Tucatinib Medication Guide: Detailed explanation of indications, dosage, and side effects

Overview of indications:

Tucatinib, in combination with trastuzumab and capecitabine, is indicated for the treatment of patients with advanced or metastatic breast cancerHER2-positive breast cancer, including cases with brain metastases, who have previously received one or more anti-HER2 therapies.

At the same time, the combination therapy of tucatinib and trastuzumab is also suitable for patients with RAS wild-type HER2-positive unresectable or metastatic colorectal cancer, especially those whose disease has progressed after receiving chemotherapy with fluoropyrimidine, oxaliplatin and irinotecan.

Mechanism of action: Tucatinib is a tyrosine kinase inhibitor of HER2. In vitro, tucatinib inhibits the phosphorylation of HER2 and HER3, thereby inhibiting downstream MAPK and AKT signaling and cell proliferation, and displays antitumor activity in HER2-expressing tumor cells. In vivo, tucatinib inhibits the growth of HER2-expressing tumors. The combination of tucatinib and trastuzumab demonstrated greater antitumor activity in vitro and in vivo than either agent alone.

Medication and dosage recommendations:

Tucatinib is available as an oral tablet at a recommended dose of 300 mg twice daily for use in combination with trastuzumab and capecitabine (for breast cancer) or trastuzumab (for colorectal cancer) until disease progression or intolerable toxicity occurs.

Patients should swallow tucatinib tablets whole and avoid chewing, crushing, or splitting tablets. It is not recommended to take damaged or incomplete tablets.

It is recommended to take tucatinib at a fixed time every day, with an interval of about 12 hours between two doses.It can be taken with or without food.

If the patient vomits or misses a dose, he or she should continue taking the medication at the next scheduled time.

Possible side effects and countermeasures:

Diarrhea is one of the common side effects of tucatinib, which in severe cases can lead to dehydration, hypotension, and renal damage. Patients should pay close attention to changes in bowel habits and consult a doctor promptly if severe diarrhea occurs.

Tucatinib may also cause serious liver problems. Therefore, doctors will regularly monitor the patient's liver function through blood tests before and during treatment. If symptoms such as itching, jaundice, dark urine, right upper quadrant pain, persistent fatigue, loss of appetite, or abnormal bleeding occur, seek medical attention immediately.

Other common side effects include hand-foot syndrome (redness, swelling, pain, etc. on the palms or soles), nausea, fatigue, increased liver function indicators, vomiting, mouth ulcers, loss of appetite, stomach pain, headache, anemia, and rash. Doctors will adjust drug dosage or suspend treatment based on the patient's specific condition.

In addition, tucatinib may have an impact on fertility, and patients who are concerned about this should communicate with their doctors in a timely manner.

Storage method:

Tucatinib should be stored at room temperature, between 68°F and 77°F (20°C and 25°C), in the original container.

The desiccant packet included in the bottle helps keep the tablets dry; do not throw them away.

Please close the bottle cap tightly after each dose and make sure to use it within 3 months after opening the bottle Unused tablets older than 3 months should be discarded.