The potential for aclidinium bromide,a new anticholinergic,in the management of chronic obstructive pulmonary disease

Abstract

Long-acting muscarinic antagonists (LAMAs) play a central role in the management of chronic obstructive pulmonary disease (COPD). Previously, only one LAMA (tiotropium) was available for the treatment of COPD, necessitating the development of other therapeutic options due to the heterogeneity of COPD and patient responses to treatment. This article reviews the COPD management potential of aclidinium bromide, a LAMA administered twice daily (BID) by a multidose dry powder inhaler that is indicated for maintenance treatment of COPD. Aclidinium possesses kinetic selectivity for the M₃ versus M₂ receptor and is rapidly hydrolyzed in plasma to two major inactive metabolites, resulting in a low and transient systemic exposure and minimizing the potential for systemic side effects. A pharmacokinetic study with multiple doses of twice-daily aclidinium demonstrated the short half-life of aclidinium in plasma, suggesting that a steady state may be reached as early as the second day postdose. In a phase II study, twice-daily aclidinium 400 µg provided 24-hour bronchodilation, with significant improvements versus tiotropium during the second half of the day. In two phase III studies (ACCORD I and ATTAIN), both aclidinium 200 µg and 400 µg BID provided statistically significant improvements in trough forced expiratory volume in 1 second (FEV₁) and other related lung function measurements. Improvements in peak FEV₁ on day 1 were comparable to those at study end, demonstrating that aclidinium provides maximal bronchodilation after the first dose that is maintained over time. Health status was significantly improved and dyspnea, nighttime and morning symptoms of COPD were likewise significantly reduced with aclidinium. Numerically greater improvements in efficacy were observed with the 400 µg dose compared with the lower dose, with similar safety profiles between the two doses and a low incidence of anticholinergic side effects. The approved therapeutic dose of aclidinium 400 µg BID is thus an effective new treatment option for patients with COPD.

Keywords

chronic obstructive pulmonary disease (COPD)long-acting muscarinic antagonist (LAMA)aclidinium bromide lung function COPD symptoms bronchodilation

Introduction

Chronic obstructive pulmonary disease (COPD) is defined as a common preventable and treatable disease that is characterized by persistent airflow limitation that is usually progressive in response to inhaled cigarette smoke and other noxious particles or gases [Vestbo et al. 2012]. COPD presents a major global health concern as it is currently the third leading cause of death in the United States [Kochanek et al. 2011] and is the fourth leading cause of death worldwide [WHO, 2008].

The severity of COPD is most frequently characterized by its effects on lung function, including airflow limitation and lung hyperinflation [Cazzola et al. 2008]. While physiologic measures of lung function provide an objective means to categorize and characterize the illness, they fail to fully capture a patient’s experience of living with COPD. The severity of airflow limitation alone has been shown to be a poor predictor of other features of COPD such as breathlessness and health status, with exacerbations being reported even in patients with only moderate COPD [Agusti et al. 2010]. As such, the Canadian COPD Guidelines and the latest update to the Global Initiative for Chronic Obstructive Lung Disease (GOLD) guidelines recommend a combined approach to COPD assessment using spirometric classification based on airflow limitation, in combination with assessment of patient symptoms and COPD exacerbation history [O’Donnell et al. 2007; Vestbo et al. 2012].

In patients with COPD, the burden of illness is high in terms of health-related quality of life and health status [Halpin and Miravitlles, 2006]. Patients experience poor physical functioning and live with symptoms such as breathlessness, cough, sputum production, exercise intolerance, physical inactivity, and exacerbations, which are driving forces in the further worsening of lung function, symptoms, and quality of life [Halpin and Miravitlles, 2006]. Thus, relief of symptoms, improvement of exercise tolerance and health status, and prevention of exacerbations are goals for the treatment of COPD [Vestbo et al. 2012]. New treatments for the management of COPD should ideally have a positive effect on each of these outcomes, in addition to improvements in lung function and minimal side effects.

Long-acting muscarinic antagonists

Inhaled bronchodilator medications, including long-acting beta-2 adrenergic agonists (LABAs) and long-acting muscarinic antagonists (LAMAs), are central to the symptomatic treatment of COPD [Vestbo et al. 2012]. LABAs stimulate β₂-adrenergic receptors to relax airway smooth muscles [Tashkin and Fabbri, 2010] while LAMAs block the effects of acetylcholine on muscarinic receptors to reverse airway obstruction [Barnes, 2004]. Cholinergic tone is considered the major reversible component of bronchoconstriction in COPD [Gross and Skorodin, 1984], and LAMAs are recommended as one of the first choices of therapy for patients with moderate-to-very severe COPD (GOLD 2 and higher) [Vestbo et al. 2012].

Five distinct muscarinic receptor subtypes have been identified throughout the body (M₁ through M₅), and each subtype mediates distinct physiologic functions. Three of these subtypes (M₁, M₂, and M₃) have been identified in airway smooth muscle [Barnes, 2004]. M₁ receptors facilitate neurotransmission though parasympathetic ganglia in the airways, thereby enhancing cholinergic reflex bronchoconstriction. M₂ receptors are autoreceptors located on cholinergic nerve endings that act as feedback inhibitors of acetylcholine release. M₃ receptors are located directly on airway smooth muscle cells and lead to bronchoconstriction in response to acetylcholine. Thus, M₂ and M₃ have opposing actions in response to antagonism; blockade of M₂ leads to unregulated acetylcholine release resulting in bronchoconstriction, while blockade of M₃ prevents acetylcholine-induced bronchoconstriction.

As muscarinic receptors are not limited to the airways, anticholinergics have the potential to produce unwanted systemic physiological effects. For example, M₂ receptors are also located on cardiac tissue where they play a prominent role in cardiac function [Abrams et al. 2006]. This receptor subtype may therefore be responsible for some of the cardiac adverse events (AEs) associated with nonselective or M₂-selective anticholinergic treatment. Thus, a muscarinic antagonist with selective activity for the M₃ receptor would be ideal for providing effective bronchodilation and symptom relief with a favorable safety profile.

