An update on bronchodilators in Phase I and II clinical trials

Inhaled RNA Therapeutics for Obstructive Airway Diseases: Recent Advances and Future Prospects

Obstructive airway diseases, e.g., chronic obstructive pulmonary disease (COPD) and asthma, represent leading causes of morbidity and mortality worldwide. However, the efficacy of currently available inhaled therapeutics is not sufficient for arresting disease progression and decreasing mortality, hence providing an urgent need for development of novel therapeutics. Local delivery to the airways via inhalation is promising for novel drugs, because it allows for delivery directly to the target site of action and minimizes systemic drug exposure. In addition, novel drug modalities like RNA therapeutics provide entirely new opportunities for highly specific treatment of airway diseases. Here, we review state of the art of conventional inhaled drugs used for the treatment of COPD and asthma with focus on quality attributes of inhaled medicines, and we outline the therapeutic potential and safety of novel drugs. Subsequently, we present recent advances in manufacturing of thermostable solid dosage forms for pulmonary administration, important quality attributes of inhalable dry powder formulations, and obstacles for the translation of inhalable solid dosage forms to the clinic. Delivery challenges for inhaled RNA therapeutics and delivery technologies used to overcome them are also discussed. Finally, we present future prospects of novel inhaled RNA-based therapeutics for treatment of obstructive airways diseases, and highlight major knowledge gaps, which require further investigation to advance RNA-based medicine towards the bedside.

Long-Acting Muscarinic Antagonists Under Investigational to Treat Chronic Obstructive Pulmonary Disease

Introduction

Bronchodilators are the cornerstone of chronic obstructive pulmonary disease (COPD) therapy and long-acting muscarinic antagonists (LAMAs) as a mono or combination treatment play a pivotal role. Several LAMAs are already available on the market in different formulations, but developing a new compound with a higher M3 receptor selectivity and a lower affinity to M2 receptors to increase the therapeutic effect and minimize the adverse effects is still a goal. Moreover, new formulations could improve adherence to therapy.

Areas Covered

This systematic review assesses investigational long-acting muscarinic antagonist in Phase I and II clinical trials over the last decade. It offers insights on whether LAMAs and/or their new formulations in clinical development can become effective treatments for COPD in the future.

Expert Opinion

Research on LAMA seems to have come to a standstill, the few new molecules under study do not show distinctive characteristics compared to the previous ones. Muscarinic antagonist/β2-agonist (MABAs) appear to be the major innovation currently under investigation, and they could theoretically open new research frontiers on the effect between adrenergic and muscarinic interaction in the same cell.

Design, synthesis and biological evaluation of 8-(2-amino-1-hydroxyethyl)-6-hydroxy-1,4-benzoxazine-3(4H)-one derivatives as potent β2-adrenoceptor agonists

A series of β₂-adrenoceptor agonists with an 8-(2-amino-1-hydroxyethyl)-6-hydroxy-1,4-benzoxazine-3(4H)-one moiety is presented. The stimulatory effects of the compounds on human β₂-adrenoceptor and β₁-adrenoceptor were characterized by a cell-based assay. Their smooth muscle relaxant activities were tested on isolated guinea pig trachea. Most of the compounds were found to be potent and selective agonists of the β₂-adrenoceptor. One of the compounds, (R)-18c, possessed a strong β₂-adrenoceptor agonistic effect with an EC₅₀ value of 24 pM. It produced a full and potent airway smooth muscle relaxant effect same as olodaterol. Its onset of action was 3.5 min and its duration of action was more than 12 h in an in vitro guinea pig trachea model of bronchodilation. These results suggest that (R)-18c is a potential candidate for long-acting β₂-AR agonists.

