Interaction between corticosteroids and muscarinic antagonists in human airways

An update on long-acting muscarinic agents for asthma therapy

INTRODUCTION

The manifestations of asthma are influenced by the dysfunction of the autonomic nervous system, which results in elevated vagal tone within the airways. Acetylcholine (ACh) plays a pivotal role in the pathophysiology of asthma through its interaction with muscarinic acetylcholine receptors (mAChRs). Consequently, using mAChR antagonists to counteract the actions of ACh is scientifically sound.

AREAS COVERED

This narrative review methodically examines the latest information on the mechanisms and evidence supporting the use of long-acting muscarinic antagonists (LAMAs) in asthma.

EXPERT OPINION

Adding a LAMA to existing asthma treatments involving an ICS and a LABA, within a single inhaler triple therapy (SITT), improves lung function regulating airflow limitation, reduces exacerbations, and eosinophilic inflammation and offers a more comprehensive approach to managing inflammation and tissue remodeling, which are linked to ACh. Additionally, it disrupts the vicious cycle of ACh release that contributes to neuronal plasticity and dysfunction of small airways. Identifying treatable traits is key to using SITT in a customized way that aligns with patients' needs. The 5T (Triple Therapy Targeting Treatable Traits) approach proposes the utilization of SITT for all asthma cases, not solely severe ones, and involves using LAMAs in ICS/LABA combinations earlier than current guidelines recommend.

The Bronchodilator and Anti-Inflammatory Effect of Long-Acting Muscarinic Antagonists in Asthma: An EAACI Position Paper

As cholinergic innervation is a major contributor to increased vagal tone and mucus secretion, inhaled long-acting muscarinic antagonists (LAMA) are a pillar for the treatment of chronic obstructive pulmonary disease and asthma. By blocking the muscarinic receptors expressed in the lung, LAMA improve lung function and reduce exacerbations in asthma patients who remained poorly controlled despite treatment with inhaled corticosteroids and long-acting β2 agonists. Asthma guidelines recommend LAMA as a third controller to be added on before the initiation of biologicals. In addition to bronchodilation, LAMA also exert anti-inflammatory and anti-fibrotic effects by inhibiting muscarinic receptors present in neutrophils, macrophages, fibroblasts and airway smooth muscle cells. Thus, besides bronchodilation, LAMA might provide additional therapeutic effects, thereby supporting an endotype-driven approach to asthma management. The Position Paper, developed by the Asthma Section of the European Academy of Allergy and Clinical Immunology, discusses the main cholinergic pathways in the lung, reviews the findings of significant clinical trials and real-life studies on LAMA use in asthma, examines the placement of these drugs in asthma clinical guidelines, and considers the potential for personalised medicine with LAMA in both adult and paediatric asthma patients.

Small airways dysfunction in severe asthma: Current treatment approaches and future directions

Severe asthma is a significant health concern due to its association with higher mortality rates, reduced quality of life, and increased healthcare costs. These challenges make it a persistent issue for both clinicians and researchers. The small airways, defined as distal airways with a diameter of less than 2 mm and comprising 98.8% of the total lung volume, play a significant role in airway resistance in individuals with asthma. Recent studies demonstrated that small airways dysfunction is found in all asthma severity levels, but it is most pronounced in severe asthma, and greater small airways dysfunction severity correlates with poorer asthma control and a higher frequency of exacerbations. Therefore, therapies aimed at targeting small airways dysfunction are essential for effective asthma management, especially in severe asthma.

Extrafine formulation of beclomethasone dipropionate/formoterol fumarate/glycopyrronium bromide delivered via pressurized metered-dose inhaler in the treatment of asthma: a review

In the management of difficult-to-treat and severe asthma, the incorporation of a Long-Acting Muscarinic Antagonist (LAMA) into a regimen of Inhaled Corticosteroids plus Long-Acting β2 agonists (ICS/LABA) represents a viable add-on therapeutic strategy. Historically, this approach required the use of separate inhalers; however, the recent advent of "single-inhaler triple therapy" (SITT) provided a valuable alternative. One such formulation is the extrafine combination of beclomethasone dipropionate (BDP), fluticasone furoate (FF), and glycopyrronium bromide (GB), which is delivered via a single pressurized metered-dose inhaler (pMDI). Clinical trials, including the TRIMARAN and TRIGGER studies, alongside subsequent post-hoc analyses, have elucidated the benefits of this SITT at both 87/5/9 μg and 172/5/9 μg dosing regimens administered daily. Findings indicated a significant improvement in respiratory function and a reduction in the frequency of exacerbations among patients with uncontrolled asthma. The BDP/FF/GB SITT confirmed efficacy and safety across various ethnic groups (including Caucasian, Japanese, and Chinese populations) and across different age cohorts (adults and adolescents), although it still remains unapproved for individuals under 18 years of age. The use of a single pMDI facilitates the deposition of extra- fine particles from all three active ingredients in the small airways enhancing therapeutic effectiveness. Moreover, the consolidation of medications into one device may improve patients' adherence by mitigating the risks associated with device mismanagement and ensuring optimal drug delivery. The cost-effectiveness analysis of the BDP/FF/GB SITT suggests favorable outcomes compared to traditional ICS/LABA and ICS/LABA plus tiotropium combinations. Additional data will be forthcoming from the ongoing real-life TRIMAXIMIZE observational study.

Interaction between fluticasone furoate and umeclidinium in passively sensitized isolated human airways

Asthma management often includes inhaled corticosteroids (ICSs), with additional controllers like long-acting muscarinic antagonists (LAMAs) for severe cases. The primary goal of this study was to investigate the pharmacological interaction between various concentrations of fluticasone furoate (FF) and umeclidinium (UME) in isolated human airways to determine the nature of their interaction, whether synergistic or additive. Medium bronchi and small airways obtained from patients undergoing lobectomy were passively sensitized to mimic asthmatic conditions. The effects of FF and UME, alone and in combination, on airway relaxation were evaluated using histamine-induced contraction and electrical field stimulation. Pharmacological interactions were analyzed using the Bliss Independence theory. Results indicated that FF induced a partial, concentration-dependent relaxation of sensitized airways, while UME induced a larger relaxation in medium bronchi but a weaker effect in small airways. The combination of FF and UME resulted in significantly greater relaxation than either drug alone, demonstrating synergism at high concentrations in medium bronchi but only additive effects in small airways. This study suggests that higher doses of FF might be necessary in a fixed dose combination to achieve optimal synergistic bronchodilation with UME. Future research should focus on clinical trials to confirm these findings and explore the molecular mechanisms underlying these interactions, potentially improving personalized asthma therapy.

A clinician's guide to single vs multiple inhaler therapy for COPD

INTRODUCTION

In the management of chronic obstructive pulmonary disease (COPD), inhalation therapy plays a pivotal role. However, clinicians often face the dilemma of choosing between single and multiple inhaler therapies for their patients. This choice is critical because it can affect treatment efficacy, patient adherence, and overall disease management.

AREAS COVERED

This article examines the advantages and factors to be taken into consideration when selecting between single and multiple inhaler therapies for COPD.

EXPERT OPINION

Both single and multiple inhaler therapies must be considered in COPD management. While single inhaler therapy offers simplicity and convenience, multiple inhaler therapy provides greater flexibility and customization. Clinicians must carefully evaluate individual patient needs and preferences to determine the most appropriate inhaler therapy regimen. Through personalized treatment approaches and shared decision-making, clinicians can optimize COPD management and improve patient well-being. Nevertheless, further research is required to compare the effectiveness of single versus multiple inhaler strategies through rigorous clinical trials, free from industry bias, to determine the optimal inhaler strategy. Smart inhaler technology appears to have the potential to enhance adherence and personalized management, but the relative merits of smart inhalers in single inhaler regimens versus multiple inhaler regimens remain to be determined.

