Safety and Dose Study of Targeted Lung Denervation in Moderate/Severe COPD Patients

Challenges in clinical practice, biological mechanism and prospects of physical ablation therapy for COPD

Chronic obstructive pulmonary disease (COPD) is projected to become the third leading cause of death globally by 2030. Despite the limited treatment options available for advanced COPD, which are mostly restricted to costly lung transplants, physical ablation therapy offers promising alternatives. This technique focuses on ablating lesioned airway epithelium, reducing secretions and obstructions, and promoting normal epithelial regeneration, demonstrating significant therapeutic potential. Physical ablation therapy primarily involves thermal steam ablation, cryoablation, targeted lung denervation, and high-voltage pulsed electric field ablation. These methods help transform the hypersecretory phenotype, alleviate airway inflammation, and decrease the volume of emphysematous lung segments by targeting goblet cells and damaged lung areas. Compared to traditional treatments, endoscopic physical ablation offers fewer injuries, quicker recovery, and enhanced safety. However, its application in COPD remains limited due to inconsistent clinical outcomes, a lack of well-understood mechanisms, and the absence of standardized guidelines. This review begins by exploring the development of these ablation techniques and their current clinical uses in COPD treatment. It then delves into the therapeutic effects reported in recent clinical studies and discusses the underlying mechanisms. Finally, the review assesses the future prospects and challenges of employing ablation technology in COPD clinical practice, aiming to provide a practical reference and a theoretical basis for its use and inspire further research.

Bronchoscopic interventions for chronic bronchitis

PURPOSE OF REVIEW

Chronic bronchitis is a phenotype of chronic obstructive pulmonary disease (COPD), characterized by chronic cough and sputum production, associated with an increased rate of COPD exacerbations and hospital admissions, a more rapid decline in lung function and reduced life expectancy. Despite optimal medical therapy, chronic bronchitis remains difficult to treat. Interventional bronchoscopic procedures offer novel therapeutic approaches to this highly symptomatic condition.

RECENT FINDINGS

A characteristic feature of chronic bronchitis is the presence of an abnormal epithelium with excessive mucus producing cells, parasympathetic overactivity, and airway inflammation. Metered cryospray and bronchial rheoplasty are designed to target this abnormal epithelium to reduce mucus production and inflammation. Targeted lung denervation aims to reduce parasympathetic overactivity, which may drive mucus hypersecretion. Here, we review the available evidence to determine the safety and efficacy across the bronchoscopic interventions.

SUMMARY

Interventional bronchoscopy is a rapidly expanding field and its application in the treatment of chronic bronchitis has been recognized by the Global initiative for chronic Obstructive Lung Disease (GOLD). The outcomes from the latest clinical trials will guide future treatment approaches in patients with difficult to treat chronic bronchitis.

[Bronchoscopic COPD treatments]

INTRODUCTION

Chronic obstructive pulmonary disease (COPD) is associated with disabling respiratory symptoms including dyspnea, frequent exacerbations and chronic bronchitis. The currently available pharmacological and non-pharmacological therapies have limited efficacy, necessitating the development of interventional strategies, many of them endoscopic.

STATE OF THE ART

Endoscopic lung volume reduction has markedly increased over recent years, principally as regards the endobronchial valves currently used in routine care. Indeed, multiple randomized trials have demonstrated a significant clinical benefit in a selected population identifiable due to the absence of interlobar collateral ventilation. Other endoscopic volume reduction techniques (polymers, thermal vapor, spirals) shall require additional studies before being considered as options in routine care. Targeted lung denervation (TLD) has aroused interest as a means of reducing exacerbations in the early phases of relevant studies. Endobronchial techniques (bronchoscopic cryospray, bronchial rheoplasty) are still at a very early stage of development, which is aimed at reducing the symptoms of chronic bronchitis.

OUTLOOK

Aside from endobronchial valves, which are currently employed in routine care, all the above-mentioned endoscopic techniques require additional studies in order to determine their benefit/risk balance and to identify the population that would benefit the most.

