Here, we describe the preclinical pharmacological profile of 5-[(R)-2-(5,6-diethyl-indan-2-ylamino)-1-hydroxy-ethyl]-8-hydroxy-1H-quinolin-2-one (indacaterol), a novel, chirally pure inhaled ␤ 2 adrenoceptor agonist, in comparison with marketed drugs. Indacaterol is close to a full agonist at the human ␤ 2 adrenoceptor (E max ϭ 73 Ϯ 1% of the maximal effect of isoprenaline; pEC 50 ϭ 8.06 Ϯ 0.02), whereas salmeterol displays only partial efficacy (38 Ϯ 1%). The functional selectivity profile of indacaterol over ␤ 1 human adrenoceptors is similar to that of formoterol, whereas its ␤ 3 adrenoceptor selectivity profile is similar to that of formoterol and salbutamol. In isolated superfused guinea pig trachea, indacaterol has a fast onset of action (30 Ϯ 4 min) similar to formoterol and salbutamol, and a long duration of action (529 Ϯ 99 min) comparable with salmeterol. In the conscious guinea pig, when given intratracheally as a dry powder, indacaterol inhibits 5-hydroxytryptamine-induced bronchoconstriction for at least 24 h, whereas salmeterol, formoterol, and salbutamol have durations of action of 12, 4, and 2 h, respectively. When given via nebulization to anesthetized rhesus monkeys, all of the compounds dose-dependently inhibit methacholine-induced bronchoconstriction, although indacaterol produces the most prolonged bronchoprotective effect and induces the lowest increase in heart rate for a similar degree of antibronchoconstrictor activity. In conclusion, the preclinical profile of indacaterol suggests that this compound has a superior duration of action compatible with once-daily dosing in human, together with a fast onset of action and an improved cardiovascular safety profile over marketed inhaled ␤ 2 adrenoceptor agonists.Agents that act as agonists of the ␤ 2 adrenoceptor are effective in the management of asthma and chronic obstructive pulmonary disease (COPD), primarily through their bronchodilatating properties. These drugs induce bronchodilatation by causing direct relaxation of airway smooth muscle through activation of adenylate cyclase, which in turn increases intracellular cAMP levels.Salbutamol is an inhaled ␤ 2 adrenoceptor agonist that provides rapid bronchodilatation and has been widely used over the past 30 years. However, its major drawback is its short duration of action (4 -6 h), requiring the drug to be administered several times a day. Two longer acting inhaled ␤ 2 adrenoceptor agonists, formoterol and salmeterol, are now available and are used in the management of asthma and COPD (Sutherland, 2004). These two drugs have a bronchodilating effect lasting for 12 h after a single inhalation and are therefore given twice daily. Despite the decrease in dosing frequency with the longer acting inhaled ␤ 2 adrenoceptor agonists, patient compliance is still an issue (Ying et al., 1999). In addition, the recent launch of tiotropium bromide, a once-daily inhaled muscarinic antagonist for the treatment of COPD (Gross, 2004), and the development of once-daily inhaled corticosteroids for the...

Chronic obstructive pulmonary disease (COPD) is a smoking-related disease that lacks effective therapies due partly to the poor understanding of disease pathogenesis. The aim of this study was to identify molecular pathways that could be responsible for the damaging consequences of smoking. To do this, we employed Gene Set Enrichment Analysis to analyze differences in global gene expression, which we then related to the pathological changes induced by cigarette smoke (CS). Sprague-Dawley rats were exposed to whole body CS for 1 day and for various periods up to 8 mo. Gene Set Enrichment Analysis of microarray data identified that metabolic processes were most significantly increased early in the response to CS. Gene sets involved in stress response and inflammation were also upregulated. CS exposure increased neutrophil chemokines, cytokines, and proteases (MMP-12) linked to the pathogenesis of COPD. After a transient acute response, the CS-exposed rats developed a distinct molecular signature after 2 wk, which was followed by the chronic phase of the response. During this phase, gene sets related to immunity and defense progressively increased and predominated at the later time points in smoke-exposed rats. Chronic CS inhalation recapitulated many of the phenotypic changes observed in COPD patients including oxidative damage to macrophages, a slowly resolving inflammation, epithelial damage, mucus hypersecretion, airway fibrosis, and emphysema. As such, it appears that metabolic pathways are central to dealing with the stress of CS exposure; however, over time, inflammation and stress response gene sets become the most significantly affected in the chronic response to CS.

