Basic, translational and clinical aspects of bronchiectasis in adults

Neutrophilic inflammation in bronchiectasis

Noncystic fibrosis bronchiectasis, hereafter referred to as bronchiectasis, is a chronic, progressive lung disease that can affect people of all ages. Patients with clinically significant bronchiectasis have chronic cough and sputum production, as well as recurrent respiratory infections, fatigue and impaired health-related quality of life. The pathophysiology of bronchiectasis has been described as a vicious vortex of chronic inflammation, recurring airway infection, impaired mucociliary clearance and progressive lung damage that promotes the development and progression of the disease. This review describes the pivotal role of neutrophil-driven inflammation in the pathogenesis and progression of bronchiectasis. Delayed neutrophil apoptosis and increased necrosis enhance dysregulated inflammation in bronchiectasis and failure to resolve this contributes to chronic, sustained inflammation. The excessive release of neutrophil serine proteases, such as neutrophil elastase, cathepsin G and proteinase 3, promotes a protease-antiprotease imbalance that correlates with increased inflammation in bronchiectasis and contributes to disease progression. While there are currently no licensed therapies to treat bronchiectasis, this review will explore the evolving evidence for neutrophilic inflammation as a novel treatment target with meaningful clinical benefits.

Unravelling the role of heart rate recovery in bronchiectasis: do we need to establish a cutoff value?

Heart rate recovery after a field walking test could be a key indicator in bronchiectasis management. Establishing a clear cutoff value in future research will enhance its clinical utility. #HeartRateRecovery #Bronchiectasis #PulmonaryRehabilitation https://bit.ly/4fNAWXe.

Assessment of online YouTube videos as a source of information and instruction for pulmonary rehabilitation

BACKGROUND/OBJECTIVES

Pulmonary rehabilitation (PR) benefits individuals with chronic respiratory conditions beyond COPD; however, the quality of online resources has not been evaluated. The aims of this study were to assess the content, quality, and comprehensibility of YouTube videos that provide PR to individuals with chronic lung diseases other than COPD.

METHODS

A search was conducted on YouTube for videos related to PR on non-COPD conditions, with the first 350 videos screened for eligibility (2004-2024). Videos were assessed for content based on predefined scoring matrix derived from PR guidelines, evaluated for their quality using the modified DISCERN tool and Global Quality Scale (GQS), and assessed for their understandability and actionability using the Patient Education Materials and Assessment Tool. Engagement metrics including viewing rate and interaction index were also analyzed.

RESULTS

Of the 59 videos included, there was significant heterogeneity in PR content (i.e. aerobic, strength training, flexibility, etc.). 83 % of the videos were published following the onset of COVID-19 pandemic (March 2020), and 85 % of the videos were not directed at specific disease states. Video quality was moderate, with median modified DISCERN and GQS of 3 IQR[3-4] and 3 IQR[2-4] out of 5, respectively. Mean understandability and actionability were above the 70 % threshold. Engagement metrics revealed that median video views were 2857 (IQR[637-10,729]), but engagement was low (1.4 % IQR[1.0-2.7]).

CONCLUSION

The study highlights variability in PR content and moderate quality of videos, with reasonable comprehensibility. There is a need for more standardized and disease-specific PR online video resources for non-COPD states.

Real-world disease burden, mortality, and healthcare resource utilization associated with bronchiectasis

OBJECTIVES

To assess real-world survival and healthcare resource utilization (HCRU) in US patients with non-cystic fibrosis bronchiectasis (NCFBE).

METHODS

This retrospective analysis, using data from the STATinMED RWD Insights database from Jan 2015-Oct 2022, included adults with NCFBE (from Jan 2015-Oct 2021) and non-NCFBE comparators (from Jan 2015-Aug 2020); baseline characteristics were balanced by inverse probability treatment weighting. Outcomes included survival through end of study. HCRU was assessed over 12 months.

RESULTS

117,718 patients with NCFBE and 306,678 comparators were included. Patients with NCFBE had a 77% higher risk of death than comparators (hazard ratio [HR] 1.77 [95% CI 1.74-1.80]). Risk of death was higher among patients aged ≥65 years (vs 18-34 years; HR 11.03 [95% CI 10.36-11.74]), among Black patients (vs White; HR 1.53 [95% CI 1.50-1.55]), and among patients with comorbid COPD (HR 1.42 [95% CI 1.40-1.44]). Patients with NCFBE incurred higher all-cause and respiratory-related HCRU than comparators for outpatient office, outpatient hospital, emergency department (ED), inpatient and respiratory-related pulmonologist visits (all p < .0001); HCRU increased with exacerbations.

