Tucatinib with trastuzumab and pertuzumab for maintenance treatment of unresectable locally advanced or metastatic HER2-positive breast cancer

Tucatinib in combination with trastuzumab and pertuzumab is in clinical development for the maintenance treatment of unresectable locally advanced, or metastatic HER2-positive (HER2-POSITIVE) breast cancer. Breast cancer is cancer that starts in the breast tissue. HER2-positive breast cancer means that the cancer cells express more of the HER2 protein on their surface. HER2 encourages cell growth and therefore HER2-positive cancers can grow more quickly. Unresectable cancer is cancer that cannot be removed by surgery. Locally advanced means cancer has grown outside the body part it started in but has not yet spread to other parts of the body, whereas metastatic cancer is cancer that has spread to other parts of the body. A high mortality rate is reported in HER2-positive breast cancer, due to limited therapeutic options. Despite advances in medicinal products to treat metastatic breast cancer, HER2-positive metastatic breast cancer is still challenging for patients particularly given the emergence of drug resistance to some treatment options.