Bifunctional glycoproteins having a modified carbohydrate complement and their use in tumor-selective therapy

A compound comprising a modified carbohydrate complement and a humanized two-chain fusion protein composed of a humanized VHCH1-hinge-S-human β-glucuronidase chain and of a humanized VLCL chain, which binds specifically to an epitope of a tumor-specific antigen,

• wherein the modified carbohydrate complement is achieved by chemical qalactosvlation or neuraminidase treatment,
• wherein the modified carbohydrate complement comprises at least one exposed carbohydrate residue selected from the group consisting of galactose, mannose, N-acetylglucosamine, fucose, N-acetyllactose, glucose, and N-acetylneuraminic acid,
• wherein said compound has been synthesized in CHO cells,
• wherein the CHO cells have been selected for a higher level of glycoprotein expression, a higher rate of elimination of glycoprotein from plasma, a higher rate of concentration of the glycoprotein at the tumor-specific antigen and a higher content of high mannose type structures as compared to BHK cells which express said humanized two-chain fusion protein with a different carbohydrate complement, and
• wherein S is a polypeptide spacer.