An inhibitory anti-factor IX antibody effectively reduces thrombus formation in a rat model of venous thrombosis

An inhibitory anti-factor IX/IXa antibody (BC2) has been investigated as an anti-thrombotic agent in a rat venous thrombosis model. The treatment of r ats post-injury with a single bolus dose of BC2 (3mg/kg, iv.) resulted in a n similar to 4 fold reduction in venous thrombus mass (P= 0.043), This effi cacy was matched by a minimal (<2.5 fold) prolongation of the aPTT and had no effect on the prothrombin time (PT). Heparin by comparison, given as a b olus followed by continuous infusion, at doses comparable in efficacy at re ducing thrombus formation, prolonged the aPTTT >50 fold. These results demo nstrate that the anti-factor IX/IXa antibody (BC2), when compared to hepari n, can effectively reduce venous thrombosis with less disruptive consequenc es on blood clotting.