Trastuzumab duocarmazine for third-line treatment of HER2-positive unresectable metastatic breast cancer

Trastuzumab duocarmazine is in clinical development for the treatment of human epidermal growth factor receptor 2 positive (HER2+) metastatic breast cancer in adult patients. Breast cancer is the most common cancer in the UK. Breast cancer is when abnormal cells in the breast begin to grow and divide in an uncontrolled way and eventually form a growth (tumour). HER2+ means that the cancer expresses a lot of HER2 protein and are likely to grow and spread faster than HER2- cancer. Metastatic breast cancer describes cancer that has spread beyond the breast to other parts of the body. Affected patients often experience disease progression after standard treatment.