Tiotropium, the first LAMA approved for treatment of COPD, has a kinetic selectivity for the M₃ and M₁ receptors over the M₂ receptors [Disse et al. 1993]. It is administered via inhalation either using a single-dose dry powder inhaler (DPI), the HandiHaler^® (approved for use worldwide), or the multidose Respimat SoftMist^® inhaler (approved for use in Europe). However, due to the heterogeneity of COPD and patients’ differential response to treatment [Rennard, 2011], the development of other treatment options may be useful for management of the disease. Aclidinium bromide is a novel, inhaled LAMA administered via a multidose DPI (Genuair^®/Pressair^™)^⋆ that is indicated for maintenance treatment of COPD. The objective of this review is to provide an overview of the preclinical and clinical studies of aclidinium bromide that have been published as of April 2012 and to assess its potential as a new and effective option for the maintenance treatment of COPD.

Pharmacology and pharmacokinetics of aclidinium

Aclidinium bromide has been shown in in vitro studies to have a long residence half-life at the human M₃ receptor (t_1/2 = 29.2 hours) and shorter residence time at the human M₂ receptor (t_1/2 = 4.7 hours), resulting in an approximate sixfold kinetic selectivity of the M₃ versus the M₂ receptor subtype [Gavalda et al. 2009]. This kinetic selectivity is advantageous, giving aclidinium the potential to provide effective bronchodilation through its effects on M₃ receptors in airway smooth muscle, while maintaining a favorable safety profile resulting from its lesser effects on M₂ receptors in cardiac tissue. Aclidinium also acts rapidly on muscarinic receptors and provides a sustained blockade of their action. In in vivo animal models, the onset of action of aclidinium (30 minutes) was similar to that of ipratropium (30 minutes) but faster than that of tiotropium (80 minutes) [Gavalda et al. 2009]. In anesthetized guinea pigs, aclidinium demonstrated a prolonged duration of action (i.e. time taken to reduce maximal bronchoconstriction by 50% [t_½]) (t_1/2 = 29 hours) compared with other antimuscarinic agents such as ipratropium (t_1/2 = 8 hours) but shorter than that of tiotropium (t_1/2 = 64 hours) [Gavalda et al. 2009].

Several preclinical and clinical studies have provided evidence of the favorable safety profile of aclidinium. First, an in vitro study has shown that aclidinium has a very short half-life in human plasma (2.4 minutes) compared with the relatively longer half-lives of tiotropium (96 minutes) and ipratropium (>6 hours) [Sentellas et al. 2010]. Second, in vitro data indicate that aclidinium undergoes hydrolysis in plasma into an acid and an alcohol metabolite, neither of which has demonstrated relevant in vivo bronchodilatory activity or significant in vitro affinity for muscarinic receptors, G-protein-coupled receptors, ion channels, or enzymes [Sentellas et al. 2010]. Third, aclidinium is hydrolyzed in human plasma primarily by butyrylcholinesterase, with no involvement of cytochrome P450 nor serum albumin [Alberti et al. 2010]. Due to the low plasma levels of aclidinium as a result of its rapid hydrolysis, drug–drug interactions involving aclidinium and human esterases are thus unlikely. Fourth, oxidative metabolism of aclidinium in liver microsomes and hepatocytes was substantially less than its ester hydrolysis, demonstrating the low potential for hepatic toxicity [Alberti et al. 2011]. Fifth, various animal models have demonstrated a favorable cardiovascular safety profile at supratherapeutic doses of aclidinium [Gavalda et al. 2009; Gras et al. 2008].

This favorable safety profile of aclidinium is attributed to its low and transient systemic exposure, initially demonstrated in vitro and confirmed in several clinical studies in healthy subjects. Overall bioavailability of aclidinium was low (<5% following an inhaled dose of aclidinium 200 µg) following both inhaled and intravenous administration of various doses of aclidinium [Ortiz et al. 2012]. The low systemic exposure of aclidinium has been demonstrated in pharmacokinetic studies in healthy subjects [Jansat et al. 2009a; Jansat et al. 2009b]. Furthermore, similar pharmacokinetic profiles of aclidinium were also observed in healthy subjects stratified by age (i.e. young [40-59 years] and elderly [≥70 years]), suggesting that no dose adjustment is necessary when treating elderly patients with COPD [De la Motte et al. 2012].

These data suggest that aclidinium has a reduced potential for producing unwanted anticholinergic adverse effects (i.e. dry mouth, constipation) typically expected with the LAMA drug class. In addition, consistent with the rapid hydrolysis of aclidinium, a pharmacokinetic study in adults with normal or impaired renal function demonstrated that less than 0.1% of the mean dose of unchanged aclidinium was excreted renally in healthy subjects as well as in subjects with mild, moderate, or severe renal impairment when administered as a single inhaled 400 µg dose [Schmid et al. 2010]. The low urinary excretion of aclidinium in patients across varying degrees of renal function suggests that no dose adjustment is needed for patients with renal impairment.

Dry powder inhaler

A novel, breath-activated, multidose DPI (Genuair^®/Pressair^™)^⋆ designed for the effective and reliable delivery of inhaled medications [Chrystyn and Niederlaender, 2012] has been used to administer aclidinium in multiple clinical trials. This DPI contains a dose indicator and is preloaded with a 1-month supply of medication (Figure 1), unlike other single-dose DPIs. It also has a safety mechanism to prevent double-dosing, multiple feedback mechanisms to indicate successful inhalation (e.g. audible click, control window changes from green to red), and a lock-out mechanism to prevent further use after the final dose has been dispensed [Chrystyn and Niederlaender, 2012]. High lung deposition of aclidinium (i.e. approximately 30% of the metered dose) has been reported in healthy subjects with this inhaler [Newman et al. 2009]. It has also been demonstrated that patients with moderate or severe COPD generate sufficient inspiratory airflow to inhale the full dose and reset the inhaler [Magnussen et al. 2009].

Figure 1.

General design and features of the Genuair^®/Pressair^™⋆ multidose dry powder inhaler.

