Discovery of Novel Quaternary Ammonium Derivatives of (3R)-Quinuclidinol Esters as Potent and Long-Acting Muscarinic Antagonists with Potential for Minimal Systemic Exposure after Inhaled Administration: Identification of (3R)-3-{[Hydroxy(di-2-thienyl)acetyl]oxy}-1-(3-phenoxypropyl)-1-azoniabicyclo[2.2.2]octane Bromide (Aclidinium Bromide)

Characterization of a novel 3-quinuclidinone reductase possessing remarkable thermostability

The 3-quinuclidinone reductase plays an irreplaceable role in the biopreparation of (R)-3-quinuclidinol, an intermediate vital for synthesis of various pharmaceuticals. Thermal robustness is a critical factor for enzymatic synthesis in industrial applications. This study characterized a new 3-quinuclidinone reductase, named SaQR, with significant thermal stability. The SaQR was overexpressed in a GST-fused state, and substrate and cofactor screening were conducted. Additionally, three-dimensional structure prediction using AlphaFold and analysis were performed, along with relevant thermostability tests, and the evaluation of factors influencing enzyme activity. The findings highlight the remarkable thermostability of SaQR, retaining over 90% of its activity after 72 h at 50°C, with an optimal operational temperature of 85°C. SaQR showed typical structural traits of the SDR superfamily, with its cofactor-determining residue being aspartic acid, conferring nicotinamide adenine dinucleotide (NAD(H)) preference. Moreover, K+ and Na+, at a concentration of 400 mM, could significantly enhance the activity, while Mg2+ and Mn2+ only display inhibitory effects within the tested concentration range. The findings of molecular dynamics simulations suggest that high temperatures may disrupt the binding of enzyme to substrate by increasing the flexibility of residues 205-215. In conclusion, this study reports a novel 3-quinuclidinone reductase with remarkable thermostability.

Investigation of aclidinium bromide degradation by stability-indicating HPLC methods, characterization of impurities by NMR, and identification of degradation products by LC-MS

Aclidinium bromide (ACL) is a long-acting muscarinic receptor antagonist used for the long-term treatment of chronic obstructive pulmonary disease (COPD). The aim of this study was to investigate the degradation of aclidinium bromide under stress and stability testing conditions, for which we developed and validated the first stability-indicating, specific, precise, accurate, and robust assay and related substances HPLC methods. Nine of the compounds used as reference standards were synthesized and fully characterized by 1H and 13C NMR, MS, and FTIR techniques. Two of these molecules, namely ACL-dimer and ACL-desphenyl, are novel compounds and reported herein for the first time. Hydrolysis of aclidinium resulted in major degradation via the formation of ACL-desDTG and DTGA metabolites. ACL-desphenyl and phenol were observed only under oxidative conditions at very low levels (< 0.10%), while ACL-hydroxy, known as a metabolite of aclidinium and confirmed by LC/QDa and LC/Q-TOF m/z data, formed under oxidative stress-testing conditions, UV light, and daylight. The identification of two impurities formed only when aclidinium bromide was treated with hydrogen peroxide was done by LC/QDa and LC/Q-TOF studies and the novel structures were proposed as ACL-bromophenoxy and ACL-bromothiophenyl formed via bromination of the phenyl and thiophene ring on the aclidinium, respectively. The stress and photostability testing studies showed that the aclidinium bromide drug substance is not sensitive to elevated temperature (105 °C, 10 days), slightly sensitive to daylight and UV-radiation, and it showed significant degradation under all hydrolysis and oxidizing conditions. The related substances HPLC method reported herein is also capable to monitor the potential genotoxic impurity 3-bromopropoxybenzene (3-BPB), a class 2 impurity according to ICH M7, and ensures that the impurity remains below the threshold of toxicological concern (TTC) limit, making it safe for patients.

