HERIZON-BTC-01 was a global, phase 2b trial evaluating zanidatimab, a monoclonal antibody binding HER2 at two domains, resulting in the formation of HER2-antibody clusters that are internalized, reducing HER2 expression, in patients with advanced, HER2-amplified biliary tract cancers with progression on gemcitabine-based therapy [40]. Here, ERBB2 is linked to biliary tract cancer.