CONCLUSIONS

Endoscopic treatments constitute a major avenue of research and innovation in the therapeutic management of COPD. Inclusion of patients in disease registries and clinical trials remains essential, the objective being to gauge the interest of these treatments and their future role in everyday COPD management.

Bronchoscopic Management of COPD and Advances in Therapy

Chronic Obstructive Pulmonary Disease (COPD) is a highly prevalent and morbid disease marked by irreversible structural changes in the lungs. Bronchoscopic therapies have significantly expanded the treatment armamentarium for patients with persistent symptoms by reducing the physiologic detriments of hyperinflation in a less invasive fashion than surgical lung volume reduction. The spectrum of bronchoscopic techniques to reduce hyperinflation includes endobronchial valves, coils, thermal ablation, and biologic sealants. Other therapies focus on reducing parasympathetic tone and mucus hypersecretion and include targeted lung denervation, bronchial rheoplasty, and cryospray techniques. In this article, we will review the variety of techniques for bronchoscopic lung volume reduction, both established and investigational, along with their respective benefits and complications and will briefly review other investigational therapies for COPD.

Modern Bronchoscopic Treatment Options for Patients with Chronic Bronchitis

Chronic Obstructive Pulmonary Disease (COPD) is one of the leading causes of death worldwide and has a large impact on a patient's quality of life due to its wide range of symptoms and comorbidities. There are known to be different phenotypes in COPD with various extents on the burden of the disease and its prognosis. Chronic bronchitis with persistent cough and mucus production is regarded as one of the main symptoms of COPD with tremendous effects on subjectively reported symptom burden and frequency of exacerbations. Exacerbations in turn are known to have an impact on disease progression and increase health care costs. Modern bronchoscopic treatment options are currently under investigation targeting the problem of chronic bronchitis and frequent exacerbations. This review summarizes the existing literature about these modern interventional treatment options and provides perspectives on upcoming studies.

Which Endoscopic Procedure to Use and in What Patient? Valves, Coils, Foam, and Heat in COPD and Asthma

Despite the latest developments in therapeutic agents targeting airway endotypes, a significant proportion of patients with asthma and chronic obstructive pulmonary disease (COPD) remain symptomatic. Endoscopic therapies have a complementary role in the management of these airway diseases. The sustained efficacy of bronchial thermoplasty (BT) among patients with asthma over 10 years has been encouraging, as it has been shown to improve symptom control and reduce hospital admissions and exacerbations. Studies suggest that BT helps ameliorate airway inflammation and reduce airway smooth muscle thickness. While studies suggest that it is as effective as biologic agents, its role in the management of severe asthma has yet to be clearly defined and GINA 2022 still suggests limiting its use to patients with characteristics of the various populations studied. Conversely, bronchoscopic lung volume reduction has shown promise among patients with advanced COPD. Rigorous patient selection is important. Patients with minimal collateral ventilation (CV) and higher heterogeneity index have shown to benefit the most from endobronchial valve (EBV) therapy. For those with ongoing CV, endobronchial coils would be more appropriate. Both therapeutic modalities have demonstrated improved quality of life, effort tolerance, and lung function indices among appropriately selected patients. The emerging evidence suggests that endoscopic procedures among airway disease still have a substantial role to play despite the development of new therapeutic options.

Advances in Surgical and Mechanical Management of Chronic Obstructive Pulmonary Disease

Chronic obstructive pulmonary disease (COPD) is the third leading cause of mortality in the United States, behind cardiovascular and malignant disorders. As the understanding of the pathogenesis has evolved, it led to targeting mechanical aspects of the disease to improve patient symptoms and quality of life. Modern management of COPD offers a variety of mechanical and surgical treatments for patients with advanced disease who do not achieve benefit from medical therapy alone. These treatments include therapies aimed at lung volume reduction, through surgical or bronchoscopic techniques. While these techniques are established and have proven benefit, others are still under development. Herein we discuss these techniques, aimed at improving clinician recognition of patients that may benefit from these interventions.

