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Novel treatments are needed to reduce inflammation, improve symptoms, address exacerbations, and slow disease progression in bronchiectasis. Cathepsin C (CatC) inhibition promises to achieve this through reduction of neutrophil-derived serine protease (including neutrophil elastase [NE] and proteinase 3 [PR3]) activation. Here, we present the phase I characterization of the novel CatC inhibitor, BI 1291583. Five phase I trials of BI 1291583 in healthy subjects are presented: a single-rising-dose study (NCT03414008) and two multiple-rising-dose studies (NCT03868540 and NCT04866160) assessing the safety, tolerability, pharmacodynamics, and pharmacokinetics of BI 1291583; a food effect study (NCT03837964); and a drug-drug interaction study (NCT03890887) of BI 1291583 and itraconazole. BI 1291583 was safe and well tolerated across the doses tested in these trials. Most adverse events (AEs) were mild or moderate in intensity, with no serious AEs, AEs of special interest or deaths reported in any trial. Drug-related skin exfoliation was not reported more frequently in subjects treated with BI 1291583 compared with placebo. BI 1291583 was readily absorbed, and pharmacokinetics were supra-proportional over the dose ranges assessed. Additionally, BI 1291583 inhibited CatC in a dose-dependent manner, inhibited downstream NE activity, and decreased PR3 levels. No food effect was observed. Co-administration of multiple doses of itraconazole increased BI 1291583 exposure approximately twofold. Due to these promising phase I results, a multinational phase II program of BI 1291583 in adults with bronchiectasis is ongoing (Airleaf™ [NCT05238675], Clairafly™ [NCT05865886], and Clairleaf™ [NCT05846230])., (© 2024 Boehringer Ingelheim International GmbH and The Author(s). Clinical and Translational Science published by Wiley Periodicals LLC on behalf of American Society for Clinical Pharmacology and Therapeutics.)

Non-cystic fibrosis bronchiectasis is a chronic inflammatory airway disease that results in permanent lung damage and can correlate with considerable clinical and economic burden. There are gaps in knowledge surrounding bronchiectasis, for which there are no published US-based treatment guidelines or FDA-approved therapies. Given the current challenges and gaps in care, the authors of this article convened for an AJMC® roundtable in March 2024. This publication summarizes the main findings of that roundtable and situates them in a scholarly context. Panelists agreed that patients with unexplained chronic cough or fatigue, purulent sputum production, hemoptysis, or repeated infection should undergo CT scanning to assess the presence of bronchiectasis, which has been estimated to affect approximately 364,000 to 558,000 individuals at least 18 years of age. They noted that disease symptoms and treatment burden can considerably diminish patient health-related quality of life (HRQOL) and that an exacerbation uniformly signifies deteriorating health and substantially impacts disease progression, hospitalization rates, and mortality. Absent an FDA-approved therapy, panelists' top management priorities were preventing or reducing exacerbations and maintaining or improving HRQOL. Panelists concluded that providers are ill-equipped to change the course of this heterogenous disease and that there is a real need for options to manage symptoms, for US-based guidelines, and for more research into epidemiology, etiology, and treatment.

Background: The long-term use of rituximab (RTX) has been gaining ground in the treatment of systemic autoimmune diseases. The adverse events (AEs) associated with its use different to infections are being reported., Methods: A cohort of patients with SAIDs treated at a high-complexity center in Cali (southwestern Colombia) with follow-up from January 2008 to December 2022 were examined to search for potential AEs associated with prolonged use of RTX., Results: From 178 patients with long-term use of RTX 3 (1.68%) had lymphadenopathies with lymphoid follicular hyperplasia related to BAFF overexpression, 4 (2.24%) with bronchiectasis, and 4 (2.24%) with lymphoplasmacytic cystitis., Conclusion: Bronchiectasis, lymphoid follicular hyperplasia related to BAFF overexpression, and lymphoplasmacytic cystitis may be life-threatening long-term AEs in patients with prolonged use of RTX., (Copyright © 2024 Elsevier España, S.L.U. and Sociedad Española de Medicina Interna (SEMI). All rights reserved.)

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., Competing Interests: Conflict of interest: E. Van Braeckel is principal investigator for clinical trials sponsored by Insmed, Boehringer Ingelheim, Vertex, and F2G. Her institution received fees for consultancy and/or lectures by Insmed and Vertex. She is the chair of Belgian Respiratory Society working group on respiratory infections. C. Bosteels has no disclosures to declare., (Copyright ©The authors 2024.)

Rationale: Chronic infection and inflammation shapes the airway microbiome in bronchiectasis. Utilizing whole-genome shotgun metagenomics to analyze the airway resistome provides insight into interplay between microbes, resistance genes, and clinical outcomes. Objectives: To apply whole-genome shotgun metagenomics to the airway microbiome in bronchiectasis to highlight a diverse pool of antimicrobial resistance genes: the "resistome," the clinical significance of which remains unclear. Methods: Individuals with bronchiectasis were prospectively recruited into cross-sectional and longitudinal cohorts ( n  = 280), including the international multicenter cross-sectional Cohort of Asian and Matched European Bronchiectasis 2 (CAMEB 2) study ( n  = 251) and two independent cohorts, one describing patients experiencing acute exacerbation and a further cohort of patients undergoing Pseudomonas aeruginosa eradication treatment. Sputum was subjected to metagenomic sequencing, and the bronchiectasis resistome was evaluated in association with clinical outcomes and underlying host microbiomes. Measurements and Main Results: The bronchiectasis resistome features a unique resistance gene profile and increased counts of aminoglycoside, bicyclomycin, phenicol, triclosan, and multidrug resistance genes. Longitudinally, it exhibits within-patient stability over time and during exacerbations despite between-patient heterogeneity. Proportional differences in baseline resistome profiles, including increased macrolide and multidrug resistance genes, associate with shorter intervals to the next exacerbation, whereas distinct resistome archetypes associate with frequent exacerbations, poorer lung function, geographic origin, and the host microbiome. Unsupervised analysis of resistome profiles identified two clinically relevant "resistotypes," RT1 and RT2, the latter characterized by poor clinical outcomes, increased multidrug resistance, and P. aeruginosa. Successful targeted eradication in P. aeruginosa -colonized individuals mediated reversion from RT2 to RT1, a more clinically favorable resistome profile demonstrating reduced resistance gene diversity. Conclusions: The bronchiectasis resistome associates with clinical outcomes, geographic origin, and the underlying host microbiome. Bronchiectasis resistotypes link to clinical disease and are modifiable through targeted antimicrobial therapy.

Background: Lung magnetic resonance imaging (MRI) with ultrashort echo-times (UTE-MRI) allows high-resolution and radiation-free imaging of the lung structure in cystic fibrosis (CF). In addition, the combination of elexacaftor/tezacaftor/ivacaftor (ETI) has improved CF clinical outcomes such as need for hospitalization. However, the effect on structural disease still needs longitudinal evaluation at high resolution., Purpose: To analyze the effects of ETI on lung structural alterations using UTE-MRI, with a focus on bronchiectasis reversibility., Study Type: Retrospective., Population: Fifty CF patients (mean age 24.3 ± 9.2; 23 males)., Field Strength/sequence: 1.5 T, UTE-MRI., Assessment: All subjects completed both UTE-MRI and pulmonary function tests (PFTs) during two annual visits (M0 and M12), and 30 of them completed a CT scan. They initiated ETI treatment after M0 within a maximum of 3 months from the annual examinations. Three observers scored a clinical MRI Bhalla score on UTE-MRI. Bronchiectasis reversibility was defined as a reduction in both outer and inner bronchial dimensions. Correlations were searched between the Bhalla score and PFT such as the forced expiratory volume in 1 second percentage predicted (FEV1%p)., Statistical Tests: Comparison was assessed using the paired t-test, correlation using the Spearman correlation test with a significance level of 0.05. Concordance and reproducibility were assessed using intraclass correlation coefficient (ICC)., Results: There was a significant improvement in MRI Bhalla score after ETI treatment. UTE-MRI demonstrated bronchiectasis reversibility in a subgroup of 18 out of 50 CF patients (36%). These patients with bronchiectasis reversibility were significantly younger, with lower severity of wall thickening but no difference in mucus plugging extent (P = 0.39) was found. The reproducibility of UTE-MRI evaluations was excellent (ICC ≥ 0.95), was concordant with CT scan (N = 30; ICC ≥ 0.90) and significantly correlated to FEV1% at PFT at M0 (N = 50; r = 0.71) and M12 (N = 50; r = 0.72)., Data Conclusion: UTE-MRI is a reproducible tool for the longitudinal follow-up of CF patients, allowing to quantify the response to ETI and demonstrating the reversibility of some structural alterations such as bronchiectasis in a substantial fraction of this study population., Level of Evidence: 4 TECHNICAL EFFICACY: Stage 2., (© 2023 The Authors. Journal of Magnetic Resonance Imaging published by Wiley Periodicals LLC on behalf of International Society for Magnetic Resonance in Medicine.)

Aims: Brensocatib is a reversible inhibitor of dipeptidyl peptidase 1 (cathepsin C), in development to treat chronic non-cystic fibrosis bronchiectasis. The phase 2, randomized, placebo-controlled WILLOW trial (NCT03218917) was conducted to examine whether brensocatib reduced the incidence of pulmonary exacerbations. Brensocatib prolonged the time to the first exacerbation and led to fewer exacerbations than placebo. Because brensocatib potentially affects oral tissues due to its action on neutrophil-mediated inflammation, we analyzed periodontal outcomes in the trial participants., Materials and Methods: Patients with bronchiectasis were randomized 1:1:1 to receive once-daily oral brensocatib 10 or 25 mg or placebo. Periodontal status was monitored throughout the 24-week trial in a prespecified safety analysis. Periodontal pocket depth (PPD) at screening, week 8, and week 24 was evaluated. Gingival inflammation was evaluated by a combination of assessing bleeding upon probing and monitoring the Löe-Silness Gingival Index on 3 facial surfaces and the mid-lingual surface., Results: At week 24, mean ± SE PPD reductions were similar across treatment groups: -0.07 ± 0.007, -0.06 ± 0.007, and -0.15 ± 0.007 mm with brensocatib 10 mg, brensocatib 25 mg, and placebo, respectively. The distribution of changes in PPD and the number of patients with multiple increased PPD sites were similar across treatment groups at weeks 8 and 24. The frequencies of gingival index values were generally similar across treatment groups at each assessment. An increase in index values 0-1 and a decrease in index values 2-3 over time and at the end of the study were observed in all groups, indicating improved oral health., Conclusions: In patients with non-cystic fibrosis bronchiectasis, brensocatib 10 or 25 mg had an acceptable safety profile after 6 months' treatment, with no changes in periodontal status noted. Improvement in oral health at end of the study may be due to regular dental care during the trial and independent of brensocatib treatment., Knowledge Transfer Statement: The results of this study suggest that 24 weeks of treatment with brensocatib does not affect periodontal disease progression. This information can be used by clinicians when considering treatment approaches for bronchiectasis and suggests that the use of brensocatib will not be limited by periodontal disease risks. Nevertheless, routine dental/periodontal care should be provided to patients irrespective of brensocatib treatment., Competing Interests: Declaration of Conflicting InterestsThe authors declared the following potential conflicts of interest with respect to the research, authorship, and/or publication of this article: J.C. Gunsolley was a paid consultant (biostatistical and periodontal) for the WILLOW trial but received no compensation for the work on this manuscript. C. Fernandez is an employee of Insmed Incorporated. O. Sibila has received a grant from Zambon and personal or other fees from Bayer Healthcare, Insmed Incorporated, and Grifols. J.D. Chalmers has received grants and personal fees from AstraZeneca, Boehringer–Ingelheim, GSK, Zambon, and Insmed Incorporated; a grant from Gilead; and personal fees from Novartis and Chiesi. F.A. Scannapieco reports no conflicts of interest.