Managing Small Airway Disease in Patients with Severe Asthma: Transitioning from the "Silent Zone" to Achieving "Quiet Asthma"

Background/Objectives: Several studies have demonstrated the positive clinical and functional impact of adding Long-Acting Muscarinic Antagonist (LAMA) to Inhaled Corticosteroids (ICS) and Long-Acting Beta-Agonists (LABA) therapy in the treatment of severe asthma. Aim and objectives: To demonstrate that treating Small Airways Disease (SAD) in severe asthma patients who are candidates for biologics can improve respiratory symptoms, lung function, and airways inflammation, potentially avoiding or delaying the use of biological therapy. Methods: Thirty-two severe asthma patients with SAD were transitioned from separate inhalers for ICS/LABA and LAMA to extrafine single-inhaler beclomethasone, formoterol, and glycopyrronium. None of these patients underwent biological therapy before the study. Follow-up evaluations were conducted at baseline (T0) and three months after initiation (T3). Assessments included clinical evaluations, spirometry, oscillometry, and inflammation markers. Results: Transitioning to single-inhaler triple therapy from T0 to T3 resulted in significant improvements in Asthma Control Test (ACT) and SAD parameters, including increased Forced Expiratory Volume in the mid-range of lung capacity and improved airway resistance and reactance measurements using impulse oscillometry. A significant reduction in airway inflammation was evidenced by lower levels of Fractional Exhaled Nitric Oxide 350 (FeNO 350) (p < 0.001 for all). Conclusions: Adopting a single-inhaler triple therapy notably enhanced clinical control and small airway function in patients with severe asthma and SAD, supporting the positive impact of target-therapy for the achievement of a stable state termed "Quiet Asthma".

Non-genomic actions of steroid hormones on the contractility of non-vascular smooth muscles

Steroid hormones play an important role in physiological processes. The classical pathway of steroid actions is mediated by nuclear receptors, which regulate genes to modify biological processes. Non-genomic pathways of steroid actions are also known, mediated by cell membrane-located seven transmembrane domain receptors. Sex steroids and glucocorticoids have several membrane receptors already identified to mediate their rapid actions. However, mineralocorticoids have no identified membrane receptors, although their rapid actions are also measurable. In non-vascular smooth muscles (bronchial, uterine, gastrointestinal, and urinary), the rapid actions of steroids are mediated through the modification of the intracellular Ca2+ level by various Ca-channels and the cAMP and IP3 system. The non-genomic action can be converted into a genomic one, suggesting that these distinct pathways may interconnect, resulting in convergence between them. Sex steroids mostly relax all the non-vascular smooth muscles, except androgens and progesterone, which contract colonic and urinary bladder smooth muscles, respectively. Corticosteroids also induce relaxation in bronchial and uterine tissues, but their actions on gastrointestinal and urinary bladder smooth muscles have not been investigated yet. Bile acids also contribute to the smooth muscle contractility. Although the therapeutic application of the rapid effects of steroid hormones and their analogues for smooth muscle contractility disorders seems remote, the actions and mechanism discovered so far are promising. Further research is needed to expand our knowledge in this field by using existing experience. One of the greatest challenges is to separate genomic and non-genomic effects, but model molecules are available to start this line of research.

The effect of combining an inhaled corticosteroid and a long-acting muscarinic antagonist on human airway epithelial cells in vitro

BACKGROUND

Airway epithelial cells (AECs) are a major component of local airway immune responses. Direct effects of type 2 cytokines on AECs are implicated in type 2 asthma, which is driven by epithelial-derived cytokines and leads to airway obstruction. However, evidence suggests that restoring epithelial health may attenuate asthmatic features.

METHODS

We investigated the effects of passive sensitisation on IL-5, NF-κB, HDAC-2, ACh, and ChAT in human bronchial epithelial cells (HBEpCs) and the effects of fluticasone furoate (FF) and umeclidinium (UME) alone and in combination on these responses.

RESULTS

IL-5 and NF-κB levels were increased, and that of HDAC-2 reduced in sensitised HEBpCs. Pretreatment with FF reversed the effects of passive sensitisation by concentration-dependent reduction of IL-5, resulting in decreased NF-κB levels and restored HDAC-2 activity. Addition of UME enhanced these effects. Sensitized HEBpCs also exhibited higher ACh and ChAT levels. Pretreatment with UME significantly reduced ACh levels, and addition of FF caused a further small reduction.

CONCLUSION

This study confirmed that passive sensitisation of AECs results in an inflammatory response with increased levels of IL-5 and NF-κB, reduced levels of HDAC-2, and higher levels of ACh and ChAT compared to normal cells. Combining FF and UME was found to be more effective in reducing IL-5, NF-κB, and ACh and restoring HDAC-2 compared to the individual components. This finding supports adding a LAMA to established ICS/LABA treatment in asthma and suggests the possibility of using an ICS/LAMA combination when needed.

The Role of Long-Acting Antimuscarinic Agents in the Treatment of Asthma

The journey of using anticholinergics in the treatment of asthma started with anticholinergic-containing plants such as Datura stramonium and Atropa belladonna, followed by ipratropium bromide and continued with tiotropium, glycopyrronium, and umeclidinium. Although antimuscarinics were used in the maintenance treatment of asthma over a century ago, after a long time (since 2014), it has been recommended to be used as an add-on long-acting antimuscarinic agent (LAMA) therapy in the maintenance treatment of asthma. The airway tone controlled by the vagus nerve is increased in asthma. Allergens, toxins, or viruses cause airway inflammation and inflammation-related epithelial damage, increased sensory nerve stimulation, ganglionic and postganglionic acetylcholine (ACh) release by inflammatory mediators, intensification of ACh signaling at M1 and M3 muscarinic ACh receptors (mAChRs), and dysfunction of M2 mAChR. Optimal anticholinergic drug for asthma should effectively block M3 and M1 receptors, but have minimal effect on M2 receptors. Tiotropium, umeclidinium, and glycopyrronium are anticholinergic agents with this feature. Tiotropium has been used in a separate inhaler as an add-on treatment to inhaled corticosteroid (ICS)/long-acting β2-agonist (LABA), and glycopyrronium and umeclidinium have been used in a single inhaler as a combination of ICS/LABA/LAMA in asthma in recent years. Guidelines recommend this regimen as an optimization step for patients with severe asthma before initiating any biologic or systemic corticosteroid therapy. In this review, the history of antimuscarinic agents, their effectiveness and safety in line with randomized controlled trials, and real-life studies in asthma treatment will be discussed according to the current data.

Revisiting asthma pharmacotherapy: where do we stand and where do we want to go?

Several current guidelines/strategies outline a treatment approach to asthma, which primarily consider the goals of improving lung function and quality of life and reducing symptoms and exacerbations. They suggest a strategy of stepping up or down treatment, depending on the patient's overall current asthma symptom control and future risk of exacerbation. While this stepwise approach is undeniably practical for daily practice, it does not always address the underlying mechanisms of this heterogeneous disease. In the last decade, there have been attempts to improve the treatment of severe asthma, such as the addition of a long-acting antimuscarinic agent to the traditional inhaled corticosteroid/long-acting β2-agonist treatment and the introduction of therapies targeting key cytokines. However, despite such strategies several unmet needs in this population remain, motivating research to identify novel targets and develop improved therapeutic and/or preventative asthma treatments. Pending the availability of such therapies, it is essential to re-evaluate the current conventional "one-size-fits-all" approach to a more precise asthma management. Although challenging, identifying "treatable traits" that contribute to respiratory symptoms in individual patients with asthma may allow a more pragmatic approach to establish more personalised therapeutic goals.

Might It Be Appropriate to Anticipate the Use of Long-Acting Muscarinic Antagonists in Asthma?

A growing number of clinical trials are documenting that adding a long-acting muscarinic antagonist (LAMA) to established asthma treatment with an inhaled corticosteroid (ICS) and a long-acting β₂-agonist (LABA) is a treatment option that improves the health of patients with uncontrolled severe asthma even when therapy is optimized. These favorable results are the reason why the leading guidelines recommend triple therapy with ICS + LABA + LAMA in patients with asthma uncontrolled by medium- to high-dose ICS-LABA. However, we suggest adding LAMAs to ICS-LABAs at an earlier clinical stage. Such action could positively influence airflow limitation, exacerbations, and eosinophilic inflammation, conditions that are associated with acetylcholine (ACh) activity. It could also interrupt the vicious cycle related to a continuous release of ACh leading to the progressive expansion of neuronal plasticity resulting in small airway dysfunction. The utility of an earlier use of triple therapy in asthma should, in any case, be confirmed by statistically powered trials.