Fixed-Dose Combination Inhalers

In asthma and chronic obstructive pulmonary disease (COPD), an important step in simplifying management and improving adherence with prescribed therapy is to reduce the dose frequency to the minimum necessary to maintain disease control. Fixed-dose combination (FDC) therapy might enhance compliance by decreasing the number of medications and/or the number of daily doses. Furthermore, they have the potential for enhancing, sensitizing, and prolonging the effects of monocomponents. Combination therapy with an inhaled corticosteroid (ICS) and a long-acting β-agonist (LABA) is considered an important approach for treating patients with asthma and patients with severe COPD who have frequent exacerbations. Several ICS/LABA FDCs are now commercially available or will become available within the next few years for the treatment of COPD and/or asthma. Several studies demonstrate that there are a number of added benefits in using combinations of β₂-agonists and antimuscarinic agents. In particular, LABA/long-acting antimuscarinic agent (LAMA) combination seems to play an important role in optimizing bronchodilation. Several once-daily and twice-daily LABA/LAMA FDCs have been developed or are in clinical development. LAMA/ICS FDCs seem to be useful in COPD and mainly in asthma, in patients with severe asthma and persistent airflow limitation. The rationale behind the ICS/LABA/LAMA FDCs seems logical because all three agents work via different mechanisms on different targets, potentially allowing for lower doses of the individual agents to be used, accompanied by improved side effect profiles. In effect, in clinical practice, concomitant use of all three compounds is common, especially in more severe COPD but also in the treatment of adults with poorly controlled asthma despite maintenance treatment with high-dose ICS and a LABA.

Muscarinic Receptor Antagonists

Parasympathetic activity is increased in patients with chronic obstructive pulmonary disease (COPD) and asthma and appears to be the major reversible component of airway obstruction. Therefore, treatment with muscarinic receptor antagonists is an effective bronchodilator therapy in COPD and also in asthmatic patients. In recent years, the accumulating evidence that the cholinergic system controls not only contraction by airway smooth muscle but also the functions of inflammatory cells and airway epithelial cells has suggested that muscarinic receptor antagonists could exert other effects that may be of clinical relevance when we must treat a patient suffering from COPD or asthma. There are currently six muscarinic receptor antagonists licenced for use in the treatment of COPD, the short-acting muscarinic receptor antagonists (SAMAs) ipratropium bromide and oxitropium bromide and the long-acting muscarinic receptor antagonists (LAMAs) aclidinium bromide, tiotropium bromide, glycopyrronium bromide and umeclidinium bromide. Concerns have been raised about possible associations of muscarinic receptor antagonists with cardiovascular safety, but the most advanced compounds seem to have an improved safety profile. Further beneficial effects of SAMAs and LAMAs are seen when added to existing treatments, including LABAs, inhaled corticosteroids and phosphodiesterase 4 inhibitors. The importance of tiotropium bromide in the maintenance treatment of COPD, and likely in asthma, has spurred further research to identify new LAMAs. There are a number of molecules that are being identified, but only few have reached the clinical development.

Investigational beta-2 adrenergic agonists for the treatment of chronic obstructive pulmonary disease

INTRODUCTION

Long-acting bronchodilators are pivotal in the therapeutic management of COPD patients with moderate-to-severe airflow obstruction. New ultra-long-acting β2-agnoists (ultra-LABAs) have been developed, some of which have been licensed for use as monotherapy and/or in combination with other bronchodilators or inhaled corticosteroids, for use in COPD patients with persistent symptoms and worsening airflow limitation. These new agents are faster in onset and have a prolonged duration of action, with a similar safety profile to the traditional twice-daily bronchodilators which may have an impact on patient concordance. Areas covered: A number of these ultra-LABAs are still under development and bi-functional hybrid molecules containing regions functioning as β2-agonists, and as muscarinic agonists (MABAs) has been developed. This review summarizes these (excluding the licensed ultra-LABAs) with attention on phase II studies data available to-date on their pharmacological profiles, clinical efficacy and safety, and future perspectives. Expert opinion: Despite all the new agents' available, the challenges that persist include any differences in efficacy and safety between the various possible LAMA/LABA combinations, relative advantages of MABAs over fixed-dose LAMA/LABAs, and the impact of these new molecules in terms of long term safety, especially in certain populations in co-morbidities frequently associated with COPD.

Specific role of combination aclidinium: formoterol in the treatment of chronic obstructive pulmonary disease

Co-administration of a long-acting β2-agonist and a long acting muscarinic antagonist produces superior bronchodilation compared with their individual effects. Our preclinical data indicated that combining aclidinium bromide (ACLI) and formoterol fumarate (FORM) provides synergistic benefit on smooth muscle relaxation of both large and small human airways. Data from more than 2,000 patients in eleven clinical trials documented that ACLI/FORM, a twice-daily fixed-dose combination, produces a greater degree of bronchodilation than ACLI or FORM monotherapy alone and is safe and well tolerated. Two large key trials have shown that there is a benefit in using ACLI/FORM when the clinical target is the variability of symptoms and mainly nighttime and/or early morning symptoms. ACLI/FORM is the only long acting muscarinic antagonist/long acting β2-agonist fixed-dose combination that has been studied for this therapeutic indication.

