Efficacy of anticholinergic drugs in asthma

Neuroimmune Pathophysiology in Asthma

Asthma is a chronic inflammation of lower airway disease, characterized by bronchial hyperresponsiveness. Type I hypersensitivity underlies all atopic diseases including allergic asthma. However, the role of neurotransmitters (NT) and neuropeptides (NP) in this disease has been less explored in comparison with inflammatory mechanisms. Indeed, the airway epithelium contains pulmonary neuroendocrine cells filled with neurotransmitters (serotonin and GABA) and neuropeptides (substance P[SP], neurokinin A [NKA], vasoactive intestinal peptide [VIP], Calcitonin-gene related peptide [CGRP], and orphanins-[N/OFQ]), which are released after allergen exposure. Likewise, the autonomic airway fibers produce acetylcholine (ACh) and the neuropeptide Y(NPY). These NT/NP differ in their effects; SP, NKA, and serotonin exert pro-inflammatory effects, whereas VIP, N/OFQ, and GABA show anti-inflammatory activity. However, CGPR and ACh have dual effects. For example, the ACh-M3 axis induces goblet cell metaplasia, extracellular matrix deposition, and bronchoconstriction; the CGRP-RAMP1 axis enhances Th2 and Th9 responses; and the SP-NK1R axis promotes the synthesis of chemokines in eosinophils, mast cells, and neutrophils. In contrast, the ACh-α7nAChR axis in ILC2 diminishes the synthesis of TNF-α, IL-1, and IL-6, attenuating lung inflammation whereas, VIP-VPAC1, N/OFQ-NOP axes cause bronchodilation and anti-inflammatory effects. Some NT/NP as 5-HT and NKA could be used as biomarkers to monitor asthma patients. In fact, the asthma treatment based on inhaled corticosteroids and anticholinergics blocks M3 and TRPV1 receptors. Moreover, the administration of experimental agents such as NK1R/NK2R antagonists and exogenous VIP decrease inflammatory mediators, suggesting that regulating the effects of NT/NP represents a potential novel approach for the treatment of asthma.

Tiotropium in asthma - perspectives for the primary care physician

Asthma is a heterogeneous disease characterized by airway inflammation resulting from complex interactions between multiple hosts as well as environmental factors. As a chronic respiratory condition, asthma exerts a significant impact on patients and the healthcare system. Per the Global Initiative for Asthma (GINA), inhaled corticosteroids (ICS) with/without long-acting beta₂-agonists (LABAs) should be used as the preferred controllers for the management of asthma. Despite a range of therapeutic options, many patients with asthma remain uncontrolled, resulting in an increased risk of hospitalization and emergency room visits and a worsened quality of life. Tiotropium (Spiriva®, Boehringer Ingelheim Pharmaceuticals, Inc; 1.25 µg, two puffs, once daily), delivered via the Respimat® inhaler (Boehringer Ingelheim Pharmaceuticals, Inc.), was the first long-acting muscarinic antagonist to be approved as an add-on maintenance treatment option for patients with asthma aged ≥6 years at GINA steps 4 and 5. By binding to the muscarinic receptors M1 and M3 in the bronchial airways, tiotropium antagonizes the action of acetylcholine, leading to smooth muscle relaxation and reduced mucus secretion.The efficacy and safety of tiotropium add-on to ICS±LABA maintenance treatment have been evaluated in randomized controlled trials (RCTs) involving patients with a range of asthma severities (mild, moderate, and severe) and across age groups (children, adolescents, and adults). Add-on tiotropium was found to be well tolerated and efficacious in all RCTs. Moreover, the findings from real-world studies complement results from RCTs, showing beneficial effects of tiotropium in reducing exacerbations, hospitalization, emergency room visits, and asthma worsening.In this review article, we discuss the pathophysiology of asthma and the role of tiotropium in the management of asthma from the perspective of a primary care physician.

