Effect of indacaterol, a novel long-acting beta2-agonist, on isolated human bronchi

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

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

Activation/Deactivation Free-Energy Profiles for the β2-Adrenergic Receptor: Ligand Modes of Action

We use enhanced-sampling simulations with an effective collective variable to study the activation of the β2-adrenergic receptor in the presence of ligands with different efficacy. The free-energy profiles are computed for the ligand-free (apo) receptor and binary (apo-receptor + G-protein α-subunit and receptor + ligand) and ternary complexes. The results are not only compatible with available experiments but also allow unprecedented structural insight into the nature of GPCR conformations along the activation pathway and their role in the activation mechanism. In particular, the simulations reveal an unexpected mode of action of partial agonists such as salmeterol and salbutamol that arises already in the binary complex without the G-protein. Specific differences in the polar interactions with residues in TM5, which are required to stabilize an optimal TM6 conformation that facilitates G-protein binding and receptor activation, play a major role in differentiating them from full agonists.

Does coupling to ADP ribosylation factor 6 explain differences between muscarinic and other receptors in interaction with β-adrenoceptor-mediated smooth muscle relaxation?

Numerous studies in airways, ileum, and urinary bladder have demonstrated that relaxation by β-adrenoceptor agonists has lower potency and/or efficacy when contraction was elicited by muscarinic receptor agonists as compared to other G-protein-coupled receptors, KCl, or basal tone, but the molecular mechanisms behind this relative resistance remain unclear. A paper by Huang et al. in this issue demonstrates that NAV2729, an inhibitor of ADP ribosylation factor 6, inhibits contraction of isolated blood vessels elicited by muscarinic receptor agonists, but not by α₁-adrenoceptor agonists or KCl. Against this background, we discuss the role of ADP ribosylation factor 6 in cellular responses to G-protein-coupled receptor stimulation. While ADP ribosylation factor 6 apparently is the only promising molecular explanation for the relative resistance of smooth muscle contraction elicited by muscarinic agonists, the existing data are insufficient for a robust conclusion.

Indacaterol acetate/glycopyrronium bromide/mometasone furoate: a combination therapy for asthma

Abstract:

Despite the wide range of available therapies, asthma remains uncontrolled in 40–65% of patients for a number of different reasons. Treatment with an inhaled corticosteroid (ICS) is recommended in the Global Initiative for Asthma 2021 report for patients across all asthma severities, with treatment options combining an ICS with a long-acting β2-agonist (LABA) or a LABA and a long-acting muscarinic antagonist (LAMA), depending on disease severity. Based on this, the availability of single inhaler fixed-dose ICS/LABA/LAMA combination is a major need in asthma management. Indacaterol acetate/glycopyrronium bromide/mometasone furoate has been developed as a once-daily inhaled asthma treatment that combines an ICS (mometasone furoate), a LABA (indacaterol acetate) and a LAMA (glycopyrronium bromide) in a formulation delivered using the dry powder inhaler Breezhaler®, for patients with uncontrolled asthma on medium- or high-dose ICS/LABA. This article provides an overview of the different and complementary mechanisms of action, and the clinical effectiveness of the monocomponents of the indacaterol/glycopyrronium/mometasone furoate fixed combination, and highlights the benefits of using the three agents in combination in patients with moderate and severe asthma.

State-of-the-art beta-adrenoreceptor agonists for the treatment of asthma

INTRODUCTION

Asthma, a heterogeneous disease, is characterized by chronic airway inflammation and hyperreactivity. β₂-adrenoreceptor agonists (β₂-agonists) remain pivotal for asthma management. Short-acting β₂-agonists (SABAs) result in rapid symptomatic alleviation and bronchospasm prevention. Patients experience significant clinical benefits from therapy with long-acting β₂-agonists (LABAs) with efficacy to bronchodilate, and prolonged lung function betterment. Recently discovered β₂-agonists with longer half-lives offer once-daily dosing.

AREAS COVERED

The authors provide a thorough review of the pharmacokinetics, pharmacodynamics, efficacy, tolerability, classification, and safety of β₂-agonists through an in-depth review of current literature using these databases: U.S. National Institutes of Health's National Library of Medicine (NIH/NLM), PubMed Central, and NLM clinical trials.

EXPERT OPINION

β₂- agonists act primarily on airway smooth muscle cells and are quintessential for adequate asthma management. Given their pharmacodynamic and pharmacokinetic properties, SABAs are used as rescue medication. Notably, the current Global Initiative for Asthma (GINA) strategy document recommends using LABA/inhaled corticosteroid combinations both as a daily controller and as a rescue medication. Clinicians should assess this new treatment plan on a per-case basis, making sure to evaluate inhaler adherence and treat modifiable risk factors. The development of next-generation β₂- agonists is an exciting research area that could significantly improve patients' adherence to treatment regimens and, consequently, asthma control and quality of life.

The Expanding Role of Pyridine and Dihydropyridine Scaffolds in Drug Design

Pyridine-based ring systems are one of the most extensively used heterocycles in the field of drug design, primarily due to their profound effect on pharmacological activity, which has led to the discovery of numerous broad-spectrum therapeutic agents. In the US FDA database, there are 95 approved pharmaceuticals that stem from pyridine or dihydropyridine, including isoniazid and ethionamide (tuberculosis), delavirdine (HIV/AIDS), abiraterone acetate (prostate cancer), tacrine (Alzheimer's), ciclopirox (ringworm and athlete's foot), crizotinib (cancer), nifedipine (Raynaud's syndrome and premature birth), piroxicam (NSAID for arthritis), nilvadipine (hypertension), roflumilast (COPD), pyridostigmine (myasthenia gravis), and many more. Their remarkable therapeutic applications have encouraged researchers to prepare a larger number of biologically active compounds decorated with pyridine or dihydropyridine, expandeing the scope of finding a cure for other ailments. It is thus anticipated that myriad new pharmaceuticals containing the two heterocycles will be available in the forthcoming decade. This review examines the prospects of highly potent bioactive molecules to emphasize the advantages of using pyridine and dihydropyridine in drug design. We cover the most recent developments from 2010 to date, highlighting the ever-expanding role of both scaffolds in the field of medicinal chemistry and drug development.

