Trastuzumab deruxtecan is in clinical development for the treatment of adults with HER2- positive, unresectable and/or metastatic breast cancer who have previously been treated with trastuzumab and taxane. HER2-positive breast cancer is when the cancer tests positive for HER2 protein, which promotes the growth of cancer cells and tend to be more aggressive than other types of breast cancer. Metastatic breast cancer (stage IV) is when the cancer has spread beyond the breast and nearby lymph nodes to other organs in the body, while unresectable means that the cancer cannot be treated by surgery. Treatment of the disease often involves the use of anti-HER2 therapies, chemotherapy, or a combination of both.
Trastuzumab deruxtecan consists of an anti-HER2 therapy (trastuzumab) and a chemotherapy agent (deruxtecan) combined as an antibody-drug conjugate. Trastuzumab deruxtecan is administered intravenously. It has been developed such that the trastuzumab specifically binds to cancer cells that are HER2-positive which provides a targeted delivery of deruxtecan inside cancer cells, which then acts to kill the cancer cells. This reduces systemic exposure to the chemotherapy with the potential to reduce associated toxicities and adverse effects. If licenced, trastuzumab deruxtecan could provide an additional second line treatment option for HER2-positive, unresectable and/or metastatic breast cancer previously treated with trastuzumab and taxane.