zanidatamab + capecitabine + tucatinib

zanidatamab + capecitabine + tucatinib is an investigational combination regimen being studied for the treatment of HER2-positive cancers, particularly metastatic breast cancer. **Zanidatamab** is a bispecific monoclonal antibody that targets two distinct epitopes on the HER2 receptor, leading to dual HER2 blockade and enhanced antitumor activity. **Capecitabine** is an oral prodrug of 5-fluorouracil, a pyrimidine analog that disrupts DNA synthesis in dividing cells, classifying it as a cytotoxic antimetabolite. **Tucatinib** is a small molecule tyrosine kinase inhibitor that selectively inhibits the HER2 receptor, blocking downstream proliferative signaling. The combination aims for synergistic anti-HER2 activity by simultaneously interrupting HER2 signaling with zanidatamab and tucatinib, and inducing DNA damage with capecitabine. This drug regimen is under phase 1/2 study for HER2-positive solid tumors and as of this date has not received regulatory approval for any indication.