The application belongs to the field of biological
medicine, and particularly relates to a HER2
antibody, a pharmaceutical composition and application thereof. The application provides an
antibody binding to HER2, which comprises a first
antigen binding part and a second
antigen binding part, the first
antigen binding part comprises an anti-HER2 nanobody, and the sequence of the anti-HER2 nanobody comprises an
amino acid sequence as shown in any one of SEQ ID NO. 5, SEQ ID NO. 6, SEQ ID NO. 7 and SEQ ID NO. 8, and the second
antigen binding part comprises
trastuzumab or
pertuzumab. The
antibody provided by the application has the effect of inhibiting HER2 related tumors, the
bispecific antibody in the antibody can specifically recognize different epitopes of HER2, inhibit non-ligand dependent and ligand dependent HER2 positive tumor
cell proliferation, has obvious inhibiting effect on HER2 positive tumors and HER2 low expression tumors resistant to
trastuzumab, and provides a new scheme for diagnosis and treatment of HER2 related tumors.