A variant of recombinant factor VIIa with enhanced procoagulant and antifibrinolytic activities in an in vitro model of hemophilia

Arterioscler Thromb Vasc Biol. 2007 Mar;27(3):683-9. doi: 10.1161/01.ATV.0000257204.82396.2b. Epub 2007 Jan 4.


Objective: Recombinant factor VIIa (rFVIIa, NovoSeven) has proven efficacy in treating bleeding in hemophilia patients with inhibitors. A rFVIIa analog with mutations V158D/E296V/M298Q (NN1731) exhibits increased procoagulant activity in in vitro and in vivo models. The aim of this work was to define the effects of NN1731 toward factor X activation, platelet activation, thrombin generation, and fibrin clot formation and stability.

Methods and results: In a cell-based in vitro model of hemophilia, rFVIIa and NN1731 similarly increased factor X activation on tissue factor-bearing cells; however, NN1731 exhibited 30-fold higher factor Xa generation on platelets than similar rFVIIa concentrations. NN1731-mediated thrombin generation depended on platelet activation, but NN1731 did not directly activate platelets. NN1731 produced 4- to 10-fold higher maximal thrombin generation rates than equal rFVIIa concentrations. Both rFVIIa and NN1731 shortened clotting times in the absence of factors IX and VIII; however, NN1731 did so at 50-fold lower concentrations than were required of rFVIIa. In fibrinolytic conditions, both rFVIIa and NN1731 increased fibrin formation and stability; however, NN1731 was effective at 50-fold lower concentrations than were required of rFVIIa.

Conclusions: By increasing factor Xa generation, NN1731 promotes the formation of thrombin and a stable clot to a greater degree than rFVIIa.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Antifibrinolytic Agents / pharmacology
  • Blood Platelets / drug effects
  • Blood Platelets / physiology*
  • Cells, Cultured
  • Factor VIIa / pharmacology*
  • Factor X / metabolism*
  • Hemophilia A / blood*
  • Hemophilia A / drug therapy*
  • Humans
  • In Vitro Techniques
  • Leukocytes, Mononuclear / drug effects
  • Leukocytes, Mononuclear / physiology
  • Platelet Activation / drug effects*
  • Recombinant Proteins
  • Sensitivity and Specificity
  • Thrombin / physiology


  • Antifibrinolytic Agents
  • Recombinant Proteins
  • Factor X
  • Factor VIIa
  • Thrombin