Tucatinib with trastuzumab emtansine for treating unresectable, locally advanced or metastatic HER2 positive breast cancer

Tucatinib in combination with trastuzumab emtansine is currently in clinical development for the treatment of unresectable, locally-advanced or metastatic human epidermal growth factor receptor 2 positive (HER2+) breast cancer, after prior treatment. Breast cancer is when abnormal cells in the breast begin to grow and uncontrollably divide and eventually form a growth (tumour). Metastatic breast cancer is cancer that has spread beyond the breast to other organs, and unresectable cancer cannot be treated with surgery. HER2 is a protein on cells that helps cell growth, development, and survival. Cancers associated with overexpression of HER2 are more aggressive. Treatment options for patients who experience disease progression after standard treatment are limited.