Pathophysiology, Therapeutic Targets, and Future Therapeutic Alternatives in COPD: Focus on the Importance of the Cholinergic System

Chronic obstructive pulmonary disease (COPD) is a progressive disease characterized by airway limitation and changes in airway structure. It has a high global burden of mortality and morbidity. The etiology of COPD is complex, but exposure to tobacco smoke and other inhaled lung oxidants are major risk factors. Both pharmacological and non-pharmacological approaches are used to manage COPD, but there remains an urgent unmet need for drugs that can modify the course of the disease. This review focuses on the role of acetylcholine and other components of the pulmonary cholinergic system in the pathogenesis of COPD, and the inhaled pharmacological agents that target it. In addition to its role as a neurotransmitter, acetylcholine regulates diverse aspects of COPD pathogenesis including bronchoconstriction, airway remodeling, mucus secretion and inflammation. Inhaled antimuscarinic drugs are a key component of therapy for COPD, as monotherapy or in combination with inhaled β2 agonists or corticosteroids. We review the evidence supporting the use of current anticholinergic agents in COPD and preview novel drugs targeting the cholinergic system and agents from other classes in clinical development, such as phosphodiesterase-4 inhibitors and monoclonal antibodies targeting inflammatory mediators.

The Impact of Corticosteroids on Human Airway Smooth Muscle Contractility and Airway Hyperresponsiveness: A Systematic Review

Classically, the effects elicited by corticosteroids (CS) are mediated by the binding and activation of cytosolic glucocorticoid receptors (GR). However, several of the non-genomic effects of CS seem to be mediated by putative non-classic membrane receptors characterized by pharmacological properties that are different from those of classic cytosolic GR. Since pre-clinical findings suggest that inhaled CS (ICS) may also regulate the bronchial contractile tone via putative CS membrane-associate receptors, the aim of this review was to systematically report and discuss the impact of CS on human airway smooth muscle (ASM) contractility and airway hyperresponsiveness (AHR). Current evidence indicates that CS have significant genomic/non-genomic beneficial effects on human ASM contractility and AHR, regardless of their anti-inflammatory effects. CS are effective in reducing either the expression, synthesis or activity of α-actin, CD38, inositol phosphate, myosin light chain kinase, and ras homolog family member A in response to several pro-contractile stimuli; overall these effects are mediated by the genomic action of CS. Moreover, CS elicited a strong bronchorelaxant effect via the rapid activation of the Gsα-cyclic-adenosine-monophosphate-protein-kinase-A pathway in hyperresponsive airways. The possibility of modulating the dose of the ICS in a triple ICS/long-acting β₂-adrenoceptor agonist/long-acting muscarinic antagonist fixed-dose combination supports the use of a Triple MAintenance and Reliever Therapy (TriMART) in those asthmatic patients at Step 3-5 who may benefit from a sustained bronchodilation and have been suffering from an increased parasympathetic tone.

Different inhaled corticosteroid doses in triple therapy for chronic obstructive pulmonary disease: systematic review and Bayesian network meta-analysis

A systematic review and Bayesian network meta-analysis is necessary to evaluate the efficacy and safety of triple therapy with different doses of inhaled corticosteroids (ICS) in stable chronic obstructive pulmonary disease (COPD). We selected 26 parallel randomized controlled trials (41,366 patients) comparing triple therapy with ICS/long-acting beta-agonist (LABA), LABA/long-acting muscarinic antagonist (LAMA), and LAMA in patients with stable COPD for ≥ 12 weeks from PubMed, EMBASE, the Cochrane Library, and clinical trial registries (search from inception to June 30, 2022). Triple therapy with high dose (HD)-ICS exhibited a lower risk of total exacerbation in pre-specified subgroups treated for ≥ 48 weeks than that with low dose (LD)-ICS (odds ratio [OR] = 0.66, 95% credible interval [CrI] = 0.52–0.94, low certainty of evidence) or medium dose (MD)-ICS (OR = 0.66, 95% CrI = 0.51–0.94, low certainty of evidence). Triple therapy with HD-ICS exhibited a lower risk of moderate-to-severe exacerbation in pre-specified subgroups with forced expiratory volume in 1 s < 65% (OR = 0.6, 95% CrI = 0.37–0.98, low certainty of evidence) or previous exacerbation history (OR = 0.6, 95% CrI = 0.36–0.999, very low certainty of evidence) than triple therapy with MD-ICS. Triple therapy with HD-ICS may reduce acute exacerbation in patients with COPD treated with other drug classes including triple therapy with LD- or MD-ICS or dual therapies.

The 5T approach in asthma: Triple Therapy Targeting Treatable Traits

Using a therapeutic strategy that is free from traditional diagnostic labels and based on the identification of "treatable traits" (TTs), which are influential in clinical presentations in each patient, might overcome the difficulties in identifying and validating asthma phenotypes and endotypes. Growing evidence is documenting the importance of using the triple therapy with ICS, LABA, and LAMAs in a single inhaler (SITT) in cases of asthma not controlled by ICS/LABA and in the prevention of exacerbations. The identification of TTs may overcome the possibility of using SITT without considering the specific needs of the patient. In effect, it allows a treatment strategy that is closer to the precision strategy now widely advocated for the management of patients with asthma. There are different TTs in asthma that may benefit from treatment with SITT, regardless of guideline recommendations. The airflow limitation and small airway dysfunction are key TTs that are present in different phenotypes/endotypes, do not depend on the degree of T2 inflammation, and respond better than other treatments to SITT. We suggest that the 5T (Triple Therapy Targeting Treatable Traits) approach should be applied to the full spectrum of asthma, not just severe asthma, and, consequently, SITT should begin earlier than currently recommended.

Muscarinic receptor antagonists and airway inflammation: A systematic review on pharmacological models

Airway inflammation is crucial in the pathogenesis of many respiratory diseases, including chronic obstructive pulmonary disease (COPD) and asthma. Current evidence supports the beneficial impact of muscarinic receptor antagonists against airway inflammation from bench-to-bedside. Considering the numerous sampling approaches and the ethical implications required to study inflammation in vivo in patients, the use of pre-clinical models is inevitable. Starting from our recently published systematic review concerning the impact of muscarinic antagonists, we have systematically assessed the current pharmacological models of airway inflammation and provided an overview on the advances in in vitro and ex vivo approaches. The purpose of in vitro models is to recapitulate selected pathophysiological parameters or processes that are crucial to the development of new drugs within a controlled environment. Nevertheless, immortalized cell lines or primary airway cells present major limitations, including the inability to fully replicate the conditions of the corresponding cell types within a whole organism.

Induced animal models are extensively used in research in the attempt to replicate a respiratory condition reflective of a human pathological state, although considering animal models with spontaneously occurring respiratory diseases may be more appropriate since most of the clinical features are accompanied by lung pathology resembling that of the human condition.

In recent years, three-dimensional organoids have become an alternative to animal experiments, also because animal models are unable to fully mimic the complexity of human pulmonary diseases. Ex vivo studies performed on human isolated airways have a superior translational value compared to in vitro and animal models, as they retain the morphology and the microenvironment of the lung in vivo.

In the foreseeable future, greater effort should be undertaken to rely on more physiologically relevant models, that provide translational value into clinic and have a direct impact on patient outcomes.

An update on the currently available and emerging synthetic pharmacotherapy for uncontrolled asthma

INTRODUCTION

: The treatment of uncontrolled asthma has improved because of triple therapy that includes a long-acting muscarinic antagonist (LAMA) and biological drugs, but several patients are resistant to corticosteroids and/or cannot achieve adequate asthma control using such therapies.