The ability of a patient to use their inhaler correctly and patient inhaler preference are important factors in selecting an appropriate treatment for COPD [Dolovich et al. 2005]. In a pilot study consisting of 48 patients with COPD, the Genuair^® inhaler was perceived by patients to be the easiest to handle and most preferred for use compared with the other inhalers tested (Diskus^®, HandiHaler^®, and Respimat^®) [Hass et al. 2010].

Rationale for the aclidinium dosing regimen

Initially, the aclidinium development program focused on once-daily (QD) dosing. To this end, a phase II dose-finding study of aclidinium 25, 50, 100, 200, and 400 µg QD demonstrated maximal improvement in morning predose (trough) forced expiratory volume in 1 second (FEV₁) with the 200 µg dose compared with placebo in patients with moderate-to-severe COPD [Chanez et al. 2010]. Based on the results of this study, several subsequent phase III studies examined the efficacy and safety of aclidinium 200 µg QD in moderate-to-severe COPD patients.

Two of these studies (ACCLAIM I and II) demonstrated that aclidinium 200 µg QD provided significant improvements over placebo in trough FEV₁ at weeks 12 and 28, the primary efficacy endpoints, ranging from 59 to 67 ml in patients with COPD (N = 843 and 804, respectively; p < 0.001) [Jones et al. 2011]. While the ACCLAIM studies were ongoing, the effect of aclidinium 200 µg QD on exercise tolerance and lung mechanics, important therapeutic goals in COPD [Vestbo et al. 2012], was evaluated in a 6-week, double-blind, placebo-controlled study. Patients with COPD with confirmed lung hyperinflation and dyspnea at baseline were included in this study (N = 181) [Maltais et al. 2011]. Constant work rate cycling exercises at 75% of peak work rate (i.e. the highest work rate that the subject can maintain for 30 seconds; W_max) were performed up to symptom limitation.

Compared with placebo, aclidinium significantly improved endurance time during constant work rate cycling exercise from baseline at day 1 (mean treatment difference of 143 seconds, p = 0.0002) to week 6 (primary endpoint, mean treatment difference of 116 seconds; p = 0.0042) versus placebo (Figure 2). In addition, inspiratory capacity (IC) measured at isotime (i.e. the minimum endurance time among the constant work-rate tests at 75% W_max) was also significantly improved with aclidinium over placebo (p < 0.01), and exertional dyspnea scores were significantly reduced (p < 0.05).

Figure 2.

Least squares mean (SE) changes from baseline in endurance time (ET) using constant work rate cycle ergometry with once-daily aclidinium 200 µg. (Adapted with permission from Maltais et al. [2011].) **p < 0.01, ***p < 0.001 versus placebo; change in ET measured at 180 ± 10 minutes after administration of study medication.

While the endurance time results from the exercise tolerance study with once-daily aclidinium exceeded the suggested minimal clinically important difference (MCID) of 105 seconds [Casaburi, 2005], the improvements in trough FEV₁ in ACCLAIM I and II did not achieve the proposed MCID of 100-140 ml [Cazzola et al. 2008], suggesting that a higher total daily dose of aclidinium may be needed to provide optimal efficacy. A double-blind, placebo-controlled, crossover study in patients with COPD that evaluated the impact of morning versus evening dosing of aclidinium 200 µg QD demonstrated that improvements in bronchodilation over 24 hours were mainly due to the effect observed during the first 12 hours after once-daily aclidinium administration [Beier et al. 2010]. Thus, a twice-daily (BID) dosing regimen was considered to increase the total daily dose of aclidinium. The BID approach is also supported by previous studies which have shown that minimum FEV₁ values are observed at night and in early morning due to circadian variation in airway caliber [Calverley et al. 2003]. In addition, nighttime symptoms have been reported to be troublesome in patients with COPD [Kessler et al. 2011] and to lead to nighttime awakenings [Anzueto et al. 2009; Tashkin et al. 2008]. Dosing of aclidinium in the morning and evening would therefore provide an opportunity to achieve sustained bronchodilation over 24 hours and to reduce COPD symptoms observed at night. A pharmacokinetic study of aclidinium administered at doses up to 800 µg twice daily for 7 days in healthy subjects confirmed that all BID doses of aclidinium were safe and well tolerated and demonstrated that pharmacokinetic steady state may have been reached as early as the second day postdose [Lasseter et al. 2012]. The efficacy and safety of twice-daily aclidinium was thus further investigated in subsequent clinical trials in patients with moderate-to-severe COPD.

Efficacy of aclidinium BID in COPD patients

The efficacy of twice-daily aclidinium in patients with COPD from four randomized, double-blind, placebo-controlled, multicenter studies (one phase IIa study [Fuhr et al. 2012]; one phase IIb study [Singh et al. 2012]; and two phase III studies: ACCORD I [AClidinium in Chronic Obstructive Respiratory Disease COPD I] [Kerwin et al. 2012] and ATTAIN [Aclidinium To Treat Airway obstruction IN COPD patients] [Jones et al. 2012]) have been reported in the literature as of April 2012. The study designs for these four trials are summarized in Table 1. Other phase III studies with twice-daily aclidinium 200 µg and 400 µg in patients with moderate-to-severe COPD (i.e. 12-week, double-blind, placebo-controlled ACCORD COPD II and 40-week open-label extension [aclidinium 400 µg alone], 52-week double-blind extension to ACCORD I, and a 1-year double-blind study) have been recently completed; publications reporting these results are currently in development.

Table 1.

Summary of aclidinium BID studies in patients with moderate-to-severe COPD.