Multitargeting nature of muscarinic orthosteric agonists and antagonists

Muscarinic receptors (mAChRs) are typical members of the G protein-coupled receptor (GPCR) family and exist in five subtypes from M1 to M5. Muscarinic receptor subtypes do not sufficiently differ in affinity to orthosteric antagonists or agonists; therefore, the analysis of receptor subtypes is complicated, and misinterpretations can occur. Usually, when researchers mainly specialized in CNS and peripheral functions aim to study mAChR involvement in behavior, learning, spinal locomotor networks, biological rhythms, cardiovascular physiology, bronchoconstriction, gastrointestinal tract functions, schizophrenia, and Parkinson's disease, they use orthosteric ligands and they do not use allosteric ligands. Moreover, they usually rely on manufacturers' claims that could be misleading. This review aimed to call the attention of researchers not deeply focused on mAChR pharmacology to this fact. Importantly, limited selective binding is not only a property of mAChRs but is a general attribute of most neurotransmitter receptors. In this review, we want to give an overview of the most common off-targets for established mAChR ligands. In this context, an important point is a mention the tremendous knowledge gap on off-targets for novel compounds compared to very well-established ligands. Therefore, we will summarize reported affinities and give an outline of strategies to investigate the subtype's function, thereby avoiding ambiguous results. Despite that, the multitargeting nature of drugs acting also on mAChR could be an advantage when treating such diseases as schizophrenia. Antipsychotics are a perfect example of a multitargeting advantage in treatment. A promising strategy is the use of allosteric ligands, although some of these ligands have also been shown to exhibit limited selectivity. Another new direction in the development of muscarinic selective ligands is functionally selective and biased agonists. The possible selective ligands, usually allosteric, will also be listed. To overcome the limited selectivity of orthosteric ligands, the recommended process is to carefully examine the presence of respective subtypes in specific tissues via knockout studies, carefully apply "specific" agonists/antagonists at appropriate concentrations and then calculate the probability of a specific subtype involvement in specific functions. This could help interested researchers aiming to study the central nervous system functions mediated by the muscarinic receptor.

Discovery of Clinical Candidate CHF-6366: A Novel Super-soft Dual Pharmacology Muscarinic Antagonist and β2 Agonist (MABA) for the Inhaled Treatment of Respiratory Diseases

The development of molecules embedding two distinct pharmacophores acting as muscarinic antagonists and β₂ agonists (MABAs) promises to be an excellent opportunity to reduce formulation issues and boost efficacy through cross-talk and allosteric interactions. Herein, we report the results of our drug discovery campaign aimed at improving the therapeutic index of a previous MABA series by exploiting the super soft-drug concept. The incorporation of a metabolic liability, stable at the site of administration but undergoing rapid systemic metabolism, to generate poorly active and quickly eliminated fragments was pursued. Our SAR studies yielded MABA 29, which demonstrated a balanced in vivo profile up to 24 h, high instability in plasma and the liver, as well as sustained exposure in the lung. In vitro safety and non-GLP toxicity studies supported the nomination of 29 (CHF-6366) as a clinical candidate, attesting to the successful development of a novel super-soft MABA compound.

An Evaluation of the Pharmacokinetics, Safety, and Tolerability of Aclidinium/Formoterol Fixed-Dose Combination Administered in Chinese Patients with Moderate-to-Severe Chronic Obstructive Pulmonary Disease

Background and Objectives

The aim of this study was to evaluate the pharmacokinetics, safety, and tolerability of aclidinium bromide/formoterol fumarate in patients from China with moderate-to-severe chronic obstructive pulmonary disease (COPD).

Methods

In this open-label, repeat-dose, 5-day pharmacokinetic study (NCT03276078) of inhaled aclidinium bromide/formoterol fumarate 400/12 µg twice daily, plasma concentrations of aclidinium, formoterol, and two aclidinium metabolites (LAS34823, LAS34850) were assessed (days 1 and 5). Adverse event (AE) data were collected.

Results

Twenty patients (15 [75%] males) with a mean age of 59.2 years were included. Median (range) time to maximum concentration on days 1 and 5 was 0.08 (0.08–0.50) and 0.08 (0.08–0.50) h, respectively, for aclidinium; and 1.00 (0.08–3.00) and 0.08 (0.08–1.50) h, respectively, for formoterol. Mean elimination half-life and accumulation ratio for area under the concentration–time curve during a dosage interval (AUC_τ) was 19.42 h and 2.0, respectively, for aclidinium; and 14.06 h and 1.4, respectively, for formoterol. Steady-state maximum concentration (C_max,ss) and AUC_τ on day 5 were 60.86 pg/mL and 168.80 h·pg/mL, respectively, for aclidinium; and 6.47 pg/mL and 31.98 h·pg/mL, respectively, for formoterol. Aclidinium produced high coefficients of variation (day 1: AUC_τ 79.0%, C_max 84.5%; day 5: AUC_τ 82.2%, C_max 150.0%). Few AEs were reported, typically one per patient. One patient discontinued due to a serious AE (considered possibly unrelated to treatment).