Chirality of β2-agonists. An overview of pharmacological activity, stereoselective analysis, and synthesis

β2-Agonists (β2-adrenergic agonists, bronchodilatants, and sympathomimetic drugs) are a group of drugs that are mainly used in asthma and obstructive pulmonary diseases. In practice, the substances used to contain one or more stereogenic centers in their structure and their enantiomers exhibit different pharmacological properties. In terms of bronchodilatory activity, (R)-enantiomers showed higher activity. The investigation of stereoselectivity in action and disposition of chiral drugs together with the preparation of pure enantiomer drugs calls for efficient stereoselective analytical methods. The overview focuses on the stereoselectivity in pharmacodynamics and pharmacokinetics of β2-agonists and summarizes the stereoselective analytical methods for the enantioseparation of racemic beta-agonists (HPLC, LC-MS, GC, TLC, CE). Some methods of the stereoselective synthesis for β2-agonists preparation are also presented.

Ultra-LABAs for the treatment of asthma

The term ultra-LABA indicates once-daily β2-AR agonists (abediterol, indacaterol, olodaterol and vilanterol) that are single enantiomers of the (R)-configuration. All have a near full-agonist profile at human β2-AR. They can be prescribed in asthmatics only when associated with an with ICS, although further confirmations need to clarify what really these agents add if used in association to ICS and in what asthmatic patients this association may have more value. They are also under development in triple inhalers that include an ultra-LABA, a LAMA and an ICS. The once-daily posology might increase adherence in long-term treatment of asthma but superiority to twice-daily LABAs has not yet been fully demonstrated. In any case, still no ultra-LABA can be recommended as preferred.

Drug-Target Association Kinetics in Drug Discovery

The important role of ligand-receptor binding kinetics in drug design and discovery is increasingly recognized by the drug research community. Over the past decade, accumulating evidence has shown that optimizing the ligand's dissociation rate constant can lead to desirable duration of in vivo target occupancy and, hence, improved pharmacodynamic properties. However, the association rate constant as a pharmacological principle remains less investigated, whereas it can play an equally important role in the selection of drug candidates. This review provides a compilation and discussion of otherwise scarce and dispersed information on this topic, bringing to light the importance of drug-target association in kinetics-directed drug design and discovery.

Morbidity and mortality in a population of patients affected by heart failure and chronic obstructive pulmonary disease: an observational study

BACKGROUND

Chronic obstructive pulmonary disease (COPD) and heart failure (HF) often coexist. Moreover, elderly patients suffering from HF have a higher incidence of COPD, which further complicates their clinical condition. Indacaterol/glycopirronium has shown benefits in the treatment of COPD, with few cardiologic adverse effects. We evaluated the safety and efficacy of this therapy in patients with history of HF.

METHODS

We enrolled 56 patients with a history of HF (New York Heart Association [NYHA] classes II and III) and stable COPD. We evaluated blood samples, clinical assessment, echocardiograms and basal spirometry at baseline and after 6 months of therapy with indacaterol/glycopirronium. In addition, the number of re-hospitalizations during the treatment period was evaluated.

RESULTS

The treatment was well tolerated. Brain natriuretic peptide (BNP) levels were significantly reduced compared with baseline (p < 0.001) after 6 months of treatment, and a higher percentage of patients improved their clinical status compared with baseline (p < 0.001). Minor changes were noted in the hemodynamic and metabolic parameters. Significant improvements in the echocardiographic parameters were noted in HF with reduced ejection fraction (HFrEF) patients. All respiratory parameters (forced expiratory volume in 1 s [FEV1], FEV1/forced vital capacity [FVC] ratio and COPD Assessment Test [CAT] scores) improved significantly (p < 0.001). No hospitalizations owing to HF or COPD exacerbation occurred. One patient died of respiratory failure.

CONCLUSION

Indacaterol/glycopirronium was well-tolerated and effective in the treatment of COPD in this cohort of patients with a history of HF. Further studies are needed to clarify whether this compound can have a direct role in improving overall cardiovascular function.

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

OBJECTIVES

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

MATERIALS AND METHODS

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

RESULTS

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

CONCLUSION

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

A validated capillary electrophoretic method for the determination of indacaterol and its application to a pharmaceutical preparation

Indacaterol is a new inhaled ultra-long acting β2-agonist. It has been recently approved in the European Union for the treatment of chronic obstructive pulmonary disease. This paper reports, for the first time, a method for the determination and validation of Indacaterol (IND) using an internal standard in capsules. Capillary electrophoretic separation was performed on an uncoated fused-silica capillary (50 cm effective length, 75 μm i.d.) and background electrolyte composed of 20 mmol L-1 of sodium tetraborate buffer, 15% (v/v) methanol (pH = 10.0) with the application of 20 kV of potential; 10 s at 5 × 103 N m-2 (50 mbar) of injection time; and wavelength of 200 nm and 25 °C of temperature. The linearity was evaluated in the range of 4.90 × 10-6 mol L-1 (2.50 μg mL-1) and 3.94 × 10-5 mol L-1 (20.00 μg mL-1), with R = 0.9993 for inter-day. LOD and LOQ values were 2.18 × 10-8 mol L-1 (0.011 μg mL-1) and 7.25 × 10-8 mol L-1 (0.037 μg mL-1) for inter-day, respectively. The precision values were 0.50-1.06% for intra-day and 2.12% for inter-day as RSD%. The accuracy was tested by the standard addition method with the recovery values being between 98.79 and 99.09 as percentages with RSD% interval of 0.01-0.80. The developed method was validated according to ICH guidelines. Indacaterol was successfully determined in Arcapta® capsule dosage form by the validated CE method with a relative error of 0.28%. The result was within the requirements of the USP 34-NF29. Therefore, the validated method may be used for the determination of Indacaterol in its capsules in quality control laboratories.

