Prolonged in-vivo half-life of factor VIIa by fusion to albumin

Summary For the treatment of haemophilia patients with inhibitors, recombinant factor VIIa (rFVIIa) is available as a therapeutic option to control bleeding episodes with a good balance of safety and efficacy. However, the short in-vivo half-life of approximately 2.5 hours makes multiple injections necessary, which is inconvenient for both physicians and patients. Here we describe the generation of a recombinant FVIIa molecule with an extended half-life based on genetic fusion to human albumin. The recombinant FVII albumin fusion protein (rVII-FP) was expressed in mammalian cells and upon activation displayed a FVII activity close to that of wild type FVIIa. Pharmacokinetic studies in rats demonstrated that the half-life of the activated recombinant FVII albumin fusion protein (rVIIa-FP) was extended six- to sevenfold compared with wild type rFVIIa. The in-vitro and in-vivo efficacy was evaluated and was found to be comparable to a commercially available rFVIIa (NovoSeven ® ). The results of this study demonstrate that it is feasible to develop a half-life extended FVIIa molecule with haemostatic properties very similar to the wild-type factor.