Overview
11 DESCRIPTION Lapatinib is a small molecule and a member of the 4-anilinoquinazoline class of kinase inhibitors. It is present as the monohydrate of the ditosylate salt, with chemical name N -(3-chloro-4-{[(3- fluorophenyl)methyl]oxy}phenyl)-6-[5-({[2-(methylsulfonyl)ethyl]amino}methyl)-2-furanyl]-4- quinazolinamine bis(4-methylbenzenesulfonate) monohydrate.
Mechanism of Action
12 CLINICAL PHARMACOLOGY 12.1 Mechanism of Action Lapatinib is a 4-anilinoquinazoline kinase inhibitor of the intracellular tyrosine kinase domains of both Epidermal Growth Factor Receptor (EGFR [ErbB1]) and of Human Epidermal Receptor Type 2 (HER2 [ErbB2]) receptors (estimated Ki app values of 3nM and 13nM, respectively) with a dissociation half-life of greater than or equal to 300 minutes. Lapatinib inhibits ErbB-driven tumor cell growth in vitro and in various animal models. An additive effect was demonstrated in an in vitro study when lapatinib and 5-FU (the active metabolite of capecitabine) were used in combination in the 4-tumor cell lines tested. The growth inhibitory effects of lapatinib were evaluated in trastuzumab-conditioned cell lines.
Indications
- 1 INDICATIONS AND USAGE Lapatinib tablets are indicated in combination with: capecitabine for the treatment of patients with advanced or metastatic breast cancer whose tumors overexpress human epidermal growth factor receptor 2 (HER2) and who have received prior therapy, including an anthracycline, a taxane, and trastuzumab. Limitations of Use : Patients should have disease progression on trastuzumab prior to initiation of treatment with lapatinib tablets in combination with capecitabine.
Common Doses
- 250 mg
- 000 mg
- 500 mg
- 2.5 mg
Dosage
2 DOSAGE AND ADMINISTRATION The recommended dosage of lapatinib tablets for advanced or metastatic breast cancer is 1,250 mg (5 tablets) given orally once daily on Days 1 to 21 continuously in combination with capecitabine 2,000 mg/m 2 /day (administered orally in 2 doses approximately 12 hours apart) on Days 1 to 14 in a repeating 21-day cycle. ( 2.1 ) The recommended dose of lapatinib tablets for hormone receptor-positive, HER2-positive metastatic breast cancer is 1,500 mg (6 tablets) given orally once daily continuously in combination with letrozole.
Black Box Warning
WARNING: HEPATOTOXICITY Hepatotoxicity has been observed in clinical trials and postmarketing experience. The hepatotoxicity may be severe and deaths have been reported. Causality of the deaths is uncertain [see Warnings and Precautions ( 5.2 )] . WARNING: HEPATOTOXICITY See full prescribing information for complete boxed warning. Hepatotoxicity has been observed in clinical trials and postmarketing experience. The hepatotoxicity may be severe and deaths have been reported. Causality of the deaths is uncertain. ( 5.2 )
Contraindications
- 4 CONTRAINDICATIONS Lapatinib tablets are contraindicated in patients with known severe hypersensitivity (e.g., anaphylaxis) to this product or any of its components. Known severe hypersensitivity (e.g., anaphylaxis) to this product or any of its components. ( 4 )
Side Effects
- 6 ADVERSE REACTIONS The most common (greater than 20%) adverse reactions during treatment with lapatinib plus capecitabine were diarrhea, palmar-plantar erythrodysesthesia, nausea, rash, vomiting, and fatigue. The most common (greater than or equal to 20%) adverse reactions during treatment with lapatinib plus letrozole were diarrhea, rash, nausea, and fatigue. ( 6.1 ) To report SUSPECTED ADVERSE REACTIONS, contact AvKARE at 1-855-361-3993 or FDA at 1-800-FDA-1088 or www.fda.gov/medwatch. 6.
Interactions
- 7 DRUG INTERACTIONS Lapatinib is likely to increase exposure to concomitantly administered drugs which are substrates of CYP3A4, CYP2C8, or P-glycoprotein (ABCB1). ( 7.1 ) Avoid strong CYP3A4 inhibitors. If unavoidable, consider dose reduction of lapatinib in patients coadministered a strong CYP3A4 inhibitor. ( 2.2 , 7.2 ) Avoid strong CYP3A4 inducers. If unavoidable, consider gradual dose increase of lapatinib in patients coadministered a strong CYP3A4 inducer. ( 2.2 , 7.2 ) 7.