Background: Inhaled antibiotics are recommended conditionally by international bronchiectasis guidelines for the treatment of patients with bronchiectasis, but results of individual studies are inconsistent. A previous meta-analysis demonstrated promising results regarding the efficacy and safety of inhaled antibiotics in bronchiectasis. Subsequent publications have supplemented the existing body of evidence further in this area., Research Question: To what extent do inhaled antibiotics demonstrate both efficacy and safety as a treatment option for adults with bronchiectasis?, Study Design and Methods: Systematic review and meta-analysis of randomized controlled trials of inhaled antibiotics in adult patients with bronchiectasis. We searched MEDLINE, Embase, the Cochrane Central Register of Controlled Trials, Web of Science, and ClinicalTrials.gov for eligible studies. Studies were included if they enrolled adults with bronchiectasis diagnosed by CT imaging and had a treatment duration of at least 4 weeks. The primary end point was exacerbation frequency, with additional key efficacy end points including severe exacerbations, bacterial load, symptoms, quality of life, and FEV 1 . Data were pooled through random-effects meta-analysis., Results: Twenty studies involving 3,468 patients were included. Inhaled antibiotics were associated with reduced number of patients with exacerbations (risk ratio, 0.85; 95% CI, 0.75-0.96), a slight reduction in exacerbation frequency (rate ratio [RR], 0.78; 95% CI, 0.68-0.91), a probable reduction in the frequency of severe exacerbations (RR, 0.48; 95% CI, 0.31-0.74), and a likely slight increase in time to first exacerbation (hazard ratio, 0.80; 95% CI, 0.68-0.94). Inhaled antibiotics likely lead to a slight increase in the Quality of Life Questionnaire-Bronchiectasis respiratory symptom score (mean difference, 2.51; 95% CI, 0.44-4.31) and may reduce scores on the St. George Respiratory Questionnaire (mean difference, -3.13; 95% CI, -5.93 to -0.32). Bacterial load consistently was reduced, but FEV 1 was not changed with treatment. Evidence suggests little to no difference in adverse effects between groups (OR, 0.99; 95% CI, 0.75-1.30). Antibiotic-resistant organisms likely were increased by treatment., Interpretation: In this systematic review and meta-analysis, inhaled antibiotics resulted in a slight reduction in exacerbations, a probable reduction in severe exacerbations, and a likely slight improvement in symptoms and quality of life in adults with bronchiectasis., Trial Registry: International Prospective Register of Systematic Reviews; No.: CRD42023384694; URL: https://www.crd.york.ac.uk/prospero/., Competing Interests: Financial/Nonfinancial Disclosures The authors have reported to CHEST the following: H. C. reports grants or contracts from the Korean Ministry of Education Basic Science Research Program [Grant 2021R1I1A3052416]; consulting fees from Boryung Pharmaceutical Co., Ltd.; and payment or honoraria for lectures, presentations, speakers bureaus, manuscript writing, or educational events from Boryung Pharmaceutical Co., Ltd. C. S. H. reports consulting fees from 30 Technology, Aradigm, CSL Behring, Chiesi, Gilead, Grifols, GSK, Insmed, Janssen, LifeArc, Meiji, Mylan, Novartis, Pneumagen, Shionogi, Teva, Vertex, and Zambon (personal fees); payment or honoraria for lectures, presentations, speakers bureaus, manuscript writing, or educational events from Chiesi, Insmed; and payment for expert testimony from Zambon. J. D. C. has received research grants from AstraZeneca, Boehringer Ingelheim, GlaxoSmithKline, Gilead Sciences, Grifols, Novartis, Insmed, and Trudell and has received consultancy or speaker fees from Antabio, AstraZeneca, Boehringer Ingelheim, Chiesi, GlaxoSmithKline, Insmed, Janssen, Novartis, Pfizer, Trudell, and Zambon. None declared (R. C.)., (Copyright © 2024 The Author(s). Published by Elsevier Inc. All rights reserved.)

Formerly regarded as a rare disease, bronchiectasis is increasingly recognised. A renewed interest in this disease has led to significant progress in bronchiectasis research. Randomised clinical trials (RCTs) have demonstrated the benefits of airway clearance techniques, inhaled antibiotics and long-term macrolide therapy in bronchiectasis patients. However, the heterogeneity of bronchiectasis remains one of the most challenging aspects of management. Phenotypes and endotypes of bronchiectasis have been identified to help find "treatable traits" and partially overcome disease complexity. The goals of therapy for bronchiectasis are to reduce the symptom burden, improve quality of life, reduce exacerbations and prevent disease progression. We review the pharmacological and non-pharmacological treatments that can improve mucociliary clearance, reduce airway inflammation and tackle airway infection, the key pathophysiological features of bronchiectasis. There are also promising treatments in development for the management of bronchiectasis, including novel anti-inflammatory therapies. This review provides a critical update on the management of bronchiectasis focusing on treatable traits and recent RCTs., Competing Interests: Conflict of interest: H. Choi reports grants from the Basic Science Research Program of the Korean Ministry of Education (grant number 2021R1I1A3052416), and consulting and lecture fees from Boryung Pharmaceutical Co., Ltd and Kolon Pharma. P.J. McShane reports study funding (paid to institution) from Boehringer Ingelheim, Armata, Paratek, Renovian, Spero, AN2 Therapeutics and Insmed, and speaker fees from Insmed. S. Aliberti reports grants or contracts from Insmed Incorporated, Chiesi, Fisher & Paykel and GlaxoSmithKline, royalties or licences from McGraw Hill, consulting fees from Insmed Incorporated, Insmed Italy, Insmed Ireland Ltd, Zambon SpA, AstraZeneca UK Ltd, AstraZeneca Pharmaceutical LP, CSL Behring GmbH, Grifols, Fondazione Internazionale Menarini, Moderna, Chiesi, MSD Italia Srl, Brahms, Physioassist SAS and GlaxoSmithKline SpA, payment or honoraria for lectures, presentations, manuscript writing or educational events from GlaxoSmithKline SpA, Thermofisher Scientific, Insmed Italy, Insmed Ireland, Zambon and Fondazione Internazionale Menarini, and participation on a data safety monitoring board or advisory board for Insmed Incorporated, Insmed Italy, AstraZeneca UK Ltd and MSD Italia Srl. J.D. Chalmers reports grants or contracts from AstraZeneca, Boehringer Ingelheim, Genentech, Gilead Sciences, GlaxoSmithKline, Grifols, Insmed, LifeArc and Novartis, and consulting fees from AstraZeneca, Chiesi, GlaxoSmithKline, Insmed, Grifols, Novartis, Boehringer Ingelheim, Pfizer, Janssen, Antabio and Zambon., (Copyright ©The authors 2024.)

Antibiotic-resistant bacteria associated with LRTIs are frequently associated with inefficient treatment outcomes. Antibiotic-resistant Streptococcus pneumoniae, Haemophilus influenzae, Pseudomonas aeruginosa, and Staphylococcus aureus, infections are strongly associated with pulmonary exacerbations and require frequent hospital admissions, usually following failed management in the community. These bacteria are difficult to treat as they demonstrate multiple adaptational mechanisms including biofilm formation to resist antibiotic threats. Currently, many patients with the genetic disease cystic fibrosis (CF), non-CF bronchiectasis (NCFB) and chronic obstructive pulmonary disease (COPD) experience exacerbations of their lung disease and require high doses of systemically administered antibiotics to achieve meaningful clinical effects, but even with high systemic doses penetration of antibiotic into the site of infection within the lung is suboptimal. Pulmonary drug delivery technology that reliably deliver antibacterials directly into the infected cells of the lungs and penetrate bacterial biofilms to provide therapeutic doses with a greatly reduced risk of systemic adverse effects. Inhaled liposomal-packaged antibiotic with biofilm-dissolving drugs offer the opportunity for targeted, and highly effective antibacterial therapeutics in the lungs. Although the challenges with development of some inhaled antibiotics and their clinicals trials have been studied; however, only few inhaled products are available on market. This review addresses the current treatment challenges of antibiotic-resistant bacteria in the lung with some clinical outcomes and provides future directions with innovative ideas on new inhaled formulations and delivery technology that promise enhanced killing of antibiotic-resistant biofilm-dwelling bacteria., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 The Authors. Published by Elsevier Ltd.. All rights reserved.)

Background: Bronchiectasis is a condition characterized by abnormal and irreversible bronchial dilation resulting from lung tissue damage and can be categorized into two main groups: cystic fibrosis (CF) and non-CF bronchiectasis (NCFB). Both diseases are marked by recurrent infections, inflammatory exacerbations, and lung damage. Given that infections are the primary drivers of disease progression, characterization of the respiratory microbiome can shed light on compositional alterations and susceptibility to antimicrobial drugs in these cases compared to healthy individuals., Methods: To assess the microbiota in the two studied diseases, 35 subjects were recruited, comprising 10 NCFB and 13 CF patients and 12 healthy individuals. Nasopharyngeal swabs and induced sputum were collected, and total DNA was extracted. The DNA was then sequenced by the shotgun method and evaluated using the SqueezeMeta pipeline and R., Results: We observed reduced species diversity in both disease cohorts, along with distinct microbial compositions and profiles of antimicrobial resistance genes, compared to healthy individuals. The nasopharynx exhibited a consistent microbiota composition across all cohorts. Enrichment of members of the Burkholderiaceae family and an increased Firmicutes/Bacteroidetes ratio in the CF cohort emerged as key distinguishing factors compared to NCFB group. Staphylococcus aureus and Prevotella shahii also presented differential abundance in the CF and NCFB cohorts, respectively, in the lower respiratory tract. Considering antimicrobial resistance, a high number of genes related to antibiotic efflux were detected in both disease groups, which correlated with the patient's clinical data., Conclusions: Bronchiectasis is associated with reduced microbial diversity and a shift in microbial and resistome composition compared to healthy subjects. Despite some similarities, CF and NCFB present significant differences in microbiome composition and antimicrobial resistance profiles, suggesting the need for customized management strategies for each disease., (© 2024. The Author(s).)