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

BACKGROUND AND PURPOSE

Long-acting muscarinic antagonists (LAMAs) have been recommended for the treatment of chronic obstructive pulmonary disease and (more recently) asthma. However, the in vitro pharmacological profiles of the four LAMAs currently marketed (tiotropium, umeclidinium, aclidinium and glycopyrronium) have not yet been compared (relative to ipratropium) by using the same experimental approach.

EXPERIMENTAL APPROACH

With a total of 560 human bronchial rings, we investigated the antagonists' potency, onset and duration of action for inhibition of the contractile response evoked by electrical field stimulation. We also evaluated the antagonists' potency for inhibiting cumulative concentration-contraction curves for acetylcholine and carbachol.

KEY RESULTS

The onset and duration of action were concentration-dependent. At submaximal, equipotent concentrations, the antagonists' onsets of action were within the same order of magnitude. However, the durations of action differed markedly. After washout, ipratropium's inhibitory activity decreased rapidly (within 30-90 min) but those of tiotropium and umeclidinium remained stable (at above 70%) for at least 9 h. Aclidinium and glycopyrronium displayed less stable inhibitory effects, with a progressive loss of inhibition at submaximal concentrations. In contrast to ipratropium, all the LAMAs behaved as insurmountable antagonists by decreasing the maximum responses to both acetylcholine and carbachol.

CONCLUSIONS AND IMPLICATIONS

The observed differences in the LAMAs' in vitro pharmacological profiles in the human bronchus provide a compelling pharmacological rationale for the differences in the drugs' respective recommended daily doses and frequencies of administration.

Translational model to predict pulmonary pharmacokinetics and efficacy in man for inhaled bronchodilators

Translational pharmacokinetic (PK) models are needed to describe and predict drug concentration‐time profiles in lung tissue at the site of action to enable animal‐to‐man translation and prediction of efficacy in humans for inhaled medicines. Current pulmonary PK models are generally descriptive rather than predictive, drug/compound specific, and fail to show successful cross‐species translation. The objective of this work was to develop a robust compartmental modeling approach that captures key features of lung and systemic PK after pulmonary administration of a set of 12 soluble drugs containing single basic, dibasic, or cationic functional groups. The model is shown to allow translation between animal species and predicts drug concentrations in human lungs that correlate with the forced expiratory volume for different classes of bronchodilators. Thus, the pulmonary modeling approach has potential to be a key component in the prediction of human PK, efficacy, and safety for future inhaled medicines.

Selective inhibition of histamine-evoked Ca2+ signals by compartmentalized cAMP in human bronchial airway smooth muscle cells

•

β₂-adrenoceptors, via cAMP and PKA, inhibit histamine-evoked Ca²⁺ signals in human bronchial airway smooth muscle cells.

•

Responses to other Ca²⁺-mobilizing receptors are unaffected or minimally affected by cAMP.

•

There is no consistent relationship between the amounts of cAMP produced by different stimuli and inhibition of histamine-evoked Ca²⁺ release.

•

Local delivery of cAMP within hyperactive signaling junctions stimulates PKA.

•

PKA inhibits an early step in the signaling pathway activated by H₁ histamine receptors.

Intracellular Ca²⁺ and cAMP typically cause opposing effects on airway smooth muscle contraction. Receptors that stimulate these pathways are therapeutic targets in asthma and chronic obstructive pulmonary disease. However, the interactions between different G protein-coupled receptors (GPCRs) that evoke cAMP and Ca²⁺ signals in human bronchial airway smooth muscle cells (hBASMCs) are poorly understood. We measured Ca²⁺ signals in cultures of fluo-4-loaded hBASMCs alongside measurements of intracellular cAMP using mass spectrometry or [³H]-adenine labeling. Interactions between the signaling pathways were examined using selective ligands of GPCRs, and inhibitors of Ca²⁺ and cAMP signaling pathways. Histamine stimulated Ca²⁺ release through inositol 1,4,5-trisphosphate (IP₃) receptors in hBASMCs. β₂-adrenoceptors, through cAMP and protein kinase A (PKA), substantially inhibited histamine-evoked Ca²⁺ signals. Responses to other Ca²⁺-mobilizing stimuli were unaffected by cAMP (carbachol and bradykinin) or minimally affected (lysophosphatidic acid). Prostaglandin E₂ (PGE₂), through EP₂ and EP₄ receptors, stimulated formation of cAMP and inhibited histamine-evoked Ca²⁺ signals. There was no consistent relationship between the inhibition of Ca²⁺ signals and the amounts of intracellular cAMP produced by different stimuli. We conclude that β-adrenoceptors, EP₂ and EP₄ receptors, through cAMP and PKA, selectively inhibit Ca²⁺ signals evoked by histamine in hBASMCs, suggesting that PKA inhibits an early step in H₁ receptor signaling. Local delivery of cAMP within hyperactive signaling junctions mediates the inhibition.

Abediterol (LAS100977), an inhaled long-acting β2-adrenoceptor agonist, has a fast association rate and long residence time at receptor

This study describes the association rate and residence time of abediterol, a novel long-acting β₂-adrenoceptor agonist (LABA) in Phase II development for treatment of asthma and COPD, in comparison with indacaterol, olodaterol, vilanterol and salmeterol, for both human β₁- and β₂-adrenoceptors. Abediterol association and dissociation rates were monitored directly by using its tritiated form. Moreover, association was determined indirectly using experimental K_i and k_off obtained from assays performed with unlabelled compound. Dissociation was also studied indirectly by measuring the association rate of ³H-CGP12177 to beta adrenoceptors previously occupied by unlabelled compounds. Abediterol shows a fast association for the β₂-adrenoceptor (k_on 1.4 × 10⁷ ± 1.8 × 10⁶M^-1min^-1) while its dissociation rate is between 30 and 64 times slower than that of the reference LABA compounds tested, with a residence time of 91.3 ± 13.3min (measured directly) and 185.5 ± 7.5min (measured indirectly). Abediterol shows kinetic selectivity for the β₂- over the β₁-adrenoceptor, with a dissociation rate from the β₁-adrenoceptor similar to the other LABA compounds tested. In conclusion, abediterol is a potent LABA with a fast association rate and a long residence time at β₂-adrenoceptors. These data are in agreement with the onset and duration of action of abediterol shown in humans.