Conclusions

Aclidinium/formoterol 400/12 µg twice daily was well-tolerated in patients from China with moderate-to-severe COPD. Safety findings were consistent with the known safety profile.

Clinical Trial Identifier

ClinicalTrials.gov, NCT03276078.

Supplementary Information

The online version contains supplementary material available at 10.1007/s40268-021-00374-z.

Antimicrobial, Cytotoxic and Mutagenic Activity of Gemini QAS Derivatives of 1,4:3,6-Dianhydro-l-iditol

A series of quaternary diammonium salts derivatives of 1,4:3,6-dianhydro-l-iditol were synthesized, using isommanide (1,4:3,6-dianhydro-d-mannitol) as a starting material. Both aromatic (pyridine, 4-(N,N-dimethylamino)pyridine (DMAP), (3-carboxamide)pyridine; N-methylimidazole) and aliphatic (trimethylamine, N,N-dimethylhexylamine, N,N-dimethyloctylamine, N,N-dimethyldecylamine) amines were used, giving eight gemini quaternary ammonium salts (QAS). All salts were tested for their antimicrobial activity against yeasts, Candida albicans and Candida glabrata, as well as bacterial Staphylococcus aureus and Escherichia coli reference strains. Moreover, antibacterial activity against 20 isolates of S. aureus collected from patients with skin and soft tissue infections (n = 8) and strains derived from subclinical bovine mastitis milk samples (n = 12) were evaluated. Two QAS with octyl and decyl residues exhibited antimicrobial activity, whereas those with two decyl residues proved to be the most active against the tested pathogens, with MIC of 16-32, 32, and 8 µg/mL for yeast, E. coli, and S. aureus reference and clinical strains, respectively. Only QAS with decyl residues proved to be cytotoxic in MTT assay against human keratinocytes (HaCaT), IC₅₀ 12.8 ± 1.2 μg/mL. Ames test was used to assess the mutagenic potential of QAS, and none of them showed mutagenic activity in the concentration range 4-2000 µg/plate.

Engineering of a Novel, Magnetic, Bi-Functional, Enzymatic Nanobiocatalyst for the Highly Efficient Synthesis of Enantiopure (R)-3-quinuclidinol

Ni2+-NTA-boosted magnetic porous silica nanoparticles (Ni@MSN) to serve as ideal support for bi-functional enzyme were fabricated for the first time. The versatility of this support was validated by one-step purification and immobilization of bi-functional enzyme MLG consisting of 3-Quinuclidinone reductase and glucose dehydrogenase, which can simultaneously catalyze both carbonyl reduction and cofactor regeneration, to fabricate an artificial bi-functional nanobiocatalyst (namely, MLG-Ni@MSN). The enzyme loading of 71.7 mg/g support and 92.7% immobilization efficiency were obtained. Moreover, the immobilized MLG showed wider pH and temperature tolerance and greater storage stability than free MLG under the same conditions. The nanosystem was employed as biocatalyst to accomplish the 3-quinuclidinone (70 g/L) to (R)-3-quinuclidinol biotransformation in 100% conversion yield with >99% selectivity within 6 h and simultaneous cofactor regeneration. Furthermore, the immobilized MLG retained up to 80.3% (carbonyl reduction) and 78.0% (cofactor regeneration) of the initial activity after being recycled eight times. In addition, the MLG-Ni@MSN system exhibited almost no enzyme leaching during biotransformation and recycling. Therefore, we have reason to believe that the Ni@MSN support gave great promise for constructing a new biocatalytic nanosystem with multifunctional enzymes to achieve some other complex bioconversions.

Synthetic approaches to FDA approved drugs for asthma and COPD from 1969 to 2020

Respiratory infections resulting from pulmonary inflammation emerging as a leading cause of death worldwide. However, only twenty-seven new drugs were approved in the last five decades. In this review, we presented synthetic approaches for twenty-seven FDA-approved medications used to treat asthma and chronic obstructive pulmonary diseases (COPD), along with their mode of action.

