AGEC in asthma prediction. AGEC achieved an accuracy of 72.50%, surpassing FWAdaBoost (61.02%), MLFE (60.98%), SVR (64.01%), SVM (69.80%) and ERM (68.40%). These results provide evidence that capturing the correlation between samples can enhance the accuracy of asthma prediction. Moreover, the obtained [Formula: see text] values also suggest that the differences between our model and other models are statistically significant, and the effect of our model does not exist by chance.

CONCLUSION

As observed from the experimental results, advanced statistical machine learning approaches such as AGEC can enable accurate diagnosis of asthma. This finding holds promising implications for improving asthma management.

Blood eosinophils and fractional exhaled nitric oxide are prognostic and predictive biomarkers in childhood asthma

BACKGROUND

Blood eosinophils and fractional exhaled nitric oxide (Feno) are prognostic biomarkers for exacerbations and predict lung function responses to dupilumab in adolescents and adults with asthma.

OBJECTIVE

We evaluated the relationship between baseline blood eosinophils and Feno and response to dupilumab in children with asthma.

METHODS

Children aged 6 to 11 years with uncontrolled moderate-to-severe asthma (n = 408) were randomized to receive dupilumab 100/200 mg by body weight or volume-matched placebo every 2 weeks for 52 weeks. Annualized exacerbation rate (AER) reduction and least squares mean change in prebronchodilator percent predicted forced expiratory volume in 1 second (ppFEV1) at week 12 were assessed according to cutoff baseline levels for Feno (<20 ppb vs ≥20 ppb) and blood eosinophil count (<150, ≥150 to <300, ≥300 to <500, and ≥500 cells/μL). Quadrant analyses in populations defined by biomarker thresholds and spline models across continuous end points assessed the relationship with Feno and eosinophil count. Interaction testing evaluated the independent roles of Feno and blood eosinophils as predictive markers.

RESULTS

Exacerbation risk and magnitude of AER reduction increased in subgroups with higher baseline biomarker levels. Quadrant analyses revealed that disease of patients with either elevated Feno or eosinophil counts demonstrated a clinical response to dupilumab. Interaction testing indicated blood eosinophil counts or Feno independently added value as predictive biomarkers.

CONCLUSIONS

In children with uncontrolled moderate-to-severe asthma, blood eosinophil counts and Feno are clinically relevant biomarkers to identify those at risk for asthma exacerbations, as well as those with disease with clinical response to dupilumab.

TRIAL REGISTRATION

Liberty Asthma VOYAGE ClinicalTrials.gov NCT02948959.

Low Serum IL-18 Levels May Predict the Effectiveness of Dupilumab in Severe Asthma

Objective Dupilumab, a monoclonal antibody specific for the human interleukin (IL)-4 receptor α, is used to treat severe asthma, especially in patients with elevated blood eosinophil counts and fractional exhaled nitric oxide (FeNO). The therapeutic response to dupilumab is highly variable. In this study, we explored new serum biomarkers to accurately predict the effect of dupilumab and examine the effect of dupilumab based on changes in the clinical parameters and cytokine levels. Methods Seventeen patients with severe asthma treated with dupilumab were enrolled. Responders, defined as those with a >0.5-point decrease in the Asthma Control Questionnaire (ACQ) score after 6 months of treatment, were included. Results There were 10 responders and 7 non-responders. Serum type 2 cytokines were equivalent between responders and non-responders; the baseline serum IL-18 level was significantly lower in responders than in non-responders (responders, 194.9±51.0 pg/mL; non-responders, 323.4±122.7 pg/mL, p=0.013). The cut-off value of IL-18 at 230.5 pg/mL could be used to distinguish non-responders from responders (sensitivity 71.4, specificity 80.0, p=0.032). Conclusion A low baseline serum IL-18 level may be a useful predictor of an unfavorable response to dupilumab in terms of the ACQ-6.

Predictive Value of Fractional Exhaled Nitric Oxide (FeNO) in the Diagnosis of Asthma for Epidemiological Purposes-An 8-Year Follow-Up Study

At the population level, respiratory symptoms in children can be estimated cross-sectionally. However, such methods require additional objective support parameters, such as the measurement of fractional exhaled nitric oxide (FeNO). The aim of the present study was to analyze if the FeNO value measured at baseline can have a predictive value for asthma-like symptoms after 8 years of measurement.

METHODS

The follow-up included 128 (out of 447) children, 70 girls and 58 boys. The FeNO was measured at baseline only. The prevalence of asthma-like symptoms was measured with the adopted version of the ISAAC questionnaire.

RESULTS

After 8 years of FeNO measurement, 5 new cases of asthma, 2 cases of attacks of dyspnoea, 1 case of wheezy in the chest, and 18 cases of allergic rhinitis occurred. The FeNO values, measured at the baseline of the study, for new cases of the above diseases were 53.4 ± 75.9 ppb, 11 ± 1.5 ppb, 12.0 ppb, and 16.3 ± 12.4 ppb, respectively. The best diagnostic accuracy parameters were found in the new cases of asthma, where the sensitivity was 40.0%, the specificity was 98.6%, and the AUC was 66.6%. The diagnostic odds ratio was 46.9 when considering the FeNO cut-off >35 ppb.

CONCLUSIONS

The FeNO measurement is a fair method for asthma prognosis in early school-aged children with asthma-like symptoms measured on the population level but requires further confirmation at the clinical level with more accurate diagnostic tools.

From preschool wheezing to asthma: Environmental determinants

Wheezing is common among preschool children, representing a group of highly heterogeneous conditions with varying natural history. Several phenotypes of wheezing have been proposed to facilitate the identification of young children who are at risk of subsequent development of asthma. Epidemiological and immunological studies across different populations have revealed the key role of environmental factors in influencing the progression from preschool wheezing to childhood asthma. Significant risk factors include severe respiratory infections, allergic sensitization, and exposure to tobacco smoke. In contrast, a farming/rural environment has been linked to asthma protection in both human and animal studies. Early and intense exposures to microorganisms and microbial metabolites have been demonstrated to alter host immune responses to allergens and viruses, thereby driving the trajectory away from wheezing illness and asthma. Ongoing clinical trials of candidate microbes and microbial products have shown promise in shaping the immune function to reduce episodes of viral-induced wheezing. Moreover, restoring immune training may be especially important for young children who had reduced microbial exposure due to pandemic restrictions. A comprehensive understanding of the role of modifiable environmental factors will pave the way for developing targeted prevention strategies for preschool wheezing and asthma.

