patritumab deruxtecan + trastuzumab + tucatinib

This is an **investigational combination therapy** comprising patritumab deruxtecan (an antibody-drug conjugate targeting HER3), trastuzumab (a monoclonal antibody targeting HER2), and tucatinib (a small molecule HER2 kinase inhibitor). Patritumab deruxtecan binds HER3 and delivers a cytotoxic payload into HER3-expressing cancer cells[1]. Trastuzumab binds to HER2, inhibiting downstream signaling and mediating antibody-dependent cellular cytotoxicity. Tucatinib selectively inhibits the kinase activity of HER2. This combination is being studied in HER2-positive breast cancer, primarily for advanced or metastatic disease, as a targeted therapy approach for patients who have progressed on previous HER2-directed therapies[1].