Endoscopic Options for Moderate COPD, Chronic Bronchitis, and Uncontrolled Asthma

Until now, interventional therapies for patients with chronic obstructive pulmonary disease have been available in the form of lung volume reduction procedures as end-stage options. Currently, the range of indications is expanding to include earlier stages of the diseases. Lung denervation is available for moderate COPD, and patients with chronic bronchitis are being evaluated for endoscopic goblet cell ablation. Rheoplasty, metered spray cryo technique, and Karakoca resector balloon are used for this indication. But also, for patients with severe uncontrolled asthma, several techniques are available today. In addition to thermoplasty as a long-proven procedure, new and currently under investigation is the targeted lung denervation.Most of these techniques are currently being tested in large pivotal trials and it will soon become clear in which phenotype which technique will be used in the different forms and stages of obstructive diseases. The current paper presents the techniques and the currently available literature.

A clinical and canine experimental study in small-airway response to bronchial thermoplasty: Role of the neuronal effect

BACKGROUND

The effects of bronchial thermoplasty (BT) on smooth muscle (SM) and nerves in small airways are unclear.

METHODS

We recruited 15 patients with severe refractory asthma, who received BT treatment. Endobronchial optical-coherence tomography (EB-OCT) was performed at baseline, 3 weeks' follow-up and 2 years' follow-up to evaluate the effect of BT on airway structure. In addition, we divided 12 healthy beagles into a sham group and a BT group, the latter receiving BT on large airways (inner diameter >3 mm) of the lower lobe. The dogs' lung lobes were resected to evaluate histological and neuronal changes of the treated large airways and untreated small airways 12 weeks after BT.

RESULTS

Patients receiving BT treatment had significant improvement in Asthma Control Questionnaire (ACQ) scores and significant reduction in asthma exacerbations. EB-OCT results demonstrated a notable increase in inner-airway area (Ai) and decrease in airway wall area percentage (Aw%) in both large (3rd-to 6th-generation) and small (7th-to 9th-generation) airways. Furthermore, the animal study showed a significant reduction in the amount of SM in BT-treated large airways but not in untreated small airways. Protein gene product 9.5 (PGP9.5)-positive nerves and muscarinic receptor 3 (M3 receptor) expression in large and small airways were both markedly decreased throughout the airway wall 12 weeks after BT treatment.

CONCLUSIONS

BT significantly reduced nerves, but not SM, in small airways, which might shed light on the mechanism of lung denervation by BT.

Bronchoscopic Targeted Lung Denervation in Patients with Severe Asthma: Preliminary Findings

Treatment options for severe asthma are limited, particularly in those patients who do not meet criteria for biologicals. Targeted lung denervation (TLD) is the bronchoscopic ablation of the peribronchial vagal nerve trunks to reduce cholinergic stimulation of airway smooth muscle and submucosal glands. This report describes the experience of the first 2 asthma patients treated with TLD worldwide. The participants were 54 and 51 years of age, and both had severe asthma (GINA 5) (FEV1: 53% and 113% of predicted; AQLQ scores: 5.3 and 4.4). Both participants were treated with TLD in a single day-case procedure under general anaesthesia. Lung function, health status, and adverse event data were collected at baseline and 12 months after TLD. No treatment-related serious adverse events were reported up to 12 months. Cough symptoms improved in both participants, and 1 participant reported a marked reduction in rescue medication use at 6 months. There were no significant changes in spirometry, lung volumes, or health status. In conclusion, TLD was performed safely in both participants, but more evidence is needed to clarify safety and efficacy of TLD in severe asthma. Therefore, further investigation of the treatment in severe asthma patients would be useful.

Interventional Pulmonology: Diagnostic and Therapeutic Advances in Bronchoscopy

BACKGROUND

Interventional pulmonology is a rapidly evolving subspecialty of pulmonary medicine that offers advanced consultative and procedural services to patients with airway diseases, pleural diseases, as well as in the diagnosis and management of patients with thoracic malignancy.

AREAS OF UNCERTAINTY

The institution of lung cancer screening modalities as well as the search of additional minimally invasive diagnostic and treatment modalities for lung cancer and other chronic lung diseases has led to an increased focus on the field of interventional pulmonology. Rapid advancements in the field over the last 2 decades has led to development of various new minimally invasive bronchoscopic approaches and techniques for patients with cancer as well as for patients with chronic lung diseases.