Introduction: Bronchiectasis is a worldwide chronic lung disorder where exacerbations are common. It affects people of all ages, but especially Indigenous populations in high-income nations. Despite being a major contributor to chronic lung disease, there are no licensed therapies for bronchiectasis and there remain relatively few randomised controlled trials (RCTs) conducted in children and adults. Our RCT will address some of these unmet needs by evaluating whether the novel mucoactive agent, erdosteine, has a therapeutic role in children and adults with bronchiectasis.Our primary aim is to determine in children and adults aged 2-49 years with bronchiectasis whether regular erdosteine over a 12-month period reduces acute respiratory exacerbations compared with placebo. Our primary hypothesis is that people with bronchiectasis who regularly use erdosteine will have fewer exacerbations than those receiving placebo.Our secondary aims are to determine the effect of the trial medications on quality of life (QoL) and other clinical outcomes (exacerbation duration, time-to-next exacerbation, hospitalisations, lung function, adverse events). We will also assess the cost-effectiveness of the intervention., Methods and Analysis: We are undertaking an international multicentre, double-blind, placebo-RCT to evaluate whether 12 months of erdosteine is beneficial for children and adults with bronchiectasis. We will recruit 194 children and adults with bronchiectasis to a parallel, superiority RCT at eight sites across Australia, Malaysia and Philippines. Our primary endpoint is the rate of exacerbations over 12 months. Our main secondary outcomes are QoL, exacerbation duration, time-to-next exacerbation, hospitalisations and lung function., Ethics and Dissemination: The Human Research Ethics Committees (HREC) of Children's Health Queensland (for all Australian sites), University of Malaya Medical Centre (Malaysia) and St. Luke's Medical Centre (Philippines) approved the study. We will publish the results and share the outcomes with the academic and medical community, funding and relevant patient organisations., Trial Registration Number: ACTRN12621000315819., Competing Interests: Competing interests: None declared., (© Author(s) (or their employer(s)) 2024. Re-use permitted under CC BY. Published by BMJ.)

Introduction: The use of monoclonal antibodies in patients with severe asthma has led clinicians to explore new levels of clinical improvement, as testified by the growing interest on clinical remission achievement. In this context, a major role is played by asthma-related comorbidities, which can influence asthma pathophysiology and treatment response., Areas Covered: In this special report, we highlighted how asthma-related comorbidities could deeply affect monoclonal antibody response as well as clinical remission achievement. As examples, we provided data from clinical trials and real-life experiences involving patients with severe asthma and chronic rhinosinusitis with nasal polyps (CRSwNP), eosinophilic granulomatosis with polyangiitis (EGPA) or bronchiectasis., Expert Opinion: Comorbidities associated with severe asthma development should be carefully assessed in everyday clinical practice, even with the help of new diagnostic technologies, artificial intelligence and multidisciplinary teams. Future studies should address the role of comorbidities in remission achievement, describing how these diseases could generate new trajectories of clinical and functional response in patient treated with monoclonal antibodies.

Background: Nontuberculous mycobacteria are environmental organisms that are increasingly causing chronic and debilitating pulmonary infections, of which Mycobacterium avium complex (MAC) is the most common pathogen. MAC pulmonary disease (MAC-PD) is often difficult to treat, often requiring long-term multidrug antibiotic therapy., Research Question: Is there an association between various guideline-based three-drug therapy (GBT) regimens and (1) therapy-associated adverse events or (2) regimen change/discontinuation, within 12 months of therapy initiation?, Study Design and Methods: In a retrospective cohort study, we examined tolerability outcomes of GBT regimens for MAC-PD in 4,626 US Medicare beneficiaries with bronchiectasis, who were prescribed a GBT as initial antibiotic treatment for presumed MAC-PD during 2006 to 2014. Using multivariable Cox proportional hazard regression, we estimated adjusted hazard ratios (aHRs) to compare the risk of adverse events and regimen change/discontinuations within 12 months of therapy initiation in various GBT regimens., Results: The cohort had a mean age ± SD of 77.9 ± 6.1 years at treatment start, were mostly female (77.7%), and were mostly non-Hispanic White (87.2%). The risk of regimen change/discontinuation within 12 months of therapy was higher for clarithromycin-based regimens than azithromycin-based regimens (aHR, 1.12; 95% CI, 1.04-1.20 with rifampin; aHR, 1.11; 95% CI, 0.93-1.32 with rifabutin as the companion rifamycin), and for rifabutin-containing regimens than rifampin-containing regimens (aHR, 1.49; 95% CI, 1.33-1.68 with azithromycin; aHR, 1.47; 95% CI, 1.27-1.70 with clarithromycin as the companion macrolide). The aHR comparing regimen change/discontinuation with clarithromycin-ethambutol-rifabutin and azithromycin-ethambutol-rifampin was 1.64 (95% CI, 1.43-1.64)., Interpretation: Overall, an azithromycin-based regimen was less likely to be changed or discontinued than a clarithromycin-based regimen, and a rifampin-containing regimen was less likely to be changed or discontinued than a rifabutin-containing regimen within 12 months of therapy start. Our work provides a population-based assessment on the tolerability of multidrug antibiotic regimens used for the treatment of MAC-PD., Competing Interests: Financial/Nonfinancial Disclosures The authors have reported to CHEST the following: E. H. has served on an advisory board for AN2 pharmaceuticals and received consult fees. K. L. W. has grants or contracts from Insmed; and has received consulting fees from Insmed, Paratek, RedHill Biopharma, Spero Therapeutics, and AN2 pharmaceuticals. T. K. M. has grants or contracts from Insmed, the Centered Outcomes Research Institute, and the Lung Health Foundation; has received consulting fees from Insmed, RedHill Biopharma, and Spero Therapeutics; has received payment or honoraria from France Foundation, Astra Zeneca, Novartis, and Insmed; and has a leadership or fiduciary role in the Toronto NTM patient group. None declared (J. H. K., K. F. C., M. M., S. K. B.)., (Copyright © 2023 American College of Chest Physicians. Published by Elsevier Inc. All rights reserved.)

Purpose of Review: Bronchiectasis is a chronic respiratory disease characterized by dilated airways, persistent sputum production and recurrent infective exacerbations. The microbiology of bronchiectasis includes various potentially pathogenic microorganisms including Pseudomonas aeruginosa which is commonly cultured from patients' sputum. P. aeruginosa is difficult to eradicate and frequently exhibits antimicrobial resistance. Bacteriophage therapy offers a novel and alternative method to treating bronchiectasis and can be used in conjunction with antibiotics to improve patient outcome., Recent Findings: Thirteen case reports/series to date have successfully used phages to treat infections in bronchiectasis patients, however these studies were constrained to few patients ( n  = 32) and utilized personalized phage preparations and adjunct antibiotics. In these studies, phage therapy was delivered by inhalation, intravenously or orally and was well tolerated in most patients without any unfavourable effects. Favourable clinical or microbiological outcomes were seen following phage therapy in many patients. Longitudinal patient follow-up reported regrowth of bacteria and phage neutralization in some studies. There are five randomized clinical controlled trials ongoing aiming to use phage therapy to treat P. aeruginosa associated respiratory conditions, with limited results available to date., Summary: More research, particularly robust clinical trials, into how phages can clear respiratory infections, interact with resident microbiota, and how bacteria might develop resistance will be important to establish to ensure the success of this promising therapeutic alternative., (Copyright © 2024 Wolters Kluwer Health, Inc. All rights reserved.)

Background: The aim of this study was to investigate the clinical features of Nocardia infections, antibiotic resistance profile, choice of antibiotics and treatment outcome, among others. In addition, the study compared the clinical and microbiological characteristics of nocardiosis in bronchiectasis patients and non-bronchiectasis patients., Methods: Detailed clinical data were collected from the medical records of 71 non-duplicate nocardiosis patients from 2017 to 2023 at a tertiary hospital in Zhengzhou, China. Nocardia isolates were identified to the species level using MALDI-TOF MS and 16S rRNA PCR sequencing. Clinical data were collected from medical records, and drug susceptibility was determined using the broth microdilution method., Results: Of the 71 cases of nocardiosis, 70 (98.6%) were diagnosed as pulmonary infections with common underlying diseases including bronchiectasis, tuberculosis, diabetes mellitus and chronic obstructive pulmonary disease (COPD). Thirteen different strains were found in 71 isolates, the most common of which were N. farcinica (26.8%) and N. cyriacigeorgica (18.3%). All Nocardia strains were 100% susceptible to both TMP-SMX and linezolid, and different Nocardia species showed different patterns of drug susceptibility in vitro. Pulmonary nocardiosis is prone to comorbidities such as bronchiectasis, diabetes mellitus, COPD, etc., and Nocardia is also frequently accompanied by co-infection of the body with pathogens such as Mycobacterium and Aspergillus spp. Sixty-one patients underwent a detailed treatment regimen, of whom 32 (52.5%) received single or multi-drug therapy based on TMP-SMX. Bronchiectasis was associated with a higher frequency of Nocardia infections, and there were significant differences between the bronchiectasis and non-bronchiectasis groups in terms of age distribution, clinical characteristics, identification of Nocardia species, and antibiotic susceptibility (P < 0.05)., Conclusions: Our study contributes to the understanding of the species diversity of Nocardia isolates in Henan, China, and the clinical characteristics of patients with pulmonary nocardiosis infections. Clinical and microbiologic differences between patients with and without bronchiectasis. These findings will contribute to the early diagnosis and treatment of patients., (© 2024. The Author(s).)

