Antithrombotic properties of a truncated recombinant tissue factor pathway inhibitor in an experimental venous thrombosis model.

The aim of this study was to investigate whether a truncated recombinant tissue factor pathway inhibitor (rTFPI1-161) had an antithrombotic effect comparable to low-molecular-weight (LMW) heparin. A randomized double-dummy study was conducted with 40 rabbits in 6 groups. An experimental thrombosis was induced in the jugular veins by a combination of destroyed endothelium and restricted blood flow. Group 1 was given placebo; group 2, LMW heparin 60 anti-factor Xa units/kg; group 3, rTFPI1-161 0.1 mg/kg; group 4, rTFPI1-161 1.0 mg/kg and group 5, rTFPI1-161 10.0 mg/kg. rTFPI1-161 reduced the thrombus weights in all treated groups, with a significant effect in doses between 1.0 and 10.0 mg/kg compared to placebo. The frequency of thrombosis was significantly reduced in all treated groups. No hemorrhagic side effects were noted. In conclusion, rTFPI1-161 (1.0-10.0 mg/kg) has an antithrombotic effect comparable to that of LMW heparin.