Inhaled tobramycin for chronic infection with pseudomonas aeruginosa in non-cystic fibrosis bronchiectasis: A systematic review and meta-analysis

Inhaled tobramycin in non-cystic fibrosis bronchiectasis: A meta-analysis of randomized controlled trials

BACKGROUND

Non-cystic fibrosis bronchiectasis (NCFB) is often complicated by chronic Pseudomonas aeruginosa infection. Inhaled antibiotics, such as tobramycin, have been explored for their efficacy in managing these infections, but their efficacy and safety in NCFB remains uncertain.

METHODS

We conducted a systematic review and meta-analysis of randomized controlled trials (RCTs) to assess the efficacy and safety of inhaled tobramycin in NCFB patients. PubMed, EMBASE, Cochrane Library, and ISI Web of Science databases were searched up to June 2024 using predefined keywords. Studies comparing inhaled tobramycin versus placebo were included if they reported outcomes related to P. aeruginosa eradication, sputum density, exacerbations, hospital admissions, and adverse events.

RESULTS

Nine RCTs involving 772 patients met the inclusion criteria. Inhaled tobramycin significantly increased P. aeruginosa eradication rates compared to placebo (I2 = 22.0 %, P = 0.255; RR 2.422, 95 % CI 1.570 to 3.738, P < 0.001). There was a marked reduction in hospital admissions (I2 = 27.9 %, P = 0.250; WMD -0.523, 95 % CI -0.879 to -0.167, P = 0.004) but no significant difference in exacerbation rates (I2 = 31.9 %, P = 0.196; RR 0.837, 95 % CI 0.519 to 1.349, P = 0.464). Adverse events leading to trial discontinuation were higher in the tobramycin group (I2 = 0.0 %, P = 0.634; RR 1.968, 95 % CI 1.197 to 3.236, P = 0.008).

CONCLUSIONS

Inhaled tobramycin therapy demonstrated efficacy in eradicating P. aeruginosa and reducing hospital admissions in patients with NCFB. However, no significant impact on exacerbation rates was observed, and the higher incidence of adverse events necessitates careful consideration in clinical practice.

Recurrent Diffuse Panbronchiolitis After Lung Transplantation: Off-Label Use of Inhaled Tobramycin for Pseudomonas aeruginosa Control in a Transplant Recipient

Diffuse panbronchiolitis (DPB) is a chronic inflammatory disease predominantly affecting East Asians. It is characterized by persistent Pseudomonas aeruginosa colonization and progressive respiratory failure. Lung transplantation (LTx) serves as a definitive treatment option for advanced cases, but post-transplant recurrence poses significant challenges. This report describes a Japanese woman who experienced DPB recurrence after bilateral LTx. Persistent P. aeruginosa colonization and recurrent respiratory symptoms were managed with off-label tobramycin solution for inhalation (TSI), which is commonly used in cystic fibrosis. TSI treatment led to significant clinical and radiological improvements, clearance of P. aeruginosa from sputum cultures, and no further hospitalizations during six months of therapy. This case suggests the potential of TSI as a therapeutic approach for managing recurrent DPB and indicates its role in stabilizing post-transplant outcomes. Further studies may clarify its efficacy and expand its application in broader DPB management strategies.

Pulmonary Delivery of Antibiotics to the Lungs: Current State and Future Prospects

This paper presents a comprehensive review of the current literature, clinical trials, and products approved for the delivery of antibiotics to the lungs. While there are many literature reports describing potential delivery systems, few of these have translated into marketed products. Key challenges remaining are the high doses required and, for powder formulations, the ability of the inhaler and powder combination to deliver the dose to the correct portion of the respiratory tract for maximum effect. Side effects, safety concerns, and disappointing clinical trial results remain barriers to regulatory approval. In this review, we describe some possible approaches to address these issues and highlight prospects in this area.

[Management of adult bronchiectasis - Consensus-based Guidelines for the German Respiratory Society (DGP) e. V. (AWMF registration number 020-030)]

Bronchiectasis is an etiologically heterogeneous, chronic, and often progressive respiratory disease characterized by irreversible bronchial dilation. It is frequently associated with significant symptom burden, multiple complications, and reduced quality of life. For several years, there has been a marked global increase in the prevalence of bronchiectasis, which is linked to a substantial economic burden on healthcare systems. This consensus-based guideline is the first German-language guideline addressing the management of bronchiectasis in adults. The guideline emphasizes the importance of thoracic imaging using CT for diagnosis and differentiation of bronchiectasis and highlights the significance of etiology in determining treatment approaches. Both non-drug and drug treatments are comprehensively covered. Non-pharmacological measures include smoking cessation, physiotherapy, physical training, rehabilitation, non-invasive ventilation, thoracic surgery, and lung transplantation. Pharmacological treatments focus on the long-term use of mucolytics, bronchodilators, anti-inflammatory medications, and antibiotics. Additionally, the guideline covers the challenges and strategies for managing upper airway involvement, comorbidities, and exacerbations, as well as socio-medical aspects and disability rights. The importance of patient education and self-management is also emphasized. Finally, the guideline addresses special life stages such as transition, family planning, pregnancy and parenthood, and palliative care. The aim is to ensure comprehensive, consensus-based, and patient-centered care, taking into account individual risks and needs.