Study (ClinicalTrials.gov identifier)	Phase	Study design	Number of randomized patients	Treatments	Treatment duration	Primary endpoint (change from baseline)
Fuhr et al. [2012] (NCT00868231)	IIa	Randomized, double-blind, crossover	N = 30	Aclidinium 400 µg BID^a	15 days per period separated by 9- to 15-day washout	FEV₁ AUC_0-12/12h at day 15
				Tiotropium 18 µg QD^b
				Matched placebo
Singh et al. [2012] (NCT01120093)	IIb	Randomized, double-blind, crossover	N = 79	Aclidinium 100 µg BID^a	7 days per period separated by 5- to 9-day washout	FEV₁ AUC_0-12/12h at day 7
				Aclidinium 200 µg BID^a
				Formoterol 12 µg BID^c
				Matched placebo
Kerwin et al. [2012] (NCT00891462)	III	Randomized, double-blind, parallel	N = 561	Aclidinium 200 µg BID^a	12 weeks	Morning predose (trough) FEV₁ at week 12
				Aclidinium 400 µg BID^a
				Placebo^a
Jones et al. [2012] (NCT01001494)	III	Randomized, double-blind, parallel	N = 828	Aclidinium 200 µg BID^a	24 weeks	Morning predose (trough) FEV₁ at week 12d and week 24
				Aclidinium 400 µg BID^a
				Placebo^a

Via Genuair^®/Pressair^™⋆, ^bVia HandiHaler^®, ^cVia Aerolizer^{®, dfor regulatory requirements in the United States}

Abbreviations: AUC_0-12/12h, area under the curve from 0 to12 hours postdose; BID, twice daily; COPD, chronic obstructive pulmonary disease; FEV1, forced expiratory volume in 1 second; QD, once daily.

Study inclusion and exclusion criteria were similar for all four studies. Included subjects were ≥40 years of age, current or former cigarette smokers with a smoking history ≥10 pack-years, and had a diagnosis of moderate-to-severe COPD (postbronchodilator FEV₁/forced vital capacity [FVC] <70% and FEV₁ ≥30% but <80% of predicted). Excluded subjects were those with a history or current diagnosis of asthma or other significant respiratory condition, a respiratory tract infection or COPD exacerbation ≤6 weeks before screening (≤3 months if COPD exacerbation required hospitalization), a known contraindication to anticholinergics, a clinically relevant electrocardiogram (ECG) abnormality, or clinically significant cardiovascular conditions such as myocardial infarction in the 6 months prior to screening, etc.

In all four studies, allowed concomitant medications included albuterol/salbuterol as needed, and inhaled corticosteroids (ICSs), systemic corticosteroids equivalent to ≤10 mg/day or 20 mg every other day of prednisone or theophylline if these treatments were stable for ≥4 weeks prior to screening. LABAs and other inhaled anticholinergics were prohibited. All twice-daily aclidinium doses were administered using a novel, multidose DPI (Genuair^®/Pressair^™)^⋆.

Phase IIa

In this phase IIa crossover study, 30 subjects received aclidinium 400 µg BID, tiotropium 18 µg QD (via HandiHaler^®), and placebo for 15 days each, separated by 9–15 day washout periods [Fuhr et al. 2012]. Tiotropium, as the only commercially available LAMA for the treatment of COPD, was selected as the active comparator to benchmark the efficacy of twice-daily aclidinium 400 µg.

Average FEV₁ changes from baseline (area under the curve [AUC]) for 0-12 hours (primary endpoint), 12–24 hours, or the entire 24-hour period postdose on day 15 were significantly improved with aclidinium versus placebo (mean improvements with aclidinium over placebo: 221, 207, and 232 ml, respectively; all p < 0.0001, Figure 3). In addition, trough FEV₁ was significantly improved with aclidinium at days 1 and 15 compared with placebo (186 ml on each day, each p < 0.0001). Significant improvements from baseline in bronchodilation at days 1 and 15 were also observed with tiotropium versus placebo (all p < 0.001, except for trough FEV₁ on day 1, p < 0.01); however, placebo-adjusted improvements from baseline in FEV₁ over the last 12 hours (FEV₁ AUC_{12–24/12 h}) on days 1 and 15 were significantly greater for aclidinium compared with tiotropium, with differences of 101 and 78 ml, respectively, in favor of aclidinium (p < 0.01 and p < 0.05, respectively, versus tiotropium; Figure 3). Although the treatment duration in this study may have been too short to properly assess COPD symptoms, improvements in bronchodilation at night with aclidinium treatment were accompanied by a reduction in nighttime symptoms with aclidinium (p < 0.05) but not with tiotropium. Comparison of patient assessments of inhalers used in the study demonstrated that patients found the Genuair^®/Pressair^™⋆ inhaler easier to use, easier to prepare the dose, and more convenient compared with the HandiHaler^® [Fuhr et al. 2011]. Overall, aclidinium 400 µg BID significantly improved 24-hour bronchodilation and nighttime symptoms compared with placebo as observed from beginning to end of the 15-day treatment period, suggesting added benefits for twice-daily aclidinium during the second half of the day.

Figure 3.

Least squares mean (SE) changes from baseline in FEV₁ AUC_0-12/12h, AUC_12-24/12h, and FEV₁ AUC_0-24/24h on days 1 and 15 with aclidinium 400 µg twice daily, tiotropium 18 µg once daily, or placebo. (Fuhr et al. [2012].) **p < 0.001, ***p < 0.0001 versus placebo; ^†p < 0.05, ^‡p < 0.01 versus tiotropium. AUC, area under the curve; FEV1, forced expiratory volume in 1 second.

Phase IIb

A phase IIb study was also conducted to establish the appropriate aclidinium dose for phase III studies. This crossover study (N = 79) consisted of five 7-day treatment sequences in which patients received placebo, aclidinium 100 µg BID, 200 µg BID, 400 µg BID, or formoterol 12 µg BID (via Aerolizer^®) with 5- to 9-day washout periods between treatments [Singh et al. 2012]. Formoterol, a currently available BID therapeutic option for COPD, was included to provide a comparison for the aclidinium BID dosing profile.

Aclidinium provided significant improvements in lung function compared with placebo as early as day 1 (p < 0.0001). At day 7, all doses of aclidinium led to significant improvements from baseline in FEV₁ AUC for 0–12 (primary endpoint), 12–24, and 0–24 hours, with differences over placebo ranging from 147 to 208 ml (p < 0.0001 versus placebo for all doses). Trough FEV₁ at day 7 was also significantly improved from baseline over placebo with all doses of aclidinium (range, 106–154 ml, all p < 0.0001). The FEV₁ time profile with aclidinium was comparable with that of twice-daily formoterol. The improvements in bronchodilation with aclidinium were dose-dependent, and aclidinium 400 µg resulted in significantly greater improvements in all lung function endpoints than those achieved with aclidinium 100 µg (all p < 0.05). Similar to the inhaler assessment results from the phase IIa study, patients in this study considered the Genuair^®/Pressair^™⋆ to be easier and more convenient to use than the Aerolizer^® [Fuhr et al. 2011]. The efficacy results from this phase IIb dosing study led to the selection of aclidinium 200 and 400 µg BID as appropriate doses for further investigation in pivotal phase III studies.