AREAS COVERED

: Herein, the authors review the current and emerging synthetic pharmacotherapy for uncontrolled asthma to overcome obstacles and limitations of biological therapies. The authors also provide their expert perspectives and opinion on the treatment of uncontrolled asthma.

EXPERT OPINION

: LAMAs should be added to inhaled corticosteroid/long-acting β₂-agonist combinations much earlier than currently recommended by the Global Initiative for Asthma strategy because they can influence the course of small airways disease, reducing lung hyperinflation and improving asthma control. Biological therapies are a major advance in the treatment of severe asthma, but their use is still very limited for several reasons. An alternative to overcome the use of biological therapies is to synthesise compounds that target inflammation-signalling pathways. Several pathways have been identified as potential targets to design either therapeutic or prophylactic drugs against asthma. Some new compounds have already been tested in humans, but results have often been disappointing probably because existing phenotypic and endotypic variants may unpredictably limit the therapeutic value of blocking a specific pathway in most asthmatics, although there may be a substantial benefit for a subgroup of patients.

A single inhaler triple therapy fluticasone furoate/umeclidinium/vilanterol for the treatment of COPD

INTRODUCTION

: Single inhaler triple therapy (SITT) with an inhaled corticosteroid, a long-acting β₂-agonist, and a long-acting muscarinic antagonist is an effective and attractive therapeutic option codified in the recommendations of guidelines and treatment strategies for the management of COPD.

AREAS COVERED

: The preclinical and clinical development in COPD of fluticasone furoate (FF)/umeclidinium (UMEC)/vilanterol (VI) SITT and its use in the real world.

EXPERT OPINION

: Findings from phase III/IV trials and the use of FF/UMEC/VI in the real-world setting support the view that it may be a useful, safe, and cost-effective option for the maintenance treatment of COPD, especially when dealing with patients who are not adequately controlled with dual ICS/LABA or LAMA/LABA therapy. Only direct head-to-head comparisons will be able to establish whether FF/UMEC/VI may be preferable to the other SITTs approved for COPD due to its pharmacokinetic and pharmacodynamic characteristics and especially the fact that it is the only one that can be taken once-daily. In addition, there is a need for further studies, especially in the real world, to optimize the positioning of FF/UMEC/VI in the treatment of COPD, also considering the availability of FF/VI and UMEC/VI and the need for better differentiation between the three treatments.

Understanding the role of long-acting muscarinic antagonists in asthma treatment

OBJECTIVE

Long-acting muscarinic antagonists (LAMAs) have been used in the treatment of obstructive pulmonary diseases for years. Long-acting muscarinic antagonists were previously mainly used as bronchodilators in chronic obstructive pulmonary disease, but the use of LAMAs in the treatment of asthma has gained great interest. There is now ample evidence of the efficacy and safety of LAMAs as add-on therapy to inhaled corticosteroid (ICS) plus long-acting β₂-agonist (LABA) combinations in patients with moderate to severe uncontrolled asthma. Long-acting muscarinic antagonists have subsequently been included in asthma guidelines. This review summarizes the scientific evidence on the use of LAMAs in asthma and aims to provide a better understanding of the role of LAMAs in the asthma treatment care algorithm and the current gaps in our knowledge.

DATA SOURCES

PubMed review using the following words: long-acting muscarinic antagonists, asthma, muscarinic receptors, tiotropium, glycopyrronium, umeclidinium.

STUDY SELECTIONS

This review focused on the key trials that led to the inclusion of LAMAs in asthma guidelines. In addition, we highlighted a number of studies with other study designs and populations.

RESULTS

We identified 6 major studies that led to inclusion in asthma guidelines and 3 studies with other study designs and populations.

CONCLUSION

Long-acting muscarinic antagonists add-on therapy to ICS-LABA improves lung function, reduces exacerbations, and modestly improves asthma control in patients with moderate to severe asthma who are uncontrolled despite the use of ICS-LABA. Long-acting muscarinic antagonists are effective in all asthma phenotypes and endotypes.

Why small particle fixed dose triple therapy? An excursus from COPD pathology to pharmacological treatment evolution

Although bronchodilators are the cornerstone in chronic obstructive pulmonary disease (COPD) therapy, the treatment with a single-agent bronchodilator may not provide adequate symptoms control in COPD. The combination of drugs with different mechanisms of action may be more effective in inducing bronchodilation and preventing exacerbations, with a lower risk of side-effects in comparison with the increase of the dose of a single molecule. Several studies comparing the triple therapy with the association of long-acting ß2 agonist (LABA)/inhaled corticosteroid (ICS) or long-acting muscarinic antagonist (LAMA)/LABA reported improvement of lung function and quality of life. A significant reduction in moderate/severe exacerbations has been observed with a fixed triple combination of beclometasone dipropionate (BDP), formoterol fumarate (FF) and glycopyrronium (G) in a single inhaler. The TRILOGY, TRINITY and TRIBUTE studies have provided confirming evidence for a clinical benefit of triple therapy over ICS/LABA combination treatment, LAMA monotherapy and LABA/LAMA combination, with prevention of exacerbations being a key finding. A pooled post hoc analysis of the published clinical studies involving BDP/FF/G fixed combination demonstrated a reduction in fatal events in patients treated with ICS-containing medications, with a trend of statistical significance [hazard ratio = 0.72, 95% confidence interval (CI) 0.50-1.02, p = 0.066], that becomes significant if we consider reduction in fatal events for non-respiratory reasons (hazard ratio = 0.65, 95% CI 0.43-0.97, p = 0.037). In conclusion, a fixed combination of more drugs in a single inhaler can improve long-term adherence to the therapy, reducing the risk of exacerbations and hospital resources utilization. The twice a day administration may provide a better coverage of night, particularly in COPD patients who are highly symptomatic. The inhaled extrafine formulation that allows drug deposition in both large and small - peripheral - airways, is the value added.

Drug interaction and chronic obstructive respiratory disorders

Chronic obstructive respiratory disorders uncontrolled by monotherapy should be given combinations of drugs that act by distinct mechanisms of action. The rationale for combining different classes of drugs should be to elicit a synergistic interaction, lower the dose of the single components in the combinations and, thus, reduce the risk of adverse events.

The aim of this systematic review was to investigate the combined effect of drugs acting on human airways, by including studies that used a validated method for assessing the nature of drug interaction.

Current evidence indicates that drug combinations modulating the bronchial contractility induce a synergistic relaxant effect when the individual components are combined at isoeffective concentrations. There are several mechanisms of action underlying drug interactions. Pharmacological research has been directed to elucidate what causes the synergism between long-acting β₂-adrenoceptor (β₂-AR) agonists (LABAs), long-acting muscarinic antagonist (LAMAs), and inhaled corticosteroids (ICS) administered as dual or triple combination. Conversely, the mechanisms behind the additive interaction between phosphodiesterase 3 and 4 inhibitors and LAMAs, and the synergistic interaction between proliferator-activated receptor gamma ligands and β₂ agonists have been only hypothesized. Overall, the synergism elicited by combined drugs for the treatment of chronic respiratory disorders is an effect of class, rather than specific for drug combinations. Optimal synergy can be achieved only when the single agents are combined at isoeffective concentrations, and when monocomponents are given concurrently to reach together the same levels of the bronchial tree.

•

Drug interaction should be identified with validated pharmacological models.

•

Synergistic efficacy is the rationale for combining drugs for respiratory diseases.

•

Synergy is favored when combined agents act by distinct mechanisms of action.

•

Optimal synergy is achieved when drugs are combined at isoeffective concentrations.

•

Synergy is a class effect and is not specific for single drug combinations.

Beclomethasone dipropionate and sodium cromoglycate protect against airway hyperresponsiveness in a human ex vivo model of cow's milk aspiration

Background

Recurrent cow's milk (CM) aspiration is often associated with gastroesophageal reflux in infants and toddlers and it seems to be implicated in the etiology of different inflammatory lung disorders. This study aimed to investigate ex vivo the impact of CM aspiration on human airways and whether treatment with beclomethasone dipropionate (BDP) or sodium cromoglycate (SCG) may prevent the potential CM-induced airway hyperresponsiveness (AHR).

