The present invention provides a chimeric protein comprising a VWF protein comprising the D′ domain and D3 domain of VWF, one or more XTEN sequence, and a FVIII protein, wherein the VWF fragment, the XTEN sequence, or the FVIII protein are linked to or associated with each other. The chimeric protein can further comprise one or more Ig constant region or a portion thereof (e.g., an Fc region). A polypeptide chain comprising a VWF fragment of the invention binds to or is associated with a polypeptide chain comprising a FVIII protein linked to an XTEN sequence and the polypeptide chain comprising the VWF fragment can prevent or inhibit binding of endogenous VWF to the FVIII protein linked to the XTEN sequence. By preventing or inhibiting binding of endogenous VWF to the FVIII protein, which is a half-life limiting factor for FVIII, the VWF fragment can induce extension of half-life of the chimeric protein comprising a FVIII protein. The invention also includes nucleotides, vectors, host cells, methods of using the VWF fragment, or the chimeric proteins.