CONCLUSIONS

Patients with NCFBE have high mortality burden and incur high HCRU, both of which are further increased with exacerbations. Prevention and delay of exacerbations are key areas for improvement of disease management.

Targeting neutrophil serine proteases in bronchiectasis

Persistent neutrophilic inflammation is a central feature in both the pathogenesis and progression of bronchiectasis. Neutrophils release neutrophil serine proteases (NSPs), such as neutrophil elastase (NE), cathepsin G and proteinase 3. When chronically high levels of free NSP activity exceed those of protective antiproteases, structural lung destruction, mucosal-related defects, further susceptibility to infection and worsening of clinical outcomes can occur. Despite the defined role of prolonged, high levels of NSPs in bronchiectasis, no drug that controls neutrophilic inflammation is licensed for the treatment of bronchiectasis. Previous methods of suppressing neutrophilic inflammation (such as direct inhibition of NE) have not been successful; however, an emerging therapy designed to address neutrophil-mediated pathology, inhibition of the cysteine protease cathepsin C (CatC, also known as dipeptidyl peptidase 1), is a promising approach to ameliorate neutrophilic inflammation, since this may reduce the activity of all NSPs implicated in bronchiectasis pathogenesis, and not just NE. Current data suggest that CatC inhibition may effectively restore the protease-antiprotease balance in bronchiectasis and improve disease outcomes as a result. Clinical trials for CatC inhibitors in bronchiectasis have reported positive phase III results. In this narrative review, we discuss the role of high NSP activity in bronchiectasis, and how this feature drives the associated morbidity and mortality seen in bronchiectasis. This review discusses therapeutic approaches aimed at treating neutrophilic inflammation in the bronchiectasis lung, summarising clinical trial outcomes and highlighting the need for more treatment strategies that effectively address chronic neutrophilic inflammation in bronchiectasis.

Brensocatib in patients with bronchiectasis: subgroup analyses from the WILLOW trial

Introduction

Bronchiectasis is a chronic inflammatory airway disease. Brensocatib, an oral, reversible inhibitor of dipeptidyl peptidase 1 (DPP1), reduces pulmonary inflammation by preventing the activation of neutrophil serine proteases. In the phase II WILLOW trial, brensocatib prolonged time to first exacerbation in patients with bronchiectasis. In this post hoc analysis we compare clinical outcomes in patients from WILLOW according to baseline disease characteristics.

Methods

Adults with bronchiectasis treated with brensocatib (10 or 25 mg) or placebo once daily were analysed by baseline Bronchiectasis Severity Index (BSI) score (≤4 (mild), 5-8 (moderate), or ≥9 (severe)), exacerbation history (2 or ≥3 in the previous year), blood eosinophil count (<300 cells per µL or ≥300 cells per µL), long-term macrolide use (≥6 months; no or yes) and Pseudomonas aeruginosa culture at screening (negative or positive). End-points were time to first exacerbation, annualised exacerbation rate, change in lung function from baseline, and safety. All patients who received brensocatib were pooled and compared with placebo.

Results

Treatment with brensocatib versus placebo was associated with a longer time to first exacerbation (hazard ratio (95% confidence interval), BSI: ≤4, 0.28 (0.08-0.96); 5-8, 0.75 (0.35-1.60); ≥9, 0.61 (0.35-1.04); prior exacerbations: 2, 0.56 (0.34-0.90); ≥3, 0.71 (0.32-1.59); blood eosinophils per µL: <300, 0.66 (0.42-1.06); ≥300, 0.49 (0.20-1.20); long-term macrolide use: no, 0.60 (0.38-0.94); yes, 0.60 (0.25-1.45); P. aeruginosa culture: negative, 0.54 (0.32-0.92); positive, 0.68 (0.37-1.27)). Safety results were similar across subgroups.

Discussion

Patients treated with brensocatib had a numerically longer time to first exacerbation and reduced annualised rate of exacerbation versus placebo across all key baseline disease characteristics.

Lung bronchiectasisas a paradigm of the interplay between infection and colonization on plastic modulation of the pre-metastatic niche

The lungs are most often a preferential target organ for malignant spreading and growth. It is well known that chronic parenchymal inflammation and prolonged injuries represents an independent risk factor for cancer onset. Growing evidence supports the implication of lung microbiota in the pathogenesis of lung cancer. However, the full interplay between chronic inflammation, bacterial colonization, pathologic condition as bronchiectasis and malignant growth deserves better clarification. We here aim at presenting and analyzing original data and discussing the state-of-the-art on the knowledge regarding how this complex milieu acts on the plasticity of the lung pre-metastatic niche to point out the rationale for early diagnosis and therapeutic targeting.

