Panelists discuss how HER2-targeted agents in biliary tract cancers include trastuzumab deruxtecan (an antibody-drug conjugate that acts like a “smart missile” delivering cytotoxic payload to HER2-expressing cells with risks of pneumonitis and myelosuppression) and zanidatamab (a bispecific antibody targeting 2 different HER2 epitopes simultaneously for enhanced cytotoxicity with primarily antibody-related toxicities like cardiac effects and diarrhea but without chemotherapy-related adverse effects).