Comparison of the in vitro pharmacological profiles of long-acting muscarinic antagonists in human bronchus

Use of human airway smooth muscle in vitro and ex vivo to investigate drugs for the treatment of chronic obstructive respiratory disorders

Isolated airway smooth muscle has been extensively investigated since 1840 to understand the pharmacology of airway diseases. There has often been poor predictability from murine experiments to drugs evaluated in patients with asthma or chronic obstructive pulmonary disease (COPD). However, the use of isolated human airways represents a sensible strategy to optimise the development of innovative molecules for the treatment of respiratory diseases. This review aims to provide updated evidence on the current uses of isolated human airways in validated in vitro methods to investigate drugs in development for the treatment of chronic obstructive respiratory disorders. This review also provides historical notes on the pioneering pharmacological research on isolated human airway tissues, the key differences between human and animal airways, as well as the pivotal differences between human medium bronchi and small airways. Experiments carried out with isolated human bronchial tissues in vitro and ex vivo replicate many of the main anatomical, pathophysiological, mechanical and immunological characteristics of patients with asthma or COPD. In vitro models of asthma and COPD using isolated human airways can provide information that is directly translatable into humans with obstructive lung diseases. Regardless of the technique used to investigate drugs for the treatment of chronic obstructive respiratory disorders (i.e., isolated organ bath systems, videomicroscopy and wire myography), the most limiting factors to produce high-quality and repeatable data remain closely tied to the manual skills of the researcher conducting experiments and the availability of suitable tissue.

Is it preferable to administer a bronchodilator once- or twice-daily when treating COPD?

Nocturnal and early morning symptoms are common and uncomfortable in many patients with COPD, and are likely to affect their long-term outcomes. However, it is still debated whether it is better to give long-acting bronchodilators once- or twice-daily to symptomatic COPD patients. The functional link between circadian rhythms of autonomic tone and airway calibre explains why the timing of administration of bronchodilators in chronic airway diseases can induce different effects when taken at different biological (circadian) times. However, the timing also depends on the pharmacological characteristics of the bronchodilator to be used. Because the profile of bronchodilation produced by once-daily vs. twice-daily long-acting bronchodilators differs throughout 24 h, selecting long-acting bronchodilators may be customized to specific patient preferences based on the need for further bronchodilation in the evening. This is especially helpful for people who experience respiratory symptoms at night or early morning. Compared to placebo, evening bronchodilator administration is consistently linked with persistent overnight improvements in dynamic respiratory mechanics and inspiratory neural drive. The current evidence indicates that nocturnal and early morning symptoms control is best handled by a LAMA taken in the evening. In contrast, it seems preferable to use a LABA for daytime symptoms. Therefore, it can be speculated that combining a LAMA with a LABA can improve bronchodilation and control symptoms better. Both LAMA and LABA must be rapid in their onset of action. Aclidinium/formoterol, a twice-daily combination, is the most studies of the available LAMA/LABA combinations in terms of impact on daytime and nocturnal symptoms.

Real-world effects of once-daily inhaled steroid (fluticasone furoate) combined with long-acting beta-2 agonist (vilanterol) and long-acting muscarinic antagonist (umeclidinium) on lung function tests of asthma patients in Japan