Secondary Immunodeficiency and Non-cystic Fibrosis Bronchiectasis

Bronchiectasis is a chronic respiratory disease characterized by abnormal dilation of the bronchi that causes cough, sputum, and recurrent infections. As it may be associated with various respiratory or systemic diseases, a critical aspect of managing bronchiectasis is to identify the underlying cause. Immunodeficiency is a rare but important cause of bronchiectasis, and its treatability is a significant trait for bronchiectasis management. While primary immunodeficiencies in bronchiectasis are well recognized, secondary immunodeficiencies remain under-reported and under-researched. Secondary immunodeficiencies may result from various diseases and conditions, such as hematologic malignancies, human immunodeficiency virus infection, renal transplantation, or the use of immunosuppressive drugs, and may contribute to the occurrence of bronchiectasis. Recurrent pulmonary and/or extrapulmonary infections in bronchiectasis may indicate the presence of secondary immunodeficiency in patients with these underlying conditions. For treatment, examining the underlying condition, managing bronchiectasis adequately, and prophylactic antibiotics (e.g., macrolide) and/or supplementary immunoglobulin G therapy may provide potential benefits. Considering the projected increase in the prevalence of secondary immunodeficiencies and bronchiectasis, future guidelines and research on the diagnosis and optimized treatment are needed.

Clarithromycin Modulates Neutrophilic Inflammation Induced by Prevotella intermedia in Human Airway Epithelial Cells

Objectives: In the present study, we aimed to clarify the mechanisms by which periodontal pathogens, particularly Prevotella intermedia, induce severe neutrophilic inflammation. In addition, we aimed to test the efficacy of macrolides, which has not been resolved in the neutrophilic inflammation induced by P. intermedia. Methods: NCl-H292 human airway epithelial cells were pre-incubated with clarithromycin for 2 h before incubation with P. intermedia supernatants. Then, C-X-C motif chemokine ligand 8 (CXCL8) transcription and interleukin (IL)-8 production were measured. To elucidate the signaling pathway, mitogen-activated protein kinase inhibitors were added to the cell culture, and the cells were subjected to Western blotting. Results:P. intermedia supernatants promoted CXCL8 transcription and IL-8 production, and the reactions were significantly suppressed by clarithromycin pretreatment. Only trametinib, the selective mitogen-activated extracellular signal-regulated kinase inhibitor, downregulated CXCL8 transcription and IL-8 production. Furthermore, Western blotting revealed that stimulation with P. intermedia supernatants specifically induces extracellular signal-regulated kinases (ERK) 1/2 phosphorylation, which is suppressed by clarithromycin pretreatment. Notably, the interference analysis revealed that ERK3 might be dispensable for IL-8 production under the stimulation of P. intermedia supernatants. Conclusions: Our results provide new insight into the mechanism underlying P. intermedia-induced production of IL-8 from human airway epithelial cells. Furthermore, macrolides might have therapeutic potential in regulating periodontal pathogen-induced neutrophilic inflammation in the lungs.

Screening for primary immune deficiency among patients with bronchiectasis

INTRODUCTION

To assess frequency and methods of PID (primary immune deficiency) screening among patients with bronchiectasis by pneumologists in clinical practice.

METHODS

All the patients hospitalized in the department of pneumology of the Poitiers University Hospital between April 2013 and April 2020 with a diagnosis of bronchiectasis on chest computerized tomography were included. Patients aged 70 and over and those with already known PID were excluded. Primary endpoint was the proportion of patients having had serum immunoglobulin (Ig) assay and serum protein electrophoresis (SPE) analysis. Secondary endpoints were factors associated with prescription of SPE and/or Ig assay, proportion of patients with newly diagnosed PID and their characteristics and factors associated with repeated courses of antibiotics.

RESULTS

Among the 133 patients included, 43% had SPE+Ig assay, 34% SPE only and 23% neither. The proportion of patients with asthma was higher in the "SPE+Ig assay" group (33.3%) compared to the "SPE only" (11.1%) and the "Neither SPE nor Ig assay" groups (6.4%) (P=0.002). Four patients were newly diagnosed for PID of whom 3 had subclass IgG deficiency. Factors associated with repeated courses of antibiotics were generalized bronchiectasis (P=0.02) and asthma (P=0.04).

CONCLUSION

PID is underscreened by pneumologists among patients with bronchiectasis. Association of SPE+Ig assay+IgG subclass assay appears as the most accurate combination.