DATA SOURCES

A review of literature was performed using PubMed database to identify all articles published up till October 2020 relevant to the field of interventional pulmonology and bronchoscopy. The reference list of each article was searched to look for additional articles, and all relevant articles were included in the article.

THERAPEUTIC ADVANCES

Newer technologies are now available such navigation platforms to diagnose and possibly treat peripheral pulmonary nodules, endobronchial ultrasound in diagnosis of mediastinal and hilar adenopathy as well as cryobiopsy in the diagnosis of diffuse lung diseases. In addition, flexible and rigid bronchoscopy continues to provide new and expanding ability to manage patients with benign and malignant central airway obstruction. Interventions are also available for diseases such as asthma, chronic bronchitis, chronic obstructive pulmonary disease, and emphysema that were traditionally treated with medical management alone.

CONCLUSIONS

With continued high quality research and an increasing body of evidence, interventional bronchoscopy has enormous potential to provide both safe and effective options for patients with a variety of lung diseases.

New bronchoscopic treatment modalities for patients with chronic bronchitis

Chronic bronchitis is a chronic, progressive disease that is difficult to treat. Despite much effort, patients remain highly symptomatic. Currently, a number of innovative bronchoscopic treatments for this disease are under investigation. Liquid nitrogen metered cryospray, bronchial rheoplasty and balloon desobstruction all aim to destroy the hyperplastic goblet cells and excess submucous glands using different strategies. These therapies are in an early phase of clinical research and larger randomised controlled trials are needed to confirm the pilot data available and to evaluate the treatment durability. The fourth technique, targeted lung denervation (TLD), aims to decrease the release of acetylcholine, which regulates smooth muscle tone and mucus production by ablating the parasympathetic nerves running alongside the main bronchi. Evaluation of this treatment is at a more advanced stage and promising effects on exacerbation frequency have been shown. However, confirmation of the benefit in improvement in chronic bronchitis symptoms is still needed.

We provide an overview of four innovative bronchoscopic treatments for chronic bronchitis. These treatments show promising results, but future work should focus specifically on chronic bronchitis symptoms and the sustainability of the treatment effect.https://bit.ly/34DNBce

Bronchoscopic management of asthma, COPD and emphysema

In recent years, many bronchoscopic techniques have been developed in chronic obstructive airway inflammatory diseases, including asthma, COPD and emphysema. The main techniques with available data from randomised controlled trials are: 1) bronchial thermoplasty in asthma; 2) valves, coils and thermal vapor ablation in emphysema; and 3) targeted lung denervation in COPD. The objectives of this article are to describe the levels of evidence for efficacy and safety, long-term follow-up results beyond 1 year, and current recommendations for clinical practice from international guidelines for each technique.

Chronic obstructive pulmonary disease - diagnosis and management of stable disease; a personalized approach to care, using the treatable traits concept based on clinical phenotypes. Position paper of the Czech Pneumological and Phthisiological Society