Efficacy and Safety of Tiotropium in Children and Adolescents

Asthma is one of the most common chronic diseases in children, with a high proportion of patients demonstrating poor control despite the availability of disease management guidelines. Global Initiative for Asthma guidelines include tiotropium as an add-on therapy option at Steps 4 and 5 in patients aged ≥ 12 years with a history of exacerbations, and tiotropium delivered via the Respimat® Soft Mist™ Inhaler has recently been approved for use as once-daily maintenance therapy for children with asthma over the age of 6 years in the USA. A large clinical trial program has been conducted in children, adolescents, and adults across the spectrum of asthma severity. Findings from these clinical studies and pooled analyses in children and adolescents with symptomatic moderate or severe asthma have demonstrated that tiotropium Respimat® as add-on to inhaled corticosteroids, with or without other maintenance therapies, is a well-tolerated and efficacious bronchodilator, showing improved lung function and trends towards improved asthma control, mirroring findings in adult studies. This review discusses the evidence to date for tiotropium Respimat® for the management of asthma in adolescents and children with symptomatic moderate and severe asthma, and considers the challenges of asthma management in these patients. Factors affecting this population group, such as poor adherence, underreporting of symptoms, and social and psychological issues, are highlighted, along with the need for active review and management of treatment to help achieve optimal control.

Allosteric modulators targeting CNS muscarinic receptors

Muscarinic acetylcholine receptors are G protein-coupled receptors (GPCRs) which are broadly expressed in the central nervous system (CNS) and other tissues in the periphery. They emerge as important drug targets for a number of diseases including Alzheimer's disease, Parkinson's disease, and schizophrenia. Muscarinic receptors are divided into five subtypes (M₁-M₅) of which M₁-M₄ have been crystalized. All subtypes possess at least one allosteric binding site which is located in the extracellular region of the receptor on top of the ACh (i.e. orthosteric) binding site. The former can be specifically targeted by chemical compounds (mostly small molecules) and binding of such allosteric modulators affects the affinity and/or efficacy of orthosteric ligands. This allows highly specific modulation of GPCR function and, from a drug discovery point of view, may be advantageous in terms of subtype selectivity and biased signaling. There is a plethora of allosteric modulators for all five muscarinic receptor subtypes. This review presents the basic principles of allosteric modulation of GPCRs on both the molecular and structural level focusing on allosteric modulators of the muscarinic receptor family. Further we discuss dualsteric (i.e. bitopic orthosteric/allosteric) ligands emphasizing their potential in modulating muscarinic receptor dynamics and signaling. The common mechanisms of muscarinic receptor allosteric modulation have been proven to be generalizable and are at play at many, if not all GPCRs. Given this paradigmatic role of muscarinic receptors we suggest that also new developments in muscarinic allosteric modulation may also be extended to other members of the GPCR superfamily. This article is part of the Special Issue entitled 'Neuropharmacology on Muscarinic Receptors'.

The evolving role of tiotropium in asthma

Tiotropium is a long-acting muscarinic antagonist (LAMA) that exerts its bronchodilatory effect by blocking endogenous acetylcholine receptors in the airways. Its safety and efficacy are well established for the treatment of COPD, and it is now being recognized for its role in improving lung function and control in asthma. This review discusses the evolving role of tiotropium delivered by the Respimat® in patients across the range of asthma severities and ages, and provides an overview of safety and efficacy data. Tiotropium is the only LAMA currently approved for the treatment of asthma, and evidence from a large-scale clinical trial program, including several Phase III studies in adults, has demonstrated that tiotropium improves lung function and asthma control, with a safety profile comparable with that of placebo. Clinical trials in adolescent patients (aged 12-17 years) have also shown improvements in lung function and trends toward improved asthma control. Of note, the efficacy and safety profiles are consistent regardless of baseline characteristics and phenotype. Given the large and growing body of evidence, it is likely that as clinical experience with tiotropium increases, this treatment may possibly emerge as the key choice for add-on therapy to inhaled corticosteroids/long-acting β2-agonists, and in patients who do not tolerate long-acting bronchodilators or other medications, in the future.