Inhalable tobramycin EEG powder formulation for treating Pseudomonas aeruginosa-induced lung infection

Pulmonary delivery of antibiotics is an effective strategy in treating bacterial lung infection for cystic fibrosis patients, by achieving high local drug concentrations and reducing overall systemic exposure compared to systemic administration. However, the inherent anatomical lung defense mechanisms, formulation characteristics, and drug-device combination determine the treatment efficacy of the aerosol delivery approach. In this study, we prepared a new tobramycin (Tobi) dry powder aerosol using excipient enhanced growth (EEG) technology and evaluated the in vitro and in vivo aerosol performance. We further established a Pseudomonas aeruginosa-induced lung infection rat model using an in-house designed novel liquid aerosolizer device. Notably, novel liquid aerosolizer yields comparable lung infection profiles despite administering 3-times lower P. aeruginosa CFU per rat in comparison to the conventional intratracheal administration. Dry powder insufflator (e.g. Penn-Century DP-4) to administer small powder masses to experimental animals is no longer commercially available. To address this gap, we developed a novel rat air-jet dry powder insufflator (Rat AJ DPI) that can emit 68-70 % of the loaded mass for 2 mg and 5 mg of Tobi-EEG powder formulations, achieving a high rat lung deposition efficiency of 79 % and 86 %, respectively. Rat AJ DPI can achieve homogenous distribution of Tobi EEG powder formulations at both loaded mass (2 mg and 5 mg) over all five lung lobes in rats. We then demonstrated that Tobi EEG formulation delivered by Rat AJ DPI can significantly decrease CFU counts in both trachea and lung lobes at 2 mg (p < 0.05) and 5 mg (p < 0.001) loaded mass compared to the untreated P. aeruginosa-infected group. Tobi EEG powder formulation delivered by the novel Rat AJ DPI showed excellent efficiencies in substantially reducing the P. aeruginosa-induced lung infection in rats.

Intravenous Tobramycin Inhalation for Patients With Advanced Bronchiectasis With Pseudomonas aeruginosa Infection in Home Medical Care: A Report of Two Cases

Home medical care faces limitations in the number of doctor and nurse visits, availability of medical devices, and economic factors, making daily injections difficult for in-home patients. We describe two cases of advanced bronchiectasis with Pseudomonas aeruginosa infection treated with inhaled tobramycin in a home setting, demonstrating clinical effectiveness. Using commercially available empty eye drop containers to prepare an aseptic inhalation solution and nebulizers easily usable at home, our experience suggests that this could be a viable therapeutic alternative in home medical care.

Phage Therapy for Respiratory Infections: Opportunities and Challenges

We are entering the post-antibiotic era. Antimicrobial resistance (AMR) is a critical problem in chronic lung infections resulting in progressive respiratory failure and increased mortality. In the absence of emerging novel antibiotics to counter AMR infections, bacteriophages (phages), viruses that infect bacteria, have become a promising option for chronic respiratory infections. However, while personalized phage therapy is associated with improved outcomes in individual cases, clinical trials demonstrating treatment efficacy are lacking, limiting the therapeutic potential of this approach for respiratory infections. In this review, we address the current state of phage therapy for managing chronic respiratory diseases. We then discuss how phage therapy may address major microbiologic obstacles which hinder disease resolution of chronic lung infections with current antibiotic-based treatment practices. Finally, we highlight the challenges that must be addressed for successful phage therapy clinical trials. Through this discussion, we hope to expand on the potential of phages as an adjuvant therapy in chronic lung infections, as well as the microbiologic challenges that need to be addressed for phage therapy to expand beyond personalized salvage therapy.

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.

Antimicrobial Resistance in Common Respiratory Pathogens of Chronic Bronchiectasis Patients: A Literature Review

Non-cystic fibrosis bronchiectasis is a chronic disorder in which immune system dysregulation and impaired airway clearance cause mucus accumulation and consequent increased susceptibility to lung infections. The presence of pathogens in the lower respiratory tract causes a vicious circle resulting in impaired mucociliary function, bronchial inflammation, and progressive lung injury. In current guidelines, antibiotic therapy has a key role in bronchiectasis management to treat acute exacerbations and chronic infection and to eradicate bacterial colonization. Contrastingly, antimicrobial resistance, with the risk of multidrug-resistant pathogen development, causes nowadays great concern. The aim of this literature review was to assess the role of antibiotic therapy in bronchiectasis patient management and possible concerns regarding antimicrobial resistance based on current evidence. The authors of this review stress the need to expand research regarding bronchiectasis with the aim to assess measures to reduce the rate of antimicrobial resistance worldwide.