The present invention concerns antibody-like binding protein specifically binding to CD3 and binding specifically to at least one further antigen, for example CD123. The present invention also concerns antibody-like binding protein specifically binding to CD123 and binding specifically to at least one further antigen. The invention further concerns anti-CD3 antibodies and anti-CD123 antibodies. The invention also relates to pharmaceutical compositions comprising the antibody-like binding protein, anti-CD3 antibodies or anti-CD123 antibodies of the invention, and their use to treat cancer. The invention further relates to isolated nucleic acids, vectors and host cells comprising a sequence encoding said antibody-like binding protein, anti-CD3 or anti-CD123 antibody and the use of said anti-CD123 antibody as a diagnostic tool.
