Tri- or tetraspecific antibodies

A trispecific or tetraspecific antibody, comprising:

• a) a light chain comprising a light chain variable domain VL and a light chain constant domain CL, and a heavy chain comprising a heavy chain variable domain VH and heavy chain constant domains CH1, CH2, and CH3, wherein the light chain and the heavy chain specifically bind to a first antigen;
• and
• b) a modified light chain and a modified heavy chain that specifically bind to a second antigen, wherein:
• (i) the modified light chain comprises in N-terminal to C-terminal direction VL, CH1, and the modified heavy chain comprises in N-terminal to C-terminal direction VH, CL, CH2, and CH3;
• (ii) the modified light chain comprises in N-terminal to C-terminal direction VH, CL, and the modified heavy chain comprises in N-terminal to C-terminal direction VL, CH1, CH2, and CH3;
• or
• (iii) the modified light chain comprises in N-terminal to C-terminal direction VH, CH1, and the modified heavy chain comprises in N-terminal to C-terminal direction VL, CL, CH2, and CH3;
• and
• c) one to four antigen binding peptides fused via a peptide connector to the C- or N-terminus of the light chains or heavy chains of a) and/or b) wherein said antigen binding peptides specifically bind one or two further antigens.