Phase III: ACCORD I and ATTAIN

The ACCORD I and ATTAIN studies were pivotal phase III studies examining aclidinium BID in patients with moderate-to-severe stable COPD. In ACCORD I, patients from the United States and Canada (N = 561) were randomized (1:1:1) to twice-daily aclidinium 200 µg, 400 µg, or placebo for 12 weeks [Kerwin et al. 2012]. In ATTAIN, patients from Europe and South Africa (N = 828) were randomized (1:1:1) to twice-daily aclidinium 200 µg, 400 µg, or placebo for 24 weeks [Agusti et al. 2011b; Jones et al. 2012]. Compared with the phase II studies, the phase III studies examined a much broader range of outcomes, including lung function, health status, breathlessness, rescue medication use, exacerbation frequency, and nighttime and early morning COPD symptoms.

In ACCORD I and ATTAIN, the primary endpoint of improvement from baseline in trough FEV₁ at 12 and 24 weeks, respectively, was achieved for both aclidinium doses, with significant differences over placebo ranging from 86 ml (200 µg, week 12, ACCORD) to 128 ml (400 µg, week 24, ATTAIN; all p ≤ 0.0001) [Kerwin et al. 2012; Jones et al. 2012]. In addition, improvements from baseline in trough FEV₁ at 12 weeks were also achieved for both aclidinium 200 µg and 400 µg in ATTAIN, resulting in increases over placebo of 77 and 105 ml, respectively (p ≤ 0.0001). Significant improvements with both doses of aclidinium over placebo in trough FEV₁ were achieved by week 1, the first time point assessed, and were sustained at all time points in each study (all p ≤ 0.0001) (Figure 4(a) and (b)).

Figure 4.

Least squares mean (SE) changes from baseline in trough FEV₁ (A and B) and peak FEV₁ (C and D) in the ACCORD I (A and C) and ATTAIN (B and D) studies. (Adapted with permission from Kerwin et al, [2012] and with permission of the European Respiratory Society. Eur Respir J erj02255-2011; Eur Respir J. 2012; 40(4):830-836. doi:10.1183/09031936.00225511.) *p ≤ 0.0001 versus placebo; ^†p < 0.05, ^‡ p < 0.01 versus aclidinium 200 µg. FEV1, forced expiratory volume in 1 second.

Significant improvements over placebo in peak FEV₁ (i.e. highest observed FEV₁ up to 3 hours postmorning dose), the secondary endpoint, were observed at week 12 for ACCORD I (200 µg, 146 ml; 400 µg, 192 ml; both p < 0.0001) and at weeks 12 and 24 for ATTAIN (week 12: 200 µg, 182 ml; 400 µg, 191 ml; week 24: 200 µg, 185 ml; 400 µg, 209 ml; all p < 0.0001) [Kerwin et al. 2012; Jones et al. 2012]. These improvements in peak FEV₁ were observed after the first dose on day 1 in both studies and maintained throughout the treatment period (Figure 4(c) and (d)). Treatment with twice-daily aclidinium 400 µg resulted in a numerically greater magnitude of improvement in bronchodilation compared with the 200 µg dose throughout both studies.

Health status was measured in both phase III studies using the St. George’s Respiratory Questionnaire (SGRQ) [Jones et al. 1992], in which a change from baseline of ≥4 units is considered clinically meaningful [Jones, 2005]. In each phase III study, SGRQ total score was significantly improved from baseline over placebo for both aclidinium doses at week 12 (both studies) and week 24 (ATTAIN) (p < 0.05 for all, Figure 5(a) and (b)); however, while these improvements were all statistically significantly improved over placebo, only the 400 µg dose group at week 24 of the ATTAIN study achieved a clinically significant improvement over placebo in SGRQ total score (≥4 units) [Jones et al. 2012; Kerwin et al. 2012]. In the ATTAIN study, a significantly greater percentage of patients treated with aclidinium 200 µg or 400 µg achieved clinically meaningful improvements in SGRQ total score at weeks 12 and 24 compared with placebo-treated patients (all p < 0.01). Similar results were seen in ACCORD I for the aclidinium 200 µg dose at week 12 (p < 0.05).

Figure 5.

Least squares mean (SE) changes from baseline in St. George’s Respiratory Questionnaire (SGRQ) total score (A and B) and Transitional Dyspnea Index (TDI) focal score (C and D) in the ACCORD I (A and C) and ATTAIN (B and D) studies. (Adapted with permission from Kerwin et al, [2012] and with permission of the European Respiratory Society. Eur Respir J erj02255-2011; Eur Respir J. 2012; 40(4):830-836. doi:10.1183/09031936.00225511.) *p < 0.05, **p < 0.01, ***p < 0.001 versus placebo. Values below or above the dotted line represent clinically significant improvements from baseline in SGRQ total score or TDI focal score, respectively.

