What is Tucatinib?

What is Tucatinib?

Tucatinib is an oral targeted therapy drug that must be used in combination with Herceptin® (trastuzumab) and Xeloda® (capecitabine). It is indicated for adult patients with human epidermal growth factor receptor 2 (HER2)-positive breast cancer that has spread to other parts of the body (such as the brain), called metastatic breast cancer, or cannot be removed by surgery. Patients must also have received one or more prior anti-HER2 breast cancer treatments (such as trastuzumab, pertuzumab, or ado-trastuzumab emtansine). It is not known whether Tucatinib is safe and effective in children.

What does HER2-positive metastatic breast cancer mean?

HER2-positive metastatic breast cancer is a subtype of breast cancer in which the cancer cells have significantly more HER2 protein on their surface than healthy breast cells, and the cancer has spread to other parts of the body, such as the bones, lungs, liver, or brain. Knowing your HER2 status is very important because it directly influences treatment options. If you have HER2-positive disease, your doctor will typically recommend HER2-targeted therapies to stop the cancer from spreading further. Sometimes, even after standard treatment, breast cancer may continue to progress, and a Tucatinib-based regimen may offer a new treatment opportunity.

How does Tucatinib work?

Tucatinib is used together with trastuzumab to attack HER2-positive cancer cells from both the outside and the inside. Trastuzumab is a large molecule that binds to HER2 from the outside of the cell, blocking growth signals. In contrast, Tucatinib is a small molecule that can penetrate the cell membrane and inhibit HER2 activity from inside the cell. Working together, they more comprehensively block the signaling pathways that stimulate cancer cell growth and division. It is important to note that HER2 is also present on some normal cells, so targeted therapy may affect normal cells as well, causing side effects, some of which may be serious.