Background: The Japanese drug use system allowed the once-daily use of inhaled corticosteroid fluticasone furoate (FF) combined with a long-acting beta-2 agonist vilanterol (VI) and a long-acting muscarinic antagonist umeclidinium (UMEC) against asthma on 18 February 2021. We investigated the real-world effects of these drugs (FF/UMEC/VI) mainly on lung function tests. Methods: This was an open-label, uncontrolled, within-group time-series (before-after) study. Prior asthma treatment (inhaled corticosteroid with/without a long-acting beta-2 agonist with/without a long-acting muscarinic antagonist) was switched to FF/UMEC/VI 200/62.5/25 μg. Subjects were evaluated by lung function tests prior to, and 1-2 months after, initiation of FF/UMEC/VI 200/62.5/25 μg. Patients were asked questions regarding the asthma control test and preference for drugs. Results: Overall, 114 asthma outpatients (97% Japanese) were enrolled from February 2021 to April 2022: 104 subjects completed the study. Forced expiratory volume in 1 s, peak flow, and asthma control test score of FF/UMEC/VI 200/62.5/25 μg-treated subjects were significantly increased (p < 0.001, p < 0.001, and p < 0.01, respectively). In contrast with FF/VI 200/25 μg, instantaneous flow at 25% of the forced vital capacity and expiratory reserve volume were significantly increased by FF/UMEC/VI 200/62.5/25 μg (p < 0.01, p < 0.05, respectively). Sixty-six percent of subjects declared they wanted to continue FF/UMEC/VI 200/62.5/25 μg in the future. Adverse effects, mainly local, were seen in 30% of patients, but no serious adverse effects were seen. Conclusion: Once-daily FF/UMEC/VI 200/62.5/25 μg was effective against asthma without serious adverse events. This is the first report that demonstrated FF/UMEC/VI dilated peripheral airways using lung function tests. This evidence on drug effects may improve our understanding of pulmonary physiology and the pathophysiology of asthma.

Neutralizing GM-CSF autoantibodies in pulmonary alveolar proteinosis, cryptococcal meningitis and severe nocardiosis

Background

Anti GM-CSF autoantibodies (aAb) have been related to acquired pulmonary alveolar proteinosis (PAP) and described in cases of severe infections such as cryptococcosis and nocardiosis in previously healthy subjects. Whether there are different anti-GM-CSF autoantibodies corresponding to these phenotypes is unclear. Therefore, we examined anti-GM-CSF autoantibodies to determine whether amount or neutralizing activity could distinguish between groups.

Methods

Plasma samples gathered in the National Institute of Health from patients with anti GM-CSF aAb and either PAP (n = 15), cryptococcal meningitis (n = 15), severe nocardiosis (n = 5) or overlapping phenotypes (n = 6) were compared. The relative amount of aAb was assessed using a particle-based approach, reported as a mouse monoclonal anti-human GM-CSF as standard curve and expressed in an arbitrary Mouse Monoclonal Antibody Unit (MMAU). The neutralizing activity of the plasma was assessed by inhibition of GM-CSF-induced intracellular phospho-STAT5 (pSTAT5) in monocytes.

Results

Anti-GM-CSF aAb relative amounts were higher in PAP patients compared to those with cryptococcosis (mean 495 ± 464 MMAU vs 197 ± 159 MMAU, p = 0.02); there was no difference with patients with nocardiosis (430 ± 493 MMAU) nor between the two types of infections.

The dilution of plasma resulting in 50% inhibition of GM-CSF-induced pSTAT5 (approximate IC₅₀) did not vary appreciably across groups of patients (1.6 ± 3.1%, 3.9 ± 6% and 1.8 ± 2.2% in PAP patients, cryptococcosis and nocardiosis patients, respectively). Nor was the concentration of GM-CSF necessary to induce 50% of maximal GM-CSF-induced pSTAT5 in the presence of 10 MMAU of anti-GM-CSF aAb (EC₅₀). When studying longitudinal samples from patients with PAP or disseminated nocardiosis, the neutralizing effect of anti-GM-CSF aAb was relatively constant over time despite targeted treatments and variations in aAb levels.

Conclusions

Despite different clinical manifestations, anti-GM-CSF antibodies were similar across PAP, cryptococcosis and nocardiosis. Underlying host genetics and functional analyses may help further differentiate the biology of these conditions.