Breathlessness was assessed in the phase III studies using the Baseline Dyspnea Index (BDI) and the Transitional Dyspnea Index (TDI) focal score [Mahler et al. 1984]; a change of ≥1-unit in TDI focal score is considered clinically meaningful [Mahler and Witek, 2005]. In both phase III studies, both doses of aclidinium resulted in significant improvements from baseline in TDI focal score compared with placebo at study end (all p < 0.05; Figure 5(c) and (d)) [Jones et al. 2012; Kerwin et al. 2012]. Clinically significant between-treatment group improvements in TDI focal score (≥1 unit) were achieved by the aclidinium 400 µg group at weeks 12 (ACCORD I; p < 0.005) and 24 (ATTAIN; p < 0.001). In addition, clinically meaningful improvements in TDI focal score were achieved at end point in each study by significantly more patients in each dose group compared with placebo (all p < 0.05). Aclidinium dose-dependently reduced the need for daily relief medication (i.e. albuterol/salmeterol) compared with placebo over the 12-week treatment period in ACCORD I (200 µg: -0.7 puffs/day, p = 0.001; 400 µg:

-0.9 puffs/day, p < 0.0001) and over the 24-week treatment period in ATTAIN (200 µg: -0.6 puffs/day, p < 0.001; 400 µg: -1.0 puffs/day, p < 0.0001) [Kerwin et al. 2012; Jones et al. 2012]. Furthermore, the percentage of days without the need for relief medication was significantly increased by 11% over placebo for both doses of aclidinium in the ATTAIN study (p < 0.001 for both).

In both the ACCORD I and the ATTAIN studies, exacerbations were defined as an increase in COPD symptoms over at least two consecutive days resulting in treatment with antibiotics and/or systemic corticosteroids (moderate exacerbation) or hospitalization (severe exacerbation) [Kerwin et al. 2012; Jones et al. 2012]. While these phase III studies were not designed nor powered to evaluate COPD exacerbations, evaluation of this outcome showed that rates of moderate or severe exacerbations per patient per year were lower with aclidinium (ACCORD I: 200 µg, 0.42; 400 µg, 0.42; ATTAIN: 200 µg, 0.35; 400 µg, 0.34) than with placebo (ACCORD I: 0.63; ATTAIN: 0.47), although these differences were not significant. Trials with an enriched population of patients at risk for COPD exacerbations and longer duration are needed to determine the treatment benefit of aclidinium on this outcome.

Nighttime and early morning symptoms were assessed in both the ACCORD I and ATTAIN studies, although different assessment tools were used in each study. In the ACCORD I study, a daily COPD Nighttime Symptoms Questionnaire, designed with a ≤24-hour recall period, assessed nighttime and early morning symptoms and sputum production [Kerwin et al. 2012]. At week 12, both aclidinium doses significantly reduced the frequency of nighttime symptoms (breathlessness, cough, sputum production, and wheezing), severity and impact of breathlessness on nighttime and early morning activity, severity and impact of cough on nighttime activity, and 24-hour sputum production versus placebo (all p < 0.05). In the ATTAIN study, nighttime and early morning symptoms of COPD (breathlessness, cough, expectoration, chest tightness or congestion, and wheezing at night) were assessed using an electronic daily diary [Agusti et al. 2011b]. Over the 24-week study period, the percentage of nights with any symptoms was significantly lower with aclidinium 400 µg versus placebo (p < 0.001) and the percentage of days with any early morning symptoms was significantly lower with both doses of aclidinium versus placebo (both p < 0.01).

Overall, the results of these phase III studies confirm the results of the phase II studies, demonstrating that aclidinium 200 µg and 400 µg BID significantly improved lung function and health status, and reduced rescue medication use and COPD symptoms. Twice-daily aclidinium was also shown to provide maximal bronchodilation after the first dose which was maintained over time. Furthermore, aclidinium 400 µg provided numerically greater benefits in these outcomes than aclidinium 200 µg throughout the 12- and 24-week studies.

Safety and tolerability of aclidinium BID

Twice-daily aclidinium has demonstrated good tolerability in healthy subjects (200–800 µg) [Lasseter et al. 2012] as well as in those with moderate-to-severe COPD (100–400 µg) [Fuhr et al. 2012; Jones et al. 2012; Kerwin et al. 2012; Singh et al. 2012]. In the phase III studies, the most frequently reported AE was COPD exacerbation [Jones et al. 2012; Kerwin et al. 2012], similar to what has been observed in other LAMA studies in COPD patients [Kesten et al. 2006]. The percentages of patients reporting this AE in the twice-daily aclidinium 200 µg and 400 µg groups were lower than those in the placebo groups; patient percentages ranged from 7.4% to 9.2% (ACCORD I) and 14.1% to 15.9% (ATTAIN) for both aclidinium doses, respectively, and 12.4% and 20.5% for placebo in ACCORD I and ATTAIN, respectively. Other AEs occurring in ≥3% of patients in either aclidinium group in either study included headache, nasopharyngitis, back pain, diarrhea, and rhinitis (Table 2). These AEs were reported in a greater percentage of patients in at least one aclidinium group compared with the respective placebo group in either study; however, these AEs were mostly mild to moderate in severity.

Table 2.

Adverse events reported by >2% of subjects in any treatment group in ACCORD I or ATTAIN (safety populations). (Adapted with permission from Kerwin et al, [2012] and with permission of the European Respiratory Society. Eur Respir J erj02255-2011; Eur Respir J. 2012; 40(4):830-836. doi:10.1183/09031936.00225511.)

