Patent ID: 8076463

Claim:
A method for forming a proteinaceous molecule comprising a von Willebrand Factor (VWF) molecule and a PEG moiety covalently bound to at least one carbohydrate residue on said VWF molecule, said proteinaceous molecule having the capability of binding at least one Factor VIII (FVIII) molecule, comprising: a) providing a VWF molecule selected from the group consisting of plasmatic VWF, recombinant VWF, and dimers and multimers thereof; b) oxidizing carbohydrate residues on said VWF molecule; c) contacting said carbohydrate residues with a PEG reagent containing a hydrazide group; and d) allowing said PEG hydrazide reagent to covalently bind to at least one carbohydrate residue on said VWF, thereby forming said proteinaceous molecule, wherein the in vivo half-life of said proteinaceous molecule is increased as compared to the in vivo half-life of a VWF molecule and the in vivo half-life of said FVIII molecule bound to said proteinaceous molecule is increased as compared to the in vivo half-life of a FVIII molecule not bound to said proteinaceous molecule.