An in vitro pharmacodynamic spiking study of befovacimab, a tissue factor pathway inhibitor monoclonal antibody, in blood samples from patients with severe FVIII deficiency.

Befovacimab has modest dose-response effects from 0.5 to 10 nM with minimal improvement with higher concentrations. In vitro befovacimab blood concentrations of 5 to 10 nM had pro-coagulant effects similar to blood supplemented with rFVIII 10- to 40%.