Growing from common ground: nontuberculous mycobacteria and bronchiectasis

Bronchiectasis and nontuberculous mycobacteria (NTM) are intricately intertwined, with NTM capable of being both a cause and consequence of bronchiectatic disease. This narrative review focuses on the common ground of bronchiectasis and NTM pulmonary disease (NTM-PD) in terms of diagnostic approach, underlying risk factors and treatment strategies. NTM-PD diagnosis relies on a combination of clinical, radiological and microbiological criteria. Although their epidemiology is complicated by detection and reporting biases, the prevalence and pathogenicity of NTM species vary geographically, with Mycobacterium avium complex and Mycobacterium abscessus subspecies most frequently isolated in bronchiectasis-associated NTM-PD. Diagnosis of nodular bronchiectatic NTM-PD should prompt investigation of host factors, including disorders of mucociliary clearance, connective tissue diseases and immunodeficiencies, either genetic or acquired. Treatment of NTM-PD in bronchiectasis involves a multidisciplinary approach and considers the (sub)species involved, disease severity and comorbidities. Current guideline-based antimicrobial treatment of NTM-PD is considered long, cumbersome and unsatisfying in terms of outcomes. Novel treatment regimens and strategies are being explored, including rifampicin-free regimens and inclusion of clofazimine and inhaled antibiotics. Host-directed therapies, such as immunomodulators and cytokine-based therapies, might enhance antimycobacterial immune responses. Optimising supportive care, as well as pathogen- and host-directed strategies, is crucial, highlighting the need for personalised approaches tailored to individual patient needs. Further research is warranted to elucidate the complex interplay between host and mycobacterial factors, informing more effective management strategies.

The role of airways microbiota on local and systemic diseases: a rationale for probiotics delivery to the respiratory tract

INTRODUCTION

Recent discoveries in the field of lung microbiota have enabled the investigation of new therapeutic interventions involving the use of inhaled probiotics.

AREAS COVERED

This review provides an overview of what is known about the correlation between airway dysbiosis and the development of local and systemic diseases, and how this knowledge can be exploited for therapeutic interventions. In particular, the review focused on attempts to formulate probiotics that can be deposited directly on the airways.

EXPERT OPINION

Despite considerable progress since the emergence of respiratory microbiota restoration as a new research field, numerous clinical implications and benefits remain to be determined. In the case of local diseases, once the pathophysiology is understood, manipulating the lung microbiota through probiotic administration is an approach that can be exploited. In contrast, the effect of pulmonary dysbiosis on systemic diseases remains to be clarified; however, this approach could represent a turning point in their treatment.

Brensocatib in non-cystic fibrosis bronchiectasis: ASPEN protocol and baseline characteristics

Introduction

Brensocatib is an investigational, oral, reversible inhibitor of dipeptidyl peptidase-1 shown to prolong time to first exacerbation in adults with bronchiectasis. Outlined here are the clinical trial design, and baseline characteristics and treatment patterns of adult patients enrolled in the phase 3 ASPEN trial (NCT04594369).

Methods

The ASPEN trial is a global study enrolling patients with a clinical history consistent with bronchiectasis (cough, chronic sputum production and/or recurrent respiratory infections), diagnosis confirmed radiologically and ≥2 exacerbations in the prior 12 months. It was designed to evaluate the impact of two brensocatib doses (10 mg and 25 mg) on exacerbation rate over a 52-week treatment period versus placebo. Comprehensive clinical data, including demographics, disease severity, lung function, Pseudomonas aeruginosa status and quality of life, were collected at baseline.

Results

1682 adults from 35 countries were randomised from December 2020 to March 2023. Mean age was 61.3 years and 64.7% were female. ∼70% had moderate-to-severe Bronchiectasis Severity Index (BSI) scores, 29.3% had ≥3 exacerbations in the prior 12 months and 35.7% were positive for P. aeruginosa. Mean BSI scores were highest in Australia/New Zealand (8.3) and lowest in Latin America (5.9). Overall, the most common aetiology was idiopathic (58.4%). In P. aeruginosa-positive versus P. aeruginosa-negative patients, lung function was lower, with greater long-term macrolide (21.5% versus 14.0%) and inhaled corticosteroid use (63.5% versus 53.9%). There was wide regional variation in long-term antibiotic use in patients with bronchiectasis and P. aeruginosa.

Discussion

ASPEN baseline characteristics and treatment profiles were representative of a global bronchiectasis population.

