Formulation and Specifications: Tablets: 0.25g
Indications: Lapatinib in combination with capecitabine is indicated for the treatment of patients with advanced or metastatic breast cancer with HER2 overexpression and prior treatment including anthracyclines, paclitaxel, and trastuzumab.
Key Points for Rational Use:
1. Patients considering this drug need to have HER2 testing of tissue specimens (primary or metastatic foci), either primary or metastatic, before it can be used in HER2-positive patients.
2. It is only indicated for patients with recurrent metastases and is not recommended for first-line use in principle, except for patients with contraindications to trastuzumab or those participating in clinical trials of new drugs.
3. When used alone, 1.25g/dose once a day for the first to 21st day. When used in combination with capecitabine, the recommended dose of lapatinib is the same as above, once daily for 1 cycle every 21 days. It is recommended that the daily dose be taken at once and splitting is not recommended. It should be taken at least 1 hour before a meal, or at least 1 hour after a meal. The recommended dose of capecitabine is 2 g/(m2▪d), divided into two oral doses. The interval between doses is approximately 12 hours for 14 days, with a 7-day break, for a 21-day cycle. Capecitabine should be taken with food or within 30 minutes after a meal.
4. The main adverse reactions are diarrhea and rash, diarrhea can be symptomatic anti-diarrhea, avoid direct sunlight during the use of the drug, and pay attention to sun protection when going out. Cardiotoxicity can occur with this product, mainly in the form of reduced LVEF. It is recommended that LVEF be evaluated prior to treatment, and that LVEF be tested periodically during treatment. If LVEF decreases to the lower limit of normal, or if symptoms associated with a grade 2 or higher decrease in LVEF occur, the drug should be discontinued. If it returns to normal and the patient is asymptomatic, the product may be reduced in dose (1 g daily in combination with capecitabine) after at least 2 weeks of discontinuation. Some patients may also develop liver function impairment.
5. If a patient misses a dose on a particular day, do not double the dose for the next day and simply continue at the next dosing time as scheduled. Treatment should be continued until disease progression or intolerable toxic effects occur.
6. This product is mainly metabolized by CYP3A4. Grapefruit and grapefruit juice are prohibited during dosing. Caution is required when co-administering with CYP3A4 inhibitors or inducers, and caution should be exercised when co-administering with proton pump inhibitors.
7. Clinical studies have also demonstrated that lapatinib in combination with other chemotherapeutic agents or endocrine therapeutic agents may result in clinical benefit to patients.