This position paper has been drafted by experts from the Czech national board of diseases with bronchial obstruction, of the Czech Pneumological and Phthisiological Society. The statements and recommendations are based on both the results of randomized controlled trials and data from cross-sectional and prospective real-life studies to ensure they are as close as possible to the context of daily clinical practice and the current health care system of the Czech Republic. Chronic Obstructive Pulmonary Disease (COPD) is a preventable and treatable heterogeneous syndrome with a number of pulmonary and extrapulmonary clinical features and concomitant chronic diseases. The disease is associated with significant mortality, morbidity and reduced quality of life. The main characteristics include persistent respiratory symptoms and only partially reversible airflow obstruction developing due to an abnormal inflammatory response of the lungs to noxious particles and gases. Oxidative stress, protease-antiprotease imbalance and increased numbers of pro-inflammatory cells (mainly neutrophils) are the main drivers of primarily non-infectious inflammation in COPD. Besides smoking, household air pollution, occupational exposure, low birth weight, frequent respiratory infections during childhood and also genetic factors are important risk factors of COPD development. Progressive airflow limitation and airway remodelling leads to air trapping, static and dynamic hyperinflation, gas exchange abnormalities and decreased exercise capacity. Various features of the disease are expressed unequally in individual patients, resulting in various types of disease presentation, emerging as the "clinical phenotypes" (for specific clinical characteristics) and "treatable traits" (for treatable characteristics) concept. The estimated prevalence of COPD in Czechia is around 6.7% with 3,200-3,500 deaths reported annually. The elementary requirements for diagnosis of COPD are spirometric confirmation of post-bronchodilator airflow obstruction (post-BD FEV₁/VCmax <70%) and respiratory symptoms assessement (dyspnoea, exercise limitation, cough and/or sputum production. In order to establish definite COPD diagnosis, a five-step evaluation should be performed, including: 1/ inhalation risk assessment, 2/ symptoms evaluation, 3/ lung function tests, 4/ laboratory tests and 5/ imaging. At the same time, all alternative diagnoses should be excluded. For disease classification, this position paper uses both GOLD stages (1 to 4), GOLD groups (A to D) and evaluation of clinical phenotype(s). Prognosis assessment should be done in each patient. For this purpose, we recommend the use of the BODE or the CADOT index. Six elementary clinical phenotypes are recognized, including chronic bronchitis, frequent exacerbator, emphysematous, asthma/COPD overlap (ACO), bronchiectases with COPD overlap (BCO) and pulmonary cachexia. In our concept, all of these clinical phenotypes are also considered independent treatable traits. For each treatable trait, specific pharmacological and non-pharmacological therapies are defined in this document. The coincidence of two or more clinical phenotypes (i.e., treatable traits) may occur in a single individual, giving the opportunity of fully individualized, phenotype-specific treatment. Treatment of COPD should reflect the complexity and heterogeneity of the disease and be tailored to individual patients. Major goals of COPD treatment are symptom reduction and decreased exacerbation risk. Treatment strategy is divided into five strata: risk elimination, basic treatment, phenotype-specific treatment, treatment of respiratory failure and palliative care, and treatment of comorbidities. Risk elimination includes interventions against tobacco smoking and environmental/occupational exposures. Basic treatment is based on bronchodilator therapy, pulmonary rehabilitation, vaccination, care for appropriate nutrition, inhalation training, education and psychosocial support. Adequate phenotype-specific treatment varies phenotype by phenotype, including more than ten different pharmacological and non-pharmacological strategies. If more than one clinical phenotype is present, treatment strategy should follow the expression of each phenotypic label separately. In such patients, multicomponental therapeutic regimens are needed, resulting in fully individualized care. In the future, stronger measures against smoking, improvements in occupational and environmental health, early diagnosis strategies, as well as biomarker identification for patients responsive to specific treatments are warranted. New classes of treatment (inhaled PDE3/4 inhibitors, single molecule dual bronchodilators, anti-inflammatory drugs, gene editing molecules or new bronchoscopic procedures) are expected to enter the clinical practice in a very few years.

Two-Year Outcomes for the Double-Blind, Randomized, Sham-Controlled Study of Targeted Lung Denervation in Patients with Moderate to Severe COPD: AIRFLOW-2

Purpose

COPD exacerbations are associated with worsening clinical outcomes and increased healthcare costs, despite use of optimal medical therapy. A novel bronchoscopic therapy, targeted lung denervation (TLD), which disrupts parasympathetic pulmonary innervation of the lung, has been developed to reduce clinical consequences of cholinergic hyperactivity and its impact on COPD exacerbations. The AIRFLOW-2 study assessed the durability of safety and efficacy of TLD additive to optimal drug therapy compared to sham bronchoscopy and optimal drug therapy alone in subjects with moderate-to-severe, symptomatic COPD two years post randomization.

Patients and Methods

TLD was performed in COPD patients (FEV1 30-60% predicted, CAT≥10 or mMRC≥2) in a 1:1 randomized, sham-controlled, double-blinded multicenter study (AIRFLOW-2) using a novel lung denervation system (Nuvaira, Inc., USA). Subjects remained blinded until their 12.5-month follow-up visit when control subjects were offered the opportunity to undergo TLD. A time-to-first-event analysis on moderate and severe and severe exacerbations of COPD was performed.