Positioning new pharmacotherapies for COPD

COPD imposes considerable worldwide burden in terms of morbidity and mortality. In recognition of this, there is now extensive focus on early diagnosis, secondary prevention, and optimizing medical management of the disease. While established guidelines recognize different grades of disease severity and offer a structured basis for disease management based on symptoms and risk, it is becoming increasingly evident that COPD is a condition characterized by many phenotypes and its control in a single patient may require clinicians to have access to a broader spectrum of pharmacotherapies. This review summarizes recent developments in COPD management and compares established pharmacotherapy with new and emerging pharmacotherapies including long-acting muscarinic antagonists, long-acting β-2 sympathomimetic agonists, and fixed-dose combinations of long-acting muscarinic antagonists and long-acting β-2 sympathomimetic agonists as well as inhaled cortiocosteroids, phosphodiesterase inhibitors, and targeted anti-inflammatory drugs. We also review the available oral medications and new agents with novel mechanisms of action in early stages of development. With several new pharmacological agents intended for the management of COPD, it is our goal to familiarize potential prescribers with evidence relating to the efficacy and safety of new medications and to suggest circumstances in which these therapies could be most useful.

Aclidinium bromide plus formoterol for the treatment of chronic obstructive pulmonary disease

INTRODUCTION

Drugs that target dynamic hyperinflation such as long-acting β-2 agonists and long-acting antimuscarinic antagonists form a cornerstone of chronic obstructive pulmonary disease (COPD) management. The idea of combining these two medications in a single formulation, which may potentially improve patient compliance, is novel and attractive.

AREAS COVERED

The pharmacologic profiles of aclidinium bromide and formoterol fumarate are discussed. However, studies to define drug interactions and alterations in the pharmacodynamics and pharmacokinetics of the fixed dose combination (FDC) of aclidinium bromide/formoterol fumarate in large populations remain unpublished. Results of Phase II and two Phase III pivotal trials, ACLIFORM/COPD and AUGMENT COPD, evaluating the FDC are discussed.

EXPERT OPINION

Initial data for the aclidinium/formoterol inhaler appears to be promising for impacting the lung function. To define if this benefit translates into improved long-term outcomes of decreased exacerbation frequency, improved quality of life and decreased disease-specific mortality are important. The introduction of this combination will likely have a significant impact on the prescribing habits of physicians across the world.

Prevention of acute exacerbations of COPD: American College of Chest Physicians and Canadian Thoracic Society Guideline

BACKGROUND

COPD is a major cause of morbidity and mortality in the United States as well as throughout the rest of the world. An exacerbation of COPD (periodic escalations of symptoms of cough, dyspnea, and sputum production) is a major contributor to worsening lung function, impairment in quality of life, need for urgent care or hospitalization, and cost of care in COPD. Research conducted over the past decade has contributed much to our current understanding of the pathogenesis and treatment of COPD. Additionally, an evolving literature has accumulated about the prevention of acute exacerbations.

METHODS

In recognition of the importance of preventing exacerbations in patients with COPD, the American College of Chest Physicians (CHEST) and Canadian Thoracic Society (CTS) joint evidence-based guideline (AECOPD Guideline) was developed to provide a practical, clinically useful document to describe the current state of knowledge regarding the prevention of acute exacerbations according to major categories of prevention therapies. Three key clinical questions developed using the PICO (population, intervention, comparator, and outcome) format addressed the prevention of acute exacerbations of COPD: nonpharmacologic therapies, inhaled therapies, and oral therapies. We used recognized document evaluation tools to assess and choose the most appropriate studies and to extract meaningful data and grade the level of evidence to support the recommendations in each PICO question in a balanced and unbiased fashion.

RESULTS

The AECOPD Guideline is unique not only for its topic, the prevention of acute exacerbations of COPD, but also for the first-in-kind partnership between two of the largest thoracic societies in North America. The CHEST Guidelines Oversight Committee in partnership with the CTS COPD Clinical Assembly launched this project with the objective that a systematic review and critical evaluation of the published literature by clinical experts and researchers in the field of COPD would lead to a series of recommendations to assist clinicians in their management of the patient with COPD.