The evidence on tiotropium bromide in asthma: from the rationale to the bedside

Severe and poorly controlled asthma still accounts for a great portion of the patients affected. Disease control and future risk management have been identified by international guidelines as the main goals in patients with asthma. The need for new treatment approaches has led to reconsider anticholinergic drugs as an option for asthma treatment. Tiotropium is the first anticholinergic drug that has been approved for children and adults with poorly controlled asthma and is currently considered as an option for steps 4 and 5 of the Global Initiative for Asthma. In large randomized clinical trials enrolling patients with moderate to severe asthma, add-on therapy with tiotropium has demonstrated to be efficacious in improving lung function, decreasing risk of exacerbation and slowing the worsening of disease; accordingly, tiotropium demonstrated to be non inferior compared to long acting beta-agonists in the maintenance treatment along with medium to high inhaled corticosteroids. In view of the numerous ancillary effects acting on inflammation, airway remodeling, mucus production and cough reflex, along with the good safety profile and the broad spectrum of efficacy demonstrated in different disease phenotypes, tiotropium can represent a beneficial alternative in the therapeutic management of poorly controlled asthma. The present extensive narrative review presents the pharmacological and pathophysiological basis that guided the rationale for the introduction of tiotropium in asthma treatment algorithm, with a particular focus on its conventional and unconventional effects; finally, data on tiotropium efficacy and safety. from recent randomized clinical trials performed in all age categories will be extensively discussed.

Umeclidinium for the treatment of uncontrolled asthma

INTRODUCTION

Smooth muscle cell contraction in the airways is the principal therapeutic target in asthmatic subjects and its insufficient treatment is often a cause of uncontrolled disease. For this reason, research has focused on targeting smooth muscle activity with anticholinergic agents, including umeclidinium. Areas covered: This review highlights the potential application of umeclidinium, a long acting muscarinic antagonist, as a novel therapeutic approach for patients with severe uncontrolled asthma, despite maximal therapy. Expert opinion: Umeclidinium, similarly to tiotropium, which has been recently included in guidelines, may act by contrasting cholinergic activation in airways, preventing or at least reducing smooth muscle cells contraction and the consequent bronchoconstriction. This is similar to what occurs in chronic obstructive pulmonary disease, for which umeclidinium has been regularly approved. However, available data is not sufficient and further studies are needed before regulatory approval can be sought, since only phase II clinical trials have been conducted at present. Both quality of life and objectifiable clinical data and parameters must be assessed, including lung function improvements, reduction of exacerbations and reduction of as required medications.

Positioning of Long-Acting Muscarinic Antagonists in the Management of Asthma

Despite a range of efficacious therapies for asthma, including inhaled corticosteroids (ICS) and long-acting β₂-agonists (LABA), a significant proportion of patients have poor asthma control and retain a risk of future worsening of their symptoms. Long-acting muscarinic antagonist (LAMA) bronchodilators offer a well-tolerated, efficacious, and cost-effective add-on to a patient's treatment. Of the LAMAs currently under investigation or available for the treatment of asthma, evidence from a comprehensive clinical trial program in adults and children shows that once-daily treatment with tiotropium provides benefits for patients with uncontrolled asthma despite the use of ICS and LABAs. Tiotropium is included in the Global Initiative for Asthma (GINA) strategy document as an add-on therapy option for patients at Step 4 or 5 with a history of asthma exacerbations. Tiotropium Respimat® has demonstrated safety and efficacy in patients with a range of disease severities, ages, and phenotypes. This review describes the evidence for the use of LAMA as add-on therapy for patients with asthma who remain uncontrolled despite the use of ICS and LABA treatments.

Long-acting muscarinic antagonists: a potential add-on therapy in the treatment of asthma?

Asthma is a chronic inflammatory disorder of the airways that is a major global burden on both individuals and healthcare systems. Despite guideline-directed treatment, a significant proportion of patients with asthma do not achieve control. This review focuses on the potential use of long-acting anticholinergics as bronchodilators in the treatment of asthma, with results published from clinical trials of glycopyrrolate, umeclidinium and tiotropium. The tiotropium clinical trial programme is the most advanced, with data available from a number of phase II and III studies of tiotropium as an add-on to inhaled corticosteroid maintenance therapy, with or without a long-acting β2-agonist, in patients across asthma severities. Recent studies using the Respimat Soft Mist inhaler have identified 5 µg once daily as the preferred dosing regimen, which has shown promising results in adults, adolescents and children with asthma. Tiotropium Respimat has recently been incorporated into the Global Initiative for Asthma 2015 treatment strategy as a recommended alternative therapy at steps 4 and 5 in adult patients with a history of exacerbations. The increasing availability of evidence from ongoing and future clinical trials will be beneficial in determining where long-acting anticholinergic agents fit in future treatment guidelines across a variety of patient populations and disease severities.

