tucatinib + trastuzumab + ramucirumab + paclitaxel

This is a four-drug combination therapy consisting of **tucatinib**, **trastuzumab**, **ramucirumab**, and **paclitaxel**. Tucatinib is a highly selective HER2-directed small-molecule tyrosine kinase inhibitor; trastuzumab is a monoclonal antibody that targets the HER2 receptor; ramucirumab is a monoclonal antibody directed against VEGFR2; and paclitaxel is a chemotherapeutic agent that stabilizes microtubules, inhibiting cell division. This combination is currently being evaluated as a second-line regimen for **HER2-positive locally advanced or metastatic gastric or gastroesophageal junction adenocarcinoma** (GEC) in patients who progressed on or after HER2-targeted antibody therapy, within the MOUNTAINEER-02 phase 2/3 clinical trial. The regimen represents a multi-modal targeted approach: two anti-HER2 agents plus anti-VEGFR2 and cytotoxic chemotherapy[2][4][7].