Background: High dose N acetylcysteine (NAC), a mucolytic, anti-inflammatory and antioxidant agent has been shown to significantly reduce exacerbations, and improve quality of life in placebo controlled, double blind randomised (RCT) studies in patients with COPD, and in an open, randomised study in bronchiectasis. In this pilot, randomised, double-blind, placebo-controlled study, we wished to investigate the feasibility of a larger clinical trial, and the anti-inflammatory and clinical benefits of high dose NAC in bronchiectasis., Aims: Primary outcome: to assess the efficacy of NAC 2400 mg/day at 6 weeks on sputum neutrophil elastase (NE), a surrogate marker for exacerbations. Secondary aims included assessing the efficacy of NAC on sputum MUC5B, IL-8, lung function, quality of life, and adverse effects., Methods: Participants were randomised to receive 2400 mg or placebo for 6 weeks. They underwent 3 visits: at baseline, week 3 and week 6 where clinical and sputum measurements were assessed., Results: The study was stopped early due to the COVID pandemic. In total 24/30 patients were recruited, of which 17 completed all aspects of the study. Given this, a per protocol analysis was undertaken: NAC (n = 9) vs placebo (n = 8): mean age 72 vs 62 years; male gender: 44% vs 50%; baseline median FEV 1 1.56 L (mean 71.5 % predicted) vs 2.29L (mean 82.2% predicted). At 6 weeks, sputum NE fell by 47% in the NAC group relative to placebo (mean fold difference (95%CI: 0.53 (0.12,2.42); MUC5B increased by 48% with NAC compared with placebo. Lung function, FVC improved significantly with NAC compared with placebo at 6 weeks (mean fold difference (95%CI): 1.10 (1.00, 1.20), p = 0.045. Bronchiectasis Quality of life measures within the respiratory and social functioning domains demonstrated clinically meaningful improvements, with social functioning reaching statistical significance. Adverse effects were similar in both groups., Conclusion: High dose NAC exhibits anti-inflammatory benefits, and improvements in aspects of quality of life and lung function measures. It is safe and well tolerated. Further larger placebo controlled RCT's are now warranted examining its role in reducing exacerbations., Competing Interests: Declaration of competing interest All the authors declare that they have no competing interests., (Copyright © 2023 Elsevier Ltd. All rights reserved.)

Background: Chronic airway diseases have been associated with an increased risk of tuberculosis (TB); however, data in patients with bronchiectasis is limited. Statins have been shown to exhibit anti-inflammatory effects by modulating the inflammatory response. This study investigated whether statin treatment could reduce the risk of TB in patients with bronchiectasis., Methods: We conducted a retrospective cohort study using a nationwide population database of patients with bronchiectasis who did or did not receive statin treatment. The defined daily dose (DDD) of statin, current or past statin user and statin exposure time were measured for the impact of statin use. The primary outcome was the incidence of new-onset TB. Considering of potential immortal time bias due to stain exposure time, Cox regression models with time-dependent covariates were employed to estimate HRs with 95% CIs for TB incidence among patients with bronchiectasis., Results: Patients with bronchiectasis receiving statin treatment had a decreased risk of TB. After adjusting for age, sex, income, comorbidities and Charlson Comorbidity Index, statin users had a 0.59-fold lower risk of TB incidence compared with non-statin users (95% CI 0.40 to 0.88; p=0.0087). Additionally, compared with non-statin users, statin treatment was a protective factor against TB in users with a cumulative DDD greater than 180 per year, with an HR of 0.32 (95% CI 0.12 to 0.87; p=0.0255)., Conclusions: Statin treatment demonstrated a dose-dependent protective effect and was associated with a reduced risk of TB in patients with bronchiectasis. These findings suggest that statins may play a role in lowering TB risk by modulating airway inflammation in this patient population., Competing Interests: Competing interests: None declared., (© Author(s) (or their employer(s)) 2024. Re-use permitted under CC BY-NC. No commercial re-use. See rights and permissions. Published by BMJ.)

Purpose: Multidrug-resistant (MDR) bacteria impose a considerable health-care burden and are associated with bronchiectasis exacerbation. This study investigated the clinical outcomes of adult patients with bronchiectasis following MDR bacterial infection., Methods: From the Chang Gung Research Database, we identified patients with bronchiectasis and MDR bacterial infection from 2008 to 2017. The control group comprised patients with bronchiectasis who did not have MDR bacterial infection and were propensity-score matched at a 1:2 ratio. The main outcomes were in-hospital and 3-year mortality., Results: In total, 554 patients with both bronchiectasis and MDR bacterial infection were identified. The types of MDR bacteria that most commonly affected the patients were MDR- Acinetobacter baumannii (38.6%) and methicillin-resistant Staphylococcus aureus (18.4%), Extended-spectrum-beta-lactamases (ESBL)- Klebsiella pneumoniae (17.8%), MDR-Pseudomonas (14.8%), and ESBL-E. coli (7.5%). Compared with the control group, the MDR group exhibited lower body mass index scores, higher rate of chronic bacterial colonization, a higher rate of previous exacerbations, and an increased use of antibiotics. Furthermore, the MDR group exhibited a higher rate of respiratory failure during hospitalization (MDR vs. control, 41.3% vs. 12.4%; p < 0.001). The MDR and control groups exhibited in-hospital mortality rates of 26.7% and 7.6%, respectively (p < 0.001); 3-year respiratory failure rates of 33.5% and 13.5%, respectively (p < 0.001); and 3-year mortality rates of 73.3% and 41.5%, respectively (p < 0.001). After adjustments were made for confounding factors, the infection with MDR and MDR bacteria species were determined to be independent risk factors affecting in-hospital and 3-year mortality., Conclusions: MDR bacteria were discovered in patients with more severe bronchiectasis and were independently associated with an increased risk of in-hospital and 3-year mortality. Given our findings, we recommend that clinicians identify patients at risk of MDR bacterial infection and follow the principle of antimicrobial stewardship to prevent the emergence of resistant bacteria among patients with bronchiectasis., (© 2024. The Author(s).)

Allergic bronchopulmonary aspergillosis (ABPA) is a complex hypersensitivity reaction to airway colonization by Aspergillus fumigatus in patients with asthma and cystic fibrosis. The pathophysiology of ABPA involves a complex interplay between the fungus and the host immune response, which causes persistent inflammation and tissue damage. Patients present with chronic cough, wheezing, and dyspnea due to uncontrolled asthma. Characteristic symptoms include the expectoration of brownish mucus plugs. Radiographic findings often reveal fleeting pulmonary infiltrates, bronchiectasis, and mucus impaction. However, the definitive diagnosis of ABPA requires a combination of clinical, radiological, and immunological findings. The management of ABPA aims to reduce symptoms, prevent disease progression, and minimize the future risk of exacerbations. The treatment approach involves systemic glucocorticoids or antifungal agents to suppress the inflammatory response or fungal growth and prevent exacerbations. Biological agents may be used in patients with severe disease or glucocorticoid dependence. This review provides an overview of the clinical manifestations and current treatment options for ABPA., Competing Interests: None declared., (Thieme. All rights reserved.)

Introduction: Pseudomonas aeruginosa is the most commonly isolated pathogen in bronchiectasis and is associated with worse outcomes. Eradication treatment is recommended by guidelines, but the evidence base is limited. The expected success rate of eradication in clinical practice is not known., Methods: We conducted a systematic review and meta-analysis according to Meta-Analysis of Observational Studies in Epidemiology guidelines. PubMed, Embase, the Cochrane Database of Systematic Reviews and Clinicaltrials.gov were searched for studies investigating P. aeruginosa eradication treatment using antibiotics (systemic or inhaled) in patients with bronchiectasis. The primary outcome was the percentage of patients negative for P. aeruginosa at 12 months after eradication treatment. Cystic fibrosis was excluded., Results: Six observational studies including 289 patients were included in the meta-analysis. Our meta-analysis found a 12-month P. aeruginosa eradication rate of 40% (95% CI 34-45%; p<0.00001), with no significant heterogeneity (I 2 =0%). Combined systemic and inhaled antibiotic treatment was associated with a higher eradication rate (48%, 95% CI 41-55%) than systemic antibiotics alone (27%, 13-45%)., Conclusion: Eradication treatment in bronchiectasis results in eradication of P. aeruginosa from sputum in ∼40% of cases at 12 months. Combined systemic and inhaled antibiotics achieve higher eradication rates than systemic antibiotics alone., Competing Interests: Conflict of interest: M. Shteinberg reports grants or contracts from GSK and Trudell pharma; consulting fees from AstraZeneca, Boehringer Ingelheim, Dexcel, Kamada, Synchrony Medical, Trumed, and Zambon; payment or honoraria for lectures, presentations, speakers bureaus, manuscript writing, or educational events from AstraZeneca, Boehringer Ingelheim, and Kamada; support for attending meetings or travel from Boehringer Ingelheim, AstraZeneca, and Kamada; participation on a Data Safety Monitoring Board or Advisory Board for Bonus Biotherapeutics, Boehringer Ingelheim, and AstraZeneca; leadership or fiduciary role in other board, society, committee, or advocacy groups with Israeli Pulmonology Society, Israeli Society for Tuberculosis and Mycobacterial Diseases, and EMBARC as unpaid management board member, and the European Respiratory Journal and Chest as an unpaid Editorial board member; and receipt of equipment, materials, drugs, medical writing, gifts or other services from Trudell Medical International. J.D. Chalmers reports grants or contracts from Grifols; consulting fees from Antabio, AstraZeneca, Boehringer Ingelheim, Chiesi, GSK, Grifols, Insmed, Janssen, Novartis, Pfizer, and Zambon; and leadership or fiduciary roles as Chair of European Respiratory Society (ERS) Bronchiectasis Guideline Task Force, Chief Editor of the European Respiratory Journal, and Chair of EMBARC Clinical Research Collaboration. All other authors have nothing to disclose., (Copyright ©The authors 2024.)

Aims: Non-cystic fibrosis bronchiectasis (NCFB) is a chronic progressive respiratory disorder occurring at a rate ranging from 4.2 to 278.1 cases per 100,000 persons, depending on age, in the United States. For many patients with NCFB, the presence of Pseudomonas aeruginosa (PA) makes treatment more complicated and typically has worse outcomes. Management of NCFB can be challenging, warranting a better understanding of the burden of illness for NCFB, treatments applied, healthcare resources used, and subsequent treatment costs. Comparing patients diagnosed with exacerbated NCFB, with or without PA on antibiotic utilization, treatments, and healthcare resources utilization and costs was the purpose of this study., Materials and Methods: This was a retrospective cohort study of commercial claims from IQVIA's PharMetrics Plus database (January 1,2006-December 31, 2020). Study patients with a diagnosis of NCFB were stratified into two groups based on the presence or absence of PA, then followed to identify demographic characteristics, comorbid conditions, antibiotic treatment regimen prescribed, healthcare resources utilized, and costs of care., Results: The results showed that patients with exacerbated NCFB who were PA + had significantly more oral antibiotic fills per patient per year, more inpatient admissions with a longer length of stay, and more outpatient encounters than those who were PA - . For costs, PA + patients also had significantly greater total healthcare costs per patient when compared to those who were PA - ., Conclusion: Exacerbated NCFB with PA + was associated with increased antibiotic usage, greater resource utilization, and increased costs. The major contributor to the cost differences was the use of inpatient services. Treatment strategies aimed at reducing the need for inpatient treatment could lessen the disparities observed in patients with NCFB.

