The Open Respiratory Medicine Journal, 2009, 3, 27-30 27 Open Access Indacaterol, A Novel Once Daily Inhaled 2-Adrenoreceptor Agonist Jorge Roig*,1, Rosana Hernando2 and Ramon Mora 1Servei de Pneumologia, Hospital Nostra Senyora de Meritxell, Escaldes, Andorra, Spain 2Servei de Pneumologia, Hospital Comarcal Sant Joan de Deu, Sant Boi de Llobregat, Barcelona, Spain Abstract: In this article we will review the role of long acting 2-adrenoreceptor agonists and long-acting muscarinic agents in the management of airflow obstruction. We will then focus our attention on indacaterol, one of the new once daily inhaled 2-adrenoreceptor agonists. Pharmacologically this drug is a nearly full 2-agonist without loss of efficacy after prolonged administration. We will also discuss its dosing, safety and tolerability. Keywords: Indacaterol, tachyphylaxis, activity profile, safety. ROLE OF LONG ACTING 2-ADRENORECEPTOR Parallel to what happens with 2-adrenoreceptor agonists AGONISTS AND LONG-ACTING MUSCARINIC new long acting antimuscarinic agents (LAMAs) are also AGENTS IN THE MANAGEMENT OF AIRFLOW under preclinical development in an attempt to improve OBSTRUCTION some aspects of the excellent therapeutic profile that tiotro- pium has shown since this drug has become commercially International guidelines on chronic obstructive pulmo- available [7]. Aclidinium, NVA237, OrM3, and CHF 5407 nary disease (COPD) and bronchial asthma [1, 2] underline are some of these new LAMAs which are also in different the clinical benefit derived from including long acting bron- phases of preclinical development. The combination of a chodilators in their therapeutic approach. The current gold long acting 2-adrenoreceptor agonist (LABA) and a long- standard therapy for treating patients with moderate-to- acting muscarinic agent (LAMA) is an innovative approach severe persistent asthma is the combination of a long acting that will most likely be a significant therapeutic progress in a 2-adrenoreceptor agonist (LABA) with an inhaled corticos- selected population of patients with airflow obstruction. teroid. Long acting 2-adrenoreceptor agonists (LABAs) However, further studies are clearly warranted before we can have also a well established role in the treatment of stable define which population of patients will really benefit from COPD. It is well known that a simplified dosing regimen these future therapeutic combined agents. will improve patients’ compliance [3], a key point in multi- step therapeutic regimens such as those that are often pre- This review focuses on indacaterol (QAB 149; Novartis, scribed to individuals with COPD or asthma. That is why Basel, Switzerland) [8, 9], one of the new once daily inhaled long acting agents, particularly once-daily inhalers, will offer 2-adrenoreceptor agonists that has completed phase II and a better adherence than other drugs that require a more com- phase III clinical trials for the treatment of asthma and plicated dosing schedule. COPD. LABAs are highly lipophilic compounds. This character- INDACATEROL: ACTIVITY PROFILE istic helps to prolong their duration of action since they dis- sociate more slowly than short-acting 2-agonists from lung Pharmacologically, indacaterol is a nearly full 2-agonist fat-soluble tissues. Formoterol and salmeterol have been the [10]. Tissue and experimental studies show longer durations LABAs usually prescribed by most clinicians during the last of action for indacaterol when compared to salmeterol or decades [4]. However, a few drugs have been developed for formoterol, demonstrating sustained bronchodilator efficacy the last years to attempt to improve the therapeutic profile of throughout the full 24-hour period [11, 12]. In a human lung these classical LABA. Ultra-LABA is the term used to de- slice model Sturton et al. [13] have demonstrated that in- scribe a variety of new 2-adrenoreceptor agonists that have dacaterol has a superior activity than salmeterol and a similar focused their action in a more prolonged half life with the intrinsic efficacy to formoterol. Onset of action, with a fast aim of making feasible a one-day dose administration. In- acting action, is very similar for indacaterol and formoterol dacaterol (QAB-149), carmoterol (CHF-4226, TA-2005), and slower for salmeterol. This experimental finding corre- GSK-159797, and GSK-642444 are some of these new lates well with what has been observed in initial clinical ultra-LABAs that are still in different phases of clinical de- studies, since a statistically significant beneficial effect is velopment [5, 6]. demonstrated in those patients receiving indacaterol within the first 5 minutes after inhalation. A rapid onset of effect may increase patients’ confidence in treatment and subse- *Address correspondence to