Fiboflapon sodium

Fiboflapon sodium (GSK2190915; AM-803) is a potent and orally bioavailable 5-lipoxygenase-activating protein (FLAP) inhibitor with a potency of 2.9 nM in FLAP binding, an IC₅₀ of 76 nM for inhibition of LTB4 in human blood^[1]. IC50 & Target: IC50: 76 nM (inhibition of LTB4 in human blood 5 h incubation)^[1]. In Vitro: Fiboflapon (AM803) exhibits excellent preclinical toxicology and pharmacokinetics in rat and dog. Fiboflapon (AM803) also demonstrated an extended pharmacodynamic effect in a rodent bronchoalveolar lavage (BAL) model^[1]. Oral administration of Fiboflapon (AM803) (1 mg/kg) resulted 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 were challenged in vivo with calcium-ionophore, Fiboflapon (AM803) inhibited 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 (AM803) dose-dependently reduced LTB4, CysLTs, plasma protein extravasation and neutrophil influx induced by peritoneal zymosan injection. Finally, AM803 increased survival time in mice exposed to a lethal intravenous injection of platelet activating factor (PAF)^[2].