1 We have investigated the effects of RP 73401, a novel, potent and highly selective cyclic nucleotide phosphodiesterase (PDE) type IV inhibitor, in guinea-pig and rat models of bronchoconstriction and allergic inflammation. In some models, the effects of RP 73401 have been compared with those of the standard PDE type IV inhibitor, rolipram. 2 RP 73401 (0.4-400 fg kg-', intratracheally (i.t.) on lactose) inhibited antigen-induced bronchospasm in previously sensitized conscious guinea-pigs (ID": 7 ± 1 gg kg-') and in anaesthetized rats (ID5: 100 ± 25 fig kg-). Rolipram inhibited the antigen-induced bronchospasm in guinea-pigs with an ID.V of 5 ± 1 ftg kg-'. In guinea-pig bronchoalveolar lavage (BAL) fluid, total inflammatory cell and eosinophil numbers were reduced by RP 73401 (ID50s: 3.9 ± 0.8 jig kg-' and 3.2 ± 0.7 jig kg-', respectively). In the rat, inflammatory cell numbers are less affected. Only the highest dose of RP 73401 (400 pg kg-') significantly inhibited eosinophil influx (41 ± 16% inhibition). 3 RP 73401 (0.02-100 jig kg-', i.v.) inhibited PAF-induced bronchial hyperreactivity to bombesin in the anaesthetized guinea-pig (ID": 0.09 ± 0.03' gkg-') and inhibited (0.4-40 jig kg-', i.t.) histamineinduced airway microvascular leakage in the anaesthetized guinea-pig by approximately 60% at all doses.4 RP 73401 relaxed guinea-pig isolated trachea under basal tone (EC": 9 nM) and when precontracted with histamine (IC5: 2 nM), methacholine (IC5o: 29 nM) or leukotriene D4 (LTD4, IC": 4 nM). 5 RP 73401 (0.4-100 pg kg-', i.t.) inhibited bronchospasm induced by histamine (ID.%: 34± 6 ig kg-'), methacholine (ID"f: 66 ± 12 pg kg-1) and LTD4 (ID50: <4 jsg kg-') in the anaesthetized guineapig. Against these same bronchoconstrictors, rolipram (i.t.) had ID5o values of 44± 4, 72 ± 18 and <4 pg kg-respectively. RP 73401 (4 and 40 pg kg-, i.t.) increased the magnitude and duration of bronchodilatation produced by salbutamol in the anaesthetized guinea-pig. At doses producing significant bronchodilatation, RP 73401 was without effect on heart rate or blood pressure in the anaesthetized guinea-pig. RP 73401 (0.01 -0.25 mg kg-', i.v.) did not affect heart rate and produced only a small fall in blood pressure in the anaesthetized rat. 6 These data demonstrate that RP 73401 and rolipram inhibit antigen-and mediator-induced bronchospasm in guinea-pigs with the same potency. Furthermore, RP 73401 administered directly into the airways, protects against allergic airway inflammation. These results indicate the importance of PDE IV in regulating smooth muscle and inflammatory cell activity. At doses suppressing the inflammatory response in the lung, RP 73401 had little effect in the cardiovascular system. RP 73401 may have a role as a bronchodilator and, more importantly, as a prophylactic anti-inflammatory agent in the treatment of asthma.

Background: The link between eosinophils and the development of airway hyperresponsiveness (AHR) in asthma is still controversial. This question was assessed in a murine model of asthma in which we performed a dose ranging study to establish whether the dose of steroid needed to inhibit the eosinophil infiltration correlated with that needed to block AHR.

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