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ANTINEOPLASTIC AND IMMUNOMODULATING AGENTS › ANTINEOPLASTIC AGENTS › PROTEIN KINASE INHIBITORS › Human epidermal growth factor receptor 2 (HER2) tyrosine kinase inhibitors
lapatinib
L01EH01
Adult Dosing
- HER2-positive advanced or metastatic breast cancer: 1250 mg orally once daily continuously in combination with capecitabine
- HER2-positive hormone receptor-positive metastatic breast cancer: 1500 mg orally once daily continuously in combination with letrozole
- Administer at least 1 hour before or 1 hour after food
Pediatric Dosing
- Safety and efficacy in pediatric patients have not been established
Indications
- In combination with capecitabine for treatment of patients with advanced or metastatic HER2-positive breast cancer who have received prior therapy including anthracycline, taxane, and trastuzumab
- In combination with letrozole for postmenopausal women with hormone receptor-positive HER2-positive metastatic breast cancer for whom hormonal therapy is indicated
Mechanism of Action
- Dual tyrosine kinase inhibitor that interrupts both ErbB1 (EGFR) and ErbB2 (HER2) pathways
- Inhibits receptor autophosphorylation, leading to cell cycle arrest and apoptosis in HER-overexpressing cancer cells
Contraindications
- Known hypersensitivity to lapatinib or any of its excipients
Adverse Reactions
- Diarrhea
- Nausea and vomiting
- Palmar-plantar erythrodysesthesia syndrome
- Rash
- Fatigue
- Decreased left ventricular ejection fraction (LVEF)
- Hepatotoxicity
Drug Interactions
- Strong CYP3A4 inhibitors (e.g., ketoconazole, ritonavir) increase lapatinib exposure; avoid or reduce dose if necessary
- Strong CYP3A4 inducers (e.g., rifampin, carbamazepine) decrease lapatinib exposure; avoid or increase dose if necessary
- CYP3A4 substrates with narrow therapeutic indices (e.g., cisapride, pimozide, ergot alkaloids) may have increased toxicity
- Substrates of P-glycoprotein (e.g., digoxin) may have increased serum concentrations
Curated Content: Needs Vetting Before Put to Clinical Use