Aclidinium bromide in fixed-dose combination with formoterol fumarate in the management of COPD: an update on the evidence base

Aclidinium bromide/formoterol fumarate (AB/FF) 400/12 µg is a twice-daily long-acting muscarinic receptor antagonist and long-acting β2 agonist (LAMA/LABA) dual-bronchodilator maintenance therapy used to relieve symptoms and reduce future risk of exacerbations in adults with chronic obstructive pulmonary disease (COPD). To date, there have been several clinical studies and post hoc analyses of AB/FF, assessing treatment outcomes in patients with moderate-to-severe COPD. These studies have looked at a range of outcomes, including lung function parameters, patient-reported symptom scores, quality-of-life measures assessing impaired health and perceived well-being, and the frequency, duration, and severity of exacerbations. In light of the major 2017 revision to the Global initiative for chronic Obstructive Lung Disease (GOLD) recommendations, and the subsequent updates, we present an update on the latest evidence supporting the efficacy and safety of AB/FF. This review discusses the clinical relevance of the improvements in lung function, symptoms, quality of life, and exacerbations in patients with COPD reported in the phase III and IV trials of AB/FF. Given the current concerns over unnecessary inhaled corticosteroid (ICS) use in COPD, we also touch briefly on the use of blood eosinophils as a biomarker for identifying those patients with COPD already using LAMA/LABA therapy for whom the addition of ICS might be of benefit.

Magnetic Combined Cross-Linked Enzyme Aggregates of Ketoreductase and Alcohol Dehydrogenase: An Efficient and Stable Biocatalyst for Asymmetric Synthesis of (R)-3-Quinuclidinol with Regeneration of Coenzymes In Situ

Enzymes are biocatalysts. In this study, a novel biocatalyst consisting of magnetic combined cross-linked enzyme aggregates (combi-CLEAs) of 3-quinuclidinone reductase (QNR) and glucose dehydrogenase (GDH) for enantioselective synthesis of (R)-3-quinuclidinolwith regeneration of cofactors in situ was developed. The magnetic combi-CLEAs were fabricated with the use of ammonium sulfate as a precipitant and glutaraldehyde as a cross-linker for direct immobilization of QNR and GDH from E. coli BL(21) cell lysates onto amino-functionalized Fe3O4 nanoparticles. The physicochemical properties of the magnetic combi-CLEAs were characterized by Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD) and magnetic measurements. Field emission scanning electron microscope (FE-SEM) images revealed a spherical structure with numerous pores which facilitate the movement of the substrates and coenzymes. Moreover, the magnetic combi-CLEAs exhibited improved operational and thermal stability, enhanced catalytic performance for transformation of 3-quinuclidinone (33 g/L) into (R)-3-quinuclidinol in 100% conversion yield and 100% enantiomeric excess (ee) after 3 h of reaction. The activity of the biocatalysts was preserved about 80% after 70 days storage and retained more than 40% of its initial activity after ten cycles. These results demonstrated that the magnetic combi-CLEAs, as cost-effective and environmentally friendly biocatalysts, were suitable for application in synthesis of (R)-3-quinuclidinol essential for the production of solifenacin and aclidinium with better performance than those currently available.

Novel long-acting antagonists of muscarinic ACh receptors

BACKGROUND AND PURPOSE

The aim of this study was to develop potent and long-acting antagonists of muscarinic ACh receptors. The 4-hexyloxy and 4-butyloxy derivatives of 1-[2-(4-oxidobenzoyloxy)ethyl]-1,2,3,6-tetrahydropyridin-1-ium were synthesized and tested for biological activity. Antagonists with long-residence time at receptors are therapeutic targets for the treatment of several neurological and psychiatric human diseases. Their long-acting effects allow for reduced daily doses and adverse effects.

EXPERIMENTAL APPROACH

The binding and antagonism of functional responses to the agonist carbachol mediated by 4-hexyloxy compounds were investigated in CHO cells expressing individual subtypes of muscarinic receptors and compared with 4-butyloxy analogues.