Methods

Human isolated bronchi were contracted by electrical field stimulation (EFS_10Hz) to mimic the contractile tone induced by the parasympathetic activity and challenged with CM, fat/lactose-free CM, or human breast milk (HM). The effect of pre-treatment with beclomethasone dipropionate (BDP) and sodium cromoglycate (SCG) was also investigated on the AHR induced by CM.

Results

After a 60 min-challenge with CM 1:10 v/v and fat/lactose-free CM 1:10 v/v, ASM significantly (P ​< ​0.05) increased compared to control (+67.04 ​± ​17.08% and +77.91 ​± ​1.34%, respectively), a condition that remained stable for 150 ​min post-treatment, whereas HM did not alter ASM contractility. BDP 1 ​μM and 10 ​μM significantly (P ​< ​0.05) reduced the AHR elicited by CM (−52.49 ​± ​10.97% and −66.98 ​± ​7.90%, respectively vs. control). At the same manner, SCG 1 ​μM and 10 ​μM significantly (P ​< ​0.05) inhibited the CM-induced AHR (−59.03 ​± ​9.24% and −73.52 ​± ​7.41%, respectively vs. control).

Conclusion

CM induces AHR in human ASM by eliciting an increased parasympathetic contractile response. Preventive treatment with nebulized SCG may be indicated in infants or toddlers fed with CM, rather than with BDP due to a superior safety profile.

•

Cow's milk aspiration seems to be associated with some inflammatory lung diseases.

•

Cow's milk aspiration induces human airway hyperresponsiveness.

•

Beclomethasone and sodium cromoglycate protect against cow's milk hyperresponsiveness in vitro.

•

Inhaled sodium cromoglycate might be suitable in children at risk of cow's milk aspiration.

Impact of long-acting muscarinic antagonists on small airways in asthma and COPD: A systematic review

Small airway disease is recognized as a cardinal pathological process of chronic obstructive pulmonary disease (COPD), and recently small airways have been recognized as a major site of airflow obstruction also in asthmatic patients. The transversal involvement of small airways in COPD and asthma has warranted research efforts to identify therapeutic strategies able to unlock the small airway compartment. The mainstay of COPD treatment is represented by long-acting β₂-adrenoceptor agonists (LABAs) and long-acting muscarinic antagonists (LAMAs). In asthma, the efficacy of LAMAs administered add-on to inhaled corticosteroids (ICSs) or ICS/LABA combinations has been investigated only in recent years. The aim of this systematic review was to examine the current literature concerning the impact of LAMAs on small airways and their lung deposition in both COPD and asthma. LAMAs administered either alone or in combination induced an effective bronchorelaxant effect of small airways, however the effectiveness of respiratory medications not only relies on the selected drug, but also on the employed inhalation device and patient's adherence. Tiotropium delivered via Respimat® SMI achieved a superior drug deposition in the peripheral lung compared to HandiHaler® dry powder inhaler and metered-dose inhalers (MDIs). The use of co-suspension™ delivery technology for MDIs and the introduction of the eFlow® nebulizer to deliver glycopyrronium improved aerosol drug delivery to the peripheral lung, by achieving uniform distribution of drug particles. This systematic review provides a synthesis of current literature concerning the impact of LAMAs on small airways and an insight on LAMAs distribution within the lung.

Indacaterol, glycopyrronium, and mometasone: pharmacological interaction and anti-inflammatory profile in hyperresponsive airways

LABA/ICS and LABA/LAMA/ICS combinations elicit beneficial effects in asthma. Specific evidence concerning the impact of combining indacaterol acetate (IND), glycopyrronium bromide (GLY), and mometasone furoate (MF) on human airway hyperresponsiveness (AHR) and airway inflammation is still missing. The aim of this study was to characterize the synergy of IND/MF and IND/GLY/MF combinations, both once-daily treatments for asthma, in hyperresponsive airways. Passively sensitized human medium and small airways were stimulated by histamine and treated with IND/MF (molar ratio: 100/45, 100/90) and IND/GLY/MF (molar ratio: 100/37/45, 100/37/90). The effect on contractility and airway inflammation was tested. Drug interaction was assessed by Bliss Independence equation and Unified Theory. IND/MF 100/90 elicited middle-to-very strong synergistic relaxation in medium and small airways (+≈20-30% vs. additive effect, P<0.05), for IND/MF 100/45 the synergy was middle-to-very strong in small airways (+≈20% vs. additive effect, P<0.05), and additive in medium bronchi (P>0.05 vs. additive effect). IND/GLY/MF 100/37/45 and 100/37/90 induced very strong synergistic relaxation in medium and small airways (+≈30-50% vs. additive effect, P<0.05). Synergy was related with significant (P<0.05) reduction in IL-4, IL-5, IL-6, IL-9, IL-13, TNF-α, TSLP, NKA, SP, and non-neuronal ACh, and enhancement in cAMP. IND/MF and IND/GLY/MF combinations synergistically interact in hyperresponsive medium and small airways and modulate the levels of cytokines, neurokinins, ACh, and intracellular cAMP. The concentrations of MF in the combinations modulate the effects in the target tissue.

Current long-acting muscarinic antagonists for the treatment of asthma

INTRODUCTION

The role of long-acting muscarinic antagonists (LAMAs) is well established in uncontrolled asthma, but not in milder stages.

AREAS COVERED

This review examines the main randomized controlled trials (RCTs) that have investigated LAMAs administered as monotherapy or in combination to asthmatic patients, according to the different phenotypes. It offers an overview of the role of LAMAs or their fixed dose combinations (FDCs) in the treatment across all the different stages of asthma.

EXPERT OPINION

Tiotropium is now widely recognized as treatment for moderate to severe uncontrolled asthma (step 4-5) in adults and children. The most recent new evidence is: a) in adults, three different LAMA/long-acting β₂-agonist (LABA)/inhaled corticosteroid (ICS) FDCs have been recently approved, extending the treatment options for these patients; b) therapy with LAMAs does not depend on patient's Th2 status and justifies the indication regardless of patient's phenotyping; c) in the milder stages, the high variability of response to LAMAs and the lack of a good phenotyping of patients represents the main obstacle in prescribing LAMAs. A better characterization of parasympathetic tone activity could improve LAMAs prescription.

Long-acting muscarinic antagonists and small airways in asthma: Which link?

Involvement of small airways, those of <2 mm in internal diameter, is present in all stages of asthma and contributes substantially to its pathophysiologic expression. Therefore, small airways are a potential target to achieve optimal asthma control. Airway tone, which is increased in asthma, is mainly controlled by the vagus nerve that releases acetylcholine (ACh) and activates muscarinic ACh receptors (mAChRs) post-synaptically on airway smooth muscle (ASM). In small airways, M₃ mAChRs are expressed, but there is no vagal innervation. Non-neuronal ACh released from the epithelial cells that may express choline acetyltransferase in response to inflammatory stimuli, as well as from other structural cells in the airways, including fibroblasts and mast cells, can activate mAChRs. By antagonizing M₃ mAChR, the contraction of the ASM is prevented and, potentially, local inflammation can be reduced and the progression of remodeling may be averted. In fact, ACh also contributes to inflammation and remodeling of the airways and regulates the growth of ASM. Several experimental studies have demonstrated the potential benefit derived from the use of mAChR antagonists, mainly long-acting mAChR antagonists (LAMAs), on small airways in asthma. However, there are several confounding factors that may cause a wrong estimation of the relationship between LAMAs and small airways in asthma. Further studies are needed to differentiate broncholytic and anti-inflammatory effects of LAMAs and to better understand the interaction between LAMAs and corticosteroids, also in the context of a triple therapy that includes a β₂ -AR agonist, at different levels of the bronchial tree.