this author at the Servei de Pneumologia, quently improve therapy compliance. Opposite to this rapid Hospital Nostra Senyora de Meritxell, AD700 - Escaldes, Andorra, Spain; absorption and onset of action for indacaterol, salmeterol Fax: +376829627; E-mail: [email protected] 1874-3064/09 2009 Bentham Open 28 The Open Respiratory Medicine Journal, 2009, Volume 3 Roig et al. improvement in FEV1 occurs within 15 minutes after inhala- mon clinical practice. Other findings from the study reported tion. Functional data show highest, about twofold, intrinsic by Naline et al. [17] were that indacaterol showed an onset activity for formoterol and indacaterol than for salbutamol or of action similar to that of salbutamol and duration of action salmeterol [8]. > 12 hours. INDACATEROL: DOSING INDACATEROL Rennard et al. [14] conducted a dose-ranging study, with Previous studies in patients and healthy volunteers have a tiotropium comparison, to elucidate which dose of in- shown that LABAs may be associated with 2 mediated dacaterol shows 24-hour effectiveness in patients with mod- systemic adverse effects such as skeletal muscle tremor, erate-to-severe COPD. Functional inclusion criteria were headache, nervousness, palpitations with changes in heart prebronchodilator FEV1 40% of predicted, FEV1 1.0 L, rate, prolongation of the QTc interval, and increased glucose and FEV1/FVC < 70%. Six hundred thirty five patients were and potassium blood levels [18-25]. On the basis of these eventually randomized to receive 50, 100, 200 or 400 g or data, safety and tolerability studies have been conducted to placebo once daily for 7 days. All indacaterol doses signifi- evaluate indacaterol effect on these parameters. An optimal cantly increased FEV1 from 5 minutes to 24 hours post-dose safety profile is mandatory for a drug, such as indacaterol, but 400 and 200 g were the dose most effective. A subset of characterized by a 24-hour bronchodilator efficacy at once- subjects from each treatment group entered an open label daily dosing. extension and received tiotropium 18 g once daily for 8 In asthma patients’ indacaterol offers an excellent overall days. Indacaterol through FEV1 levels compared favorably safety profile since even a high dose of 1000 g has not been with the improvement observed by day 8 in patients that found to be associated with any sustained systemic adverse received tiotropium in this subgroup of patients taking part effect [26-28]. It is worthwhile pointing out that a dose of in the open-label extension. Overall, a 400 g dose was the 1000 g is obviously a clearly supratherapeutic dosing, most effective in this study. which is five-fold the standard dose in asthma; this feature Single 200 g and 400 g doses provide effective and deserves to be emphasized since in clinical practice some sustained 24-hour bronchodilator control and a rapid onset of patients may self-administer additional doses of the drug as action (< 5 minutes) in asthmatic patients. A 200 g dose rescue medication or accidentally. seems to be the optimum dose regarding efficacy and safety In the COPD setting, once-daily indacaterol at doses up balance. On another dose-ranging study designed to establish to 800 g has been well tolerated. A prospective randomized the optimal dose for indacaterol inhaled treatment in patients comparative study on 163 patients with COPD receiving with persistent asthma, LaForce et al. [15] also reported that placebo or 400 g or 800 g of indacaterol did not show any a 200 g dose seems to offer the best efficacy/safety balance statistically significant difference at any dose on mean pulse in most subjects. rate and QTc interval [29]. As it has been observed in safety studies in asthma population [30], small differences, consid- INDACATEROL: TACHYPHYLAXIS ered to be without any clinical relevance, were found on It has been stated that 2 adrenoreceptor downregulation serum potassium levels, mean blood glucose levels and mean may follow chronic administration of LABAs in asthma. The blood pressure. consequence would be a subsequent reduced sensitivity, Although no serious adverse effects are found in safety known as tachyphylaxis, of airway smooth muscle and in- studies on indacaterol, mild cough is a relatively common flammatory cells response. It must be emphasized that adverse effect [31]. A short duration, less than 2 minutes tachyphylaxis has not been observed with long-term in- post-dose, and the lack of bronchospasm of any degree are dacaterol administration. Many studies have shown that there distinctive features of this indacaterol-induced cough. It has is no loss of efficacy with prolonged administration of in- been reported in up to 14.7% of patients receiving this in- dacaterol since sustained improvements on FEV1 are consis-