Fiboflapon (GSK2190915) is a potent FLAP(5-Lipoxygenase-activating protein) inhibitor with binding IC50 of 2.9 nM.
Fiboflapon (AM-803) exhibits excellent preclinical toxicology and pharmacokinetics in rat and dog. Fiboflapon (AM-803) also demonstrated an extended pharmacodynamic effect in a rodent bronchoalveolar lavage (BAL) model [1].
Oral administration of Fiboflapon (AM-803: 1 mg/kg) results in sustained inhibition of ex vivo ionophore-challenged whole blood LTB4 biosynthesis with >90% inhibition for up to 12 h and an EC50 of approximately 7 nM. When rat lungs are challenged in vivo with calcium-ionophore, Fiboflapon (AM-803) inhibits LTB4 and cysteinyl leukotriene (CysLT) production with ED50s of 0.12 mg/kg and 0.37 mg/kg, respectively. The inhibition measured 16 h following a single oral dose of 3 mg/kg was 86% and 41% for LTB4 and CysLTs, respectively. In an acute inflammation setting, Fiboflapon dose-dependently reduced LTB4, CysLTs, plasma protein extravasation and neutrophil influx induced by peritoneal zymosan injection. Finally, Fiboflapon increases survival time in mice exposed to a lethal intravenous injection of platelet activating factor (PAF)[1].
[1]. Stock NS, et al. 5-Lipoxygenase-activating protein (FLAP) inhibitors. Part 4: development of 3-[3-tert-butylsulfanyl-1-[4-(6-ethoxypyridin-3-yl)benzyl]-5-(5-methylpyridin-2-ylmethoxy)-1H-indol-2-yl]-2,2-dimethylpropionic acid (AM803), a potent, oral, once daily FLAP inhibitor. J Med Chem. 2011 Dec 8;54(23):8013-29. [2]. Lorrain DS, et al. Pharmacology of AM803, a novel selective five-lipoxygenase-activating protein (FLAP) inhibitor in rodent models of acute inflammation. Eur J Pharmacol. 2010 Aug 25;640(1-3):211-8.