CONCLUSIONS

This guideline is unique because it provides an up-to-date, rigorous, evidence-based analysis of current randomized controlled trial data regarding the prevention of COPD exacerbations.

Clinicopharmacological profile of the fixed-dose combination of aclidinium bromide and formoterol fumarate in the management of chronic obstructive pulmonary disease

The recent Global Initiative for Chronic Obstructive Lung Disease (GOLD) chronic obstructive pulmonary disease (COPD) guidelines consider symptoms and exacerbation history in addition to the degree of airflow obstruction for classifying patients. The improvement of symptoms is principally provided by bronchodilators, using β2 agonists and antimuscarinic agents. Aclidinium bromide is a novel long-acting antimuscarinic agent licensed for use in patients with COPD. Novel fixed-dose combinations that are either licensed or in their late phase of development include vilanterol/umeclidinium, indacaterol/glycopyrronium, olodaterol/tiotropium and formoterol/aclidinium. Fixed-dose combinations of aclidinium/formoterol have been evaluated in COPD patients and evidence suggests that this is efficacious, safe, has a quick onset of action and is well tolerated. This review provides a clinico-pharmacological profile of this compound.

Refractory asthma - beyond step 5, the role of new and emerging adjuvant therapies

A small percentage of asthmatics have 'severe refractory asthma', where there is suboptimal response to currently available therapies. A number of novel therapies targeting key biological targets are becoming available. Asthma is a heterogeneous disease, and systematic evaluation of patients is important to target therapies to the underlying inflammatory subtype and clinical features. This review article outlines new and emerging treatments for severe asthma, including monoclonal antibodies targeting eosinophilic disease, anti-neutrophil strategies, novel bronchodilators and bronchial thermoplasty. We highlight the importance of individualized investigation, treatment and management of severe asthmatics.

Fluticasone furoate and vilanterol inhalation powder for the treatment of chronic obstructive pulmonary disease

Fluticasone furoate/vilanterol (FF/VI) is a novel inhaled corticosteroid/long-acting β₂-agonist (ICS/LABA) fixed dose combination that, by simplifying the dosing schedule, allows, for the first time in a member of the ICS/LABA class, a shift from twice-daily to once-daily treatment. FF/VI is delivered via a novel, single-step activation, multi-dose dry powder inhaler for oral inhalation, Ellipta. Regrettably, there are no head-to-head trials that have shown superiority in the safety or efficacy of FF versus other ICSs, but evidence shows that VI has a quicker onset of effect versus salmeterol. However, the clinical utility of this effect in a maintenance medication is still questionable. Furthermore, benefits of FF/VI over twice-daily ICS/LABA comparator have not been shown yet and, in addition, its adverse event profile is generally consistent with the known class effects of an ICS/LABA fixed dose combination. In particular, there is an increase in the risk of pneumonia among patients treated with FF/VI relative to VI, mainly among those who benefit most from FF/VI. Nevertheless, the interesting pharmacological profiles of both FF and VI, the possibility that FF/VI can be administered once-daily, and the attractive characteristics of Ellipta are important features that could help FF/VI to be a successful combination in the treatment of chronic obstructive pulmonary disease.

The in vivo efficacy and side effect pharmacology of GS-5759, a novel bifunctional phosphodiesterase 4 inhibitor and long-acting β 2-adrenoceptor agonist in preclinical animal species

