Another bispecific, humanized IgG1 antibody that may be underneath investigation is zenocutuzumab (MCLA-128), which acts via two unbiased mechanisms of action: inhibition of HER2–HER3 signalling and elimination of tumour cells by way of ADCC. MCLA-128 functions via a ‘dock and block’ system whereby 1 arm in the antibody binds HER2 https://www.directivepublications.org/journal-of-clinical-breast-cancer/