Prolonged effect of a new O-glycoPEGylated FVIII (N8-GP) in a murine saphenous vein bleeding model.

Prophylaxis in severe haemophilia significantly increases health-related quality of life for patients, but the dosing frequency still constitutes a challenge. Thus, there is a need for new treatment options, utilizing compounds with longer duration of action, while still maintaining potency. The objective of this study was to evaluate the acute and prolonged effects of a new glycoPEGylated recombinant factor VIII (rFVIII) (N8-GP) in a venous bleeding model in haemophilia A mice and to compare the efficacy and potency to turoctocog alfa (rFVIII). Following intravenous administration of turoctocog alfa or N8-GP to normal and FVIII-deficient mice, bleeding time and blood loss from a saphenous vein incision were evaluated in an acute dose-response study and a duration of action study. In the acute setting, N8-GP dose dependently reduced the number and duration of bleeding episodes as well as blood loss compared to FVIII-deficient mice, reaching statistical significance at doses as low as 5-10 U kg(-1) . In the duration of action study, a significantly prolonged and maintained effect of N8-GP was found for up to 48 h after dosing, whereas the effect of rFVIII was no longer present for any end-points 24 h after dosing. Seventy-two hours after dosing, no significant effect of either compound was found. This study shows a prolonged haemostatic effect of N8-GP compared to rFVIII supporting other recent studies that N8-GP may hold a potential to increase the quality of life for patients with haemophilia A by reducing dosing frequency.