ERBB2 and neoplasm: A biparatopic ADC consisting of an antibody construct capable of binding two different epitopes (subdomains 2 and 4 of the ectodomain) on HER2 and conjugated to the tubulysin (Tub) AZ13599185 showed more anti-tumour activity than TDM-1 in trastuzumab resistant tumour models as well as demonstrating activity in TDM-1 resistant and HER2-low xenografts.