KEY RESULTS

The 4-hexyloxy derivatives were found to bind muscarinic receptors with micromolar affinity and antagonized the functional response to carbachol with a potency ranging from 30 nM at M1 to 4 μM at M3 receptors. Under washing conditions to reverse antagonism, the half-life of their antagonistic action ranged from 1.7 h at M2 to 5 h at M5 receptors.

CONCLUSIONS AND IMPLICATIONS

The 4-hexyloxy derivatives were found to be potent long-acting M1 -preferring antagonists. In view of current literature, M1 -selective antagonists may have therapeutic potential for striatal cholinergic dystonia, delaying epileptic seizure after organophosphate intoxication or relieving depression. These compounds may also serve as a tool for research into cognitive deficits.

The discovery and development of aclidinium bromide for the treatment of chronic obstructive pulmonary disease

INTRODUCTION

Bronchodilators, including long-acting muscarinic receptor antagonists (LAMAs), are a mainstay of the pharmacological treatment of chronic obstructive pulmonary disease (COPD). LAMAs act as bronchodilators principally by antagonizing airway smooth muscle cells M₃ muscarinic receptors. Aclidinium bromide is a twice-daily LAMA which was developed to improve on the efficacy and/or safety of previous LAMAs. Area covered: Herein, the authors present the pharmacotherapeutic role of aclidinium in COPD and point out unmet need in this research area. The following aspects are covered: a) the discovery and medicinal chemistry of aclidinium bromide; b) an overview of the market; c) its mechanism of action; d) its pharmacokinetic/pharmacodynamic profile derived from pre-clinical studies; e) the clinical studies which led to its licensing; f) the evidence from meta-analyses; g) the aclidinium/formoterol fixed dose combination for COPD and h) priorities in this area of research. Expert opinion: Aclidinium bromide has the pharmacological properties, safety and efficacy profile and inhaler characteristics which makes it a valuable therapeutic option for pharmacological management of patients with COPD. Due to its rapid biotransformation into inactive metabolites, aclidinium is potentially one of the safest LAMAs. Further head-to-head randomized clinical trials are required to define efficacy and safety of aclidinium when compared to once-daily LAMAs. The clinical relevance of airway anti-remodeling effects of aclidinium has to be defined.

The safety of anticholinergic bronchodilators for the treatment of chronic obstructive pulmonary disease

INTRODUCTION

Poorly absorbable quaternary ammonium-inhaled muscarinic antagonists both as the short-acting ipratropium and as long-acting (12 - 24 h) agents (tiotropium, glycopyrronium, aclidinium and umeclidinium) have all demonstrated statistically and clinically significant efficacy in chronic obstructive pulmonary disease compared with placebo. However, controversy has arisen concerning the safety of this class of agents principally regarding their association with both fatal and nonfatal cardiovascular toxicity.

AREAS COVERED

The safety of both ipratropium and the long-acting muscarinic antagonists is reviewed with a major emphasis on potential cardiovascular toxicity, based on published clinical trials data and results of analyses of pooled data, meta-analyses, and observational studies. Since glycopyrronium, aclidinium, and umeclidinium have become available only relatively recently, more emphasis will be placed on the more extensive literature concerning the safety of the older anticholinergic compounds, the short-acting ipratropium, and the long-acting tiotropium in its dry powder formulation, as well as its newer soft mist inhaler delivery device.

EXPERT OPINION

Pooled analyses and meta-analyses of randomized controlled trials (RCTs) of tiotropium in both its dry powder and soft mist formulations, as well as some observational studies, have implicated this agent as increasing the risk of nonfatal and fatal cardiovascular events. However, the most robust evidence based on large-scale randomized controlled trials (RCTs) of relatively long duration specifically designed to evaluate the cardiovascular safety of tiotropium have not confirmed these safety concerns. Because of the relatively limited amount of safety data for the newer long-acting muscarinic antagonists compared to the far more extensive experience with tiotropium, it will be important to accumulate additional safety information from post-marketing pharmacovigilance for these newer agents.