Background: This study aimed to evaluate the effectiveness and safety of fixed-dose combination (FDC) inhaled corticosteroids/long-acting β 2 -agonists (ICS/LABA) in bronchiectasis., Research Design and Methods: A retrospective cohort study analyzed electronic medical records of bronchiectasis patients initiating ICS/LABA FDC or LAMA between 2007 and 2021. All bronchiectasis diagnoses were made by radiologists using high-resolution computed tomography., Results: Of the 1,736 patients, 1,281 took ICS/LABA FDC and 455 LAMA. Among the 694 propensity score matched patients, ICS/LABA FDC had comparable outcomes to LAMA, with HRs of 1.22 (95% CI 0.81-1.83) for hospitalized respiratory infection, 1.06 (95% CI 0.84-1.33) for acute exacerbation, and 1.06 (95% CI 0.66-1.02) for all-cause hospitalization. Beclomethasone/formoterol (BEC/FOR) or budesonide/formoterol (BUD/FOR) led to a lower risk of acute exacerbation compared to fluticasone/salmeterol (FLU/SAL) (BEC/FOR HR 0.59, 95% CI 0.43-0.81; BUD/FOR HR 0.68, 95% CI 0.50-0.93). BEC/FOR resulted in lower risks of hospitalized respiratory infection (HR 0.48, 95% 0.26-0.86) and all-cause hospitalization (HR 0.55, 95% 0.37-0.80) compared to FLU/SAL., Conclusion: Our findings provide important evidence on the effectiveness and safety of ICS/LABA FDC compared with LAMA for bronchiectasis. BEC/FOR and BUD/FOR were associated with better outcomes than FLU/SAL.

Patients with nontuberculous mycobacterial (NTM) lung infection require life-long attention to their bronchiectasis, whether or not their NTM infection has been cured. The identification of the cause of bronchiectasis and/or coexisting diseases is important because it may affect therapeutic strategies. Airway clearance is the mainstay of bronchiectasis management. It can include multiple breathing techniques, devices, and mucoactive agents. The exact airway clearance regimen should be customized to each individual patient. Chronic pathogenic airway bacteria, such as Pseudomonas aeruginosa, may warrant consideration of eradication therapy and/or chronic use of maintenance inhaled antibiotics., (Copyright © 2023 Elsevier Inc. All rights reserved.)

Rationale: Longitudinal epidemiological and clinical data are needed to improve the management of patients with bronchiectasis developing nontuberculous mycobacterial (NTM) pulmonary disease., Objectives: To describe the epidemiology, patient management, and treatment outcomes of NTM infections in patients with bronchiectasis enrolled in the United States Bronchiectasis and NTM Research Registry (US BRR)., Methods: This was a retrospective cohort study of patients with bronchiectasis and NTM infections enrolled with follow-up in the US BRR in 2008-2019. The study included patients with ≥1 positive NTM respiratory culture in the 24-month baseline period (baseline NTM cohort) and/or during the annual follow-up visits (incident NTM cohort). Incidence, prevalence, baseline patient characteristics, treatment exposure, treatment outcomes, and respiratory clinical outcomes were described in the baseline NTM cohort, incident NTM cohort, and both cohorts combined (prevalent NTM cohort)., Results: Between 2008 and 2019, 37.9% (1457/3840) of patients with bronchiectasis in the US BRR met the inclusion criteria for this study and were reported to have Mycobacterium avium complex (MAC) and/or Mycobacterium abscessus complex (MABSC) infections. MAC prevalence increased steadily in the US BRR during 2009-2019; incidence was relatively stable, except for a peak in 2011 followed by a slow decrease. MABSC and mixed MAC/MABSC infections were rare. Most patients with bronchiectasis and NTM infections in the registry were female, White, and aged >65 years. The antibiotics administered most commonly reflected current guidelines. In the prevalent cohort, 44.9% of MAC infections and 37.1% of MABSC infections remained untreated during follow-up, and MAC treatment was initiated with delay (>90 days after positive NTM respiratory culture) twice as frequently as promptly (≤90 days after positive NTM respiratory culture) (68.6% vs 31.4%, respectively). The median time from diagnosis to treatment was shorter for MABSC versus MAC infections (194.0 days [interquartile range (IQR) 8.0, 380.0] vs 296.0 days [IQR 35.0, 705.0], respectively). Among patients with MAC infections who completed treatment, 27.6% were classified as cured and 29.6% as treatment failure during the annual follow-up visit window. For MABSC, these proportions were 25.0% and 28.0%, respectively., Conclusions: A considerable proportion of MAC and MABSC infections were untreated or treated after initial delay/observation. MABSC infections were more likely to be treated and start treatment sooner than MAC infections. Further longitudinal studies are warranted to evaluate the monitor-with-delay approach and inform clinical guidelines., Competing Interests: Declaration of competing interest MD, HS, IG, ST, SS: employees of GSK and GSK shareholders at the time of this study; all GSK employees were involved in the study design, decision to publish, data analysis and interpretation, and preparation of the manuscript. ST: scientific liaison officer of The Union; deputy editor of the International Journal of Tuberculosis and Lung Disease. CS: speaker fees from Insmed. DM: consulting fees from AstraZeneca and COPD Foundation; honoraria from Medscape; payment for expert testimony from Schlesinger Law Firm; stock or stock options with GSK and Johnson and Johnson. MM: advisory board, grants, and consulting fees from Insmed. NL: grants for educational projects and conference travel fees from Insmed. PMS: grants as primary investigator for clinical trials from AN2 Therapeutics, Boehringer Ingelheim, Electromed, Hillrom, Insmed, Parateck, RedHill Biopharma, and Revovion; honorarium for steering committee from Insmed; speaker fees for Arikayce from Insmed. KW: grants and/or consulting fees from AN2, Insmed, Paratek, Renovion, RedHill Biopharma, and Vast; advisory board fees from RedHill Biopharma., (Copyright © 2023. Published by Elsevier Ltd.)

Background: Respiratory exacerbations in children and adolescents with bronchiectasis are treated with antibiotics. However, antibiotics can have variable interindividual effects when treating exacerbations., Research Question: Can phenotypic features associated with symptom resolution after a 14-day course of oral antibiotics for a nonsevere exacerbation of bronchiectasis be identified?, Study Design and Methods: Combining data from two multicenter randomized controlled trials, we identified 217 children with bronchiectasis assigned to at least 14 days of oral antibiotics to treat nonsevere (nonhospitalized) exacerbations. Univariable and then multivariable logistic regression were used to identify factors associated with symptom resolution within 14 days of commencing antibiotics. Identified associations were re-evaluated by mediation analysis., Results: Of the 217 study participants (52% male patients), 41% were Indigenous (Australian First Nations, New Zealand Māori, or Pacific Islander). The median age was 6.6 years (interquartile range, 4.0-10.1 years). By day 14, symptoms had resolved in 130 children (responders), but persisted in the remaining 87 children (nonresponders). Multivariable analysis found those who were Indigenous (adjusted OR [AOR], 3.59; 95% CI, 1.35-9.54) or showed new abnormal auscultatory findings (AOR, 3.85; 95% CI, 1.56-9.52) were more likely to be responders, whereas those with multiple bronchiectatic lobes at diagnosis (AOR, 0.66; 95% CI, 0.46-0.95) or higher cough scores when starting exacerbation treatment (AOR, 0.55; 95% CI, 0.34-0.90) were more likely to be nonresponders. Detecting a respiratory virus at the beginning of an exacerbation was not associated with antibiotic failure at 14 days., Interpretation: Children with Indigenous ethnicity, milder bronchiectasis, mild exacerbations (low reported cough scores), or new abnormal auscultatory signs are more likely to respond to appropriate oral antibiotics than those without these features. These patient and exacerbation phenotypes may assist clinical management and development of biomarkers to identify those whose symptoms are more likely to resolve after 14 days of oral antibiotics., Trial Registry: Australian New Zealand Clinical Trials Registry; Nos.: ACTRN12612000011886 and ACTRN12612000010897; URL: https://www.anzctr.org.au., Competing Interests: Financial/Nonfinancial Disclosures The authors have reported to CHEST the following: A. B. C. reports other fees to her institution from work relating to independent data management committee membership for an unlicensed vaccine from GlaxoSmithKline, unlicensed monoclonal antibody for respiratory syncytial viruses from AstraZeneca and a COVID-19 vaccine from Moderna outside the submitted work and fees to her institution from work relating to unlicensed therapies for bronchiectasis: inhaled antibiotics from Zambon and a molecule from Boehringer Ingelheim. C. A. B. is a trustee of the BronchiectasisFoundation (no payment) and chairs the Clinical Advisory Panel for Cystic Fibrosis (no payment)., (Copyright © 2023 American College of Chest Physicians. All rights reserved.)

A woman in her 70s with a history of nodular bronchiectatic Mycobacterium avium complex pulmonary disease (MAC-PD) presented with an exacerbated productive cough and worsening findings on chest imaging. Although repeated sputum culture tests were negative for acid-fast bacilli and only revealed normal respiratory flora, a bronchoscopy identified Nocardia sp. Consequently, she was diagnosed with pulmonary nocardiosis and was successfully treated with levofloxacin. It is known that pulmonary nocardiosis can manifest in immunocompetent individuals with bronchiectasis. For cases of refractory nodular bronchiectatic MAC-PD, it is vital to consider bronchoscopy to identify potential co-infections, such as Nocardia ., Competing Interests: Competing interests: None declared., (© BMJ Publishing Group Limited 2023. No commercial re-use. See rights and permissions. Published by BMJ.)

This study retrospectively analyzed the treatment outcomes of 110 patients with non-cavitary nodular bronchiectatic-type Mycobacterium avium complex pulmonary disease who received intermittent or daily treatment with a three-drug oral antibiotic regimen (i.e., a macrolide, ethambutol, and rifampin) at a tertiary referral center in South Korea. Among these patients, 36 had sputum smear positivity. Of these 36 patients, intermittent treatment led to a lower culture conversion rate than daily treatment [50.0% (8/16) vs 85.0% (17/20), P = 0.034]., Competing Interests: The authors declare no conflict of interest.

