ERBB2 and biliary tract cancer: Data from the ongoing phase 1 study (NCT02892123) demonstrate that zanidatamab is well tolerated and has single agent activity in patients with advanced HER2-expressing cancers, including breast, gastric, and biliary tract cancers, that have progressed after standard of care therapies, including administration of HER2-targeted agents such as trastuzumab, pertuzumab, and T-DM160,61.