Treatable traits models of care

Treatable traits is a personalized approach to the management of respiratory disease. The approach involves a multidimensional assessment to understand the traits present in individual patients. Traits are phenotypic and endotypic characteristics that can be identified, are clinically relevant and can be successfully treated by therapy to improve clinical outcomes. Identification of traits is followed by individualized and targeted treatment to those traits. First proposed for the management of asthma and chronic obstructive pulmonary disease (COPD) the approach is recommended in many other areas of respiratory and now immunology medicine. Models of care for treatable traits have been proposed in different diseases and health care setting. In asthma and COPD traits are identified in three domains including pulmonary, extrapulmonary and behavioural/lifestyle/risk-factors. In bronchiectasis and interstitial lung disease, a fourth domain of aetiological traits has been proposed. As the core of treatable traits is personalized and individualized medicine; there are several key aspects to treatable traits models of care that should be considered in the delivery of care. These include person centredness, consideration of patients' values, needs and preferences, health literacy and engagement. We review the models of care that have been proposed and provide guidance on the engagement of patients in this approach to care.

A phase 4 multicentre, 2×2 factorial randomised, double-blind, placebo-controlled trial to investigate the efficacy and safety of tobramycin inhalation solution for Pseudomonas aeruginosa eradication in bronchiectasis: ERASE

Chronic Pseudomonas aeruginosa (PA) infection significantly contributes to morbidity and mortality in bronchiectasis patients. Initiating antibiotics early may lead to the eradication of PA. Here we outline the design of a trial (ERASE; NCT06093191) assessing the efficacy and safety of inhaled tobramycin, alone or with oral ciprofloxacin, in bronchiectasis patients with a new isolation of PA. This multicentre, 2×2 factorial randomised, double-blind, placebo-controlled, parallel-group trial includes a 2-week screening period, a 12-week treatment phase (with a combination of ciprofloxacin or a placebo at initial 2 weeks) and a 24-week follow-up. 364 adults with bronchiectasis and a new PA isolation will be randomly assigned to one of four groups: placebo (inhaled saline and ciprofloxacin placebo twice daily), ciprofloxacin alone (750 mg ciprofloxacin and inhaled saline twice daily), inhaled tobramycin alone (inhaled 300 mg tobramycin and ciprofloxacin placebo twice daily) or a combination of both drugs (inhaled 300 mg tobramycin and 750 mg ciprofloxacin twice daily). The primary objective of this study is to assess the proportion of patients successfully eradicating PA in each group by the end of the study. Efficacy will be evaluated based on the eradication rate of PA at other time points (12, 24 and 36 weeks), the occurrence of exacerbations and hospitalisations, time to first pulmonary exacerbations, patient-reported outcomes, symptom measures, pulmonary function tests and the cost of hospitalisations. To date no randomised trial has evaluated the benefit of different PA eradication strategies in bronchiectasis patients. The ERASE trial will therefore generate crucial data to inform future clinical guidelines.

Antibiotic resistance, bacterial transmission and improved prediction of bacterial infection in patients with antibody deficiency

Background

Antibody-deficient patients are at high risk of respiratory tract infections. Many therefore receive antibiotic prophylaxis and have access to antibiotics for self-administration in the event of breakthrough infections, which may increase antimicrobial resistance (AMR).

Objectives

To understand AMR in the respiratory tract of patients with antibody deficiency.

Methods

Sputum samples were collected from antibody-deficient patients in a cross-sectional and prospective study; bacteriology culture, 16S rRNA profiling and PCR detecting macrolide resistance genes were performed. Bacterial isolates were identified using MALDI-TOF, antimicrobial susceptibility was determined by disc diffusion and WGS of selected isolates was done using Illumina NextSeq with analysis for resistome and potential cross-transmission. Neutrophil elastase was measured by a ProteaseTag immunoassay.

Results

Three hundred and forty-three bacterial isolates from sputum of 43 patients were tested. Macrolide and tetracycline resistance were common (82% and 35% of isolates). erm(B) and mef(A) were the most frequent determinants of macrolide resistance. WGS revealed viridans streptococci as the source of AMR genes, of which 23% also carried conjugative plasmids linked with AMR genes and other mobile genetic elements. Phylogenetic analysis of Haemophilus influenzae isolates suggested possible transmission between patients attending clinic.In the prospective study, a negative correlation between sputum neutrophil elastase concentration and Shannon entropy α-diversity (Spearman's ρ = -0.306, P = 0.005) and a positive relationship with Berger-Parker dominance index (ρ = 0.502, P < 0.001) were found. Similar relationships were noted for the change in elastase concentration between consecutive samples, increases in elastase associating with reduced α-diversity.

Conclusions

Measures to limit antibiotic usage and spread of AMR should be implemented in immunodeficiency clinics. Sputum neutrophil elastase may be a useful marker to guide use of antibiotics for respiratory infection.