Inhaled long-acting muscarinic antagonists in asthma - A narrative review

Long-acting muscarinic antagonists (LAMAs) have a recognised role in the management of chronic obstructive pulmonary disease. In asthma, muscarinic antagonists (both short- and long-acting) were historically considered less effective than β₂-agonists; only relatively recently have studies been conducted to evaluate the efficacy of LAMAs, as add-on to either inhaled corticosteroid (ICS) monotherapy or ICS/long-acting β₂-agonist (LABA) combinations. These studies led to the approval of the first LAMA, tiotropium, as an add-on therapy in patients with poorly controlled asthma. Subsequently, a number of single-inhaler ICS/LABA/LAMA triple therapies have been approved or are in clinical development for the management of asthma. There is now substantial evidence of the efficacy and safety of LAMAs in asthma that is uncontrolled despite treatment with an ICS/LABA combination. This regimen is recommended by GINA as an optimisation step for patients with severe asthma before any biologic or systemic corticosteroid treatment is initiated. This narrative review summarises the potential mechanisms of action of LAMAs in asthma, together with the initial clinical evidence supporting this use. We also discuss the studies that led to the approval of tiotropium for asthma and the data evaluating the efficacy and safety of the various triple therapies, before considering other potential uses for triple therapy.

The Impact of Muscarinic Receptor Antagonists on Airway Inflammation: A Systematic Review

Long-acting muscarinic receptor antagonists (LAMAs) are the cornerstone for the treatment of chronic obstructive pulmonary disease (COPD); furthermore, tiotropium is approved as add-on therapy in severe asthmatic patients. Accumulating evidence suggests that LAMAs may modulate airway contractility and airway hyperresponsiveness not only by blocking muscarinic acetylcholine receptors (mAchRs) expressed on airway smooth muscle but also via anti-inflammatory mechanisms by blocking mAchRs expressed on inflammatory cells, submucosal glands, and epithelial cells. The aim of this systematic review, performed according to the PRISMA-P guidelines, was to provide a synthesis of the literature on the anti-inflammatory impact of muscarinic receptor antagonists in the airways. Most of the current evidence originates from studies on tiotropium, that demonstrated a reduction in synthesis and release of cytokines and chemokines, as well as the number of total and differential inflammatory cells, induced by different pro-inflammatory stimuli. Conversely, few data are currently available for aclidinium and glycopyrronium, whereas no studies on the potential anti-inflammatory effect of umeclidinium have been reported. Overall, a large body of evidence supports the beneficial impact of tiotropium against airway inflammation. Further well-designed randomized controlled trials are needed to better elucidate the anti-inflammatory mechanisms leading to the protective effect of LAMAs against exacerbations via identifying suitable biomarkers.

Synergy across the drugs approved for the treatment of asthma

INTRODUCTION

Inhaled corticosteroids are the cornerstone for the treatment of stable asthma, however, when disease severity increases, escalating therapy to combinations of drugs acting on distinct signalling pathways is required. It is advantageous to providing evidence of a synergistic interaction across drug combinations, as it allows optimizing bronchodilation while lowering the dose of single agents. In the respiratory pharmacology field, two statistical models are accepted as gold standard to characterize drug interactions, namely the Bliss Independence criterion and the Unified Theory. In this review, pharmacological interactions across drugs approved for the treatment of asthma have been systematically assessed.

EVIDENCE ACQUISITION

A comprehensive literature search was performed in MEDLINE for studies that used a validated pharmacological method for assessing drug interaction. The results were extracted and reported via qualitative synthesis.

EVIDENCE SYNTHESIS

Overall, 45 studies were identified from literature search and 5 met the inclusion criteria. Current evidence coming from ex vivo models of asthma indicates that drug combinations modulating bronchial contractility induce a synergistic bronchorelaxant effect. In murine models of lung inflammation, the combination between inhaled corticosteroids and β2- adrenoceptor agonists synergistically improve lung function and the inflammatory profile.

CONCLUSIONS

There is still limited knowledge regarding the mechanistic basis underlying pharmacological interactions across drugs approved for asthma. The synergism elicited by combined agents is an effect of class. Specifically designed clinical trials are needed to confirm the results coming from preclinical evidence, but also to establish the minimal dose for combined agents to induce a synergistic interaction and maximize bronchodilation.

Small airways in asthma: from bench-to-bedside

INTRODUCTION

Historically, asthma was considered a disease predominantly of the large airways, but gradually small airways have been recognized as the major site of airflow obstruction. Small airway dysfunction (SAD) significantly contributes to the pathophysiology of asthma and it is present across all asthma severities. Promising pre-clinical findings documented enhanced beneficial effects of combination therapies on small airways compared to monocomponents, thus it was questioned whether this could translate into further clinical implications from bench-to-bedside. The aim of this review was to systematically assess the state of the art of small airway involvement in asthma, especially in response to different pharmacological treatments acting on the respiratory system.

EVIDENCE ACQUISITION

A comprehensive literature search was performed in MEDLINE for randomized controlled trials (RCTs) characterizing the impact on small airways of different pharmacological treatments acting on the respiratory system. The results were extracted and reported via qualitative synthesis.

EVIDENCE SYNTHESIS

Overall, 63 studies were identified from the literature search, whereas 23 RCTs met the inclusion criteria. Evidence confirms that both drug particle size and the type of inhalation devices represent two of the most important variables for an effective peripheral lung distribution.

CONCLUSIONS

Despite the numerous methodological tools to detect SAD, there is still no gold standard diagnostic method to assess small airways, especially in severe asthma. Further research should be directed to improve primary and secondary prevention strategies by supporting the combined approach of different non-invasive techniques for an early detection of peripheral abnormalities and optimization of asthma therapy.

Targeting IL-5 pathway against airway hyperresponsiveness: A comparison between benralizumab and mepolizumab

BACKGROUND AND PURPOSE

Airway hyperresponsiveness (AHR) is a central abnormality in asthma. IL-5 may modulate AHR in animal models of asthma, but the available data is inconsistent on the impact of targeting IL-5 pathway against AHR. The difference between targeting IL-5 or the IL-5 receptor, α subunit (IL-5Rα) in modulating AHR remains to be investigated in human airways. The aim of this study was to compare the role of the anti-IL-5Rα benralizumab and the anti-IL-5 mepolizumab against AHR and to assess whether these agents influence the levels of cAMP.

EXPERIMENTAL APPROACH

Passively sensitized human airways were treated with benralizumab and mepolizumab. The primary endpoint was the inhibition of AHR to histamine. The secondary endpoints were the protective effect against AHR to parasympathetic activation and mechanical stress, and the tissue modulation of cAMP.

KEY RESULTS

Benralizumab and mepolizumab significantly inhibited the AHR to histamine (maximal effect -134.14 ± 14.93% and -108.29 ± 32.16%, respectively), with benralizumab being 0.73 ± 0.10 logarithm significantly more potent than mepolizumab. Benralizumab and mepolizumab significantly inhibited the AHR to transmural stimulation and mechanical stress. Benralizumab was 0.45 ± 0.16 logarithm significantly more potent than mepolizumab against AHR to parasympathetic activation. The effect of these agents was significantly correlated with increased levels of cAMP.

CONCLUSION AND IMPLICATIONS

Targeting the IL-5/IL-5Rα axis is an effective strategy to prevent the AHR. Benralizumab was more potent than the mepolizumab and the concentration-dependent beneficial effects of both these monoclonal antibodies were related to improved levels of cAMP in hyperresponsive airways.

Advances with glucocorticoids in the treatment of asthma: state of the art

INTRODUCTION

Asthma is one of the most frequent chronic diseases all over the world. Glucocorticoids (GCs), both inhaled (ICSs) and oral (OCSs), are the most effective treatment in asthma because they control symptoms and prevent exacerbations.

AREAS COVERED

The present article reviews the new therapeutic indications of GCs for the treatment of asthma and focuses on new molecules and safety issues.

EXPERT OPINION

Most patients with asthma benefit from corticosteroid-based treatments. Side effects are mainly due to prolonged use of oral GCs, while they are minor with inhaled GCs. Interesting insights come from the new ICSs, which are characterized by lower oral bioavailability and higher lipophilicity and are more effective with less side effects. Recent trials have shown the efficacy of early use of ICSs in mild asthma. Furthermore, the possibility to prescribe targeted therapies using specific biomarkers in steroid-sensitive asthma can reduce doses and duration of treatment, while biological agents should be reserved for non-responding patients. All this evidence confirm the need to continue on the path toward precision medicine, in which the treatments are based on clinical and molecular traits.