Results

Eighty-two subjects (FEV1 41.6±7.4% predicted, 50.0% male, age 63.7±6.8 yrs, 24% with prior year respiratory hospitalization) were randomized. Time-to-first severe COPD exacerbation was significantly lengthened in the TLD arm (p=0.04, HR=0.38) at 2 years post-TLD therapy and trended towards similar attenuation for moderate and severe COPD exacerbations (p=0.18, HR=0.71). No significant changes in lung function or SGRQ-C were found 2 years post randomization between groups.

Conclusion

In a randomized trial, TLD demonstrated a durable effect of significantly lower risk of severe AECOPD over 2 years. Further, lung function and quality of life remained stable following TLD.

Clinical Trial Registration

NCT02058459.

Chronic obstructive pulmonary disease phenotypes: imprint on pharmacological and non-pharmacological therapy

Chronic obstructive pulmonary disease (COPD) is a heterogeneous disease associated with significant morbidity and mortality. Over the past few years, there has been cumulating interest in describing this heterogeneity and using this information to group patients into different COPD phenotypes. The term phenotype is defined as single or combination of disease attributes that describe differences between individuals with COPD as they relate to clinically meaningful outcomes. It describes also the physical appearance or biochemical characteristics which result from the genotype-environment interaction. Furthermore, it clearly identifies subgroups with a significant impact in the prognosis. Recently, approaches to COPD phenotyping have been significantly enhanced in tandem with developments in understanding the disease’s various pathological, clinical and genetic features. This knowledge inspired the researchers to investigate more tailored therapeutic strategies that could not only give a more potent effect but also help to avoid the traditional therapy’s undesirable side effects. Eventually, it could be said that the phenotypic approach to COPD in the last decade had a huge impact on daily practice and management delivered to COPD patients. In this review, we highlight the impact of pharmacological and non-pharmacological treatment options on COPD outcomes, using a personalized treatment strategy based on different phenotypes.

Interventional Bronchoscopy

For over 150 years, bronchoscopy, especially flexible bronchoscopy, has been a mainstay for airway inspection, the diagnosis of airway lesions, therapeutic aspiration of airway secretions, and transbronchial biopsy to diagnose parenchymal lung disorders. Its utility for the diagnosis of peripheral pulmonary nodules and therapeutic treatments besides aspiration of airway secretions, however, has been limited. Challenges to the wider use of flexible bronchoscopy have included difficulty in navigating to the lung periphery, the avoidance of vasculature structures when performing diagnostic biopsies, and the ability to biopsy a lesion under direct visualization. The last 10-15 years have seen major advances in thoracic imaging, navigational platforms to direct the bronchoscopist to lung lesions, and the ability to visualize lesions during biopsy. Moreover, multiple new techniques have either become recently available or are currently being investigated to treat a broad range of airway and lung parenchymal diseases, such as asthma, emphysema, and chronic bronchitis, or to alleviate recurrent exacerbations. New bronchoscopic therapies are also being investigated to not only diagnose, but possibly treat, malignant peripheral lung nodules. As a result, flexible bronchoscopy is now able to provide a new and expanding armamentarium of diagnostic and therapeutic tools to treat patients with a variety of lung diseases. This State-of-the-Art review succinctly reviews these techniques and provides clinicians an organized approach to their role in the diagnosis and treatment of a range of lung diseases.

Interventional Bronchoscopic Therapies for Chronic Obstructive Pulmonary Disease

Patients with severe chronic obstructive pulmonary disease who fail maximal medical therapy have bronchoscopic options that can improve lung function, quality of life, and exercise performance. Those with upper lobe predominant emphysema can consider bronchoscopic lung volume reduction with endobronchial valves. Select patients with diffuse emphysema and severe hyperinflation can also be considered for endobronchial valves. Bronchoscopic techniques targeting cholinergic pathways and mucus hypersecretion are under development. Ultimately, patients with advanced chronic obstructive pulmonary disease who are not eligible for or have failed bronchoscopic interventions can consider lung volume reduction surgery or even lung transplantation, if free from major comorbidities.