Tiotropium in asthma: what is the evidence and how does it fit in?

Despite current therapeutic approaches asthma remains uncontrolled in a significant proportion of patients. Short-acting anticholinergic bronchodilators have a very long history of use in asthma, and recent data confirms the importance of acetylcholine as both a bronchoconstrictor and as a regulator of inflammation and remodeling in the lungs. Data from a comprehensive clinical trial programme, as well as use in primary care, show the efficacy and safety of tiotropium in adults with mild to moderate asthma when it is added to ICS and in severe asthma when it is added to high doses of ICS plus LABA, as well as in adolescents. Tiotropium is cost effective and its benefits are not restricted to particular phenotypes, making it a useful addition to the therapeutic options recommended by the Global Initiative for Asthma (GINA) for people with poorly controlled asthma at steps 4 & 5.

Advances in the treatment of virus-induced asthma

Viral exacerbations continue to represent the major burden in terms of morbidity, mortality and health care costs associated with asthma. Those at greatest risk for acute asthma are those with more severe airways disease and poor asthma control. It is this group with established asthma in whom acute exacerbations triggered by virus infections remain a serious cause of increased morbidity. A range of novel therapies are emerging to treat asthma and in particular target this group with poor disease control, and in most cases their efficacy is now being judged by their ability to reduce the frequency of acute exacerbations. Critical for the development of new treatment approaches is an improved understanding of virus-host interaction in the context of the asthmatic airway. This requires research into the virology of the disease in physiological models in conjunction with detailed phenotypic characterisation of asthma patients to identify targets amenable to therapeutic intervention.

Emerging therapeutic options for the treatment of patients with symptomatic asthma

OBJECTIVE

Asthma is a chronic inflammatory disorder of the airways with increasing worldwide prevalence. Despite treatment according to guidelines, a considerable proportion of patients with asthma remain symptomatic. Different potential therapeutic options for the treatment of these patients are currently in development and undergoing clinical trials, and it is important to regularly review their status.

DATA SOURCES

A search of ClinicalTrials.gov was performed and supported by a PubMed literature search and restricted to the previous 10 years to ensure currency of data. The results were manually filtered to identify relevant articles.

STUDY SELECTIONS

Emerging therapies that are currently in phase 2 and 3 development include anti-interleukin agents (benralizumab, reslizumab, dupilumab, brodalumab, lebrikizumab, and mepolizumab), a chemoattractant receptor-homologous molecule expressed on a T-helper type 2 lymphocyte antagonist (OC000459), a phosphodiesterase-4 inhibitor (roflumilast), and long-acting muscarinic antagonists (glycopyrronium bromide, umeclidinium bromide, and tiotropium bromide).

RESULTS

The clinical trial program of the long-acting muscarinic antagonist tiotropium is currently the most advanced, with data available from different phase 2 and 3 studies. Results demonstrate that it is an efficacious add-on to at least inhaled corticosteroid maintenance therapy across severities of symptomatic asthma.

CONCLUSION

The results of ongoing and future studies will help to determine whether these emerging therapeutic options will help address the unmet need for improvement in asthma management.