Aclidinium bromide/formoterol fixed-dose combination therapy for COPD: the evidence to date

The quest for the right combination of bronchodilators with different mechanisms of action such as long-acting muscarinic antagonists and long-acting β-agonists in the management of stable moderate-to-severe chronic obstructive pulmonary disease (COPD) is a topic of intense research activity currently, given the rising morbidity and mortality due to this disease. The fixed-dose combination of aclidinium bromide and formoterol fumarate in a single inhaler seems to offer superior advantages over either drugs given alone or as separate inhalers concurrently. Since the fixed-dose combination needs to be given twice daily, it is likely to achieve control of symptoms most crucial to the quality of life in COPD, namely, the morning hours. This is reflected in significant trough FEV₁ (forced expiratory volume in 1 second) improvements after the dose. This paper reviews the various studies related to this combination put in the perspective of its safety and efficacy and potential benefits over other therapeutic options. However, there is a dearth of data on the long-term safety and efficacy in terms of improvement in lung function. This combination could emerge as an excellent option in the management of stable COPD if data on exacerbation rates and patient-reported outcomes become available from longer-term studies. Moreover, we need some more studies to define the ideal phenotype of COPD best suited for the use of this combination.

Clinical potential of aclidinium bromide in chronic obstructive pulmonary disease

Chronic obstructive pulmonary disease (COPD) is increasing worldwide and is predicted to become the third most frequent cause of death by 2030. Muscarinic receptor antagonists, alone or in combination with long-acting β2-agonists, are frequently used for COPD therapy. Aclidinium bromide is a novel muscarinic receptor antagonist, and clinical studies indicate that its metabolism is more rapid than that of other muscarinic receptor inhibitors, so systemic side effects are expected to occur less frequently. Aclidinium bromide is well tolerated, and when compared with other muscarinic receptor antagonists, the drug achieves better control of lung function, especially night-time symptoms in COPD patients. This review summarizes the safety profile and side effects reported by recent clinical studies using aclidinium bromide alone.

Clinical use of aclidinium in patients with COPD

Chronic obstructive pulmonary disease (COPD) is the sixth-leading cause of death in the US. The Global initiative for Chronic Obstructive Lung Disease (GOLD) guidelines provide evidence-based recommendations for the clinical management of chronic COPD. Long-acting inhaled bronchodilators continue to be the mainstay of current management. Aclidinium bromide (Tudorza™ Pressair™) joins tiotropium as a long-acting inhaled antimuscarinic bronchodilator approved by the US Food and Drug Administration for the maintenance treatment of COPD. Early studies demonstrated aclidinium's significant bronchodilatory effects supporting once-daily dosing; however, two Phase III studies, Aclidinium Clinical Trial Assessing Efficacy and Safety in Moderate to Severe COPD Patients (ACCLAIM/COPD) I and ACCLAIM/COPD II, in which patients were randomized to receive aclidinium 200 μg daily, failed to achieve the minimal clinically important difference in improvement of trough forced expiratory volume in 1 second (FEV1), suggesting the need for higher doses or more frequent dosing. Additional studies - Aclidinium to Treat Airway Obstruction in COPD Patients (ATTAIN) and Aclidinium in Chronic Obstructive Respiratory Disease (ACCORD) I - were undertaken to compare 200 and 400 μg twice-daily dosing. The mean improvements from baseline in trough FEV1 in the 400 μg groups were +129 mL over 24 weeks and +124 mL over 12 weeks in ATTAIN and ACCORD I, respectively. Aclidinium also had beneficial effects on health-related quality of life and other endpoints, such as rescue medication use and rates of exacerbations. Aclidinium bromide inhalation powder is generally well tolerated in patients with COPD, with headache, cough, diarrhea, and rhinosinusitis among the most commonly reported adverse events. Cardiovascular side effects were rarely reported. Patient satisfaction studies found that patients using the aclidinium delivery device had fewer errors affecting drug delivery than those using the tiotropium device and, overall, the aclidinium device was preferred to the tiotropium device. In conclusion, aclidinium bromide is approved for use in the US at a dose of 400 μg twice daily and is a promising alternative to tiotropium.

