PT - JOURNAL ARTICLE AU - Stacey L. Tannheimer AU - Eric A. Sorensen AU - Zhi-Hua Cui AU - Musong Kim AU - Leena Patel AU - William R. Baker AU - Gary B. Phillips AU - Clifford D. Wright AU - Michael Salmon TI - The In Vitro Pharmacology of GS-5759, A Novel Bifunctional Phosphodiesterase 4 Inhibitor and Long Acting <em>β</em><sub>2</sub>-Adrenoceptor Agonist AID - 10.1124/jpet.113.210997 DP - 2014 Apr 01 TA - Journal of Pharmacology and Experimental Therapeutics PG - 85--93 VI - 349 IP - 1 4099 - http://jpet.aspetjournals.org/content/349/1/85.short 4100 - http://jpet.aspetjournals.org/content/349/1/85.full SO - J Pharmacol Exp Ther2014 Apr 01; 349 AB - Inhaled long-acting β2-adrenoceptor agonists (LABA) that act as bronchodilators and the oral anti-inflammatory phosphodiesterase 4 (PDE4) inhibitor roflumilast are both approved therapies for chronic obstructive pulmonary disease (COPD). Here we describe the activity of a novel, inhaled, bifunctional, small molecule (R)-6-[(3-{[4-(5-{[2-hydroxy-2-(8-hydroxy-2-oxo-1,2-dihydroquinolin-5-yl)ethyl]amino}pent-1-yn-1-yl)phenyl]carbamoyl}phenyl)sulfonyl]-4-[(3-methoxyphenyl)amino]-8-methylquinoline-3-carboxamide (GS-5759), which has specific β2 agonist and PDE4 inhibitory activity. GS-5759 demonstrated potent and full agonist activity at β2 adrenoceptors (EC50 = 8 ± 4 nM) and is a potent inhibitor of the PDE4 enzyme (IC50 = 5 ± 3 nM). In cell assays, GS-5759 inhibited lipopolysaccharide (LPS)-induced tumor necrosis factor α (TNFα) production in human peripheral mononuclear cells (PBMC) with an IC50 = 0.3 nM [confidence interval (CI) 0.1–0.6] and in human neutrophils formyl-methionyl-leucyl-phenylalanine (fMLP)-induced super oxide anion production with an IC50 = 3 nM (CI 0.8–8). The addition of the β2 antagonist ICI 118551 shifted the IC50 in these cell assays to 4 and 38 nM, respectively, demonstrating the contribution of both β2 agonist and PDE4 inhibitory activity to GS-5759. GS-5759 was also a potent inhibitor of profibrotic and proinflammatory mediator release from human lung fibroblasts. GS-5759 relaxed guinea pig airway smooth muscle strips precontracted with carbachol in a concentration-dependent manner with an EC50 = 0.5 µM (CI 0.2–2) and had slow dissociation kinetics with an Off T1/2 &gt; 720 minutes at an EC80 concentration of 3 µM. GS-5759 is a novel bifunctional molecule with both potent β2 agonist and PDE4 inhibitor activity that could provide inhaled bronchodilator and anti-inflammatory therapy for COPD.