Effects of the inhalation of the m3 receptor antagonist bencycloquidium bromide in a mouse cigarette smoke-induced airway inflammation model

Bencycloquidium bromide (BCQB), a novel M3 receptor antagonist, alleviates airway hyperresponsiveness, inflammation, and airway remodeling in a murine model of asthma. The aim of this study was to investigate the anti-inflammatory activity of inhaled BCQB in a cigarette smoke (CS)-induced model of acute lung inflammation. Mice exposed to CS developed chronic obstructive pulmonary disease (COPD). Inhalation of BCQB suppressed the accumulation of neutrophils and macrophages in airways and lung and also inhibited the CS-induced increases in mRNA levels of keratinocyte-derived chemokine, monocyte chemotactic protein-1, tumor necrosis factor-alpha, and interleukin-1β in lung and protein expression levels in bronchoalveolar lavage fluid. Moreover, BCQB (300 μg/ml) inhibited the CS-induced changes in superoxide dismutase and myeloperoxidase activities in the lungs. Our study suggests that BCQB might be a potential therapy for inflammation in CS-induced pulmonary diseases, including COPD.

Magnesium in man: implications for health and disease

Magnesium (Mg(2+)) is an essential ion to the human body, playing an instrumental role in supporting and sustaining health and life. As the second most abundant intracellular cation after potassium, it is involved in over 600 enzymatic reactions including energy metabolism and protein synthesis. Although Mg(2+) availability has been proven to be disturbed during several clinical situations, serum Mg(2+) values are not generally determined in patients. This review aims to provide an overview of the function of Mg(2+) in human health and disease. In short, Mg(2+) plays an important physiological role particularly in the brain, heart, and skeletal muscles. Moreover, Mg(2+) supplementation has been shown to be beneficial in treatment of, among others, preeclampsia, migraine, depression, coronary artery disease, and asthma. Over the last decade, several hereditary forms of hypomagnesemia have been deciphered, including mutations in transient receptor potential melastatin type 6 (TRPM6), claudin 16, and cyclin M2 (CNNM2). Recently, mutations in Mg(2+) transporter 1 (MagT1) were linked to T-cell deficiency underlining the important role of Mg(2+) in cell viability. Moreover, hypomagnesemia can be the consequence of the use of certain types of drugs, such as diuretics, epidermal growth factor receptor inhibitors, calcineurin inhibitors, and proton pump inhibitors. This review provides an extensive and comprehensive overview of Mg(2+) research over the last few decades, focusing on the regulation of Mg(2+) homeostasis in the intestine, kidney, and bone and disturbances which may result in hypomagnesemia.

Is there a rationale and role for long-acting anticholinergic bronchodilators in asthma?

Despite current guidelines and the range of available treatments, over a half of patients with asthma continue to suffer from poor symptomatic control and remain at risk of future worsening. Although a number of non-pharmacological measures are crucial for good clinical management of asthma, new therapeutic controller medications will have a role in the future management of the disease. Several long-acting anticholinergic bronchodilators are under investigation or are available for the treatment of respiratory diseases, including tiotropium bromide, aclidinium bromide, glycopyrronium bromide, glycopyrrolate and umeclidinium bromide, although none is yet licensed for the treatment of asthma. A recent Phase III investigation demonstrated that the once-daily long-acting anticholinergic bronchodilator tiotropium bromide improves lung function and reduces the risk of exacerbation in patients with symptomatic asthma, despite the use of inhaled corticosteroids (ICS) and long-acting β₂-agonists (LABAs). This has prompted the question of what the rationale is for long-acting anticholinergic bronchodilators in asthma. Bronchial smooth muscle contraction is the primary cause of reversible airway narrowing in asthma, and the baseline level of contraction is predominantly set by the level of ‘cholinergic tone’. Patients with asthma have increased bronchial smooth muscle tone and mucus hypersecretion, possibly as a result of elevated cholinergic activity, which anticholinergic compounds are known to reduce. Further, anticholinergic compounds may also have anti-inflammatory properties. Thus, evidence suggests that long-acting anticholinergic bronchodilators might offer benefits for the maintenance of asthma control, such as in patients failing to gain control on ICS and a LABA, or those with frequent exacerbations.