Standardization of clinical outcomes used in allergen immunotherapy in allergic asthma: An EAACI position paper

INTRODUCTION

In allergic asthma patients, one of the more common phenotypes might benefit from allergen immunotherapy (AIT) as add-on intervention to pharmacological treatment. AIT is a treatment with disease-modifying modalities, the evidence for efficacy is based on controlled clinical trials following standardized endpoint measures. However, so far there is a lack of a consensus for asthma endpoints in AIT trials. The aim of a task force (TF) of the European Academy of Allergy and Clinical Immunology (EAACI) is evaluating several outcome measures for AIT in allergic asthma.

METHODS

The following domains of outcome measures in asthmatic patients have been evaluated for this position paper (PP): (i) exacerbation rate, (ii) lung function, (iii) ICS withdrawal, (iv) symptoms and rescue medication use, (v) questionnaires (PROMS), (vi) bronchial/nasal provocation, (vii) allergen exposure chambers (AEC) and (viii) biomarkers.

RESULTS

Exacerbation rate can be used as a reliable objective primary outcome; however, there is limited evidence due to different definitions of exacerbation. The time after ICS withdrawal to first exacerbation is considered a primary outcome measure. Besides, the advantages and disadvantages and clinical implications of further domains of asthma endpoints in AIT trials are elaborated in this PP.

CONCLUSION

This EAACI-PP aims to highlight important aspects of current asthma measures by critically evaluating their applicability for controlled trials of AIT.

Assessing Asthma Control by Impulse Oscillometry and Fractional Expiratory Nitric Oxide in Children With Normal Spirometry

BACKGROUND

Because spirometric parameters fail to address current status of asthma in some patients, additional tests are required for better evaluation of asthma.

OBJECTIVE

We aimed to test the ability of impulse oscillometry (IOS) and fractional expiratory nitric oxide (FeNO) in identifying inadequately controlled asthma (ICA) that was not uncovered by spirometry.

METHODS

Recruited asthmatic children between ages of 8 and 16 years underwent spirometry, IOS, and FeNO measurements on the same day. Only subjects who had spirometric indices within normal range were included. Asthma Control Questionnaire-6 scores of 0.75 or lower and greater than 0.75 indicated well-controlled asthma (WCA) and ICA. Percent predicted values of IOS parameters and IOS reference values for upper and lower limits of normal (>95th and <5th percentiles, respectively) were calculated on the basis of previously published equations.

RESULTS

There were no significant differences in all spirometric indices between the WCA (n = 59) and the ICA (n = 101) groups. The % predicted values of IOS parameters except resistance at 20 Hz (R20) were significantly different between the 2 groups. Receiver operating characteristic analysis showed that the highest and lowest areas under the curve were 0.81 and 0.67 for the difference between the resistances at 5 Hz and 20 Hz (R5-R20) and R20 in discrimination of ICA versus WCA. The areas under the curve for IOS parameters were improved by combination with FeNO. The better discriminative ability of IOS was also supported by the higher values of the concordance index for the resistance at 5 Hz (R5), R5-R20, the reactance at 5 Hz (X5), and the resonant frequency of reactance than those for spirometric parameters. Compared with those with normal values, subjects with abnormal IOS parameters or high FeNO had significantly higher odds of having ICA.

CONCLUSIONS

The IOS parameters and FeNO were shown to be useful in identifying children with ICA when spirometry was normal.

Effectiveness of FeNO-guided treatment in adult asthma patients: A systematic review and meta-analysis

OBJECTIVE

Asthma control is generally monitored by assessing symptoms and lung function. However, optimal treatment is also dependent on the type and extent of airway inflammation. Fraction of exhaled Nitric Oxide (FeNO) is a noninvasive biomarker of type 2 airway inflammation, but its effectiveness in guiding asthma treatment remains disputed. We performed a systematic review and meta-analysis to obtain summary estimates of the effectiveness of FeNO-guided asthma treatment.

DESIGN

We updated a Cochrane systematic review from 2016. Cochrane Risk of Bias tool was used to assess risk of bias. Inverse-variance random-effects meta-analysis was performed. Certainty of evidence was assessed using GRADE. Subgroup analyses were performed based on asthma severity, asthma control, allergy/atopy, pregnancy and obesity.

DATA SOURCES

The Cochrane Airways Group Trials Register was searched on 9 May 2023.

ELIGIBILITY CRITERIA

We included randomized controlled trials (RCTs) comparing the effectiveness of a FeNO-guided treatment versus usual (symptom-guided) treatment in adult asthma patients.

RESULTS

We included 12 RCTs (2,116 patients), all showing high or unclear risk of bias in at least one domain. Five RCTs reported support from a FeNO manufacturer. FeNO-guided treatment probably reduces the number of patients having ≥1 exacerbation (OR = 0.61; 95%CI 0.44 to 0.83; six RCTs; GRADE moderate certainty) and exacerbation rate (RR = 0.67; 95%CI 0.54 to 0.82; six RCTs; moderate certainty), and may slightly improve Asthma Control Questionnaire score (MD = -0.10; 95%CI -0.18 to -0.02, six RCTs; low certainty), however, this change is unlikely to be clinically important. An effect on severe exacerbations, quality of life, FEV1, treatment dosage and FeNO values could not be demonstrated. There were no indications that effectiveness is different in subgroups of patients, although evidence for subgroup analysis was limited.

CONCLUSIONS

FeNO-guided asthma treatment probably results in fewer exacerbations but may not have clinically important effects on other asthma outcomes.

Validation of a Pathological Score for the Assessment of Bronchial Biopsies in Severe Uncontrolled Asthma: Beyond Blood Eosinophils

BACKGROUND

Blood eosinophil count (BEC) is currently used as a surrogate marker of T2 inflammation in severe asthma but its relationship with tissue T2-related changes is elusive. Bronchial biopsy could add reliable information but lacks standardization.

OBJECTIVES

To validate a systematic assessment of the bronchial biopsy for the evaluation of severe uncontrolled asthma (SUA) by standardizing a pathological score.

METHODS

A systematic assessment of submucosal inflammation, tissue eosinophilic count/field (TEC), goblet cells hyperplasia, epithelial changes, basement membrane thickening, prominent airway smooth muscle and submucosal mucous glands was initially agreed and validated in representative bronchial biopsies of 12 patients with SUA by 8 independent pathologists. In a second phase, 62 patients with SUA who were divided according to BEC≥300cells/mm³ or less underwent bronchoscopy with bronchial biopsies and the correlations between the pathological findings and the clinical characteristics were investigated.