Targeted lung denervation in sheep: durability of denervation and long-term histologic effects on bronchial wall and peribronchial structures

BACKGROUND

Targeted lung denervation (TLD), a novel bronchoscopic procedure which attenuates pulmonary nerve input to the lung to reduce the clinical consequences of neural hyperactivity, may be an important emerging treatment for COPD. While procedural safety and impact on clinical outcomes have recently been reported, the mechanism of action has not been reported. We explored the long-term pathologic and histopathologic effects in a sheep model of ablation of bronchial branches of the vagus nerve using a novel dual-cooled radiofrequency ablation catheter.

METHODS

Nineteen sheep underwent circumferential ablation of both main bronchi with simultaneous balloon surface cooling using a targeted lung denervation system (Nuvaira, Inc., USA). Animals were followed over an extended time course (30, 365, and 640 days post procedure). At each time point, lung denervation (axonal staining in bronchial nerves), and effect on peribronchial structures near the treatment site (histopathology of bronchial epithelium, bronchial cartilage, smooth muscle, alveolar parenchyma, and esophagus) were quantified. One way analysis of variance (ANOVA) was performed to reveal differences between group means on normal data. Non-parametric analysis using Kruskal-Wallis Test was employed on non-normal data sets.

RESULTS

No adverse clinical effects were observed in any sheep. Nerve axon staining distal to the ablation site was decreased by 60% at 30 days after TLD and efferent axon staining was decreased by >70% at 365 and 640 days. All treated airways exhibited 100% epithelial integrity. Effect on peribronchial structures was strictly limited to lung tissue immediately adjacent to the ablation site. Tissue structure 1 cm proximal and distal to the treatment area remained normal, and the pulmonary veins, pulmonary arteries, and esophagus were unaffected.

CONCLUSIONS

The denervation of efferent axons induced by TLD therapy is durable and likely a contributing mechanism through which targeted lung denervation impacts clinical outcomes. Further, long term lung denervation did not alter the anatomy of the bronchioles or lung, as evaluated from both a gross and histologic perspective.

Safety and Adverse Events after Targeted Lung Denervation for Symptomatic Moderate to Severe Chronic Obstructive Pulmonary Disease (AIRFLOW). A Multicenter Randomized Controlled Clinical Trial

Rationale: Targeted lung denervation (TLD) is a bronchoscopic radiofrequency ablation therapy for chronic obstructive pulmonary disease (COPD), which durably disrupts parasympathetic pulmonary nerves to decrease airway resistance and mucus hypersecretion.

Objectives: To determine the safety and impact of TLD on respiratory adverse events.

Methods: We conducted a multicenter, randomized, sham bronchoscopy–controlled, double-blind trial in patients with symptomatic (modified Medical Research Council dyspnea scale score, ≥2; or COPD Assessment Test score, ≥10) COPD (FEV₁, 30–60% predicted). The primary endpoint was the rate of respiratory adverse events between 3 and 6.5 months after randomization (defined as COPD exacerbation, tachypnea, wheezing, worsening bronchitis, worsening dyspnea, influenza, pneumonia, other respiratory infections, respiratory failure, or airway effects requiring therapeutic intervention). Blinding was maintained through 12.5 months.

Measurements and Main Results: Eighty-two patients (50% female; mean ± SD: age, 63.7 ± 6.8 yr; FEV₁, 41.6 ± 7.3% predicted; modified Medical Research Council dyspnea scale score, 2.2 ± 0.7; COPD Assessment Test score, 18.4 ± 6.1) were randomized 1:1. During the predefined 3- to 6.5-month window, patients in the TLD group experienced significantly fewer respiratory adverse events than those in the sham group (32% vs. 71%, P = 0.008; odds ratio, 0.19; 95% confidence interval, 0.0750–0.4923, P = 0.0006). Between 0 and 12.5 months, these findings were not different (83% vs. 90%; P = 0.52). The risk of COPD exacerbation requiring hospitalization in the 0- to 12.5-month window was significantly lower in the TLD group than in the sham group (hazard ratio, 0.35; 95% confidence interval, 0.13–0.99; P = 0.039). There was no statistical difference in the time to first moderate or severe COPD exacerbation, patient-reported symptoms, or other physiologic measures over the 12.5 months of follow-up.

