Inhaled medication therapy for bronchiectasis: status quo and the next frontier

The Efficacy and Safety of Inhaled Antibiotics for the Treatment of Bronchiectasis in Adults: Updated Systematic Review and Meta-Analysis

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 FEV1. 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 FEV1 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/.

Advances in pharmacotherapy for bronchiectasis in adults

INTRODUCTION

Bronchiectasis has become a growing concern of chronic airway disease because of the enormous socioeconomic burden. Four cardinal interdependent components - impaired airway defense, recurrent airway infections, inflammatory response, and airway damage, in conjunction with the underlying etiology, have collectively played a role in modulating the vicious vortex of the pathogenesis and progression of bronchiectasis. Current pharmacotherapy aims to target at these aspects to break the vicious vortex.

AREAS COVERED

The authors retrieve and review, in MEDLINE, Web of Science and ClinicalTrials.gov registry, the studies about pharmacotherapy for bronchiectasis from these aspects: antibiotics, mucoactive medications, bronchodilators, anti-inflammatory drug, and etiological treatment.

EXPERT OPINION

Future drug development and clinical trials of bronchiectasis need to pay more attention to the different phenotypes or endotypes of bronchiectasis. There is a need for the development of novel inhaled antibiotics that could reduce bacterial loads, improve quality-of-life, and decrease exacerbation risks. More efforts are needed to explore the next-generation neutrophil-targeted therapeutic drugs that are expected to ameliorate respiratory symptom burden, reduce exacerbation risks, and hinder airway destruction in bronchiectasis.

A Double-Blind Randomized Placebo-Controlled Phase 3 Trial of Tobramycin Inhalation Solution in Adults With Bronchiectasis With Pseudomonas aeruginosa Infection

BACKGROUND

Few large-scale studies have demonstrated the efficacy of tobramycin nebulization in bronchiectasis. We evaluated the efficacy and safety of nebulized tobramycin inhalation solution (TIS) in adults with bronchiectasis with Pseudomonas aeruginosa infection.

RESEARCH QUESTION

Can TIS effectively reduce sputum P aeruginosa density and improve the bronchiectasis-specific quality of life in patients with bronchiectasis with P aeruginosa infection?

STUDY DESIGN AND METHODS

This was a phase 3, 16-week, multicenter, randomized, double-blind, placebo-controlled trial. Eligible adults with bronchiectasis were recruited from October 2018 to July 2021. On the basis of usual care, patients nebulized TIS (300 mg/5 mL twice daily) or normal saline (5 mL twice daily) via vibrating-mesh nebulizer. Treatment consisted of two cycles, each consisting of 28 days on-treatment and 28 days off-treatment. The coprimary end points included changes from baseline in P aeruginosa density and Quality-of-Life Bronchiectasis Respiratory Symptoms score on day 29.

RESULTS

The modified intention-to-treat population consisted of 167 patients in the tobramycin group and 172 patients in the placebo group. Compared with placebo, TIS resulted in a significantly greater reduction in P aeruginosa density (adjusted mean difference, 1.74 log₁₀ colony-forming units/g; 95% CI, 1.12-2.35; P < .001) and greater improvement in Quality-of-Life Bronchiectasis Respiratory Symptoms score (adjusted mean difference, 7.91; 95% CI, 5.72-10.11; P < .001) on day 29. Similar findings were observed on day 85. TIS resulted in a significant reduction in 24-h sputum volume and sputum purulence score on days 29, 57, and 85. More patients became culture negative for P aeruginosa in the tobramycin group than in the placebo group on day 29 (29.3% vs 10.6%). The incidence of adverse events and serious adverse events were comparable between the two groups.

INTERPRETATION

TIS is an effective treatment option and has an acceptable safety profile in patients with bronchiectasis with P aeruginosa infection.

TRIAL REGISTRATION

ClinicalTrials.gov; No. NCT03715322; URL: www.

CLINICALTRIALS

gov.

Assessing effects of inhaled antibiotics in adults with non-cystic fibrosis bronchiectasis--experiences from recent clinical trials

INTRODUCTION

Non-cystic fibrosis bronchiectasis (NCFB) results from a permanent and progressive destruction of the airways leading to poor lung function. NCFB is characterized by recurrent lung infection, sputum production, and cough, often requiring long-term antibiotic therapy and hospitalization. At present, there are no approved therapies available. Clinical trials of inhaled antibiotics have shown promise against sputum bacterial load, but mixed results on clinical outcomes. Areas covered: The objective of this review is to provide an overview of NCFB and critically evaluate the evidence supporting the outcome measures used in recent clinical trials of inhaled antibiotics. These include quantitative changes in bacterial load, sputum purulence and yield, inflammatory markers, and lung function, as well as clinical changes in exacerbations, exacerbation frequency, hospitalizations, and health-related quality of life. Expert commentary: Recently completed large trials of inhaled antibiotics in NCFB did not consistently meet pre-specified end points, suggesting that we have not yet found the best enrollment criteria or outcome measures to evaluate efficacy, although reduced exacerbation frequency may be clinically most meaningful. Future trials may focus on specific patient populations at high risk with new information obtained through analyses of large international patient registries.

ABBREVIATIONS

6-MWT: Six-Minute Walk Test; AIR-BX: Aztreonam for Inhalation Solution in Patients with Non-Cystic Fibrosis Bronchiectasis trial; BSI: Bronchiectasis Severity Index; CAT: COPD Assessment Test; CF: Cystic Fibrosis; CFTR: Cystic Fibrosis Transmembrane Conductance Regulator; CFU: Colony-Forming Units; COPD: Chronic Obstructive Pulmonary Disease; CRP: C-Reactive Protein; DPI: Dry Powder for Inhalation; EMA: European Medicines Agency; ERS: European Respiratory Society; FACED: FEV1, Age, Chronic colonization by P. aeruginosa, Extension of bronchiectasis and Dyspnea; FDA: US Food and Drug Administration; FEV₁: Forced Expiration in 1 s; FVC: Forced Vital Capacity; HFCC: High-Frequency Chest Compression; HRCT: High-Resolution Computed Tomography; HRQoL: Health-Related Quality of Life; LCQ: Leicester Cough Questionnaire; MID: Minimal Important Difference; NCFB: Non-Cystic Fibrosis Bronchiectasis; NTM: Nontuberculous Mycobacteria; ORBIT: Once-daily Respiratory Bronchiectasis Inhalation Treatment trial; PRO: Patient-Reported Outcomes; QoL-B: Quality of Life-Bronchiectasis; SGRQ: St. George's Respiratory Questionnaire; SWT: Shuttle Walk Test; TORCH: Towards a Revolution in COPD Health trial; UPLIFT: Understanding Potential Long-term Impacts on Function with Tiotropium trial.