Next generation beta adrenoreceptor agonists for the treatment of asthma

INTRODUCTION

A fixed-dose inhalation of a long-acting β-agonist (LABA) and inhaled corticosteroids (ICS) is commonly recommended for moderate to severe asthmatic patients not adequately controlled by an ICS only. In order to improve the patients' adherence and the control of disease there is a noteworthy interest for the next generation inhaled β adrenoreceptor agonists maintaining an over 24 hours bronchodilatation and used once-daily (ultra-LABAs). This review focuses on the currently available evidences on the clinical role of any single ultra-LABAs in the treatment of asthmatic patients. Areas covered: New ultra-LABAs have been developed in recent years for the treatment of asthma. In particular, several evidences in asthmatic patients include indacaterol, vilanterol, olodaterol, and abediterol. Expert opinion: Pharmacologically, all new ultra-LABAs considered have demonstrated a good ability to maintain a true bronchodilatation for over 24 hours and a good safety profile. This aspect could be a key point to improve the patient's perspective, the adherence to the treatment regimens and therefore the control of disease. At this time, however, limited data are available and no ultra-LABA+ICS may be recommended as preferred.

Bronchoprotective tolerance with indacaterol is not modified by concomitant tiotropium in persistent asthma

BACKGROUND

Tiotropium is a long acting muscarinic antagonist (LAMA), licensed as triple therapy with inhaled corticosteroid and long-acting beta-agonist (ICS/LABA). There may be a synergistic benefit between LAMA and LABA as a consequence of receptor cross-talk, which in turn could modify beta-2 receptor downregulation and associated tolerance induced by LABA.

OBJECTIVE

We hypothesize this mechanism may result in a reduction of airway hyperresponsiveness (AHR) when using triple therapy.

METHODS

We evaluated 14 non-smoking asthmatics using an open-label, randomized crossover design. ICS with Indacaterol and Tiotropium (IND/TIO) vs ICS with Indacaterol (IND) over 4 weeks with challenge performed after first and last doses at trough.

RESULTS

We found no significant difference in mannitol sensitivity, expressed as the provocative dose of mannitol required to reach a 15% drop in FEV₁ , or mannitol reactivity, expressed as the response dose ratio (RDR: max % fall in FEV₁ /cumulative dose), when comparing ICS/IND/TIO to ICS/IND. Geometric mean fold differences for RDR comparing single and chronic dosing were 3.26-fold (95% CI 1.46-7.29) and 2.51-fold (95% CI 1.32-4.79) for IND and IND/TIO, respectively. Furthermore, salbutamol recovery post-challenge was significantly blunted after chronic compared to single dosing with either ICS/IND (P<.005) or ICS/IND/TIO (P<.05).

CONCLUSION AND CLINICAL RELEVANCE

Our data suggest that concomitant tiotropium does not modify the bronchoprotective tolerance induced by Indacaterol, in turn suggesting that cross-talk may not be clinically relevant when using triple therapy. This study was registered on clinicaltrials.gov as NCT02039011.

Human lung and monocyte-derived macrophages differ with regard to the effects of β2-adrenoceptor agonists on cytokine release

Background

β₂-adrenoceptor agonists have been shown to reduce the lipopolysaccharide (LPS)-induced cytokine release by human monocyte-derived macrophages (MDMs). We compare the expression of β₂-adrenoceptors and the inhibitory effect of formoterol and salmeterol on the LPS-induced release of tumor necrosis factor (TNF)-α, interleukin (IL)-1β, IL-6 and a range of chemokines (CCL2, 3, 4, and IL-8) by human lung macrophages (LMs) and MDMs.

Methods

LMs were isolated from patients undergoing resection and MDMs were obtained from blood monocytes in the presence of GM-CSF. LMs and MDMs were incubated in the absence or presence of formoterol or salmeterol prior to stimulation with LPS. The effects of formoterol were also assessed in the presence of the phosphodiesterase inhibitor roflumilast.

Results

LPS-induced cytokine production was higher in LMs than in MDMs. Salmeterol and formoterol exerted an inhibitory effect on the LPS-induced production of TNF-α, IL-6, CCL2, CCL3, and CCL4 in MDMs. In contrast, the β₂-adrenoceptor agonists were devoid of any effect on LMs - even in the presence of roflumilast. The expression of β₂-adrenergic receptors was detected on Western blots in MDMs but not in LMs.

Conclusions

Concentrations of β₂-adrenoceptor agonists that cause relaxation of the human bronchus can inhibit cytokine production by LPS-stimulated MDMs but not by LMs.

Electronic supplementary material

The online version of this article (doi:10.1186/s12931-017-0613-y) contains supplementary material, which is available to authorized users.

In vitro and in vivo preclinical profile of abediterol (LAS100977), an inhaled long-acting β2-adrenoceptor agonist, compared with indacaterol, olodaterol and vilanterol

Abediterol is a novel long-acting β2-adrenoceptor agonist (LABA) currently in development for once-daily combination maintenance therapy of asthma and COPD. This study investigated the preclinical profile of abediterol in terms of affinity, potency, selectivity, duration of action and cardiac effects in comparison to the marketed once-daily LABAs indacaterol, olodaterol and vilanterol. Abediterol was the compound with the highest in vitro potency for dog, guinea pig and human β2-adrenoceptors. In electrical field stimulated guinea pig trachea, abediterol demonstrated 5-, 44- and 77-fold greater potency than olodaterol, indacaterol and vilanterol, respectively. In anaesthetised guinea pigs, inhaled abediterol was also the most potent compound, with 5-20 times higher bronchoprotective potency than other once-daily LABAs against acetylcholine. The bronchoprotective half-life of abediterol in guinea pigs was 36h compared with 51h for indacaterol, 47h for olodaterol, and 18h for vilanterol. In anaesthetised dogs, abediterol also inhibited acetylcholine-induced bronchoconstriction, with higher potency than olodaterol and vilanterol [ID40 (dose inhibiting bronchoconstriction by 40%) of 0.059µg/kg, 0.180µg/kg and 2.870µg/kg, respectively]. In parallel, effects on heart rate in dogs were also measured. Abediterol showed greater safety index (defined as the ratio of the maximal dose without effect on heart rate and the ID40) than olodaterol and vilanterol (10.5 versus 4.9 and 2.4, respectively). Taken together, these data suggest that abediterol offers potent bronchodilation and a sustained duration of action suited to once-daily dosing, plus a reduced potential for class-related cardiac side effects.