Preferred term	ACCORD I (12 weeks)			ATTAIN (24 weeks)
	Placebo (n = 186) n (%)	Aclidinium 200 µg (n = 184) n (%)	Aclidinium 400 µg (n = 190) n (%)	Placebo (n = 273) n (%)	Aclidinium 200 µg (n = 277) n (%)	Aclidinium 400 µg (n = 269) n (%)
Any AE	97 (52.2)	93 (50.5)	85 (44.7)	156 (57.1)	151 (54.5)	144 (53.5)
COPD exacerbation	23 (12.4)	17 (9.2)	14 (7.4)	56 (20.5)	44 (15.9)	38 (14.1)
Headache	4 (2.2)	6 (3.3)	3 (1.6)	22 (8.1)	30 (10.8)	33 (12.3)
Nasopharyngitis	2 (1.1)	6 (3.3)	3 (1.6)	23 (8.4)	32 (11.6)	30 (11.2)
Back pain	1 (0.5)	5 (2.7)	3 (1.6)	10 (3.7)	12 (4.3)	5 (1.9)
Cough	5 (2.7)	4 (2.2)	4 (2.1)	5 (1.8)	7 (2.5)	7 (2.6)
Diarrhea	3 (1.6)	3 (1.6)	4 (2.1)	3 (1.1)	5 (1.8)	8 (3.0)
Hypertension	3 (1.6)	0	1 (0.5)	9 (3.3)	5 (1.8)	7 (2.6)
Arthralgia	1 (0.5)	4 (2.2)	5 (2.6)	6 (2.2)	5 (1.8)	3 (1.1)
Upper respiratory tract infection	7 (3.8)	2 (1.1)	2 (1.1)	3 (1.1)	5 (1.8)	4 (1.5)
Rhinitis	0	1 (0.5)	1 (0.5)	7 (2.6)	4 (1.4)	9 (3.3)
Bronchitis	4 (2.2)	2 (1.1)	0	6 (2.2)	1 (0.4)	7 (2.6)
Dyspnea	6 (3.2)	4 (2.2)	5 (2.6)	1 (0.4)	1 (0.4)	2 (0.7)
Urinary tract infection	4 (2.2)	2 (1.1)	3 (1.6)	2 (0.7)	6 (2.2)	2 (0.7)
Oropharyngeal pain	3 (1.6)	2 (1.1)	4 (2.1)	4 (1.5)	3 (1.1)	2 (0.7)
Insomnia	6 (3.2)	3 (1.6)	3 (1.6)	3 (1.1)	1 (0.4)	2 (0.7)
Influenza	2 (1.1)	0	0	6 (2.2)	3 (1.1)	5 (1.9)
Dyspepsia	0	1 (0.5)	0	6 (2.2)	5 (1.8)	1 (0.4)
Toothache	1 (0.5)	1 (0.5)	1 (0.5)	1 (0.4)	3 (1.1)	6 (2.2)
Dizziness	1 (0.5)	4 (2.2)	2 (1.1)	2 (0.7)	3 (1.1)	1 (0.4)
Fatigue	4 (2.2)	0	4 (2.1)	1 (0.4)	1 (0.4)	1 (0.4)
Nausea	4 (2.2)	2 (1.1)	2 (1.1)	1 (0.4)	1 (0.4)	0

AE, adverse event; COPD, chronic obstructive pulmonary disease.

COPD exacerbation was the most frequent AE leading to study discontinuation, occurring in seven, four, and one patients in the placebo, aclidinium 200 µg, and 400 µg groups, respectively (ACCORD I) [Kerwin et al. 2012], and in five, three, and four patients in the placebo, aclidinium 200 µg, and 400 µg groups, respectively (ATTAIN) [Bateman et al. 2011]. The percentages of patients reporting serious adverse events (SAEs) were low and similar to the phase III studies, ranging from 2.2% to 4.3% in ACCORD I and from 4.3% to 5.6% in ATTAIN; COPD exacerbation was the most frequently reported SAE in each study [Kerwin et al. 2012; Jones et al. 2012; ].

Potential anticholinergic-related AEs occurred at a similarly low percentage of patients (≤2.5%) in each treatment group in each study [Bateman et al. 2011; D’Urzo et al. 2011]. The number (%) of patients reporting dry mouth was low in both the ACCORD I (placebo, two patients [1.1%]; 200 µg, three patients [1.6%]; 400 µg, one patient [0.5%]) and ATTAIN (placebo, one patient [0.4%]; 200 µg, two patients [0.7%]; 400 µg, one patient [0.4%]) studies.

Given the high rate of cardiovascular comorbidity with COPD [Agusti et al. 2010; Holguin et al. 2005], a placebo- and moxifloxacin-controlled study was conducted to assess the effects of multiple doses of once-daily aclidinium 200 µg or 800 µg on QT interval and overall cardiac safety in healthy subjects (N = 272) [Lasseter et al. 2011]. The results of this study demonstrated that once-daily aclidinium at doses up to 800 µg has no effect on QT interval. The favorable cardiovascular safety profile of aclidinium has also been demonstrated in both phase III studies with twice-daily aclidinium 200 µg and 400 µg; any specific cardiac AE was reported in a low percentage of patients across treatment groups in the ACCORD I and ATTAIN studies (i.e. <1.5% of patients in any group for any event) [D’Urzo et al. 2011; Bateman et al. 2011].

The only reported deaths in the phase III studies were due to metastatic lung cancer 23 days after the first dose of aclidinium 400 µg in the ACCORD I study (n = 1), and due to a road traffic accident (n = 1, placebo), myocardial infarction (n = 1, aclidinium 200 µg), and acute cardiac failure (n = 1, aclidinium 400 µg) in the ATTAIN study [Kerwin et al. 2012; Jones et al. 2012]. None of these deaths was considered related to treatment.

No clinically significant changes in laboratory assessments, vital signs, or ECG parameters were observed in ACCORD I [Kerwin et al. 2012]. In ATTAIN, no clinically relevant changes from baseline were observed in laboratory assessments or blood pressure, and mean changes from baseline in 12-lead ECG parameters were generally small, with no apparent treatment- or dose-related trend [Jones et al. 2012].

Discussion

Aclidinium 400 µg is an inhaled LAMA administered twice daily that is indicated for the maintenance treatment of COPD. The two phase II studies of the aclidinium BID program demonstrated that aclidinium provided significant improvements in bronchodilation that were comparable to other currently approved therapies, the once-daily LAMA tiotropium and the twice-daily LABA formoterol. Further investigation into the efficacy and safety of aclidinium in subsequent larger phase III studies (ACCORD I and ATTAIN) demonstrated that aclidinium provided statistically significant improvements in lung function compared with placebo starting at 1 day after treatment initiation, as measured by peak FEV₁, which were sustained at all time points in each study. Improvements in trough FEV₁ over placebo with the aclidinium 400 µg dose were consistently above the suggested MCID for FEV₁ (>100 ml) in both studies, similar to what has been observed in the tiotropium registration studies [Brusasco et al. 2003; Casaburi et al. 2002; Vincken et al. 2002].