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.

Investigational treatments in phase I and II clinical trials: a systematic review in chronic obstructive pulmonary disease (COPD)

Introduction. The current pharmacological treatments for the management of stable COPD permit the reduction of symptoms and frequency and severity of exacerbations, and the improvement of exercise tolerance and health status. However, they do not modify the long-term decline in lung function and patient health. Consequently, there is the strong need for 'highly innovative' medications that are focused on new targets and/or mechanisms for the treatment of COPD. Areas covered. This systematic review assesses investigational agents in Phase I and II clinical trials over the last six years. It offers insights on whether drugs and/or formulations in clinical development offer future effective treatments of COPD. Expert opinion. There is no evidence to suggest that current investigational agents can reduce lung function decline and cure COPD. However, looking forward, investigational, innovative treatments in combination with the therapies already recommended by the Global Initiative for Chronic Obstructive Lung Disease (GOLD) may provide future suitable tools to counteract the progression of COPD.

New perspectives on the role of muscarinic antagonists in asthma therapy

INTRODUCTION

There is increasing evidence that tiotropium, a long-acting muscarinic agent (LAMA), is useful in the presence of severe-uncontrolled asthma despite the optimization of therapy with inhaled corticosteroids (ICSs) and long-acting β₂ agonists (LABAs) as recommended by the current guidelines. Furthermore, in recent years there have been several  preclinical and clinical studies on the pharmacological and therapeutic impact of other LAMAs in asthma.

AREAS COVERED

We have conducted an extensive search on muscarinic antagonists in asthma therapy throughout several sources and discuss what has emerged in the last 3 years (January 2017-March 2020).

EXPERT OPINION

New evidence indicates that the effectiveness of adding a LAMA, at least tiotropium, is independent of the degree of the type 2 inflammation and age of patient. Therefore, tiotropium can be administered without the need for patient phenotyping. Umeclidinium and glycopyrronium also appear effective in asthma. Initial treatment with LAMA+ICS for those with mild asthma may be an equally effective therapeutic option as LABA+ICS but this hypothesis should be confirmed by statistically powered trials.

Beclomethasone dipropionate, formoterol fumarate and glycopyrronium bromide: Synergy of triple combination therapy on human airway smooth muscle ex vivo

BACKGROUND AND PURPOSE

Combining inhaled corticosteroids (ICSs), long-acting β₂ -adrenoceptor agonists (LABAs) and long-acting muscarinic antagonists (LAMAs) is recommended to treat severe forms of asthma and chronic obstructive pulmonary disease (COPD). Clinical benefits have been demonstrated for ICS/LABA/LAMA combinations. This study characterized the interaction between the ICS beclomethasone dipropionate, the LABA formoterol fumarate and the LAMA glycopyrronium bromide in human airways.

EXPERIMENTAL APPROACH

Human passively sensitized airways and bronchi from COPD donors were stimulated with histamine or carbachol. Tissues were incubated overnight with beclomethasone and then treated with formoterol and glycopyrronium, alone or in triple combination. The interaction was assessed by using Bliss Independence and Unified Theory theorems.

KEY RESULTS

Beclomethasone/formoterol/glycopyrronium combination synergistically relaxed medium bronchi and small airways. Beclomethasone/formoterol/glycopyrronium combination at 100:6:12.5 combination ratio was a balanced drug mixture leading to very strong synergistic effect on relaxation of medium bronchi (Combination Index: from 0.042 to 0.96) and middle to very strong synergy in small airways (Combination Index: from 0.018 to 0.310). The synergy was related with the activation of intracellular glucocorticoid receptors and G_sα subunit G-protein of β₂ -adrenoceptors, leading to the modulation of cyclic AMP-dependent PKA pathway.

CONCLUSION

Triple beclomethasone/formoterol/glycopyrronium combination induces synergistic bronchorelaxant effect in medium and small human airways, at least in ex vivo experiments. Further research is needed to confirm these findings in clinical studies in patients with asthma or COPD.

Pharmacology and Therapeutics of Bronchodilators Revisited

Bronchodilators remain the cornerstone of the treatment of airway disorders such as asthma and chronic obstructive pulmonary disease (COPD). There is therefore considerable interest in understanding how to optimize the use of our existing classes of bronchodilator and in identifying novel classes of bronchodilator drugs. However, new classes of bronchodilator have proved challenging to develop because many of these have no better efficacy than existing classes of bronchodilator and often have unacceptable safety profiles. Recent research has shown that optimization of bronchodilation occurs when both arms of the autonomic nervous system are affected through antagonism of muscarinic receptors to reduce the influence of parasympathetic innervation of the lung and through stimulation of β 2-adrenoceptors (β 2-ARs) on airway smooth muscle with β 2-AR-selective agonists to mimic the sympathetic influence on the lung. This is currently achieved by use of fixed-dose combinations of inhaled long-acting β 2-adrenoceptor agonists (LABAs) and long-acting muscarinic acetylcholine receptor antagonists (LAMAs). Due to the distinct mechanisms of action of LAMAs and LABAs, the additive/synergistic effects of using these drug classes together has been extensively investigated. More recently, so-called "triple inhalers" containing fixed-dose combinations of both classes of bronchodilator (dual bronchodilation) and an inhaled corticosteroid in the same inhaler have been developed. Furthermore, a number of so-called "bifunctional drugs" having two different primary pharmacological actions in the same molecule are under development. This review discusses recent advancements in knowledge on bronchodilators and bifunctional drugs for the treatment of asthma and COPD. SIGNIFICANCE STATEMENT: Since our last review in 2012, there has been considerable research to identify novel classes of bronchodilator drugs, to further understand how to optimize the use of the existing classes of bronchodilator, and to better understand the role of bifunctional drugs in the treatment of asthma and chronic obstructive pulmonary disease.

Optimizing the Development Strategy of Combination Therapy in Respiratory Medicine: From Isolated Airways to Patients

The current recommendations for the treatment of chronic obstructive pulmonary disease (COPD) are pushing towards triple combination therapy based on the combination of an inhaled corticosteroid (ICS) associated with two bronchodilator agents. However, dual bronchodilation remains the cornerstone for the treatment of most COPD patients. Combining a long-acting β₂ adrenoceptor agonist (LABA) with a long-acting muscarinic antagonist (LAMA) induces appreciable synergistic bronchorelaxant effect in human airways, especially when the medications are combined at isoeffective concentrations. Thus, each LABA/LAMA combination is characterized by a specific range of concentration-ratio at which the drug mixture may induce sustained synergistic interaction. Results of a recent randomized controlled trial (RCT, NCT00696020) and evidences from pre-clinical studies in human isolated airways poses the question whether combining tiotropium 5 μg with olodaterol 5 μg is the best combination option: tiotropium/olodaterol 5/5 μg has the same efficacy profile of tiotropium/olodaterol 5/2 μg, and it is less effective than tiotropium/olodaterol 5/10 μg. Furthermore, tiotropium/olodaterol 5/2 μg, 5/5 μg, and 5/10 μg combinations are generally characterized by the same safety profile. Indeed tiotropium/olodaterol 5/5 μg is effective and safe in COPD, but a different development strategy based on solid data obtained from human isolated airways would have driven towards a better-balanced FDC to be tested in Phase III RCTs. Accurate bench-to-bedside plans are needed also in the development of triple combination therapies for asthma and COPD, in which the presence of an ICS in the formulation may further modulate the beneficial interaction between the LABA and the LAMA.