Turning a molecule into a medicine: the development of indacaterol as a novel once-daily bronchodilator treatment for patients with COPD

Indacaterol is the first once-daily, long-acting β2-adrenergic agonist (LABA) approved for the treatment of chronic obstructive pulmonary disease (COPD). Indacaterol was developed using a combination of informed drug design and molecular chemistry to generate a β2-adrenergic agonist with a fast onset and long duration of action, enabling once-daily dosing with an acceptable safety profile. Early preclinical studies with indacaterol demonstrated these characteristics, and this promising molecule was taken into clinical development, originally for asthma treatment. Subsequent safety concerns over LABA monotherapy in patients with asthma redirected indacaterol's development to centre on COPD, where a good evidence base and guideline recommendations for bronchodilator monotherapy existed. Clinical development was initially complicated by different inhaler devices and differing doses of indacaterol. Using a phase III innovative adaptive-design clinical trial (INHANCE), indacaterol 150 and 300 μg once-daily doses were selected to be taken forward into the phase III INERGIZE programme. This programme delivered placebo-controlled and active-comparator data, including comparisons with formoterol, tiotropium and salmeterol/fluticasone, as well as the use of indacaterol in combination with tiotropium. Together, these studies provided a comprehensive assessment of the benefit-risk profile of indacaterol, allowing for regulatory submission. Indacaterol was first approved at once-daily doses of 150 and 300 μg in the European Union in 2009, followed by 150 µg in Japan (2011) and China (2012), and 75 μg in the United States (2011). To date, indacaterol is approved and marketed in more than 100 countries worldwide for once-daily maintenance treatment of COPD.

Cannabinoids inhibit cholinergic contraction in human airways through prejunctional CB1 receptors

BACKGROUND AND PURPOSE

Marijuana smoking is widespread in many countries, and the use of smoked synthetic cannabinoids is increasing. Smoking a marijuana joint leads to bronchodilation in both healthy subjects and asthmatics. The effects of Δ(9) -tetrahydrocannabinol and synthetic cannabinoids on human bronchus reactivity have not previously been investigated. Here, we sought to assess the effects of natural and synthetic cannabinoids on cholinergic bronchial contraction.

EXPERIMENTAL APPROACH

Human bronchi isolated from 88 patients were suspended in an organ bath and contracted by electrical field stimulation (EFS) in the presence of the phytocannabinoid Δ(9) -tetrahydrocannabinol, the endogenous 2-arachidonoylglycerol, the synthetic dual CB1 and CB2 receptor agonists WIN55,212-2 and CP55,940, the synthetic, CB2 -receptor-selective agonist JWH-133 or the selective GPR55 agonist O-1602. The receptors involved in the response were characterized by using selective CB1 and CB2 receptor antagonists (SR141716 and SR144528 respectively).

KEY RESULTS

Δ(9) -tetrahydrocannabinol, WIN55,212-2 and CP55,940 induced concentration-dependent inhibition of cholinergic contractions, with maximum inhibitions of 39, 76 and 77% respectively. JWH-133 only had an effect at high concentrations. 2-Arachidonoylglycerol and O-1602 were devoid of any effect. Only CB1 receptors were involved in the response because the effects of cannabinoids were antagonized by SR141716, but not by SR144528. The cannabinoids did not alter basal tone or contractions induced by exogenous Ach.

CONCLUSIONS AND IMPLICATIONS

Activation of prejunctional CB1 receptors mediates the inhibition of EFS-evoked cholinergic contraction in human bronchus. This mechanism may explain the acute bronchodilation produced by marijuana smoking.

Detection and pharmacokinetics of salbutamol in thoroughbred racehorses following inhaled administration

Salbutamol sulphate (Ventolin Evohaler) was administrated via the inhalation route to six horses at a dose of 0.5 mg every 4 h during the day for 2 days (total dose 4 mg). Urine and blood samples were taken up to 92 h postadministration. Hydrolyzed plasma and urine were extracted using solid phase extraction (SPE). A sensitive tandem mass spectrometric method was developed in this study, achieving a lower limit of quantification (LLOQ) for salbutamol of 10 pg/mL in plasma and urine. The parent drug was identified using UPLC-MS/MS. Most of the determined salbutamol plasma concentrations, post last administration, lie below the LLOQ of the method and so cannot be used for plasma PK analysis. Urine PK analysis suggests a half-life consistent with the pharmacological effect duration. An estimate of the urine average concentration at steady-state was collected by averaging the concentration measurements in the dosing period from -12 to 0 h relative to the last administered dose. The value was averaged across the six horses and used to estimate an effective urine concentration as a marker of effective lung concentration. The value estimated was 9.6 ng/mL and from this a number of detection times were calculated using a range of safety factors.

Update on ultra-long-acting β agonists in chronic obstructive pulmonary disease

INTRODUCTION

For the last two decades, long-acting β agonists (LABAs) have been a cornerstone in the management of chronic obstructive pulmonary disease (COPD). They relax airway smooth muscle and augment expiratory airflow, which reduces hyperinflation and improves dyspnea, functional capacity and quality of life. In recent years, Indacaterol, a LABA with an ultra-long duration of action (ultra-LABA), which only requires once-daily dosing, was approved by the FDA. The clinical efficacy of indacaterol is comparable, and, in some aspects better, than the currently available LABAs.

AREAS COVERED

This article reviews the pharmacological properties, clinical efficacy, safety and potential role of the ultra-LABAs in COPD management.