Although treatment with either twice-daily aclidinium 400 µg and once-daily tiotropium 18 µg in the phase IIa study led to significantly greater bronchodilation compared with placebo, significant differences between aclidinium and tiotropium were observed as early as day 1, in favor of aclidinium. This may be due to aclidinium reaching pharmacokinetic steady state as early as 2 days postdose [Lasseter et al. 2012]. In contrast, tiotropium requires 8 days to reach pharmacodynamic steady state and 2–3 weeks to reach pharmacokinetic steady state [Boehringer Ingelheim Pharmaceuticals, 2011], suggesting that maximum efficacy may be reached earlier with aclidinium. As any delayed onset of effect may discourage treatment adherence [Make, 2003], the observed maximal bronchodilation after the first day of aclidinium treatment may have a positive effect on treatment compliance. Furthermore, improvements in bronchodilation with aclidinium were significantly greater than those with tiotropium, notably during the latter half of the day, suggesting added benefits achieved with twice-daily aclidinium.

In addition to improving lung function, the GOLD guidelines also recommend symptomatic relief of COPD and improvement of health status as important therapeutic goals [Vestbo et al. 2012]. The phase III studies of twice-daily aclidinium 200 µg and 400 µg demonstrated significant improvements in both dyspnea (as measured by TDI) and health status (as measured by SGRQ), with greater percentages of patients demonstrating clinically significant improvements in either parameter compared with placebo at study end. It is remarkable to note the large improvement from baseline in SGRQ total score observed with aclidinium at the end of the 24-week ATTAIN study [Jones et al. 2012], which is greater than the MCID of 4 units [Jones, 2005] and of a magnitude not commonly reported in clinical trials. These significant improvements in breathlessness and health status with aclidinium treatment would thus likely provide noticeable benefits to patients in symptom management.

Nighttime and early morning symptoms are commonly experienced by patients with COPD and contribute to sleep disruption and poor health status [Agusti et al. 2011a; Kessler et al. 2011; Partridge, 2011; Partridge et al. 2009a]. Aclidinium 400 µg BID demonstrated significant reductions in nighttime symptoms versus placebo in a phase IIa study. A more in-depth investigation into nighttime and early morning symptoms in the phase III studies confirmed the positive effect of aclidinium 200 µg and 400 µg BID in alleviating these symptoms in patients with COPD. The significant improvements in nighttime and early morning symptoms observed in these studies suggest an added advantage that may be obtained with twice-daily aclidinium compared with other therapies administered once daily in the morning. Improvements in the impact of nighttime and morning symptoms using a variety of patient-reported outcomes have also been similarly observed with other twice-daily therapies for COPD [Partridge et al. 2009b; Rennard et al. 2009; Tashkin et al. 2008]. A growing awareness of the prevalence and impact of nighttime symptoms in patients with COPD has highlighted the importance of treating such symptoms for effective COPD management and the need to further investigate these outcomes with validated tools.

In patients with COPD, airflow obstruction may be associated with dyspnea and hyperinflation at rest and during exercise, resulting in mechanical constraints that limit the increase in tidal volume and ventilation during exercise [O’Donnell et al. 2012; Ofir et al. 2008]. A direct consequence of these mechanical limitations is reduced exercise tolerance, which has been shown to be significantly correlated with mortality [Oga et al. 2003]. Improving exercise tolerance is thus also recommended as an important goal in the management of COPD [Vestbo et al. 2012]. The significant improvements in endurance time, inspiratory capacity, and dyspnea observed with once-daily aclidinium are comparable with those reported in similarly designed constant work rate cycling exercises with tiotropium [Maltais et al. 2005; O’Donnell et al. 2004]. Given the improved bronchodilation efficacy and comparable safety profile of aclidinium twice daily versus once daily discussed above, a higher total daily dose of aclidinium may provide similar or even larger improvements in exercise endurance and lung volume. An exercise tolerance study with the current twice-daily dosing regimen of aclidinium was recently completed and its results will be reported elsewhere.

In the phase III studies, both aclidinium doses were safe and well tolerated in patients with moderate-to-severe COPD, and no differences in safety profiles were observed between the aclidinium 200 µg and

400 µg doses. Incidences of anticholinergic and cardiac AEs with aclidinium were low and similar to placebo. This is likely due to the low and transient systemic exposure of aclidinium resulting from its rapid plasma hydrolysis. As such, neither renal impairment nor advanced age affects exposure to the drug, making dose adjustment of aclidinium unnecessary in patients with impaired renal function or in elderly subjects [Schmid et al. 2010; De la Motte et al. 2012]. In contrast, tiotropium is excreted by the kidneys [Turck et al. 2004], leading to the recommendation that patients with moderate-to-severe renal impairment be monitored closely for anticholinergic side effects [Boehringer Ingelheim Pharmaceuticals, 2011]. Data from recently completed long-term studies would allow a more comprehensive evaluation of the safety profile of twice-daily aclidinium.

Conclusion

In summary, the available data provide support that the approved therapeutic dosage of twice-daily aclidinium 400 µg administered via a novel, easy to use, multidose DPI is a promising bronchodilator for the maintenance treatment of COPD. Its advantageous efficacy and safety profile indicate that this new antimuscarinic agent will be a useful addition to the current therapeutic arsenal in this disease. The twice-daily dosing regimen of aclidinium may also provide significant benefits at night and early morning when COPD symptoms are more burdensome.

Footnotes

Acknowledgements

The authors would like to thank Joy Ramos, PhD of Prescott Medical Communications Group of Chicago, IL for medical writing assistance funded by Forest Research Institute, Inc. (FRI), a wholly owned subsidiary of Forest Laboratories, Inc.

Funding

This research received no specific grant from any funding agency in the public, commercial, or not-for-profit sectors.

Conflict of interest statement

François Maltais received fees for speaking at conferences sponsored by Boehringer Ingelheim, Pfizer and GlaxoSmithKline and served on an advisory board for GlaxoSmithKline and Boehringer Ingelheim. He also received research grants for participating in multicenter trials sponsored by GlaxoSmithKline, Boehringer Ingelheim, ALTANA Pharma, Merck, AstraZeneca, Nycomed and Novartis and received unrestricted research grants from Boehringer Ingelheim and GlaxoSmithKline. He holds a CIHR/GSK research chair on COPD at Université Laval. Julie Milot declares that no conflict of interest exists.

Notes

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