RESULTS

The score yielded good agreement among pathologists regarding submucosal eosinophilia, TEC, goblet cells hyperplasia and mucosal glands (ICC=0.85, 0.81, 0.85 and 0.87 respectively). There was a statistically significant correlation between BEC and TEC (r=0.393, p=0.005) that disappeared after correction by oral corticosteroids (OCS) use (r=0.170, p=0.307). However, there was statistically significant correlation between FeNO and TEC (r=0.481, p=0.006) that was maintained after correction to OCS use (r=0.419, p=0.021). 82.4% of low-BEC had submucosal eosinophilia, 50% of them moderate to severe.

CONCLUSION

A standardized assessment of endobronchial biopsy is feasible and could be useful for a better phenotyping of SUA especially in those receiving OCS.

Update on the Role of FeNO in Asthma Management

Asthma is a heterogenous disorder characterized by presence of different phenotypes and endotypes. Up to 10% of the individuals suffer from severe asthma and are at increased risk of morbidity and mortality. Fractional exhaled nitric oxide (FeNO) is a cost-effective, point of care biomarker that is used to detect type 2 airway inflammation. Guidelines have proposed to measure FeNO as an adjunct to diagnostic evaluation in individuals with suspected asthma and to monitor airway inflammation. FeNO has lower sensitivity, suggesting that it may not be a good biomarker to rule out asthma. FeNO may also be used to predict response to inhaled corticosteroids, predict adherence and deciding on biologic therapy. Higher levels of FeNO have been associated with lower lung function and increased risk for future asthma exacerbations and its predictive value increases when combined with other standard measurements of asthma assessment.

Biologics in the treatment of asthma in children and adolescents

Severe asthma in childhood confers substantial patient- and society-level burdens. Although biologics have been available for the management in adults and adolescents for nearly 20 years, research on the efficacy and safety of biologics in children and adolescents has lagged. Fortunately, more recent research specifically in children has provided an evidence base for biologic use in this age group. Most children with severe asthma demonstrate a type 2 inflammatory phenotype, the primary target of currently approved biologics. Three biologics, omalizumab, mepolizumab, and duplilumab, are Food and Drug Administration-approved for children as young as 6 years, whereas benralizumab and tezepelumab are approved for adolescents older than 12 years. All these agents reduce the rates of severe asthma exacerbations, whereas their effects on pulmonary function vary across agents. Safety profiles are reassuring, although additional long-term safety data in children are still needed. The choice of a biologic agent follows a careful assessment of other factors that contribute to uncontrolled asthma and includes biomarkers of blood eosinophils, fractional exhaled nitric oxide, allergic sensitization, and IgE levels. This review focuses on the underlying pathophysiology of childhood asthma, an approach to phenotyping patients, and the efficacy, safety, and use of biologics in children and adolescents with severe asthma.

Toward a Predict and Prevent Approach in Obstructive Airway Diseases

Asthma and chronic obstructive pulmonary disease are currently diagnosed and treated after the demonstration of variable airflow limitation and symptoms. Under this framework, undiagnosed and unchecked airway inflammation is associated with recurrent acute attacks, airway remodeling, airflow limitation, adverse effects of corticosteroids, and impaired quality of life, ultimately leading to the collection of side effects termed "people remodeling." This one-size-fits-all damage control approach aims to control symptoms and treat exacerbations rather than modify the underlying disease process. The advent of highly effective therapies targeting proximal drivers of airway inflammation calls for a paradigm shift; upstream-acting therapies offer potential to alter the disease course and achieve clinical remission. We propose moving away from downstream firefighting and toward a "predict and prevent" model, measuring inflammation and providing anti-inflammatory therapy early, without waiting for further clinical deterioration. Much in the same way that high blood pressure and cholesterol are used to predict and prevent heart attacks, in asthma, elevated blood eosinophils and/or exhaled nitric oxide can be used to predict and prevent asthma attacks. We also advocate moving research further upstream by identifying patients with subclinical airway inflammation or disease who may be at risk of progressing to airflow limitation and associated morbidities and intervening early to prevent them. In summary, we call for a predict and prevent approach in obstructive airway disease.

Exhaled Biomarkers for Point-of-Care Diagnosis: Recent Advances and New Challenges in Breathomics

Cancers, chronic diseases and respiratory infections are major causes of mortality and present diagnostic and therapeutic challenges for health care. There is an unmet medical need for non-invasive, easy-to-use biomarkers for the early diagnosis, phenotyping, predicting and monitoring of the therapeutic responses of these disorders. Exhaled breath sampling is an attractive choice that has gained attention in recent years. Exhaled nitric oxide measurement used as a predictive biomarker of the response to anti-eosinophil therapy in severe asthma has paved the way for other exhaled breath biomarkers. Advances in laser and nanosensor technologies and spectrometry together with widespread use of algorithms and artificial intelligence have facilitated research on volatile organic compounds and artificial olfaction systems to develop new exhaled biomarkers. We aim to provide an overview of the recent advances in and challenges of exhaled biomarker measurements with an emphasis on the applicability of their measurement as a non-invasive, point-of-care diagnostic and monitoring tool.

Efficacy of dupilumab in patients with moderate-to-severe asthma and persistent airflow obstruction

BACKGROUND

The 52-week, phase 3 LIBERTY ASTHMA QUEST study (NCT02414854) in patients aged above or equal to 12 years with uncontrolled, moderate-to-severe asthma demonstrated the efficacy and safety of dupilumab 200 mg and 300 mg every 2 weeks vs matched placebo.

OBJECTIVE

To assess whether dupilumab improves clinical outcomes in QUEST patients with persistent airflow obstruction (PAO) defined as post-bronchodilator forced expiratory volume in 1 second/forced vital capacity ratio less than 0.7 at baseline.

METHODS

End points were annualized rate of severe exacerbations, pre and post-bronchodilator forced expiratory volume in 1 second over time, proportion achieving reversal of PAO, and quality of life. Efficacy was evaluated in patients with or without PAO at baseline in subpopulations with eosinophils ≥ 150 cells/µL or fractional exhaled nitric oxide (FeNO) ≥ 25 ppb or eosinophils ≥ 300 cells/µL and FeNO ≥ 25 ppb.

RESULTS

Of 1902 patients enrolled in QUEST, 1039 (55%) had PAO at baseline. Dupilumab vs placebo rapidly and significantly improved lung function in patients with PAO and elevated type 2 inflammatory biomarkers at baseline. Dupilumab improved probability of reversing airflow obstruction (hazard ratio vs placebo 1.616 [95% confidence interval, 1.272-2.052] and 1.813 [1.291-2.546]; both P < .001) and significantly reduced severe exacerbations by 69% (relative risk, 0.411; 95% confidence interval [0.327-0.516]; P < .0001) and by 75% (0.252 [0.178-0.356]; P < .0001) in patients with PAO with eosinophils ≥ 150 cells/µL or FeNO ≥ 25 ppb and eosinophils ≥ 300 cells/µL and FeNO ≥ 25 ppb, respectively. Similar results were observed in patient subgroups without PAO.