Conclusions: Patients with symptomatic COPD treated with TLD combined with optimal pharmacotherapy had fewer study-defined respiratory adverse events, including hospitalizations for COPD exacerbation.

Clinical trial registered with www.clinicaltrials.gov (NCT02058459).

Design for a multicenter, randomized, sham-controlled study to evaluate safety and efficacy after treatment with the Nuvaira® lung denervation system in subjects with chronic obstructive pulmonary disease (AIRFLOW-3)

Background

Targeted lung denervation (TLD) is a bronchoscopically delivered ablation therapy that selectively interrupts pulmonary parasympathetic nerve signaling. The procedure has the potential to alter airway smooth muscle tone and reactivity, decrease mucous secretion, and reduce airway inflammation and reflex airway hyperresponsiveness. Secondary outcome analysis of a previous randomized, sham-controlled trial showed a reduction in moderate-to-severe exacerbations in patients with COPD after TLD treatment. A pivotal trial, AIRFLOW-3 has been designed to evaluate the safety and efficacy of TLD combined with optimal medical therapy to reduce moderate or severe exacerbations throughout 1 year, compared with optimal medical therapy alone.

Methods

The study design is a multicenter, randomized, full sham bronchoscopy controlled, double-blind trial that will enroll 400 patients (1:1 randomization). Key inclusion criteria are FEV₁/FVC < 0.7, FEV₁ 30 to 60% of predicted, post-bronchodilator, ≥ 2 moderate or 1 severe COPD exacerbations in the prior year, and COPD assessment test (CAT) ≥ 10. Primary objective will be the comparison of moderate or severe COPD exacerbations through 12 months of TLD therapy with optimal medical therapy versus optimal medical therapy alone. The sham group will be allowed to cross over at 1 year. Patients will be followed for up to 5 years.

Discussion

The multicenter, randomized, full sham bronchoscopy controlled, double-blind AIRFLOW-3 trial will evaluate the efficacy of TLD to reduce moderate or severe COPD exacerbations beyond optimal medical therapy alone. The target population are patients with COPD, who suffer persistent symptoms and exacerbations despite optimal treatment, defining an unmet medical need requiring novel therapeutic solutions. This trial is registered at clinicaltrials.gov: NCT03639051.

Respiratory Sinus Arrhythmia Attenuation via Targeted Lung Denervation in Sheep and Humans

BACKGROUND

Targeted lung denervation (TLD) is a novel bronchoscopic therapy that disrupts parasympathetic pulmonary nerve input to the lung. Parasympathetic input to the heart originating from the lungs contributes to respiratory sinus arrhythmia (RSA) and disruption of pulmonary nerves via TLD may impact RSA.

OBJECTIVE

The aim of this study was to assess the potential of TLD to affect RSA in sheep and humans.

METHODS

TLD was performed in 5 sheep and 9 humans using a novel lung denervation system (Nu-vaira Inc., Minneapolis, MN, USA) with an electrocardiogram collected before and after the procedure. Frequency domain analysis of heart rate variability was performed in 5 sheep and 6 humans with presence of RSA approximated as high-frequency power (HF power).

RESULTS

HF power decreased in 3 of 5 sheep with 1 animal reaching less than 7% of its baseline HF power 30 days after TLD. The average treatment location was more distal in the remaining 2 animals, which did not exhibit RSA attenuation, suggesting diminished denervation. HF power decreased in 5 of 6 humans, with 3 subjects reaching less than 50% of their baseline HF power 90 days after TLD.

CONCLUSIONS

TLD appeared to attenuate RSA in both sheep and human cohorts of this sub-study. Further confirmation in humans is necessary to allow for RSA attenuation to be used as a marker of successful lung denervation via TLD.