Muscarinic receptor M3 activation promotes fibrocytes contraction

Fibrocytes are monocyte-derived cells able to differentiate into myofibroblasts-like cells. We have previously shown that they are increased in the bronchi of Chronic Obstructive Pulmonary Disease (COPD) patients and associated to worse lung function. COPD is characterized by irreversible airflow obstruction, partly due to an increased cholinergic environment. Our goal was to investigate muscarinic signalling in COPD fibrocytes. Fibrocytes were isolated from 16 patients with COPD’s blood and presence of muscarinic M3 receptor was assessed at the transcriptional and protein levels. Calcium signalling and collagen gels contraction experiments were performed in presence of carbachol (cholinergic agonist) ± tiotropium bromide (antimuscarinic). Expression of M3 receptor was confirmed by Western blot and flow cytometry in differentiated fibrocytes. Immunocytochemistry showed the presence of cytoplasmic and membrane-associated pools of M3. Stimulation with carbachol elicited an intracellular calcium response in 35.7% of fibrocytes. This response was significantly blunted by the presence of tiotropium bromide: 14.6% of responding cells (p < 0.0001). Carbachol induced a significant contraction of fibrocytes embedded in collagen gels (13.6 ± 0.3% versus 2.5 ± 4.1%; p < 0.0001), which was prevented by prior tiotropium bromide addition (4.1 ± 2.7% of gel contraction; p < 0.0001). Finally, M3-expressing fibrocytes were also identified in situ in the peri-bronchial area of COPD patients’ lungs, and there was a tendency to an increased density compared to healthy patient’s lungs. In conclusion, around 1/3 of COPD patients’ fibrocytes express a functional muscarinic M3 receptor. Cholinergic-induced fibrocyte contraction might participate in airway diameter reduction and subsequent increase of airflow resistance in patients with COPD. The inhibition of these processes could participate to the beneficial effects of muscarinic antagonists for COPD treatment.

Inhaled Medicines: Past, Present, and Future

The purpose of this review is to summarize essential pharmacological, pharmaceutical, and clinical aspects in the field of orally inhaled therapies that may help scientists seeking to develop new products. After general comments on the rationale for inhaled therapies for respiratory disease, the focus is on products approved approximately over the last half a century. The organization of these sections reflects the key pharmacological categories. Products for asthma and chronic obstructive pulmonary disease include β -2 receptor agonists, muscarinic acetylcholine receptor antagonists, glucocorticosteroids, and cromones as well as their combinations. The antiviral and antibacterial inhaled products to treat respiratory tract infections are then presented. Two "mucoactive" products-dornase α and mannitol, which are both approved for patients with cystic fibrosis-are reviewed. These are followed by sections on inhaled prostacyclins for pulmonary arterial hypertension and the challenging field of aerosol surfactant inhalation delivery, especially for prematurely born infants on ventilation support. The approved products for systemic delivery via the lungs for diseases of the central nervous system and insulin for diabetes are also discussed. New technologies for drug delivery by inhalation are analyzed, with the emphasis on those that would likely yield significant improvements over the technologies in current use or would expand the range of drugs and diseases treatable by this route of administration. SIGNIFICANCE STATEMENT: This review of the key aspects of approved orally inhaled drug products for a variety of respiratory diseases and for systemic administration should be helpful in making judicious decisions about the development of new or improved inhaled drugs. These aspects include the choices of the active ingredients, formulations, delivery systems suitable for the target patient populations, and, to some extent, meaningful safety and efficacy endpoints in clinical trials.

Clinical relevance of the relaxant effects of roflumilast on human bronchus: potentiation by a long-acting beta-2-agonist

Roflumilast is an oral, add-on option for treating patients with severe COPD and frequent exacerbations despite optimal therapy with inhaled drugs. The present study focused on whether this phosphodiesterase 4 inhibitor and its active metabolite roflumilast N-oxide affect the tone of human bronchial rings. We also investigated the interactions between roflumilast, roflumilast N-oxide and the long-acting β₂ -agonist formoterol with regard to the relaxation of isolated human bronchial rings at basal tone or pre-contracted with histamine. Our results demonstrated for the first time that at a clinically relevant concentration (1 nm), roflumilast N-oxide and roflumilast induce a weak relaxation of the isolated human bronchus either at resting tone (22% and 16%, respectively) or even weaker on pre-contracted bronchus with histamine (7% and 5%, respectively). In addition, the combination of formoterol with roflumilast or roflumilast N-oxide is more potent than each component alone for relaxing pre-contracted isolated bronchi - the apparent pD2 of formoterol was significantly reduced for the threshold concentration of 1 nm of the phosphodiesterase 4 inhibitors by a factor of 2.4 for roflumilast N-oxide and 1.9 for roflumilast. The full inhibition of phosphodiesterase 4 activity is achieved at 100 nm but this high concentration only caused partial relaxations of the human bronchi. At a clinically relevant concentration, these oral phosphodiesterase 4 inhibitors are not effective direct bronchodilators but could enhance the efficacy of inhaled long-acting β2-agonists.