CONCLUSION

In patients with uncontrolled moderate-to-severe asthma, treatment with dupilumab facilitates reversal of PAO status and improves clinical outcomes.

TRIAL REGISTRATION

ClinicalTrials.gov identifier: NCT02414854.

Exhaled nitric oxide in asthma: from diagnosis to management

PURPOSE OF REVIEW

Exhaled nitric oxide (FENO) is a noninvasive marker of eosinophilic airway inflammation, therefore, highly informative in asthma. Although FENO measurement is a potentially accessible tool to many physicians, recommendations regarding its clinical utility in diagnosing or tailoring treatment have not reached the expected diffusion. More recently FENO emerged as a biomarker for type-2 asthma phenotyping and a predictor of response to biologics.

RECENT FINDINGS

The physiological discoveries and relevant acquisitions in clinical practice regarding FENO in asthma are presented. The FENO story draw a wavy path, characterized by promising findings, exciting confirmations and periods of low visibility. FENO emerged as a tool to increase the probability of asthma diagnosis. FENO predicts response to inhaled glucocorticoids (ICS), favoring the development of tailored treatment strategies and unrevealing nonadherence to ICS in difficult-to-treat or uncontrolled asthma. Finally, FENO was associated with a more severe phenotype and became a consolidated biomarker of type-2 inflammation.

SUMMARY

FENO demonstrated to be a noninvasive and very reproducible test, encompassing many applications in the field of asthma management. Its routinely use, according to international guidelines, may improve the quality of patient assistance, from difficult-to-treat cases to biologic monitoring.

Asthma exacerbations during the pandemic: Time to rethink clinical markers

Background

Reductions in asthma exacerbations during the coronavirus disease 2019 (COVID-19) pandemic may have an impact on clinical trial enrollment and outcomes.

Objective

Our aim was to review clinical studies and reports evaluating asthma exacerbations before and during the COVID-19 pandemic.

Methods

We reviewed clinical studies conducted with biologics over the past decade that evaluated asthma exacerbations as the primary end point. We also reviewed recent clinical reports evaluating asthma exacerbations during the COVID-19 pandemic.

Results

We showed that studies requiring at least 2 exacerbations in the prior year resulted in a higher number of exacerbations on study in the placebo arm, and conversely, those studies in which exacerbations were not required for entering the study failed to meet the primary end point. This result confirmed that history of prior exacerbations is a good maker to predict future exacerbations. In addition, a review of the literature confirmed a reduction of asthma exacerbations during the COVID-19 pandemic. The data presented are descriptive; no formal statistics were used.

Conclusion

Because of the COVID-19 pandemic, historical exacerbations may no longer be the best predictor for exacerbations in a clinical trial or clinical practice. Other clinical markers associated with exacerbations, such as blood eosinophil count and fractional exhaled nitric oxide level, should be considered for enrollment in clinical studies assessing asthma exacerbations.

Consequences of severe asthma exacerbations

PURPOSE OF REVIEW

Asthma exacerbations are major factors in asthma morbidity and also have long-term consequences.

RECENT FINDINGS

Asthma is characterized by an accelerated and progressive loss of lung function. Recent evidence has pointed to the frequency of exacerbations as being a significant contributor to a loss of lung function in asthma.

SUMMARY

A consequence of asthma exacerbations is a greater loss of lung function. Airway inflammation is central to asthma severity and susceptibility for exacerbations. Evidence suggests that the increase in airway inflammation during an asthma exacerbation further compromised lung function. Treatment of severe asthma with Type (T)-2 directed biologics significantly prevents the frequency of exacerbations in severe asthma. Early indications also suggest that prevention of exacerbations by biologics may reduce a loss in lung function from exacerbations.

Dupilumab reduced impact of severe exacerbations on lung function in patients with moderate-to-severe type 2 asthma

BACKGROUND

Severe asthma exacerbations increase the risk of accelerated lung function decline. This analysis examined the effect of dupilumab on forced expiratory volume in 1 s (FEV₁ ) in patients with moderate-to-severe asthma and elevated type 2 biomarkers from phase 3 LIBERTY ASTHMA QUEST (NCT02414854).

METHODS

Changes from baseline in pre- and post-bronchodilator (BD) FEV₁ and 5-item Asthma Control Questionnaire (ACQ-5) scores were assessed in patients with elevated type 2 biomarkers at baseline (type 2-150/25: eosinophils ≥150 cells/μl and/or fractional exhaled nitric oxide [FeNO] ≥25 ppb; type 2-300/25: eosinophils ≥300 cells/μl and/or FeNO ≥25 ppb), stratified as exacerbators (≥1 severe exacerbation during the study) or non-exacerbators.

RESULTS

In exacerbators and non-exacerbators, dupilumab increased pre-BD FEV₁ by Week 2 vs placebo; differences were maintained to Week 52 (type 2-150/25: LS mean difference (LSMD) vs placebo: 0.17 L (95% CI: 0.10-0.24) and 0.17 L (0.12-0.23); type 2-300/25: 0.22 L (0.13-0.30) and 0.21 L (0.15-0.28)), in exacerbators and non-exacerbators, respectively (p < .0001). Similar trends were seen for post-BD FEV₁ . Dupilumab vs placebo also showed significantly greater improvements in post-BD FEV₁ 0-42 days after first severe exacerbation in type 2-150/25 (LSMD vs placebo: 0.13 L [0.06-0.20]; p = .006) and type 2-300/25 (0.14 L [0.06-0.22]; p = .001) patients. ACQ-5 improvements were greater with dupilumab vs placebo in both groups.

CONCLUSION

Dupilumab treatment led to improvements in lung function independent of exacerbations and appeared to reduce the impact of exacerbations on lung function in patients who experienced a severe exacerbation during the study.