EXPERT OPINION

Ultra-LABAs are effective bronchodilators with a prolonged duration of action. By decreasing dosing frequency, ultra-LABAs potentially may improve respiratory medication adherence, which is associated with better survival and less healthcare utilization. In addition to their salubrious benefits, β agonists may produce untoward effects. Increased mortality and hospitalizations among patients with left ventricular heart failure, who were treated with β agonists, has caused concern about their use in patients with COPD and heart disease. Further experience and testing will determine the optimal role of ultra-LABAs in the management of COPD.

Indacaterol inhibits tumor cell invasiveness and MMP-9 expression by suppressing IKK/NF-κB activation

The β2 adrenergic receptor (ADRB2) is a G protein-coupled transmembrane receptor expressed in the human respiratory tract and widely recognized as a pharmacological target for treatments of asthma and chronic obstructive pulmonary disorder (COPD). Although a number of ADRB2 agonists have been developed for use in asthma therapy, indacaterol is the only ultra-long-acting inhaled β2-agonist (LABA) approved by the FDA for relieving the symptoms in COPD patients. The precise molecular mechanism underlying the pharmacological effect of indacaterol, however, remains unclear. Here, we show that β-arrestin-2 mediates the internalization of ADRB2 following indacaterol treatment. Moreover, we demonstrate that indacaterol significantly inhibits tumor necrosis factor-α (TNF-α)-induced NF-κB activity by reducing levels of both phosphorylated-IKK and -IκBα, thereby decreasing NF-κB nuclear translocation and the expression of MMP-9, an NF-κB target gene. Subsequently, we show that indacaterol significantly inhibits TNF-α/NF-κB-induced cell invasiveness and migration in a human cancer cell line. In conclusion, we propose that indacaterol may inhibit NF-κB activity in a β-arrestin2-dependent manner, preventing further lung damage and improving lung function in COPD patients.

The pharmacological rationale for combining muscarinic receptor antagonists and β-adrenoceptor agonists in the treatment of airway and bladder disease

•

Muscarinic receptors increase smooth muscle tone in airways and urinary bladder.

•

β-Adrenoceptors relax smooth muscle tone and oppose muscarinic contraction.

•

Opposition involves transmitter release, signal transduction and receptor expression.

•

This supports the combined use of muscarinic antagonists and β-adrenoceptor agonists.

Muscarinic receptor antagonists and β-adrenoceptor agonists are used in the treatment of obstructive airway disease and overactive bladder syndrome. Here we review the pharmacological rationale for their combination. Muscarinic receptors and β-adrenoceptors are physiological antagonists for smooth muscle tone in airways and bladder. Muscarinic agonism may attenuate β-adrenoceptor-mediated relaxation more than other contractile stimuli. Chronic treatment with one drug class may regulate expression of the target receptor but also that of the opposing receptor. Prejunctional β₂-adrenoceptors can enhance neuronal acetylcholine release. Moreover, at least in the airways, muscarinic receptors and β-adrenoceptors are expressed in different locations, indicating that only a combined modulation of both systems may cause dilatation along the entire bronchial tree. While all of these factors contribute to a rationale for a combination of muscarinic receptor antagonists and β-adrenoceptor agonists, the full value of such combination as compared to monotherapy can only be determined in clinical studies.

New developments in the management of COPD: clinical utility of indacaterol 75 μg

Chronic obstructive pulmonary disease (COPD) is a global health challenge and a major cause of mortality worldwide. Bronchodilators, particularly long-acting β₂-agonists and long-acting antimuscarinic agents, used singly or in combination, aim to improve lung function, reduce symptoms, prevent exacerbations, and enhance quality of life of COPD patients. Indacaterol is a novel, inhaled, long-acting β₂-agonist, with rapid onset of action and once-daily dosing providing 24-hour bronchodilation. Currently, the recommended dose differs between Europe (150 μg; maximum 300 μg) and USA (75 μg), the latter is lower than that assessed in the majority of the conducted studies. This review summarises published evidence regarding the efficacy, tolerability, and safety of indacaterol at a dose of 75 μg. Indacaterol 75 μg was found to be superior than placebo regarding lung function, dyspnea, health status, use of rescue medication, and rate of exacerbations. Furthermore, indacaterol 75 μg was well tolerated, while the most frequent adverse effect was deterioration of COPD occurring at a frequency similar to placebo, without major cardiovascular adverse effects. In conclusion, indacaterol 75 μg, administered once daily, is efficacious and has an excellent tolerability and safety profile, and is therefore a valid alternative in the treatment of COPD patients.

Use of indacaterol for the treatment of COPD: a pharmacokinetic evaluation

INTRODUCTION

Indacaterol is a β2-agonist with a rapid onset of action and a bronchodilating effect that lasts for 24 h.

AREAS COVERED

This review considers indacaterol in chronic obstructive pulmonary disease patients, in whom it is rapidly absorbed into the systemic circulation with serum levels measurable after 5 min and Cmax being reached approximately 15 min post-dose. Its disposition kinetics are characterized by at least two phases, a relatively fast decline of the concentrations within the first 12 h, followed by a terminal elimination phase. The increase in systemic exposure is dose-proportional, but systemic concentrations are low at the recommended doses. Indacaterol is relatively highly bound to plasma proteins regardless of concentration. Metabolic clearance and/or biliary clearance account for the majority of its systemic excretion. Weight, age, gender and ethnicity significantly influence its pharmacokinetic profile, but it is not necessary to adjust the dose based on these covariates. Substrates, inhibitors or inducers of UGT1A1 and CYP3A may also affect the pharmacokinetic profile of indacaterol.

EXPERT OPINION

Blood concentrations of indacaterol are unable to predict its bronchodilator effects. Furthermore, at the recommended doses, systemic concentrations of indacaterol are low and this is the likely reason for its safe profile.

Can the anti-inflammatory activities of β2-agonists be harnessed in the clinical setting?

