Can tucatinib be used together with trastuzumab?

Tucatinib and trastuzumab are two targeted drugs for HER2-positive metastatic breast cancer that can be used together in certain circumstances. The combination of tucatinib, trastuzumab, and capecitabine is often used as a triple therapy in combination with chemotherapy drugs such as paclitaxel or loplatin to treat HER2-positive metastatic breast cancer. This triple therapy is called T-DM1 follow-on therapy.

The combined use of trastuzumab and tucatinib helps to inhibit the HER2 signaling pathway more comprehensively and provides a stronger therapeutic effect. Trastuzumab inhibits tumor growth by inhibiting the dimerization of HER2 receptors, blocking cell signaling pathways. Tucatinib further inhibits the proliferation and spread of tumor cells by selectively inhibiting the activity of HER2 receptors. It may also be used together to treat a certain type of colorectal cancer that has spread to other parts of the body and cannot be treated with surgery in adults who have been treated with other chemotherapy drugs and have not improved or gotten worse.

It is understood that the original drug Tucatinib has not yet been launched in China, so it has not entered the scope of domestic medical insurance. Patients in need cannot yet purchase this drug in pharmacies or hospitals. The price of the European version of tucatinib original drug sold overseas is around RMB 72,000 (the price may fluctuate due to exchange rates), which is expensive. There are also generic drugs of tucatinib produced in other countries. The price of Tucatinib produced by a Lao pharmaceutical factory is around 6,400 yuan (the price may fluctuate due to the exchange rate). The price is much cheaper than the original drug, and the ingredients of foreign generic drugs are basically the same as the original drug.