Tiotropium sustains the anti-inflammatory action of olodaterol via the cyclic AMP pathway

Mesenchymal cells (fibroblasts) of the airway wall respond to cholinergic stimulation by releasing pro-inflammatory and chemotactic cytokines and may thus contribute to chronic inflammation of the lung. Here, we studied the anti-inflammatory potential of olodaterol, a long acting β2-adrenergic receptor agonist, and tiotropium, a long-acting muscarinic receptor antagonist, and whether they interact at the level of the cyclic AMP dependent signaling pathway. Pulmonary fibroblasts of asthmatic (n = 9) and non-asthmatic (n = 8) subjects were stimulated with the muscarinic receptor agonist carbachol and interleukin-1β (IL-1 beta) in presence or absence of tiotropium or olodaterol alone, or their combination. We also measured cAMP levels and phosphorylation of the cAMP response element binding protein (CREB). As single components, carbachol, olodaterol and tiotropium did not affect IL-6 and IL-8 release. Carbachol concentration-dependently enhanced the production of IL-1β-induced IL-6 and IL-8, which was blocked by the simultaneous addition of tiotropium. The combination of olodaterol plus tiotropium further reduced IL-6 and IL-8 release. Olodaterol induced cAMP and the phosphorylation of CREB, an effect counteracted by carbachol, but rescued by tiotropium. We conclude that olodaterol plus tiotropium cooperate to decrease the inflammatory response in pulmonary fibroblasts in vitro.

Emerging targets for novel therapy of asthma

Significant advances in understanding the cell and molecular biology of inflammation and airway smooth muscle (ASM) contractility have identified several potential novel targets for therapies of asthma. New agents targeting G-protein coupled receptors (GPCRs) including bitter taste receptors (TAS2R) agonists and prostaglandin EP4 receptor agonists elicit ASM relaxation. The cAMP/PKA pathway continues to be a promising drug target with the emergence of new PDE inhibitors and a novel PKA target protein, HSP20, which mediates smooth muscle relaxation via actin depolymerization. Smooth muscle relaxation can also be elicited by inhibitors of the RhoA/Rho kinase pathway via inhibition of myosin light chain phosphorylation and actin depolymerization. Targeting epigenetic processes that control chromatin remodeling and RNA-induced gene silencing in airway cells also holds great potential for novel asthma therapy. Further investigation may identify agents that inhibit smooth muscle contraction and/or restrain or reverse obstructive remodeling of the airways.

Ten years of tiotropium: clinical impact and patient perspectives

Tiotropium bromide is an anticholinergic agent that has gained worldwide acceptance as a first-line, once daily maintenance therapy for patients with moderate-to-severe chronic obstructive pulmonary disease. The purpose of this review is to synthesize the evidence base in the past 10 years on the development of tiotropium and its efficacy compared to other able interventions such as long-acting beta agonists (LABAs), as well as to assess its safety profile and its effects on health-related outcomes in patients with COPD. Treatment with tiotropium bromide has generally improved patients' health-related quality of life, reduced the number of patients suffering from acute exacerbations, decreased the number of hospitalizations, improved dyspnea, and reduced adverse events compared to placebo. In the past decade, several studies have examined the safety and efficacy of tiotropium in comparison to placebo and to LABAs (salmeterol, formoterol, and indacaterol) over periods ranging from 3 months to 48 months of follow-up. Head-to-head comparisons of tiotropium 18μg (once daily) with salmeterol 50μg (twice daily) in well-controlled trials demonstrated that tiotropium was superior in reducing acute exacerbation events and in improving quality of life. In a few short-term studies, indacaterol was comparable to tiotropium in its efficacy in improving health-related outcomes. Although the safety record of tiotropium has been exemplary in comparison to placebo, anticholinergic events such as dry mouth can be encountered in some patients. While the long-term safety of tiotropium when delivered in the HandiHaler® has been well documented, its delivery using the Respimat® Soft Mist Inhaler™ was associated with an elevated risk of cardiovascular complications, including increased mortality when compared to placebo. The exact mechanism for this is not known but is being investigated in a large multinational study that will evaluate the long-term safety of different doses of tiotropium delivered by the Respimat® soft mist inhaler versus the HandiHaler®. Further studies are required to investigate the efficacy and safety of tiotropium in comparison with novel LABAs such as indacaterol and vilanterol, and with other emerging novel anticholinergic agents such as aclidinium bromide and NVA237 (glycopyrronium bromide).