Dupilumab Improves Outcomes in Patients with Chronic Rhinosinusitis with Nasal Polyps and Coexisting Asthma Irrespective of Baseline Asthma Characteristics

Purpose

Chronic rhinosinusitis with nasal polyps (CRSwNP) is a predominantly type 2 inflammatory disease frequently coexisting with other type 2 conditions including asthma and non-steroidal anti-inflammatory drug-exacerbated respiratory disease (NSAID-ERD). Coexisting asthma leads to increased CRSwNP symptom burden. Dupilumab, a monoclonal antibody that blocks the shared receptor component for interleukin-4 and -13, demonstrated efficacy in adults with severe CRSwNP in the Phase 3 SINUS-24 (NCT02912468) and SINUS-52 (NCT02898454) studies, including in patients with coexisting asthma/NSAID-ERD. However, the impact of different asthma characteristics on dupilumab treatment in this population is unknown. We report CRSwNP and asthma outcomes with dupilumab in patients with CRSwNP and coexisting asthma according to baseline asthma characteristics.

Methods

Change from baseline at Week 24 (pooled studies) and Week 52 (SINUS-52) in CRSwNP outcomes (nasal polyp score, nasal congestion, 22-item Sino-Nasal Outcome Test [SNOT-22], loss of smell score, University of Pennsylvania Smell Identification Test) and asthma outcomes (5-item Asthma Control Questionnaire [ACQ-5], pre-bronchodilator forced expiratory volume in 1 second [FEV₁]) were analyzed post hoc for placebo and dupilumab 300 mg every 2 weeks according to baseline blood eosinophils ≥150/≥300 cells/µL, ACQ-5 scores <1.5/≥1.5, and FEV₁ <80%.

Results

In the pooled studies, 428/724 patients (59.1%) had coexisting asthma, of which 181/428 (42.3%) had coexisting NSAID-ERD. Dupilumab significantly improved all CRSwNP and asthma outcomes vs placebo at Week 24 (P < 0.001) regardless of baseline eosinophil or ACQ-5 category, or FEV₁ <80%. Similar magnitude of improvement was seen at Week 52 (SINUS-52) and in patients with NSAID-ERD (pooled studies, Week 24). By Week 24, improvements with dupilumab exceeded the minimum clinically important differences for ACQ-5 and SNOT-22 in 35.2% to 74.2% and 72.0% to 78.7% of patients, respectively.

Conclusion

Dupilumab improved CRSwNP outcomes in patients with CRSwNP and coexisting asthma, and improved asthma outcomes, regardless of differences in baseline asthma characteristics.

Variability of fractional exhaled nitric oxide is associated with the risk and aetiology of COPD exacerbations

BACKGROUND AND OBJECTIVE

Acute exacerbations of chronic obstructive pulmonary disease (AECOPD) are heterogeneous in aetiology and accelerate disease progression. Here, we aimed to investigate the association of fractional exhaled nitric oxide (FeNO) and its variability with AECOPD of different aetiology.

METHODS

FeNO was determined in 2157 visits (1697 stable, 133 AECOPD and 327 follow-up) of 421 COPD patients from the PREVENT study, an investigator-initiated, longitudinal and interventional study, who were on daily treatment with inhaled corticosteroids/long-acting β2-agonists.

RESULTS

Longitudinal measurements of FeNO revealed an intra-subject variability of FeNO that was significantly higher in exacerbators compared to non-exacerbators (p < 0.001) and positively associated with the number of AECOPD. As FeNO variability increased, the probability of patients to remain AECOPD-free decreased. In patients included in the highest FeNO variability quartile (≥15.0 ppb) the probability to remain free of AECOPD was only 35% as compared to 80% for patients included in the lowest FeNO variability quartile (0.50-4.39 ppb). The change of FeNO from the last stable visit to AECOPD was positively associated with the probability of viral infections and this association was stronger in current smokers than ex-smokers. In contrast, the change in FeNO from the last stable visit to an AECOPD visit was inversely associated with the probability of bacterial infections in ex-smokers but not in current smokers.

CONCLUSION

FeNO variability was associated with the risk and aetiology of AECOPD differentially in current and ex-smokers.

Baseline FeNO Independently Predicts the Dupilumab Response in Patients With Moderate-to-Severe Asthma

BACKGROUND

FeNO may have a role as both a prognostic and predictive biomarker in combination with eosinophils for assessing responsiveness to some biological therapies.

OBJECTIVE

We evaluated the value of baseline FeNO, adjusted for baseline blood eosinophil levels and other clinical characteristics, as an independent predictor of treatment response to dupilumab in patients with uncontrolled moderate-to-severe asthma.

METHODS

We performed a post hoc analysis of LIBERTY ASTHMA QUEST (NCT02414854), a phase 3, double-blind study in patients aged 12 years and older with uncontrolled moderate-to-severe asthma, who received dupilumab 200 or 300 mg, or placebo every 2 weeks up to 52 weeks. We assessed the annualized event rate of severe exacerbations and least-squares mean change from baseline in prebronchodilator FEV₁ at weeks 12 and 52 in relationship to baseline FeNO, adjusted for eosinophils and other clinical characteristics.

RESULTS

The annualized event rate increased with increasing baseline FeNO in placebo and decreased in dupilumab groups. The relative risk of severe exacerbations was 22·7%, 58·3%, and 69·3% lower for dupilumab versus placebo for the FeNO less than 25, 25 to less than 50, and 50 and greater parts per billion subgroups. The magnitude of FEV₁ improvement increased with higher baseline FeNO for dupilumab and was consistent across the continuum of FeNO levels in placebo. Both findings were independent of blood eosinophil levels. Significant differences were observed between FeNO subgroups.

CONCLUSIONS

Increased baseline FeNO was associated with greater clinical effects in dupilumab versus placebo independently of eosinophil levels and other clinical characteristics.

Asthma exacerbations: the Achilles heel of asthma care

Asthma exacerbations significantly impact millions of patients worldwide to pose large disease burdens on affected patients, families, and health-care systems. Although numerous environmental factors cause asthma exacerbations, viral respiratory infections are the principal triggers. Advances in the pathophysiology of asthma have elucidated dysregulated protective immune responses and upregulated inflammation that create susceptibility and risks for exacerbation. Biologics for the treatment of severe asthma reduce rates of exacerbations and identify specific pathways of inflammation that contribute to altered pathophysiology, novel therapeutic targets, and informative biomarkers. Major steps to prevent exacerbations include the identification of molecular pathways whose blockage will prevent asthma attacks safely, predictably, and effectively.

Down-regulated surfactant protein B in obese asthmatics

BACKGROUND

Obesity is a common comorbid condition in adult asthmatics and known as a feature of asthma severity. However, the molecular mechanism under obesity-induced inflammation has not yet been fully understood.

OBJECTIVE

Considering the essential role of hydrophobic surfactant protein B (SP-B) in lung function, SP-B was targeted to examine its involvement in the development of obesity-induced airway inflammation in asthmatics.

