BISPECIFIC ANTIBODY WITH DOUBLE HER2 SITES FOR TUMOR IMMUNOTHERAPY

摘要

Disclosed is a bispecific antibody with double Her2 sites, the antibody containing: (a) an anti-CD3 antigen-binding fragment Fab, which has a light chain variable region VL and a light chain constant region CL, and a heavy chain variable region VH and a heavy chain constant region CH1; (b) an anti-Her2 single-domain antigen-binding fragment VHH1, which is connected to the C-terminus of the CL of the Fab, and is capable of binding to a first Her2 epitope; and (c) an anti-Her2 single-domain antigen-binding fragment VHH2, which is connected to the C-terminus of the CH1 of the Fab, and is capable of binding to a second Her2 epitope, wherein the first Her2 epitope and the second Her2 epitope are non-overlapping epitopes of Her2. The bispecific antibody with double Her2 sites of the present invention also has an effect on Her2 tumors with an IHC score of +1, or can act on trastuzumab-resistant tumors.