Long-acting muscarinic receptor antagonists for the treatment of chronic airway diseases

Acetylcholine (neuronal and non-neuronal origin) regulates bronchoconstriction, and mucus secretion. It has an inflammatory effect by inducing attraction, survival and cytokine release from inflammatory cells. Muscarinic receptors throughout the bronchial tree are mainly restricted to muscarinic M1, M2 and M3 receptors. Three long-acting muscarinic receptor antagonists (LAMAs) were approved for the treatment of chronic obstructive pulmonary disease (COPD) in Europe: once-daily tiotropium bromide; once-daily glycopyrronium bromide; and twice-daily aclidinium bromide. All have higher selectivity for M3 receptors than for M2 receptors, and dissociate more slowly from the M3 receptors than they do from the M2 receptors. Some LAMAs showed anti-inflammatory effects [inhibition of neutrophil chemotactic activity and migration of alveolar neutrophils, decrease of several cytokines in the bronchoalveolar lavage (BAL) including interleukin (IL)-6, tumor necrosis factor (TNF)-α and leukotriene (LT)B4] and antiremodeling effects (inhibition of mucus gland hypertrophy and decrease in MUC5AC-positive goblet cell number, decrease in MUC5AC overexpression). In the clinic, LAMAs showed a significant improvement of forced expiratory volume in 1 second (FEV1), quality of life, dyspnea and reduced the number of exacerbations in COPD and more recently in asthma. This review will focus on the three LAMAs approved in Europe in the treatment of chronic airway diseases.

Aclidinium bromide: an alternative long-acting inhaled anticholinergic in the management of chronic obstructive pulmonary disease

OBJECTIVE

To evaluate the efficacy and safety of aclidinium bromide, a novel, long-acting inhaled muscarinic receptor antagonist approved by the Food and Drug Administration (FDA) in July 2012, as a treatment in the management of moderate to severe chronic obstructive pulmonary disease (COPD).

DATA SOURCES

Literature was identified through PubMed/MEDLINE (2000-March 2013) and International Pharmaceutical Abstracts using the search terms aclidinium, COPD, chronic bronchitis, emphysema, anticholinergic, and muscarinic antagonist. In addition, US government websites, including fda.gov and clinicaltrials.gov, were reviewed for pertinent information. Forest Laboratories, Inc provided previously unpublished clinical trial data. All reference citations from identified publications were reviewed for possible inclusion.

STUDY SELECTION AND DATA EXTRACTION

All identified Phase 1, 2a, 2b, and 3 studies evaluating the safety and efficacy of aclidinium bromide were reviewed.

DATA SYNTHESIS

Once- and twice-daily aclidinium bromide was assessed for efficacy and safety in patients with moderate to severe COPD. In comparison to placebo, aclidinium significantly improves trough and peak forced expiratory volume in 1 second (FEV1). Significant increases in trough and peak FEV1 were sustainable for up to 64 weeks. In addition to improvement in trough and peak FEV1, twice-daily aclidinium 400 μg induced clinically meaningful improvements in the health status of patients with moderate to severe COPD. Aclidinium was generally well tolerated, with headache, cough, diarrhea, and nasopharyngitis the most common treatment-related adverse effects noted in clinical trials. Aclidinium did not demonstrate a difference in the incidence of systemic anticholinergic-associated adverse effects in comparison to placebo or active comparator.

CONCLUSIONS

Aclidinium bromide is a novel, inhaled, long-acting anticholinergic that, when administered at the FDA-approved dose, safely produces clinically and statistically significant bronchodilation and improves health status in patients with moderate to severe COPD. Long-term clinical trials assessing the efficacy and safety of aclidinium are warranted.

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.

Aclidinium bromide twice daily for the treatment of chronic obstructive pulmonary disease: a review