Budesonide enhances agonist-induced bronchodilation in human small airways by increasing cAMP production in airway smooth muscle

The nongenomic mechanisms by which glucocorticoids modulate β₂ agonist-induced-bronchodilation remain elusive. Our studies aimed to elucidate mechanisms mediating the beneficial effects of glucocorticoids on agonist-induced bronchodilation. Utilizing human precision-cut lung slices (hPCLS), we measured bronchodilation to formoterol, prostaglandin E₂ (PGE₂), cholera toxin (CTX), or forskolin in the presence and absence of budesonide. Using cultured human airway smooth muscle (HASM), intracellular cAMP was measured in live cells following exposure to formoterol, PGE₂, or forskolin in the presence or absence of budesonide. We showed that simultaneous budesonide administration amplified formoterol-induced bronchodilation and attenuated agonist-induced phosphorylation of myosin light chain, a necessary signaling event mediating force generation. In parallel studies, cAMP levels were augmented by simultaneous exposure of HASM cells to formoterol and budesonide. Budesonide, fluticasone, and prednisone alone rapidly increased cAMP levels, but steroids alone had little effect on bronchodilation in hPCLS. Bronchodilation induced by PGE₂, CTX, or forskolin was also augmented by simultaneous exposure to budesonide in hPCLS. Furthermore, HASM cells expressed membrane-bound glucocorticoid receptors that failed to translocate with glucocorticoid stimulation and that potentially mediated the rapid effects of steroids on β₂ agonist-induced bronchodilation. Knockdown of glucocorticoid receptor-α had little effect on budesonide-induced and steroid-dependent augmentation of formoterol-induced cAMP generation in HASM. Collectively, these studies suggest that glucocorticoids amplify cAMP-dependent bronchodilation by directly increasing cAMP levels. These studies identify a molecular mechanism by which the combination of glucocorticoids and β₂ agonists may augment bronchodilation in diseases such as asthma or chronic obstructive pulmonary disease.

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.

Pharmacological treatment and current controversies in COPD

Bronchodilators, corticosteroids, and antibiotics are still key elements for treating chronic obstructive pulmonary disease in the 2019 Global Initiative for Chronic Obstructive Lung Disease (GOLD) recommendations and this is due in part to our current inability to discover new drugs capable of decisively influencing the course of the disease. However, in recent years, information has been produced that, if used correctly, can allow us to improve the use of the available therapies.

Relaxant effect of Lippia origanoides essential oil in guinea-pig trachea smooth muscle involves potassium channels and soluble guanylyl cyclase

ETHNOPHARMACOLOGICAL RELEVANCE

Lippia origanoides H.B.K. is an aromatic species used in folk medicine to treat respiratory diseases, including asthma.

AIM OF THE STUDY

The aim of this work was to evaluate the relaxing potential and mechanism of action of the L. origanoides (LOO) essential oil in isolated guinea-pig trachea.

MATERIALS AND METHODS

Leaves from L. origanoides were collected at experimental fields under organic cultivation, at the Forest Garden of Universidade Estadual de Feira de Santana. Essential oil was extracted by hydrodistillation, analyzed by GC/FID and GC/MS and the volatile constituents were identified. Spasmolytic activity and relaxant mechanism of LOO were assayed in isolated guinea-pig trachea contracted with histamine, carbachol or hyperpolarizing KCl.

RESULTS

Chemical analysis revealed the presence of carvacrol (53.89%) as major constituent. LOO relaxed isolated guinea-pig trachea pre-contracted with KCl 60 mM [EC₅₀ = 30.02 μg/mL], histamine 1 µM [EC₅₀ = 9.28 μg/mL] or carbachol 1 µM [EC₅₀ = 51.80 μg/mL]. The pre-incubation of glibenclamide, CsCl, propranolol, indomethacin, hexamethonium, aminophylline or L-NAME in histamine-induced contractions did not alter significantly the relaxant effect of LOO. However, the presence of 4-aminopyridine, tetraethylammonium or methylene blue reduced LOO effect, while the presence of dexamethasone or atropine potentialized the LOO relaxant effect. LOO pre-incubation inhibited carbachol-evoked contractions, with this effect potentialized in the presence of sodium nitroprusside and blocked in the presence of ODQ.

CONCLUSIONS

The relaxant mechanism of LOO on the tracheal smooth muscle possibly involves stimulating of soluble guanylyl cyclase with consequent activation of the voltage-gated and Ca²⁺-activated K⁺ channels.

Beclomethasone dipropionate and formoterol fumarate synergistically interact in hyperresponsive medium bronchi and small airways

Background

Corticosteroids increase the expression of β₂-adrenoceptors (β₂-ARs) and protect them against down-regulation. Conversely, β₂-AR agonists improve the anti-inflammatory action of corticosteroids. Nevertheless, it is still uncertain whether adding a long-acting β₂-AR agonist (LABA) to an inhaled corticosteroid (ICS) results in an additive effect, or there is true synergy.

Therefore, the aim of this study was to pharmacologically characterize the interaction between the ICS beclomethasone diproprionate (BDP) and the LABA formoterol fumarate (FF) in a validated human ex vivo model of bronchial asthma.

Methods

Human medium and small airways were stimulated by histamine and treated with different concentrations of BDP and FF, administered alone and in combination at concentration-ratio reproducing ex vivo that of the currently available fixed-dose combination (FDC; BDP/FF 100:6 combination-ratio). Experiments were performed in non-sensitized (NS) and passively sensitized (PS) airways. The pharmacological interaction was assessed by using Bliss Independence and Unified Theory equations.

Results

BDP/FF synergistically increased the overall bronchorelaxation in NS and PS airways (+ 15.15% ± 4.02%; P < 0.05 vs. additive effect). At low-to-medium concentrations the synergistic interaction was greater in PS than in NS bronchioles (+ 16.68% ± 3.02% and + 7.27% ± 3.05%, respectively). In PS small airways a very strong synergistic interaction (Combination Index: 0.08; + 20.04% ± 2.18% vs. additive effect) was detected for the total concentrations of BDP/FF combination corresponding to 10.6 ng/ml.

Conclusion

BDP/FF combination synergistically relaxed human bronchi; the extent of such an interaction was very strong at low-to-medium concentrations in PS small airways.

Trial registration

Not applicable.

Electronic supplementary material

The online version of this article (10.1186/s12931-018-0770-7) contains supplementary material, which is available to authorized users.

Long-Acting Muscarinic Antagonists for Difficult-to-Treat Asthma: Emerging Evidence and Future Directions

Asthma is a complex disease where many patients remain symptomatic despite guideline-directed therapy. This suggests an unmet need for alternative treatment approaches. Understanding the physiological role of muscarinic receptors and the parasympathetic nervous system in the respiratory tract will provide a foundation of alternative therapeutics in asthma. Currently, several long-acting muscarinic antagonists (LAMAs) are on the market for the treatment of respiratory diseases. Many studies have shown the effectiveness of tiotropium, a LAMA, as add-on therapy in uncontrolled asthma. These studies led to FDA approval for tiotropium use in asthma. In this review, we discuss how the neurotransmitter acetylcholine itself contributes to inflammation, bronchoconstriction, and remodeling in asthma. We further describe the current clinical studies evaluating LAMAs in adult and adolescent patients with asthma, providing a comprehensive review of the current known physiological benefits of LAMAs in respiratory disease.

Role of muscarinic antagonists in asthma therapy

INTRODUCTION

Higher parasympathetic tone has been reported in asthmatics. In general, cholinergic contractile tone is increased by airway inflammation associated with asthma. Nevertheless, the role of muscarinic antagonists for the treatment of asthma has not yet been clearly defined. Areas covered: The use of SAMAs and LAMAs in asthma has been examined and discussed according with the published evidence. Particular attention has been given to the large Phase III clinical trial program designed to evaluate the efficacy and safety of tiotropium respimat added to standard treatment in adults, adolescents and children with persistent asthma across the spectrum of asthma severity. Expert commentary: The current evidence is that in patients with poorly controlled severe asthma despite the use of ICS and LABA, the addition of tiotropium significantly increases the time to the first severe exacerbation and provides a modest but sustained bronchodilation. Identical results should be produced using other LAMAs. In any case, the documentation that, at least in animal or in vitro models, LAMAs show significant anti-inflammatory and anti-proliferative capacities and are able to inhibit airway remodeling induced by allergens makes a strong presumption that the use of LAMAs in asthma may go beyond the simple bronchodilator effect.