A Selective Small Molecule Factor VIIa Inhibitor, CRA-027483, Suppresses Acute Inflammation in Mice.

Factor VIIa (FVIIa) is a well known member of the extrinsic coagulation cascade and therefore an attractive therapeutic target for thrombosis. CRA-027483 is a potent, selective, reversible small molecule inhibitor of human FVIIa that displays anti-thrombotic activities in vitro and in vivo. In addition to the well-characterized role of the FVIIa/tissue factor (TF) complex in coagulation, FVIIa/TF complex has more recently been implicated in inflammation via intracellular signaling initiated by the cleavage of protease activated receptors (PARs) by the complex. Therefore, we assessed the ability of CRA-027483 to inhibit acute inflammation using a mouse model of endotoxemia. The compound was delivered subcutaneously one hour prior to LPS challenge and serum or plasma was harvested at varying time points post-challenge. Soluble mediators of coagulation and inflammation induced by LPS were measured by ELISA. Additionally, prothrombin time (PT) and compound exposure were determined. CRA-027483 dose-dependently increased PT in mice as expected. Increases in PT correlated with increases in compound plasma concentrations. Coagulation markers plasminogen activator inhibitor-1 (PAI-1), D-dimer, and thrombin antithrombin (TAT) complex were dose-dependently inhibited by CRA-027483. In addition to increasing PT and inhibiting coagulation markers as expected, CRA-027483 also dose-dependently inhibited several pro-inflammatory mediators including cytokines, chemokines, and acute phase proteins. Inhibitory effects correlated with extension of PT, suggesting that the anti-inflammatory action of CRA-027483 was likely the direct result of inhibiting FVIIa/TF signaling rather than an off-target effect. Thus, we have demonstrated that selective inhibition of FVIIa with CRA-027483 results in suppression of acute inflammation in mice.