Bronchodilators are a central therapy for symptom relief in respiratory diseases such as chronic obstructive pulmonary disease (COPD) and asthma, with inhaled β 2-adrenoceptor agonists and anticholinergics being the primary treatments available. The present studies evaluated the in vivo pharmacology of (R)-6-[[3-[[4-[5-[[2-Hydroxy-2-(8-hydroxy-2-oxo-1,2-dihydroquinolin-5-yl)ethyl]amino]pent-1-ynyl]phenyl]carbamoyl]phenyl]sulfonyl]-4-[(3-methoxyphenyl)amino]-8-methylquinoline-3-carboxamide (GS-5759), a novel bifunctional compound with both phosphodiesterase 4 (PDE4) inhibitor and long-acting β 2-adrenoceptor agonist (LABA) activity, which has been optimized for inhalation delivery. GS-5759 dose-dependently inhibited pulmonary neutrophilia in a lipopolysaccharide (LPS) aerosol challenge model of inflammation in rats with an ED50 ≤ 10 μg/kg. GS-5759 was also a potent bronchodilator with an ED50 of 0.09 μg/kg in guinea pigs and 3.4 μg/kg in dogs after methylcholine (MCh) and ragweed challenges respectively. In cynomolgus monkeys, GS-5759 was dosed as a fine-particle dry powder and was efficacious in the same dose range in both MCh and LPS challenge models, with an ED50 = 70 μg/kg for bronchodilation and ED50 = 4.9 μg/kg for inhibition of LPS-induced pulmonary neutrophilia. In models to determine therapeutic index (T.I.), efficacy for bronchodilation was evaluated against increased heart rate and GS-5759 had a T.I. of 700 in guinea pigs and >31 in dogs. In a ferret model of emesis, no emesis was seen at doses several orders of magnitude greater than the ED50 observed in the rat LPS inflammation model. GS-5759 is a bifunctional molecule developed for the treatment of COPD, which has both bronchodilator and anti-inflammatory activity and has the potential for combination as a triple therapy with a second compound, within a single inhalation device.

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

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

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

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Opposition involves transmitter release, signal transduction and receptor expression.

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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.

Profile of fluticasone furoate/vilanterol dry powder inhaler combination therapy as a potential treatment for COPD

Currently, there is no cure for chronic obstructive pulmonary disease (COPD). The limited efficacy of current therapies for COPD indicates a pressing need to develop new treatments to prevent the progression of the disease, which consumes a significant amount of health care resources and is an important cause of mortality worldwide. Current national and international guidelines for the management of stable COPD patients recommend the use of inhaled long-acting bronchodilators, inhaled corticosteroids, and their combination for maintenance treatment of moderate to severe stable COPD. Once-daily fluticasone furoate/vilanterol dry powder inhaler combination therapy has recently been approved by the US Food and Drug Administration and the European Medicines Agency as a new regular treatment for patients with stable COPD. Fluticasone furoate/vilanterol dry powder inhaler combination therapy has been shown to be effective in many controlled clinical trials involving thousands of patients in the regular treatment of stable COPD. This is the first once-daily combination of ultra-long-acting inhaled β₂-agonists and inhaled glucocorticoids that is available for the treatment of stable COPD and has great potential to improve compliance to long-term regular inhaled therapy and hence to improve the natural history and prognosis of COPD patients.

Considerations for new dual-acting bronchodilator treatments for chronic obstructive pulmonary disease

Current guidelines recommend treatment with one or more bronchodilators for chronic obstructive pulmonary disease (COPD) patients. Combination therapy with long-acting muscarinic antagonists (LAMA) and long-acting β2-agonists (LABA) should be recommended in patients who are not fully controlled with one of them. In this article, two closely related approaches to provide long-acting treatments are compared: the LABA/LAMA fixed-dose combination therapy, and the dual-acting muscarinic receptor antagonist and β2-adrenoceptor agonist (MABA). The author in that study concludes that both approaches have been shown to provide clinically enhanced bronchodilator activity that is superior to that offered by current standard treatment. LAMA/LABA fixed-dose combinations are expected to become a new standard in the treatment of COPD. It is important to know the characteristics of the different LAMA or LABA, the inhalation device and the duration of action, because diversity can help to personalize the treatment. Dose-finding studies are required. It is also required to investigate the existence of pharmacodynamics or pharmacokinetic interactions between the components as well as the safety profile. MABA represent an alternative to these combinations, but there is little clinical data yet reported. They have the potential to act as a useful platform for the development of triple therapy in one inhaler.

Inhaled corticosteroids for chronic obstructive pulmonary disease

INTRODUCTION

Current guidelines recommend the use of inhaled long-acting bronchodilators, inhaled corticosteroids (ICSs) and their combinations for maintenance treatment of moderate-to-severe chronic obstructive pulmonary disease (COPD); however, it is questionable whether all COPD patients should be treated, as the long-term use of ICSs is accompanied by side effects.

AREAS COVERED

This article reviews the evidence about the effects of ICSs in the treatment of COPD. It mainly focuses on meta-analyses of published data and pooled analyses of primary data. It also offers an overview of pipeline developments.

