Anti-tumor effect and mechanism of tucatinib/tucatinib

Tucatinib/Tucatinib is a tyrosine kinase inhibitor targeting human epidermal growth factor receptor 2 (HER2). It is often combined with other anti-tumor drugs such as trastuzumab and capecitabine to treat difficult-to-treat, advanced or metastatic HER2-positive breast cancer and colorectal cancer. By effectively inhibiting tyrosine kinases, it exhibits significant anti-tumor effects, especially in shrinking HER2-positive breast cancer tumors. Clinical trial data show that the combination treatment regimen of tucatinib and trastuzumab showed stronger anti-tumor activity in both in vivo and in vitro experiments compared with other drugs alone.

Research has confirmed that tucatinib can significantly prolong the survival of patients with advanced or metastatic HER2-positive breast cancer while maintaining disease stability. In a pivotal study, patients treated with tucatinib lived an average of 7.8 months without disease progression. Even more encouraging is that about 41% of patients responded positively to the treatment, and their average life span was extended to 22 months. Another study pointed out that the combination therapy of tucatinib and trastuzumab is expected to become a new standard treatment option. During a median follow-up of 20.7 months, 38.1% of 86 patients with metastatic colorectal cancer who received this combination therapy achieved an objective response, and 71.4% had their disease effectively controlled. The median duration of response of patients reached 12.4 months, the median progression-free survival was 8.2 months, and the median overall survival was extended to 24.1 months.

HER-2 gene mutations are observed in certain types of breast cancer and lead to abnormal increases in cell signaling and proliferation, leading to malignancy. Tucatinib blocks this abnormal cell signaling by inhibiting the tyrosine kinase in the HER-2 gene. In vitro studies further revealed that tucatinib can inhibit the phosphorylation process of HER-2 and HER-3, thereby affecting the MAPK and AKT signaling pathways, as well as downstream changes in cell proliferation. In an in vivo environment, tucatinib effectively inhibits the growth of HER-2-positive tumors through the same mechanism.

However, some side effects may occur after the use of tucatinib, such as diarrhea and increased aminotransferase levels. When using tucatinib, the patient's physical condition needs to be closely monitored and the treatment plan adjusted according to the specific situation. Therefore, as an effective targeted therapy, tucatinib is highly selective and can accurately target HER2, reducing the potential impact on other normal cells and providing a new treatment option for patients with HER2-positive metastatic breast cancer.