The inhaled, long-acting muscarinic antagonist, aclidinium bromide, was indicated in July 2012 in Europe and the USA for the maintenance of bronchodilator treatment to relieve symptoms of chronic obstructive pulmonary disease (COPD) in adults. Although initially investigated as a once-daily agent, a lower than expected improvement in trough forced expiratory volume over 1 s prompted re-evaluation as a twice-daily (b.i.d.) regimen. The dose approved for use in Europe, 400 μg b.i.d., achieved statistically significant improvements in lung function, reductions in breathlessness, and improved health-related quality of life (HRQoL) for up to 24 weeks of treatment in the pivotal phase 3 trials (AClidinium in Chronic Obstructive Respiratory Disease I [ACCORD COPD I] [12 weeks] and Aclidinium To Treat Airway obstruction In COPD patieNts [ATTAIN] [24 weeks]). These improvements were sustained during maintenance therapy of up to 52 weeks. Pooled data from the ATTAIN and ACCORD studies (both included a placebo arm) showed that exacerbation frequency was significantly reduced, although neither study was prospectively designed to evaluate this endpoint. Pharmacological and preclinical studies demonstrated the low systemic bioavailability of aclidinium and the low propensity to induce cardiac arrhythmias. The good tolerability of aclidinium was confirmed in the phase 3 program up to 52 weeks of treatment. The adverse event (AE) profile of the approved dose, 400 μg b.i.d., was similar to that of placebo, with a low incidence of anticholinergic and cardiac AEs. Aclidinium is delivered via the Genuair(®) multidose dry powder inhaler (Almirall Sofotec GmBH, Bad Homburg, Germany). The device is simple to use with multiple feedback mechanisms ensuring consistent dose delivery. In summary, aclidinium 400 μg b.i.d. is effective for the treatment of patients with COPD, offering improvements in lung function, breathlessness, and HRQoL, with a good safety profile and a low incidence of anticholinergic and cardiac AEs.

Expression, purification, crystallization and preliminary X-ray analysis of carbonyl reductase S1 from Candida magnoliae

The NADPH-dependent carbonyl reductase S1 from Candida magnoliae stereoselectively catalyzes the reduction of ethyl 4-chloro-3-oxobutanoate (COBE) to ethyl (S)-4-chloro-3-hydroxybutanoate (CHBE), which is a chiral compound valuable as a building block for pharmaceuticals. Carbonyl reductase S1 was expressed in Escherichia coli and purified by Ni-affinity, ion-exchange and size-exclusion chromatography. Crystals of carbonyl reductase S1 were obtained by the sitting-drop vapour-diffusion method using PEG 400 as a precipitant. X-ray diffraction data were collected to 1.90 Å resolution using a synchrotron-radiation source. The crystals belonged to space group P6(1)22 or P6(5)22, with unit-cell parameters a = b = 77.7, c = 307.5 Å. The asymmetric unit contained two molecules of the protein, with a solvent content of 44.2%.

Mass balance and metabolism of aclidinium bromide following intravenous administration of [¹⁴C]-aclidinium bromide in healthy subjects

Aclidinium bromide is a novel, inhaled long-acting muscarinic antagonist with low systemic activity developed for the treatment of COPD. It is an ester compound rapidly hydrolysed in plasma into inactive alcohol and acid metabolites. In this Phase I, open-label study, the rates and routes of elimination of radioactivity following intravenous administration of [¹⁴C]-aclidinium bromide were determined. The metabolites of aclidinium were also characterized and identified in plasma and excreta. Twelve healthy males were randomized (1:1) to receive a single intravenous 400 µg dose of [phenyl-U-¹⁴C]- or [glycolyl-U-¹⁴C]-aclidinium bromide (via 5 min infusion) to label alcohol or acid metabolites of aclidinium, respectively. Safety and tolerability were assessed over a 9-day period. Following intravenous administration, the parent compound was rapidly hydrolysed into its acid and alcohol metabolites. Primary excretion routes for [phenyl-U-¹⁴C]- and [glycolyl-U-¹⁴C]-aclidinium were renal (urine: 65% and 54%, respectively; feces: 33% and 20%, respectively), with 1% excreted as unchanged aclidinium. A total of three treatment-emergent adverse events in two subjects were reported and were related to infusion site pain. Overall, aclidinium is rapidly hydrolysed into two main metabolites, which are predominantly excreted in urine. Aclidinium bromide 400 µg administered intravenously was safe and well tolerated in healthy subjects.

Inhaled long-acting muscarinic antagonists in chronic obstructive pulmonary disease

In 2002, the first long-acting muscarinic antagonist, tiotropium bromide (Spiriva®), was launched as a once-daily bronchodilating agent for the treatment of chronic obstructive pulmonary disease. Since then, there has been intense discovery research activity in this area and, currently, several alternative inhaled long-acting muscarinic antagonists are reported under clinical development by several pharmaceutical companies. This article will review the current inhaled development candidates, as well as literature reports of the most significant preclinical chemical series specifically designed as inhaled antimuscarinic agents.