METHODS

The aim was to examine an alteration in circulating SP-B according to obesity in adult asthmatics, 129 asthmatics were enrolled and classified into 3 groups (obese, overweight and normal-weight groups) according to body mass index (BMI). Circulating SP-B levels were determined by enzyme-linked immunosorbent assay. Four single nucleotide polymorphisms of SFTPB gene were genotyped. Serum ceramide levels were measured by liquid chromatography-tandem mass spectrometry.

RESULTS

Significantly lower serum SP-B levels were noted in the obese group than in the overweight or normal-weight group (p = .002). The serum SP-B level was significantly correlated with serum levels of C18:0 ceramide and transforming growth factor beta 1 as well as BMI (r = -0.200; r = -0.215; r = -0.332, p < .050 for all). An inverse correlation was noted between serum SP-B and fractional exhaled nitric oxide levels in female asthmatics (r = -0.287, p = .009). Genetic predisposition of the SFTPB gene at 9306 A>G to the obese and overweight groups was noted.

CONCLUSION

Obesity altered ceramide metabolism leading to pulmonary surfactant dysfunction and impaired resolution of airway inflammation, finally contributing to the phenotypes of obese asthmatics.

Corticosteroid Responsiveness Following Mepolizumab in Severe Eosinophilic Asthma-A Randomized, Placebo-Controlled Crossover Trial (MAPLE)

BACKGROUND

Mepolizumab inhibits IL-5 activity and reduces exacerbation frequency and maintenance oral corticosteroid (OCS) dosage in patients with severe eosinophilic asthma (SEA). Some patients remain dependent on OCS despite anti-IL-5 treatment, suggesting residual corticosteroid-responsive mechanisms.

OBJECTIVE

To determine the clinical and anti-inflammatory effects of OCS in patients with SEA on mepolizumab.

METHODS

We conducted a randomized, triple-blind, placebo-controlled crossover trial of prednisolone (0.5 mg/kg/d, maximum 40 mg/d, for 14 ± 2 days) in adults with SEA after 12 or more weeks of mepolizumab. We compared change in asthma symptoms, quality of life, lung function measured by spirometry and airwave oscillometry, fractional exhaled nitric oxide, and blood and sputum eosinophil cell count after prednisolone and placebo treatment.

RESULTS

A total of 27 patients completed the study. Prednisolone did not improve 5-item Asthma Control Questionnaire (mean difference in change for prednisolone vs placebo, -0.23; 95% CI, -0.58 to 0.11), mini-Asthma Quality of Life Questionnaire (0.03; 95% CI, -0.26 to 0.42), St. George's Respiratory Questionnaire (0.24; 95% CI, -3.20 to 3.69), or Visual Analogue Scale scores for overall asthma symptoms (0.11; 95% CI, -0.58 to 0.80). The mean difference for FEV₁ in favor of prednisolone was 105 mL (95% CI, -4 to 213 mL); forced expiratory flow at 25% and 75% 484 mL/s (95% CI, 151 to 816 mL/s); fractional exhaled nitric oxide reduction 41% (95% CI, 25% to 54%); blood eosinophil count reduction 49% (95% CI, 31% to 62%); and percentage of sputum eosinophil reduction 71% (95% CI, 26% to 89%).

CONCLUSIONS

OCS improved small-airway obstruction and reduced biomarkers of type 2 inflammation but had no significant effect on symptoms or quality of life in patients with SEA receiving treatment with mepolizumab.

Dupilumab Is Effective in Patients With Moderate-to-Severe Uncontrolled GINA-Defined Type 2 Asthma Irrespective of an Allergic Asthma Phenotype

BACKGROUND

The Global Initiative for Asthma report recommends consideration of add-on biologics for patients with type 2 inflammation (blood eosinophils ≥150 cells/μL, fractional exhaled nitric oxide [Feno] ≥20 parts per billion or allergic asthma) whose asthma cannot be controlled by high-dose inhaled corticosteroids. In QUEST (NCT02414854), add-on dupilumab versus placebo was efficacious in patients with uncontrolled, moderate to severe asthma, including those with eosinophils greater than or equal to 150 cells/μL and/or Feno greater than or equal to 25 parts per billion.

OBJECTIVE

To assess dupilumab efficacy in patients with a type 2 phenotype in the presence or absence of allergic asthma phenotype.

METHODS

Patients aged 12 years or older received add-on dupilumab 200/300 mg versus matched placebo every 2 weeks for 52 weeks. Allergic asthma phenotype was defined as baseline serum total IgE greater than or equal to 30 IU/mL and 1 or more perennial aeroallergen-specific IgE level greater than or equal to 0.35 kU/L. Annualized rate of severe asthma exacerbations and changes from study baseline in prebronchodilator and postbronchodilator FEV₁ were evaluated in patients with allergic and nonallergic phenotype with baseline blood eosinophils greater than or equal to 150 cells/μL and/or Feno greater than or equal to 20 parts per billion.

RESULTS

Of 1902 patients in QUEST, 83.3% had eosinophils and/or Feno above Global Initiative for Asthma thresholds; 56.9% had evidence for allergic asthma. Dupilumab significantly reduced the rate of severe asthma exacerbations in patients with (48.8%) and without (64.0%) evidence of allergic asthma and improved prebronchodilator and postbronchodilator FEV₁ in patients with elevated type 2 biomarkers, irrespective of whether they showed evidence of an allergic asthma phenotype.

CONCLUSIONS

In patients with type 2 biomarkers over Global Initiative for Asthma thresholds, dupilumab significantly reduced exacerbations and improved lung function. Efficacy was not impacted by allergic status.

Use of FeNO to predict anti-IL-5 and IL-5R biologics efficacy in a real-world cohort of adults with severe eosinophilic asthma

INTRODUCTION

Severe eosinophilic asthma (SEA) is associated with multiple exacerbations. Fractional exhaled nitric oxide (FeNO), a biomarker of airway T2 inflammation, is known to be correlated with the risk of exacerbations. While the use of FeNO is well established to predict the therapeutic response to dupilumab (anti-IL-4/IL-13), it remains uncertain for biologics targeting the IL-5 pathway.

METHODS

We conducted an observational, retrospective, monocentric analysis of adults with SEA who started mepolizumab (anti-IL-5) or benralizumab (anti-IL-5R) between January 1, 2016 and December 31, 2020.