Background and Objective: Outside clinical trials, there is limited long-term data following bronchial thermoplasty (BT). In a cohort of real-world severe asthmatics in an era of biological therapy, we sought to evaluate the safety and efficacy of BT 5 years post-treatment., Methods: Every patient treated with BT at two Australian tertiary centres were recalled at 5 years, and evaluated by interview and record review, Asthma Control Questionnaire (ACQ), spirometry and high-resolution CT Chest. CT scans were interpreted using the modified Reiff and BRICS CT scoring systems for bronchiectasis., Results: Fifty-one patients were evaluated. At baseline, this cohort had a mean age of 59.0 ± 11.8 years, mean ACQ of 3.0 ± 1.0, mean FEV1 of 55.5 ± 18.8% predicted, and 53% were receiving maintenance oral steroids in addition to triple inhaler therapy. At 5 years, there was a sustained improvement in ACQ scores to 1.8 ± 1.0 (p < 0.001). Steroid requiring exacerbation frequency was reduced from 3.8 ± 3.6 to 1.0 ± 1.6 exacerbations per annum (p < 0.001). 44% of patients had been weaned off oral steroids. No change in spirometry was observed. CT scanning identified minor degrees of localized radiological bronchiectasis in 23/47 patients with the modified Reiff score increasing from 0.6 ± 2.6 at baseline to 1.3 ± 2.5 (p < 0.001). However, no patients exhibited clinical features of bronchiectasis, such as recurrent bacterial infection., Conclusion: Sustained clinical benefit from BT at 5 years was demonstrated in this cohort of very severe asthmatics. Mild, localized radiological bronchiectasis was identified in a portion of patients without clinical features of bronchiectasis., (© 2023 The Authors. Respirology published by John Wiley & Sons Australia, Ltd on behalf of Asian Pacific Society of Respirology.)

Background: The long-term outcomes of allergic bronchopulmonary aspergillosis (ABPA) are poorly characterised., Methods: We retrospectively included treatment-naïve subjects of acute stage ABPA-complicating asthma from three randomised trials. All the subjects received oral prednisolone for 4 months and were monitored every 6 weeks for 6 months and then every 6 months. Our primary objective was to estimate the incidence rate and the frequency of subjects experiencing ABPA exacerbation. The key secondary objectives were to evaluate the factors predicting ABPA exacerbation and the changes in serum total IgE seen during treatment., Results: We included 182 subjects. Eighty-one (44.5%) patients experienced 120 exacerbations during 512 patient-years of follow-up. The incidence rate of ABPA exacerbations was 234/1000 patient-years. Most (73/81, 90.1%) subjects experienced ABPA exacerbation within three years of stopping therapy. On multivariate logistic regression analysis, peripheral blood eosinophil count ≥1000 cells/μL (adjusted odds ratio [aOR] 2.43; 95% confidence interval (CI), 1.26-4.67), the extent of bronchiectasis (aOR 1.10; 95% CI, 1.03-1.18), age (aOR 0.97; 95% CI, 0.94-0.99), and female sex (aOR 2.16; 95% CI, 1.10-4.24) independently predicted ABPA exacerbation after adjusting for serum total IgE and high-attenuation mucus. The best cut-off for serum total IgE after 6 weeks for identifying treatment response and ABPA exacerbations was a 20% decline and a 50% increase, respectively., Conclusions: ABPA exacerbations were common within 3 years of stopping treatment. Age, female sex, peripheral blood eosinophilia and the extent of bronchiectasis predicted ABPA exacerbations. The optimal serum total IgE cut-off for defining ABPA response and exacerbations is a 20% decline and a 50% increase, respectively., (© 2023 Wiley-VCH GmbH. Published by John Wiley & Sons Ltd.)

Background: In Thailand, the incidence of community-acquired pseudomonal pneumonia among 60- to 65-year-olds ranges from 10.90% to 15.51%, with a mortality rate of up to 19.00%. Antipseudomonal agents should be selected as an empirical treatment for elderly patients at high risk for developing this infection. The purpose of this study was to identify risk factors and develop a risk predictor for Pseudomonas aeruginosa infection in older adults with community-acquired pneumonia (CAP)., Methods: A retrospective data collection from an electronic database involved the elderly hospitalized patients with P. aeruginosa- and non-P. aeruginosa-causing CAP, admitted between January 1, 2016, and June 30, 2021. Risk factors for P. aeruginosa infection were analysed using logistic regression, and the instrument was developed by scoring each risk factor based on the beta coefficient and evaluating discrimination and calibration using the area under the receiver operating characteristic curve (AuROC) and observed versus predicted probability (E/O) ratio., Results: The inclusion criteria were met by 81 and 104 elderly patients diagnosed with CAP caused by P. aeruginosa and non-P. aeruginosa, respectively. Nasogastric (NG) tube feeding (odd ratios; OR = 40.68), bronchiectasis (B) (OR = 4.13), immunocompromised condition (I) (OR = 3.76), and other chronic respiratory illnesses (r) such as atelectasis, pulmonary fibrosis, and lung bleb (OR = 2.61) were the specific risk factors for infection with P. aeruginosa. The "60-B-r-I-NG" risk score was named after the 4 abbreviated risk variables and found to have good predicative capability (AuROC = 0.77) and accuracy comparable to or near true P. aeruginosa infection (E/O = 1). People who scored at least two should receive empirically antipseudomonal medication., Conclusions: NG tube feeding before admission, bronchiectasis, immunocompromisation, atelectasis, pulmonary fibrosis and lung bleb were risk factors for pseudomonal CAP in the elderly. The 60-B-r-I-NG was developed for predicting P. aeruginosa infection with a high degree of accuracy, equal to or comparable to the existing P. aeruginosa infection. Antipseudomonal agents may be started in patients who are at least 60 years old and have a score of at least 2 in order to lower mortality and promote the appropriate use of these medications., (© 2023. BioMed Central Ltd., part of Springer Nature.)

Background: Inhaled corticosteroids (ICS) increase the risk of pneumonia in COPD and commonly are used in patients with COPD-bronchiectasis overlap., Research Question: Is the risk of pneumonia associated with ICS further heightened in COPD-bronchiectasis?, Study Design and Methods: Electronic health care records (from 2004-2019) were used to obtain a cohort of patients with COPD and a nested case-control group (age and sex matched 1:4). Analyses were conducted to determine the risk of hospitalization for pneumonia in COPD associated with ICS use in those with bronchiectasis. Findings were confirmed by several sensitivity analyses. Additionally, a smaller nested case-control group containing only patients with COPD-bronchiectasis overlap and those with recent blood eosinophil counts (BECs) was used to determine any association with BEC., Results: Three hundred sixteen thousand six hundred sixty-three patients were eligible for the COPD cohort; bronchiectasis significantly increased the risk of pneumonia (adjusted hazard ratio, 1.24; 95% CI, 1.15-1.33). In the first nested case-control group of 84,316 patients with COPD, ICS was found to increase the odds of pneumonia (adjusted OR [AOR], 1.26; 95% CI, 1.19-1.32) only if used in the previous 180 days. However, bronchiectasis was a significant modifier such that ICS use did not augment further the already elevated bronchiectasis-associated pneumonia risk (COPD-bronchiectasis: AOR, 1.01; 95% CI, 0.8-1.28; no bronchiectasis: AOR, 1.27; 95% CI, 1.20-1.34). Several sensitivity analyses and a second smaller nested case-control group confirmed these findings. Finally, we found that BEC modified the ICS-associated pneumonia risk in COPD-bronchiectasis overlap, where lower BEC was associated significantly with pneumonia (BEC ≤ 3 × 10 9 /L: AOR, 1.56; 95% CI, 1.05-2.31; BEC > 3 × 10 9 /L: AOR, 0.89; 95% CI, 0.53-1.24)., Interpretation: ICS use does not augment further the already increased risk of hospitalization for pneumonia associated with concomitant bronchiectasis in patients with COPD., Competing Interests: Financial/Nonfinancial Disclosures None declared., (Copyright © 2023 The Author(s). Published by Elsevier Inc. All rights reserved.)

Background: Bronchiectasis is a common comorbidity in patients with asthma and is associated with increased disease severity. In patients with severe eosinophilic asthma, biologics targeting IL-5/5Ra have beneficial effects on oral corticosteroid (OCS) use and exacerbation frequency. However, how coexisting bronchiectasis affects the response to such treatments is unknown., Objective: To evaluate the real-world effectiveness of anti-IL-5/5Ra therapy in patients with severe eosinophilic asthma and comorbid bronchiectasis on exacerbation frequency and daily maintenance and cumulative OCS dose., Methods: This real-world study evaluated data from 97 adults with severe eosinophilic asthma and computed tomography-confirmed bronchiectasis from the Dutch Severe Asthma Registry, who initiated anti-IL5/5Ra biologics (mepolizumab, reslizumab, and benralizumab) and had follow-up data for 12 months or greater. The analysis was performed for the total population and subgroups with or without maintenance OCS use., Results: Anti-IL-5/5Ra therapy significantly reduced exacerbation frequency in patients with maintenance OCS use as well as in those without it. In the year before biologic initiation, 74.5% of all patients had two or more exacerbations, which decreased to 22.1% in the follow-up year (P < .001). The proportion of patients on maintenance OCS decreased from 47% to 30% (P < .001), and in the OCS-dependent patients (n = 45) maintenance OCS dose decreased from median (interquartile range) of 10.0 mg/d (5-15 mg/d) to 2.5 mg/d (0-5 mg/d) after 1 year (P < .001)., Conclusions: This real-world study shows that anti-IL-5/5Ra therapy reduces exacerbation frequency and daily maintenance as well as the cumulative OCS dose in patients with severe eosinophilic asthma and comorbid bronchiectasis. Although it is an exclusion criterion in phase 3 trials, comorbid bronchiectasis should not preclude anti-IL-5/5Ra therapy in patients with severe eosinophilic asthma., (Copyright © 2023 American Academy of Allergy, Asthma & Immunology. Published by Elsevier Inc. All rights reserved.)