Emerging muscarinic receptor antagonists for the treatment of asthma

INTRODUCTION

The increased acetylcholine signaling in asthma pathophysiology offers the rationale for the use of LAMAs in the treatment of asthmatic patients. Tiotropium is still the only LAMA approved for use in asthma but there is a real interest in developing novel LAMAs for the treatment of asthma, or at least to extend this indication to other LAMAs already on the market.

AREAS COVERED

We examined and discussed trials and research that have studied or are evaluating the role of LAMAs already on the market in asthma and possible novel muscarinic acetylcholine receptor antagonists.

EXPERT OPINION

Glycopyrronium and umeclidinium will soon be included in the GINA strategy with the same current indications of tiotropium. It is likely that the choice of the LAMA will be influenced not so much by its pharmacological profile as by the type of triple therapy chosen. It is extremely difficult to identify a new LAMA that is more effective than tiotropium, but is it plausible that new technologies that will allow delivering the drug in a more targeted way and with a lower risk of adverse effects may represent the real progress in the use of LAMAs in asthma in the coming years.

Day and Night Control of COPD and Role of Pharmacotherapy: A Review

The topic of 24-hour management of COPD is related to day-to-night symptoms management, specific follow-up and patients’ adherence to therapy. COPD symptoms strongly vary during day and night, being worse in the night and early morning. This variability is not always adequately considered in the trials. Night-time symptoms are predictive of higher mortality and more frequent exacerbations; therefore, they should be a target of therapy. During night-time, in COPD patients the supine position is responsible for a different thoracic physiology; moreover, during some sleep phases the vagal stimulation determines increased bronchial secretions, increased blood flow in the bronchial circulation (enhancing inflammation) and increased airway resistance (broncho-motor tone). Moreover, in COPD patients the circadian rhythm may be impaired. The role of pharmacotherapy in this regard is still poorly investigated. Symptoms can be grossly differentiated according to the different phenotypes of the disease: wheezing recalls asthma, while dyspnea is strongly related to emphysema (dynamic hyperinflation) or obstructive bronchiolitis (secretions). Those symptoms may be different targets of therapy. In this regard, GOLD recommendations for the first time introduced the concept of phenotype distinction suggesting the use of inhaled corticosteroids (ICS) particularly when an asthmatic pattern or eosiophilic inflammations are present, and hypothesized different approaches to target symptoms (ie, dyspnea) or exacerbations. Pharmacotherapy should be evaluated and possibly directed on the basis of circadian variations, for instance, supporting the use of twice-daily rapid-action bronchodilators and evening dose of ICS. Recommendations on day and night symptoms monitoring strategies and choice of the specific drug according to patient’s profile are still not systematically investigated or established. This review is the summary of an advisory board on the topic “24-hour control of COPD and role of pharmacotherapy”, held by five pulmonologists, experts in respiratory pathophysiology, pharmacology and sleep medicine.

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A potential role of triple therapy for asthma patients

Introduction: The use of LAMAs in asthma is now supported by pharmacological and clinical evidence, whereas the effectiveness of therapy with ICS/LABA/LAMA fixed dose combinations in patients with asthma still remains to be determined. Areas covered: The pharmacological rationale that explains why it is possible to use triple therapy in asthma and the results of clinical studies that have explored the effects of this therapy in asthmatics is critically examined. A systematic search was conducted on 10 August 2019, and included six electronic databases: EMBASE, MEDLINE, Scopus, The Cochrane Library, Web of Science, and Google Scholar. Expert opinion: The real role of single inhaler triple therapy in asthma will be demonstrated when the various trials that are currently ongoing or are scheduled will be completed. We believe that it is appropriate to treat with triple therapy asthmatic patients who have smoked and remain symptomatic or suffer from frequent exacerbations despite initial inhaler therapy with ICS/LABA. However, we must establish when to step up or mainly step down triple therapy especially in patients who are well controlled, and what will be the cost of these combinations in the management of asthma.

