936350-00-4

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].