Beta2-adrenoreceptor agonists (β2-agonists) are primarily bronchodilators, targeting airway smooth muscle and providing critical symptomatic relief in conditions such as bronchial asthma and chronic obstructive pulmonary disease. These agents also possess broad-spectrum, secondary, anti-inflammatory properties. These are mediated largely, though not exclusively, via interactions with adenylyl cyclase-coupled β2-adrenoreceptors on a range of immune and inflammatory cells involved in the immunopathogenesis of acute and chronic inflammatory disorders of the airways. The clinical relevance of the anti-inflammatory actions of β2-agonists, although often effective in the experimental setting, remains contentious. The primary objectives of the current review are: firstly, to assess the mechanisms, both molecular and cell-associated, that may limit the anti-inflammatory efficacy of β2-agonists; secondly, to evaluate pharmacological strategies, several of which are recent and innovative, that may overcome these limitations. These are preceded by a consideration of the various types of β2-agonists, their clinical applications, and spectrum of anti-inflammatory activities, particularly those involving adenosine 3',5'-cyclic adenosine monophosphate-activated protein kinase-mediated clearance of cytosolic calcium, and altered gene expression in immune and inflammatory cells.

The role of indacaterol for chronic obstructive pulmonary disease (COPD)

Indacaterol is the first long-acting β2-agonist (LABAs) approved for the treatment of chronic obstructive pulmonary disease (COPD) that allows for once-daily (OD) administration. It is rapidly acting, with an onset of action in 5 minutes, like salbutamol and formoterol but with a sustained bronchodilator effect, that last for 24 hours, like tiotropium. In long-term clinical studies (12 weeks to 1 year) in patients with moderate to severe COPD, OD indacaterol 150 or 300 μg improved lung function (primary endpoint) significantly more than placebo, and improvements were significantly greater than twice-daily formoterol 12 μg or salmeterol 50 μg, and noninferior to OD tiotropium bromide 18 μg. Indacaterol was well tolerated at all doses and with a good overall safety profile. Cost-utility analyses show that indacaterol 150 μg has lower total costs and better outcomes than tiotropium and salmeterol. These findings suggest that indacaterol can be considered a first choice drug in the treatment of the patient with mild/moderate stable COPD. However, in people with COPD who remain symptomatic on treatment with indacaterol, adding a long-acting muscarinic antagonist (LAMA) is the preferable option. In any case, it is advisable to combine indacaterol with a OD inhaled corticosteroid (ICS), such as mometasone furoate or ciclesonide, in patients with low FEV1, and, in those patients who have many symptoms and a high risk of exacerbations, to combine it with a LAMA and a OD ICS.

β2-agonist therapy in lung disease

β2-Agonists are effective bronchodilators due primarily to their ability to relax airway smooth muscle (ASM). They exert their effects via their binding to the active site of β2-adrenoceptors on ASM, which triggers a signaling cascade that results in a number of events, all of which contribute to relaxation of ASM. There are some differences between β2-agonists. Traditional inhaled short-acting β2-agonists albuterol, fenoterol, and terbutaline provide rapid as-needed symptom relief and short-term prophylactic protection against bronchoconstriction induced by exercise or other stimuli. The twice-daily β2-agonists formoterol and salmeterol represent important advances. Their effective bronchodilating properties and long-term improvement in lung function offer considerable clinical benefits to patients. More recently, a newer β2-agonist (indacaterol) with a longer pharmacodynamic half-life has been discovered, with the hopes of achieving once-daily dosing. In general, β2-agonists have an acceptable safety profile, although there is still controversy as to whether long-acting β2-agonists may increase the risk of asthma mortality. In any case, they can induce adverse effects, such as increased heart rate, palpitations, transient decrease in PaO2, and tremor. Desensitization of β2-adrenoceptors that occurs during the first few days of regular use of β2-agonist treatment may account for the commonly observed resolution of the majority of these adverse events after the first few doses. Nevertheless, it can also induce tolerance to bronchoprotective effects of β2-agonists and has the potential to reduce bronchodilator sensitivity to them. Some novel once-daily β2-agonists (olodaterol, vilanterol, abediterol) are under development, mainly in combination with an inhaled corticosteroid or a long-acting antimuscarinic agent.

Indacaterol 75 μg once daily for the treatment of patients with chronic obstructive pulmonary disease: a North American perspective

Chronic obstructive pulmonary disease (COPD) is a progressive disease in which patients become increasingly disabled by their symptoms and limited in their activities. Health-related quality of life may be profoundly impaired even in the early stages of the disease. Treatment with long-acting inhaled bronchodilators can improve lung function, symptoms and health status and reduce exacerbations of COPD. This review profiles the efficacy, safety and tolerability of indacaterol, an inhaled β(2)-agonist bronchodilator for once-daily maintenance treatment of patients with COPD. After 12 weeks of treatment with a once-daily dose of 75 µg (the dose approved in the USA and Canada) in patients with moderate to severe COPD, compared with placebo, indacaterol provided significant and clinically relevant levels of bronchodilation [difference in trough forced expiratory volume in 1 s: 131 ml; 95% confidence interval (CI) 104-159; p < 0.001], together with significant reductions in symptom scores (difference in transition dyspnea index total score: 0.84 points; 95% CI 0.37-1.31; p < 0.001) and improvements in health status (difference in St George's Respiratory Questionnaire total score: -3.8 units; 95% CI -5.6 to -2.0; p < 0.001). The overall safety and tolerability of once-daily treatment with indacaterol 75 µg for 12 weeks did not differ in any substantial aspect from placebo treatment. Indirect comparisons analyzing pooled clinical data and meta-analyses suggest that treatment with indacaterol 75 µg once daily may be effective in reducing exacerbations of COPD, and that its effects on lung function and health status will be comparable with other currently available inhaled long-acting bronchodilators used for COPD. Treatment with indacaterol 75 µg once daily provides effective bronchodilation, improves dyspnea and health status, and has a well characterized profile of safety and tolerability.