Comparison of clinical efficacy between ultra-LABAs and ultra-LAMAs in COPD: a systemic review with meta-analysis of randomized controlled trials

Background

A single long-acting bronchodilator, ultra-long acting muscarinic antagonist (ultra-LAMA) or ultra-long acting β₂-agonist (ultra-LABA) is preferred for the initial treatment of patients with chronic obstructive pulmonary disease (COPD); however, there are few head-to-head comparative studies between the two. Here, a meta-analysis of randomized controlled trials was performed to compare the clinical efficacy between ultra-LABA and ultra-LAMA in patients with moderate-to-severe COPD.

Methods

MEDLINE, EMBASE, and the Cochrane Central Register of Controlled Trials were searched (to March 1, 2017) to identify all published randomized controlled trials.

Results

Of the 12,906 articles found by searching the databases, we obtained data from 10,591 patients with COPD (LABA, n=5,058; LAMA, n=5,533) in seven published studies. Our results showed that COPD exacerbation were significantly lower in patients taking ultra-LAMA than those taking ultra-LABA (odds ratio =0.857, P=0.0008). However, no significant differences were observed between ultra-LAMA and ultra-LABA patients regarding improvement in trough forced expiratory volume in 1 s, the transitional dyspnea index, or St. George's Respiratory Questionnaire score.

Conclusions

This study suggests that COPD exacerbation occurred less often in patients taking an ultra-LAMA than in those taking an ultra-LABA with similar efficacy of lung function and quality of life.

LABA/LAMA fixed-dose combinations in patients with COPD: a systematic review

OBJECTIVES

The aim of this study was to assess the current evidence for long-acting β2-agonist (LABA)/long-acting muscarinic antagonist (LAMA) fixed-dose combinations (FDCs) in the treatment of COPD.

MATERIALS AND METHODS

A systematic literature search of randomized controlled trials published in English up to September 2017 of LABA/LAMA FDCs vs LABA or LAMA or LABA/inhaled corticosteroid (ICS) FDCs in COPD patients was performed using PubMed, Embase, Scopus, and Google Scholar. Outcomes including forced expiratory volume in 1 second (FEV1), Transition Dyspnea Index (TDI) scores, St George's Respiratory Questionnaire (SGRQ) scores, exacerbations, exercise tolerance (endurance time [ET]), inspiratory capacity (IC), and rescue medication use were evaluated.

RESULTS

In total, 27 studies were included in the review. LABA/LAMA FDCs significantly improved lung function (FEV1) at 12 weeks compared with LABA or LAMA or LABA/ICS. These effects were maintained over time. Significant improvements with LABA/LAMA FDCs vs each evaluated comparator were also observed in TDI and SGRQ scores, even if significant differences between different LABA/LAMA FDCs were detected. Only the LABA/LAMA FDC indacaterol/glycopyrronium has shown superiority vs LAMA and LABA/ICS for reducing exacerbation rates, while olodaterol/tiotropium and indacaterol/glycopyrronium have been shown to improve ET and IC vs the active comparators. Rescue medication use was significantly reduced by LABA/LAMA FDCs vs the evaluated comparators. LABA/LAMA FDCs were safe, with no increase in the risk of adverse events with LABA/LAMA FDCs vs the monocomponents.

CONCLUSION

Evidence supporting the efficacy of LABA/LAMA FDCs for COPD is heterogeneous, particularly for TDI and SGRQ scores, exacerbation rates, ET, and IC. So far, indacaterol/glycopyrronium is the LABA/LAMA FDC that has the strongest evidence for superiority vs LABA, LAMA, and LABA/ICS FDCs across the evaluated outcomes. LABA/LAMA FDCs were safe; however, more data should be collected in a real-world setting to confirm their safety.