Modulation of Extravascular Binding of Recombinant Factor IX Impacts the Duration of Efficacy in Mouse Models.

Background:  There is an emerging concept that in addition to circulating coagulation factor IX (FIX), extravascular FIX contributes to hemostasis.

Objective:  Our objective was to evaluate the efficacy of extravascular FIX using animal models of tail clip bleeding and ferric chloride-induced thrombosis.

Methods:  Mutant rFIX proteins with described enhanced (rFIX) or reduced (rFIX) binding to extracellular matrix were generated and characterized using aPTT, one-stage clotting, and modified FX assays.