RESULTS

Data were collected for 109 patients. All participants reported uncontrolled asthma with a median of 3 annual exacerbations and a median Asthma Control Test score of 12. They all had an initial blood eosinophilia >300/mm³, with a median at 610/mm³ (IQR 420-856). Patients with a baseline FeNO ≥50 ppb reported more exacerbations in the previous year than those with a FeNO <50 ppb (p = 0.02). After initiation of treatment, change in FeNO was not associated with therapeutic response. However, decrease in the annual number of exacerbations was significantly greater in patients with a baseline FeNO ≥50 ppb than in those with a baseline FeNO <50 ppb (-3.3 ± 2.7 vs -0.9 ± 2.4, respectively; p = 0.01). There was no association between baseline FeNO values and subsequent lung function, asthma control or reduction of oral corticosteroids use.

CONCLUSION

In this real-world cohort, adults with SEA who had a baseline FeNO ≥50 ppb experienced a greater decrease in exacerbations after 12 months of anti-IL-5 or IL-5R biologics than those with a FeNO <50 ppb.

Biologics for chronic severe asthma: a network meta‐analysis

This is a protocol for a Cochrane Review (intervention). The objectives are as follows:

To evaluate the benefits and harms of biological agents targeting type‐2 inflammation (benralizumab, dupilumab, mepolizumab, omalizumab, reslizumab, tezepelumab) in people with severe asthma, with a network meta‐analysis and to rank agents by effectiveness.

A machine learning approach to characterize patients with asthma exacerbation attending an acute care setting

BACKGROUND

One of the main problems in poorly controlled asthma is the access to the Emergency Department (ED). Using a machine learning (ML) approach, the aim of our study was to identify the main predictors of severe asthma exacerbations requiring hospital admission.

METHODS

Consecutive patients with asthma exacerbation were screened for inclusion within 48 hours of ED discharge. A k-means clustering algorithm was implemented to evaluate a potential distinction of different phenotypes. K-Nearest Neighbor (KNN) as instance-based algorithm and Random Forest (RF) as tree-based algorithm were implemented in order to classify patients, based on the presence of at least one additional access to the ED in the previous 12 months.

RESULTS

To train our model, we included 260 patients (31.5% males, mean age 47.6 years). Unsupervised ML identified two groups, based on eosinophil count. A total of 86 patients with eosinophiles ≥370 cells/µL were significantly older, had a longer disease duration, more restrictions to daily activities, and lower rate of treatment compared to 174 patients with eosinophiles <370 cells/μL. In addition, they reported lower values of predicted FEV₁ (64.8±12.3% vs. 83.9±17.3%) and FEV₁/FVC (71.3±9.3 vs. 78.5±6.8), with a higher amount of exacerbations/year. In supervised ML, KNN achieved the best performance in identifying frequent exacerbators (AUROC: 96.7%), confirming the importance of spirometry parameters and eosinophil count, along with the number of prior exacerbations and other clinical and demographic variables.

CONCLUSIONS

This study confirms the key prognostic value of eosinophiles in asthma, suggesting the usefulness of ML in defining biological pathways that can help plan personalized pharmacological and rehabilitation strategies.

Challenges in severe asthma: Do we need new drugs or new biomarkers?

Severe asthma is a complex, heterogenous airway condition. There have been significant advances in severe asthma management in the past decade using monoclonal antibody therapies that target the inflammatory component of the disease. Patient selection has been paramount for the success of these biologicals, leading to significant interest in biomarkers to guide treatment. Some severe asthmatics remain suboptimally controlled despite trials of biologicals and many of these patients still require chronic systemic corticosteroids. New therapeutics are currently in development to address this unmet need. However, whether these patients could be better treated by using novel biomarkers that inform selection among currently available biologics, and that objectively measure disease control is unclear. In this review, we examine the currently used biomarkers that guide severe asthma management and emerging biomarkers that may improve asthma therapy in the future.

Recent insights in the role of biomarkers in severe asthma management

Contemporary asthma management requires a proactive and individualized approach, combining precision diagnosis and personalized treatment. The introduction of biologic therapies for severe asthma to everyday clinical practice, increases the need for specific patient selection, prediction of outcomes and monitoring of these costly and long-lasting therapies. Several biomarkers have been used in asthma in disease identification, prediction of asthma severity and prognosis, and response to treatment. Novel advances in the area of personalized medicine regarding disease phenotyping and endotyping, encompass the development and application of reliable biomarkers, accurately quantified using robust and reproducible methods. The availability of powerful omics technologies, together with integrated and network-based genome data analysis, and microbiota changes quantified in serum, body fluids and exhaled air, will lead to a better classification of distinct phenotypes or endotypes. Herein, in this review we discuss on currently used and novel biomarkers for the diagnosis and treatment of asthma.

Levels of eicosanoids in nasal secretions associated with nasal polyp severity in chronic rhinosinusitis

Severe nasal polyposis and mucosal inflammation, in patients with chronic rhinosinusitis (CRS) may include a dysregulated eicosanoid profile, but a clinical role for eicosanoids in CRS with nasal polyps (NP; CRSwNP) remains to be elucidated. This study focused on assessing levels and clinical implications of inflammatory mediators in nasal secretions and urine from patients with different NP severity or Aspirin Exacerbated Respiratory Disease (AERD). Levels of leukotrienes E₄ and B₄, prostaglandins D₂ and E₂ as well as 15(S)-hydroxyeicosatetraenoic acid were measured with enzyme immunoassays and cytokines with magnetic bead immunoassays. Patients with CRSwNP were subdivided based on NP score; CRSwNP-low (NP score ≤ 4, n = 11) or CRSwNP-high (NP score ≥ 5, n = 32) and compared to CRS without polyps (CRSsNP, n = 12), CRSwNP-AERD (n = 11) and individuals without CRS (n = 25). Smell test score, fractional exhaled nitric oxide (FeNO), blood eosinophils and Sinonasal outcome test-22 were assessed as clinical markers. Leukotriene E₄, prostaglandin D₂ and 15(S)-hydroxyeicosatetraenoic acid in nasal secretions correlated with NP score. Nasal leukotriene E₄ also correlated with FeNO and smell test score, with highest levels found in CRSwNP-AERD. Levels of prostaglandin D₂ in nasal secretion as well as urinary levels of the prostaglandin D₂ metabolite 11β-prostaglandin F_2α differed between CRSNP-high and CRSwNP-low. Urinary 11β-prostaglandin F_2α was associated with asthma comorbidity whereas a similar association with prostaglandin D₂ in nasal secretions was not observed. In conclusion, subdividing patients based on NP severity in combination with analysis of eicosanoids in non-invasively collected nasal secretions, may have clinical implications when assessing CRS disease severity.