EXPERT OPINION

There is now more evidence that there are subsets of patients (mainly, frequent exacerbators with predominant chronic bronchitis and those with overlap between COPD and asthma) with a favorable response to treatment with ICSs (i.e., reduced progression of lung function loss, reduced exacerbation rate and improved health-related quality of life). Therefore, nowadays, the right question is not whether ICSs should not be used at all unless patients have concomitant asthma, but, instead, which COPD patient can benefit from a therapy with ICSs. Unfortunately, however, the number of studies that have investigated the clinical features that might predict corticosteroid response in COPD is still inadequate.

New developments in the combination treatment of COPD: focus on umeclidinium/vilanterol

An increasing body of evidence suggests that the long-acting muscarinic antagonist (LAMA)/long-acting β2-agonist (LABA) combination appears to play an important role in maximizing bronchodilation, with studies to date indicating that combining different classes of bronchodilators may result in significantly greater improvements in lung function compared to the use of a single drug, and that these combinations are well tolerated in patients with moderate-to-severe chronic obstructive pulmonary disease (COPD). An inhaled, fixed-dose combination of two 24-hour bronchodilators, the LAMA umeclidinium and the LABA vilanterol, is under development as a once-daily treatment for COPD. The efficacy of both mono-components has already been demonstrated. The information currently available suggests that umeclidinium/vilanterol is an effective once-daily dual bronchodilator fixed-dose combination in the treatment of COPD. However, it remains to be seen if it compares favorably with current therapies. Moreover, the question remains whether umeclidinium/vilanterol fixed-dose combination, which significantly improves FEV1, is also associated with improvements in other outcome measures that are important to COPD patients.

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.

Combination bronchodilator therapy in the management of chronic obstructive pulmonary disease

Chronic obstructive pulmonary disease (COPD) represents a significant cause of global morbidity and mortality, with a substantial economic impact. Recent changes in the Global initiative for chronic Obstructive Lung Disease (GOLD) guidance refined the classification of patients for treatment using a combination of spirometry, assessment of symptoms, and/or frequency of exacerbations. The aim of treatment remains to reduce existing symptoms while decreasing the risk of future adverse health events. Long-acting bronchodilators are the mainstay of therapy due to their proven efficacy. GOLD guidelines recommend combining long-acting bronchodilators with differing mechanisms of action if the control of COPD is insufficient with monotherapy, and recent years have seen growing interest in the additional benefits that combination of long-acting muscarinic antagonists (LAMAs), typified by tiotropium, with long-acting β(2)-agonists (LABAs), such as formoterol and salmeterol. Most studies have examined free combinations of currently available LAMAs and LABAs, broadly showing a benefit in terms of lung function and other patient-reported outcomes, although evidence is limited at present. Several once- or twice-daily fixed-dose LAMA/LABA combinations are under development, most involving newly developed monotherapy components. This review outlines the existing data for LAMA/LABA combinations in the treatment of COPD, summarizes the ongoing trials, and considers the evidence required to inform the role of LAMA/LABA combinations in treatment of this disease.

Aclidinium bromide for the treatment of chronic obstructive pulmonary disease

INTRODUCTION

Although there are some challenges with current therapies, the growing evidence that tiotropium bromide is important in the maintenance treatment of chronic obstructive pulmonary disease (COPD) has led to enthusiastic investigation in search of novel muscarinic antagonists which share some of the beneficial characteristics of tiotropium and perhaps improve upon less desirable ones.

AREAS COVERED

Aclidinium bromide is a new muscarinic antagonist that has been developed to relieve symptoms in patients with COPD. Preclinical data showed that it has an intriguing pharmacodynamic and pharmacokinetic profile. Aclidinium bromide was initially assessed as a once-daily bronchodilator. Subsequently, it has been evaluated as a twice-daily agent to increase the size of the clinical effect. Pivotal Phase III trials have documented that aclidinium bromide 400 μg twice-daily shows clinically meaningful effects in lung function and other important supportive outcomes, such as health-related quality of life, dyspnea and night-time/early morning symptoms, and is safe.

EXPERT OPINION

Aclidinium bromide can to be used as an alternative to tiotropium or a long-acting β₂-agonist. It is likely that the device used to deliver aclidinium, Genuair inhaler, a novel, multidose and a breath-actuated dry powder inhaler (DPI), will be important for the possible success of this drug. However, additional Phase III trials to assess advantages over tiotropium bromide and long-acting β₂-agonists are required to allow the place of aclidinium bromide to be fully elucidated.