Background: Although a proven relationship exists between the blood eosinophil count (BEC) and the severity of both asthma and COPD, its relationship with bronchiectasis has not been well established. The objective of this study was to analyze the relationship between BEC and the number and severity of exacerbations, and patients' responses to inhaled corticosteroid (IC) treatment in bronchiectasis RESEARCH QUESTION: Does an association exist among BEC, the number of exacerbations and severity of bronchiectasis, and IC treatment?, Study Design and Methods: This was a multicenter (43 centers) prospective observational study derived from the Spanish Bronchiectasis Registry. Patients with proven bronchiectasis and a known BEC were included, whereas those with asthma or antieosinophilic treatments were excluded. Patients were divided into four groups according to the BEC at the time of inclusion in the study in a steady-state situation: (1) eosinopenic bronchiectasis (< 50 eosinophils/μL), (2) low number of eosinophils (51-100/μL), (3) normal number of eosinophils (101-300/μL), and (4) eosinophilic bronchiectasis (> 300 eosinophils/μL)., Results: Nine hundred twenty-eight patients finally were included: 123 patients (13.3%) with < 50 eosinophils/μL (eosinopenic group), 164 patients (17.7%) with 50-100 eosinophils/μL, 488 patients (52.6%) with 101-300 eosinophils/μL, and 153 patients (16.5%) with > 300 eosinophils/μL (eosinophilic group). BEC showed a significant U-shaped relationship with severity, exacerbations, lung function, microbiologic profile, and IC treatment (these being higher in the eosinopenic group compared with the eosinophilic group). IC treatment significantly decreased the number and severity of exacerbations only in the group of bronchiectasis patients with > 300 eosinophils/μL., Interpretation: A significant U-shaped relationship was found between BEC and severity and exacerbations in bronchiectasis that was more pronounced in the eosinopenic group. IC treatment decreased the number and severity of exacerbations only in the eosinophilic group., (Copyright © 2023 American College of Chest Physicians. Published by Elsevier Inc. All rights reserved.)

Introduction: Bronchiectasis is a long-term lung condition, with dilated bronchi, chronic inflammation, chronic infection and acute exacerbations. Recurrent exacerbations are associated with poorer clinical outcomes such as increased severity of lung disease, further exacerbations, hospitalisations, reduced quality of life and increased risk of death. Despite an increasing prevalence of bronchiectasis, there is a critical lack of high-quality studies into the disease and no treatments specifically approved for its treatment. This trial aims to establish whether inhaled dual bronchodilators (long acting beta agonist (LABA) and long acting muscarinic antagonist (LAMA)) taken as either a stand-alone therapy or in combination with inhaled corticosteroid (ICS) reduce the number of exacerbations of bronchiectasis requiring treatment with antibiotics during a 12 month treatment period., Methods: This is a multicentre, pragmatic, double-blind, randomised controlled trial, incorporating an internal pilot and embedded economic evaluation. 600 adult patients (≥18 years) with CT confirmed bronchiectasis will be recruited and randomised to either inhaled dual therapy (LABA+LAMA), triple therapy (LABA+LAMA+ICS) or matched placebo, in a 2:2:1 ratio (respectively). The primary outcome is the number of protocol defined exacerbations requiring treatment with antibiotics during the 12 month treatment period., Ethics and Dissemination: Favourable ethical opinion was received from the North East-Newcastle and North Tyneside 2 Research Ethics Committee (reference: 21/NE/0020). Results will be disseminated in peer-reviewed publications, at national and international conferences, in the NIHR Health Technology Assessments journal and to participants and the public (using lay language)., Trial Registration Number: ISRCTN15988757., Competing Interests: Competing interests: ADS has received speakers fees or advisory board fees from AstraZeneca, Bayer, GSK, Insmed, Novartis, Gilead and Zambon and has received grants from AstraZeneca, GSK, Novartis and the US COPD Foundation., (© Author(s) (or their employer(s)) 2023. Re-use permitted under CC BY. Published by BMJ.)

Introduction: Tobramycin inhalation solution (TIS) is a treatment option for patients with frequent exacerbations of bronchiectasis. A possible side effect of TIS is the development of chronic cough and bronchospasm, whereby the guidelines suggest a (in hospital) tolerance test with the first dose of TIS. However, data on respiratory adverse events are not consistent. In the present analysis from the BATTLE study (NCT02657473), we evaluated the added value of the tolerance test and aimed to observe the development of inhaled treatment related bronchial hyperreactivity., Methods: Fifty-seven patients from the BATTLE study were analyzed. Patients were randomized to receive TIS or placebo OD for 1 year. A tolerance test was performed with spirometry measurements before and after the first dose and with a bronchodilator in advance. Adverse events were strictly monitored., Results: Fifty-seven patients (100%) passed the tolerance test with no decrease in spirometry measurements or development of local intolerability. During the study treatment, a total of five TIS-treated patients (17.8%) withdrew due to airway hyperresponsiveness after a mean of 9.2 (SD13.9) weeks and one placebo-treated patient (3.5%) after 2 weeks (TIS vs. placebo; p = 0.66). The other TIS-related adverse events were not clinically significant., Conclusion: The use of inhaled medication is well tolerated in the heterogenous bronchiectasis population, without signs of airway hyperresponsiveness after the first dose of inhaled medication. From this observation, it can be concluded that there is no additional value for this advised tolerance test. However, closely monitoring on adverse effects during the first weeks after starting TIS is recommended., (© 2023 The Authors. The Clinical Respiratory Journal published by John Wiley & Sons Ltd.)

Background: Airway inflammation in chronic inflammatory lung diseases (e.g. bronchiectasis) is partly mediated by neutrophil-derived serine protease (NSP)/antiprotease imbalance. NSPs are activated during neutrophil myelopoiesis in bone marrow by cathepsin C (CatC; DPP1). CatC is therefore an attractive target to reduce NSP activity in the lungs of patients with bronchiectasis, restoring the protease/antiprotease balance. We report results from the preclinical pharmacological assessment of the novel CatC inhibitor BI 1291583., Methods: Binding kinetics of BI 1291583 to human CatC were determined by surface plasmon resonance. In vitro inhibition of human CatC activity was determined by CatC-specific fluorescent assay, and selectivity was assessed against related cathepsins and unrelated proteases. Inhibition of NSP neutrophil elastase (NE) production was assessed in a human neutrophil progenitor cell line. In vivo inhibition of NE and NSP proteinase 3 (PR3) in bronchoalveolar lavage fluid (BALF) neutrophils after lipopolysaccharide (LPS) challenge and distribution of BI 1291583 was determined in a mouse model., Results: BI 1291583 bound human CatC in a covalent, reversible manner, selectively and fully inhibiting CatC enzymatic activity. This inhibition translated to concentration-dependent inhibition of NE activation in U937 cells and dose-dependent, almost-complete inhibition of NE and PR3 activity in BALF neutrophils in an in vivo LPS-challenge model in mice. BI 1291583 exhibited up to 100 times the exposure in the target tissue bone marrow compared with plasma., Conclusion: BI 1291583-mediated inhibition of CatC is expected to restore the protease-antiprotease balance in the lungs of patients with chronic airway inflammatory diseases such as bronchiectasis., (© 2023. The Author(s).)

Objective: This retrospective study aimed at ascertaining the clinical usefulness of nebulized myo-inositol in the management of patients affected by bronchiectasis., Patients and Methods: 19 patients, aged between 63 and 73 years old, with bronchiectasis, were treated for 15 days with nebulized myo-inositol or placebo. Lung functionality [forced expiratory volume in the 1st second (FEV1)], solid content of expectorate, and surfactant tension were analyzed., Results: All patients treated with nebulized myo-inositol had a significant decrease in the percentage of solid content in the expectorate (T0 7.9±2.8% vs. T1 5.2±2.7%; p<0.001) and surfactant tension (T0 81.5±6.9 mN/m vs. T1 77.4±7.2 mN/m; p<0.001). Among treated patients, these variations correlated with FEV1 (rs=- 0.79; p<0.01) and forced expiratory flow at 25-75% of FVC (FEF25-75%) (rs=-0.81; p<0.01) scores. Also, variation of surfactant tension correlated with FEV1 (rs= -0.74; p<0.05) score., Conclusions: Nebulized myo-inositol increases lung functionality and mucus clearance in patients affected by bronchiectasis.

Background: Nontuberculous mycobacteria (NTM), predominately Mycobacterium avium complex (MAC), cause chronic pulmonary disease. Improvements in symptoms and health-related quality of life (HRQoL) are important treatment outcomes, but no validated patient-reported outcome (PRO) measure exists., Research Question: What are the validity and responsiveness of the Quality of Life-Bronchiectasis (QOL-B) questionnaire respiratory symptoms scale and key HRQoL measures during the first 6 months of MAC pulmonary disease (MAC-PD) treatment?, Study Design and Methods: Comparison of Two- vs Three-antibiotic Therapy for Pulmonary Mycobacterium Avium Complex Disease (MAC2v3) is an ongoing randomized, multisite pragmatic clinical trial. Patients with MAC-PD were randomized to azithromycin-based two-drug or three-drug therapy; treatment groups were combined for this analysis. PROs were measured at baseline, 3 months, and 6 months. The QOL-B respiratory symptoms, vitality, physical functioning, health perceptions, and NTM symptom domain scores (on a scale of 0-100, with 100 being best) were analyzed separately. We performed psychometric and descriptive analyses in the population enrolled as of the time of analysis and calculated the minimal important difference (MID) using distribution-based methods. Finally, we evaluated responsiveness using paired t tests and latent growth curve analysis in the subset with longitudinal surveys completed by the time of analysis., Results: The baseline population included 228 patients, of whom 144 had completed longitudinal surveys. Patients predominately were female (82%) and had bronchiectasis (88%); 50% were 70 years of age or older. The respiratory symptoms domain showed good psychometric properties (no floor or ceiling effects; Cronbach's α, 0.85) and an MID of 6.4 to 6.9. Vitality and health perceptions domain scores performed similarly. Respiratory symptoms domain scores improved by 7.8 points (P < .0001) and 7.5 points (P < .0001), and the physical functioning domain score improved by 4.6 points (P < .003) and 4.2 points (P = .01) at 3 and 6 months, respectively. Latent growth curve analysis confirmed a nonlinear, statistically significant improvement in respiratory symptoms and physical functioning domain scores by 3 months., Interpretation: The QOL-B respiratory symptoms and physical functioning scales exhibited good psychometric properties in patients with MAC-PD. Respiratory symptoms scores improved beyond the MID by 3 months after treatment initiation., Trial Registry: ClinicalTrials.gov; No.: NCT03672630; URL: www., Clinicaltrials: gov., (Copyright © 2023 American College of Chest Physicians. Published by Elsevier Inc. All rights reserved.)

