Tucatinib/tucatinib usage and dosage

Tucatinib is a tyrosine kinase inhibitor targeting human epidermal growth factor receptor 2 (HER2). It can be used in combination with other anti-tumor drugs to treat refractory, advanced or metastatic HER 2-positive breast cancer and colorectal cancer. Common drugs include trastuzumab and capecitabine. However, for patients with unresectable or metastatic colorectal cancer, before choosing to use tucatinib, it should be confirmed thatHER2 is overexpressed or gene amplified and is RAS wild-type.

According to clinical guidelines, patients should take tucatinib 300mg twice daily until disease progression or drug toxicity reaches an unacceptable level. When used in combination with trastuzumab and capecitabine, the recommended dose of capecitabine is 1000 mg/m² twice daily, taken within 30 minutes after a meal. All medications should be administered in accordance with relevant clinical guidelines. Patients should swallow tucatinib whole and do not chew, crush, or split the tablet. Tablets should not be taken if they are broken, cracked, or incomplete. The two doses should be taken approximately 12 hours apart, regardless of meal times. If the patient vomits or misses a dose, the next dose can be taken at the scheduled time.

Based on adverse reactions, doctors may adjust the dosage of tucatinib, which can be reduced to 250 mg twice daily for the first time, 200 mg twice daily for the first time, 200 mg twice daily for the first time, and finally 150 mg twice daily. For patients unable to tolerate the 150 mg dose, the drug should be permanently discontinued. Patients with severe liver impairment should reduce to 200 mg twice daily. At the same time, concurrent use with strong CYP2C8 inhibitors should be avoided. If this cannot be avoided, tucatinib should be reduced to 100 mg twice daily. After stopping the inhibitor, the previous dose should be resumed.