Autonomic nervous control of the urinary bladder

The autonomic nervous system plays an important role in the regulation of the urinary bladder function. Under physiological circumstances, noradrenaline, acting mainly on β(3) -adrenoceptors in the detrusor and on α(1) (A) -adrenoceptors in the bladder outflow tract, promotes urine storage, whereas neuronally released acetylcholine acting mainly on M(3) receptors promotes bladder emptying. Under pathophysiological conditions, however, this system may change in several ways. Firstly, there may be plasticity at the levels of innervation and receptor expression and function. Secondly, non-neuronal acetylcholine synthesis and release from the urothelium may occur during the storage phase, leading to a concomitant exposure of detrusor smooth muscle, urothelium and afferent nerves to acetylcholine and noradrenaline. This can cause interactions between the adrenergic and cholinergic system, which have been studied mostly at the post-junctional smooth muscle level until now. The implications of such plasticity are being discussed.

Pharmacology and therapeutics of bronchodilators

Bronchodilators are central in the treatment of of airways disorders. They are the mainstay of the current management of chronic obstructive pulmonary disease (COPD) and are critical in the symptomatic management of asthma, although controversies around the use of these drugs remain. Bronchodilators work through their direct relaxation effect on airway smooth muscle cells. at present, three major classes of bronchodilators, β(2)-adrenoceptor (AR) agonists, muscarinic receptor antagonists, and xanthines are available and can be used individually or in combination. The use of the inhaled route is currently preferred to minimize systemic effects. Fast- and short-acting agents are best used for rescue of symptoms, whereas long-acting agents are best used for maintenance therapy. It has proven difficult to discover novel classes of bronchodilator drugs, although potential new targets are emerging. Consequently, the logical approach has been to improve the existing bronchodilators, although several novel broncholytic classes are under development. An important step in simplifying asthma and COPD management and improving adherence with prescribed therapy is to reduce the dose frequency to the minimum necessary to maintain disease control. Therefore, the incorporation of once-daily dose administration is an important strategy to improve adherence. Several once-daily β(2)-AR agonists or ultra-long-acting β(2)-AR-agonists (LABAs), such as indacaterol, olodaterol, and vilanterol, are already in the market or under development for the treatment of COPD and asthma, but current recommendations suggest the use of LABAs only in combination with an inhaled corticosteroid. In addition, some new potentially long-acting antimuscarinic agents, such as glycopyrronium bromide (NVA-237), aclidinium bromide, and umeclidinium bromide (GSK573719), are under development, as well as combinations of several classes of long-acting bronchodilator drugs, in an attempt to simplify treatment regimens as much as possible. This review will describe the pharmacology and therapeutics of old, new, and emerging classes of bronchodilator.

Pharmacological characterization of abediterol, a novel inhaled β(2)-adrenoceptor agonist with long duration of action and a favorable safety profile in preclinical models

Abediterol is a novel potent, long-acting inhaled β(2)-adrenoceptor agonist in development for the treatment of asthma and chronic obstructive pulmonary disease. Abediterol shows subnanomolar affinity for the human β(2)-adrenoceptor and a functional selectivity over β(1)-adrenoceptors higher than that of formoterol and indacaterol in both a cellular model with overexpressed human receptors and isolated guinea pig tissue. Abediterol is a full agonist at the human β(2)-adrenoceptor (E(max) = 91 ± 5% of the maximal effect of isoprenaline). The potency and onset of action that abediterol shows in isolated human bronchi (EC(50) = 1.9 ± 0.4 nM; t½ onset = 7-10 min) is not significantly different from that of formoterol, but its duration of action (t½ ∼ 690 min) is similar to that of indacaterol. Nebulized abediterol inhibits acetylcholine-induced bronchoconstriction in guinea pigs in a concentration-dependent manner, with higher potency and longer duration of action (t½ = 36 h) than salmeterol (t½ = 6 h) and formoterol (t½ = 4 h) and similar duration of action to indacaterol up to 48 h. In dogs, the bronchoprotective effect of abediterol is more sustained than that of salmeterol and indacaterol at doses without effects on heart rate, thus showing a greater safety margin (defined as the ratio of dose increasing heart rate by 5% and dose inhibiting bronchospasm by 50%) than salmeterol, formoterol, and indacaterol (5.6 versus 3.3, 2.2, and 0.3, respectively). In conclusion, our results suggest that abediterol has a preclinical profile for once-daily dosing in humans together with a fast onset of action and a favorable cardiovascular safety profile.

Indacaterol: a novel long-acting β(2) -agonist

Bronchodilator drugs are the foundation for the treatment of chronic obstructive pulmonary disease. The principal inhaled bronchodilator treatments used are β(2) -agonists and anticholinergics, either alone or in combination. Currently available β(2) -agonists are of either short duration and used multiple times/day, or of long duration, which requires twice-daily administration. Indacaterol is considered an ultra-long-acting β(2) -agonist and was recently approved for use in the United States. Its duration of action is approximately 24 hours, allowing for once-daily administration. Cough was the most commonly reported adverse effect with use of indacaterol. Cough usually occurred within 15 seconds of inhalation of the drug, lasted around 6 seconds, was not associated with bronchospasm, and did not cause discontinuation of the drug. Otherwise, the drug's safety profile was similar to that of other bronchodilators. Based on similar improvement in spirometric measurements compared with other bronchodilator drugs and the convenience of its once-daily dosing, indacaterol may be beneficial in the management of mild-to-moderate chronic obstructive pulmonary disease, either alone or in combination with anticholinergic drugs administered once/day.

New bronchodilators

Bronchodilators are central in the treatment of airway diseases including chronic obstructive pulmonary disease (COPD). Bronchodilators in COPD aim to improve lung function, reduce symptoms, prevent exacerbation, and enhance quality of life. The majority of programs in development for novel bronchodilators are focused on enhancing existing targets to once daily dosing and improving their safety profiles. However, just as important are other programs that aim to discover novel pharmacologic targets such as EP4 receptor agonists, bitter taste receptors, and selective PDE inhibitors. Furthermore, existing and novel bronchodilators have become vital components of multiple combination therapies targeting COPD. This review will discuss emerging bronchodilators highlighting preclinical data and available clinical trials.