Background: Bronchiectasis is a heterogeneous, neglected disease with few multicentre studies exploring the causes, severity, microbiology, and treatment of the disease across Europe. This aim of this study was to describe the clinical characteristics of bronchiectasis and compare between different European countries., Methods: EMBARC is an international clinical research network for bronchiectasis. We report on a multicentre, prospective, observational, non-interventional, cohort study (the EMBARC registry) conducted across 27 European countries and Israel. Comprehensive clinical data were collected from adult patients (aged ≥18 years) at baseline and annual follow-up visits using electronic case report form. Data from individual countries were grouped into four regions (the UK, northern and western Europe, southern Europe, and central and eastern Europe according to modified EU EuroVoc classification). Follow-up data were used to explore differences in exacerbation frequency between regions using a negative binomial regression model., Findings: Between Jan 12, 2015, and April 12, 2022, 16 963 individuals were enrolled. Median age was 67 years (IQR 57-74), 10 335 (60·9%) participants were female and 6628 (39·1%) were male. The most common cause of bronchiectasis in all 16 963 participants was post-infective disease in 3600 (21·2%); 6466 individuals (38·1%) were classified as idiopathic. Individuals with bronchiectasis experienced a median of two exacerbations (IQR 1-4) per year and 4483 (26·4%) patients had a hospitalisation for exacerbation in the previous year. When examining the percentage of all isolated bacteria, marked differences in microbiology were seen between countries, with a higher frequency of Pseudomonas aeruginosa and lower Haemophilus influenzae frequency in southern Europe, compared with higher H influenzae in the UK and northern and western Europe. Compared with other regions, patients in central and eastern Europe had more severe bronchiectasis measured by the Bronchiectasis Severity Index (51·3% vs 35·1% in the overall cohort) and more exacerbations leading to hospitalisations (57·9% vs 26·4% in the overall cohort). Overall, patients in central and eastern Europe had an increased frequency of exacerbations (adjusted rate ratio [RR] 1·12, 95% CI 1·01-1·25) and a higher frequency of exacerbations leading to hospitalisations (adjusted RR 1·71, 1·44-2·02) compared with patients in other regions. Treatment of bronchiectasis was highly heterogeneous between regions., Interpretation: Bronchiectasis shows important geographical variation in causes, microbiology, severity, and outcomes across Europe., Funding: European Union-European Federation of Pharmaceutical Industries and Associations Innovative Medicines Initiative., Translations: For the Arabic, French, German, Greek, Hebrew, Irish, Russian and Spanish translations of the abstract see Supplementary Materials section., Competing Interests: Declaration of interests JC reports grants or contracts from Grifols; consulting fees from Antabio, AstraZeneca, Boehringer Ingelheim, Chiesi, Glaxosmithkline, Grifols, Insmed, Janssen, Novartis, Pfizer, and Zambon; and leadership or fiduciary roles as Chair of European Respiratory Society (ERS) Bronchiectasis Guideline Task Force, Chief Editor of European Respiratory Journal, and Chair of EMBARC Clinical Research Collaboration. EP reports grants or contracts from Grifols; consulting fees from Bayer, Zambon, Pfizer, Chiesi, Shire, Shionogi, Insmed, Moderna, and Pfizer; payment for expert testimony from Chiesi; leadership or fiduciary roles as ERS Task Force for Bronchiectasis Guidelines, co-chair of EMBARC; and receipt of equipment, materials, drugs, medical writing, gifts, or other services from Zambon. FR reports grants or contracts from German Center for Lung Research (DZL), German Center for Infection Research (EU and European Federation of Pharmaceutical Industries and Associations [EFPIA]) and iABC Consortium (including Alaxia, Basilea, Novartis, and Polyphor), Mukoviszidose Institute, Novartis, Insmed Germany, Grifols, Bayer, and InfectoPharm, to the institution; consulting fees from Parion, Grifols, Zambon, Insmed, Helmholtz-Zentrum für Infektionsforschung; payment or honoraria for lectures, presentations, speakers bureaus, manuscript writing, or educational events from I!DE Werbeagentur, Interkongress, AstraZeneca, Insmed, Grifols, and Universitätsklinikum Frankfurt am Main; payment for expert testimony from Social Court Cologne, to the institution; support for attending meetings or travel from German Kartagener Syndrome and PCD PAG, and Mukoviszidose; participation on a Data Safety Monitoring Board or Advisory Board for Insmed, Grifols, and Shionogi; leadership or fiduciary role in other board, society, committee, or advocacy groups as Coordinator of the ERN-LUNG Bronchiectasis Core Network; Chair of the German Bronchiectasis Registry PROGNOSIS; Member of the SteerCo of the European Bronchiectasis Registry EMBARC; Member of the SteerCo of the European Non-tuberculous Mycobacterial registry EMBARC-NTM; Co-Speaker of the Medical Advisory Board of the German Kartagener Syndrome and PCD PAG; Speaker of the Respiratory Infections and tuberculosis group of the German Respiratory Society (DGP; Speaker of the Cystic Fibrosis group of DGP; Prinicipal Investigator for DZL; Member of the Protocol Review Committee of the PCD-CTN; Member of Physician Association of the German Cystic Fibrosis PAG; and fees for clinical trial participation paid to the institution from AstraZeneca, Boehringer Ingelheim, Celtaxsys, Corbus, Insmed, Novartis, Parion, University of Dundee, Vertex, and Zambon. ADS reports grants or contracts from Bayer, Gilead, Pfizer, Astrazeneca, and Novartis, outside of the submitted work; consulting fees from Boehringer, Bayer, Gilead, Pfizer, GSK, and Astrazeneca, outside of the submitted work; support for attending meetings or travel from AstraZeneca, Chiesi, and GSK; and participation on a Data Safety Monitoring Board or Advisory Board for Bayer. MV reports participation in EMBARC registry; grants or contracts from Chiesi; payment or honoraria for lectures, presentations, speakers bureaus, manuscript writing or educational events from Insmed and Publi creation; support for attending meetings or travel from Zambon, Chiesi, Novartis, Behring; participation on a Data Safety Monitoring Board or Advisory Board for Insmed; and receipt of equipment, materials, drugs, medical writing, gifts, or other services from Insmed and Novartis. PRB reports grants or contracts from GSK and Vertex, to the institution; consulting fees from Insmed, Vertex, Viatris, and Zambon; and participation on a Data Safety Monitoring Board or Advisory Board for Insmed. CH reports grants or contracts from the National Institute for Health and Care Research (NIHR 2020, NIHR133876 Seven versus Fourteen Days Antibiotics for Patients with Bronchiectasis Requiring Intravenous Antibiotics to the institution and NIHR [2020–2023] Bronchodilators and corticosteroids in bronchiectasis) to the institution; consulting fees from 30 Technology, CSL Behring, Chiesi, Insmed, Janssen, LifeArc, Meiji, Mylan, Novartis, Pneumagen, Shionogi, and Zambon; and payment or honoraria for lectures, presentations, speakers bureaus, manuscript writing, or educational events from Zambon, Insmed, Chiesi, and 30 Technology. ML reports consulting fees from Armata, 30T, AstraZeneca, Parion, Insmed, Chiesi, Zambon, Electromed, Recode, AN2, and Savara; payment or honoraria for lectures, presentations, speakers bureaus, manuscript writing, or educational events from Insmed; and the ERS Infection Group chair role. KD reports payment or honoraria for lectures, presentations, speakers bureaus, manuscript writing or educational events from Pfizer, Novartis, AstraZeneca, Boehringer Ingelheim, Chiesi, and Norma Hellas; and upport for attending meetings or travel from Novartis, AstraZeneca, Boehringer Ingelheim, Chiesi, Pfizer, Norma Hellas, and Menarini. MM reports payment or honoraria for lectures, presentations, speakers bureaus, manuscript writing or educational events from Pfizer; payment for expert testimony from Vertex; support for attending meetings or travel from Zambon; and participation on a Data Safety Monitoring Board or Advisory Board from Zambon, and Viatris. TW reports grants or contracts from German Ministry of Research and Education and consulting fees from AstraZeneca, GSK, and Insmed. FB reports grants or contracts from AstraZeneca, Chiesi, GSK, Insmed; consulting fees from GSK, Menarini, OM Pharma; and payment or honoraria for lectures, presentations, speakers bureaus, manuscript writing, or educational events from AstraZeneca, Chiesi, GSK, Grifols, Insmed, Menarini, Novartis, Ompharma, Pfizer, Sanofi, Vertex, Viatris, and Zambon. MS reports grants or contracts from GSK and Trudell pharma; consulting fees from AstraZeneca, Boehringer Ingelheim, Dexcel, Kamada, Synchrony Medical, Trumed, and Zambon; payment or honoraria for lectures, presentations, speakers bureaus, manuscript writing, or educational events from AstraZeneca, Boehringer Ingelheim, and Kamada; support for attending meetings or travel from Boehringer Ingelheim, AstraZeneca, and Kamada; participation on a Data Safety Monitoring Board or Advisory Board for Bonus Biotherapeutics, Boehringer Ingelheim, and AstraZeneca; leadership or fiduciary role in other board, society, committee, or advocacy group with Israeli Pulmonology Society, Israeli Society for Tuberculosis and Mycobacterial Diseases, and EMBARC as unpaid management board member and ERJ, Chest as unpaid Editorial board member; and receipt of equipment, materials, drugs, medical writing, gifts, or other services from Trudell Medical International. JSE reports grants or contracts from EU FP7 with Novartis and Polyphor; and consulting fees from Vertex. PG reports payment or honoraria for a lecture on bronchiectasis from GSK. SA reports grants or contracts from Insmed, Chiesi, Fisher & Paykel, to the institution; royalties or licenses with McGraw Hill; consulting fees from Insmed Incorporated, Insmed Italy, Insmed Ireland, Zambon, AstraZeneca UK, AstraZeneca Pharmaceutical, CSL Behring, Grifols, Fondazione Charta, Boehringer Ingelheim, Chiesi Farmaceutici Spa, Zcube, MENARINI, MSD Italia, Physioassist SAS, and GlaxoSmithKline Spa; payment or honoraria for lectures, presentations, speakers bureaus, manuscript writing or educational events from GlaxoSmithKline Spa, Thermofisher Scientific, Insmed Italy, Insmed Ireland, Zambon, and Fondazione Internazionale Menarini; and participation on a Data Safety Monitoring Board or Advisory Board for Insmed Incorporated, Insmed Italy, AstraZeneca UK, and MSD Italia. All other authors declare no competing interests., (Copyright © 2023 The Author(s). Published by Elsevier Ltd. This is an Open Access article under the CC BY 4.0 license. Published by Elsevier Ltd.. All rights reserved.)