Respiratory Reviews in Asthma 2022

Asthma is a chronic inflammatory disease of the airways characterized by varying and recurrent symptoms, reversible airway obstruction, and bronchospasm. In this paper reviews clinical important studies on asthma between March 2021 and February 2022.<br/> A study on the relationship between asthma and chronic rhinosinusitis, bronchiectasis, and hormone replacement therapy was published, and a journal on the usefulness of fractional exhaled nitric oxide for the prediction of severe acute exacerbation was also introduced. Studies on the effect of inhaler, one of the most important treatments for asthma, and studies to control severe asthma continued, and phase 2 and 3 studies of new biologics were also published. As the COVID-19 pandemic has been prolonged, many studies have explored the prevalence and mortality of COVID-19 infection in asthma patients.

What is the added value of FeNO as T2 biomarker?

There is increasing evidence about the role of nitric oxide in type 2 (T2) immune response. Fraction of exhaled nitric oxide (FeNO) is a product of airways inflammation and it is increased in patients with asthma. Since Gustaffson published the first article about this biomarker in the 1990s, interest has continued to grow. Compared with other T2 biomarkers such as blood eosinophil count, induced sputum, or serum periostin, FeNO has some remarkable advantages, including its not invasive nature, easy repeatability, and possibility to be performed even in patients with severe airway obstruction. It is considered as an indicator of T2 inflammation and, by the same token, a useful predictor for inhaled steroid response. It is difficult to determine the utility of nitric oxide (NO) for initial asthma diagnosis. In such a heterogenous disease, a single parameter would probably not be enough to provide a complete picture. There is also an important variability among authors concerning FeNO cutoff values and the percentage of sensibility and specificity for diagnosis. Its high specificity indicates a potential role to “rule in” asthma; however, its lower sensibility could suggest a lower capacity to “rule out” this pathology. For this reason, if a diagnosis of asthma is being considered, FeNO should be considered along with other tests. FeNO has also shown its utility to detect response to steroids, adherence to treatment, and risk of exacerbation. Even though there is not enough quality of evidence to establish overall conclusions, FeNO could be an alternative procedure to diagnose or exclude asthma and also a predictive tool in asthma treated with corticosteroids.

Documento de consenso de asma grave en adultos. Actualización 2022

Severe asthma is a heterogeneous syndrome with several clinical variants and often represents a complex disease requiring a specialized and multidisciplinary approach, as well as the use of multiple drugs. The prevalence of severe asthma varies from one country to another, and it is estimated that 50% of these patients present a poor control of their disease. For the best management of the patient, it is necessary a correct diagnosis, an adequate follow-up and undoubtedly to offer the best available treatment, including biologic treatments with monoclonal antibodies. With this objective, this consensus process was born, which began in its first version in 2018, whose goal is to offer the patient the best possible management of their disease in order to minimize their symptomatology. For this 2020 consensus update, a literature review was conducted by the authors. Subsequently, through a two-round interactive Delphi process, a broad panel of asthma experts from SEPAR and the regional pulmonology societies proposed the recommendations and conclusions contained in this document.

The Combined Value of Type2 Inflammatory Markers in Chronic Obstructive Pulmonary Disease

The roles of type2 inflammatory markers in chronic airway diseases have been assessed in previous studies. However, the relationship between the combined value of these biomarkers and chronic obstructive pulmonary disease (COPD) has not been fully elucidated. We aimed to investigate the roles of the combined value of the fraction of exhaled nitric oxide (FeNO) level and blood eosinophil count in COPD and the predictive capability of these biomarkers. In total, 266 patients were included in our analysis. When the two type2 biomarkers were assessed separately, there were limited correlations between either increased FeNO level or blood eosinophil count and decreased incidence of total exacerbation or frequency of mild exacerbation. Combining these two biomarkers strengthened their association with both incidence and frequency of acute exacerbation. In addition, during further assessment, simultaneously increased FeNO level and blood eosinophil count were associated with both mild and moderate acute exacerbation. Among the subjects included in this analysis, although the predictive capability was improved when these two biomarkers were combined, the improvement was not statistically significant, indicating the need to increase the sample size. The combination of FeNO level and blood eosinophil count exhibited strong and independent additive value in the assessment of acute exacerbation in COPD; simultaneously increased FeNO level and blood eosinophil count played a protective role in progression of COPD.

Treatment Resistance in Severe Asthma Patients With a Combination of High Fraction of Exhaled Nitric Oxide and Low Blood Eosinophil Counts

Background: Combining a fraction of exhaled nitric oxide (FeNO) and blood eosinophil count (B-EOS) may be a useful strategy for administration of biologics such as anti-IgE or anti-IL-5 to patients with type 2 inflammatory-predominant severe asthma and is important to be elucidated considering the increasing use of biologics.

Methods: This cross-sectional study analyzed the clinical data from 114 adult patients with severe asthma, who were treated at Saitama Medical University Hospital. The eligible patients were stratified into four subgroups defined by thresholds of FeNO and blood eosinophil (B-EOS) counts to detect sputum eosinophilia, using the receiver operating characteristic curve analysis. A total of 75 patients with optimal samples were stratified into four subtypes defined by thresholds of sputum eosinophilia and neutrophilia. Clinical characteristics, pattern of biologics, and distribution of sputum subtypes were analyzed in the stratified subclasses according to the FeNO and B-EOS thresholds. The asthma exacerbation (AE)-free time of the FeNO/B-EOS subgroups and any biologics treatment including anti-IgE or anti-IL-5 use were examined using the Kaplan–Meier method. The hazard ratios (HRs) for AE-free time were examined using the Cox proportional hazard model.

Results: The optimal cutoff values for prediction of sputum eosinophilia were defined as ≥2.7% wherein for FeNO as ≥27 ppb and B-EOS as ≥265/µL were considered. The high-FeNO subgroups showed significant high total IgE, compared with the low FeNO. The high-FeNO/high-B-EOS and the high-FeNO/low-B-EOS subgroups showed the largest prevalence of mepolizumab and benralizumab use among the other FeNO/B-EOS, respectively. The high-FeNO/low-B-EOS showed the largest frequency of AEs, high HR, and the shortest AE-free time, among the other FeNO/B-EOS. The sputum eosinophil-predominant subtype was the great majority in the high FeNO/high B-EOS. A diverse distribution of sputum leukocyte-predominant subtype was observed in the other FeNO/B-EOS. The subsequent AE-free time and its HR were comparable among the biologics use groups.

Conclusion: The strategy of classifying severe asthma based on the combination of FeNO and B-EOS proposes particular refractory type 2 severe asthma and underlying airway inflammation as a feasible trait for optimal biologics use.