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CancerQuest > Drugs > Lapatinib (Tykerb®)

Lapatinib (Tykerb®)

Generic Name: Lapatinib Brand Name(s): Tykerb® IUPAC: FDA Approval: yes Manufacturer Link

Usage: Lapatanib was approved by the FDA in 2007 for use in combination with capecitabine for treatment of patients with advanced or metastatic breast cancer if a) their tumors overexpress HER2 and b) they have received prior therapy including anthracycline, a taxane, and trastuzumab. Lapatinib has the ability to penetrate the blood-brain barrier, so its use in treating brain metastasis is currently under investigation. ⁽¹⁾ Lapatinib is administered as an oral tablet.

Mechanism: Lapatinib (Tykerb®) is a small molecule that functions as tyrosine kinase inhibitor. It inhibits both EGFR (ErbB1) and HER2 (ErbB2). EGFR (epidermal growth factor receptor) and HER2 (human epidermal growth factor receptor 2) are receptor proteins found on the surface of cells. They bind growth factors, triggering a sequence of events that lead to cell division. Lapatinib prevents the receptors from sending signals by competing with ATP for its binding site on the tyrosine kinase domains of these proteins.⁽²⁾ Lapatanib binds the inactive form of EGFR, whereas previously utilized EGFR kinase inhibitors bind the active form. This has been shown to produce a longer lasting effect at the target site in cell culture.⁽³⁾

Side Effects: The most common side effects include mouth sores, loss of appetite, indigestion, diarrhea, rash, nausea and vomiting, fatigue, hand-foot syndrome (redness, swelling, and pain on the palms of the hands and/or the soles of the feet.) Inform your doctor about any heart conditions prior to treatment with lapatinib. It has been shown to decrease left ventricle ejection fraction (LVEF) in some patients, therefore LVEF should be evaluated in all patients. Lapatinib may also cause toxic effects on the hepatic (liver) system, so inform your doctor about any pre-existing liver conditions. Lapatinib may have harmful effects on a developing fetus, women who are pregnant should not take lapatinib and any woman who becomes pregnant while on lapatinib should inform their doctor immediately. Also, women who are breast feeding should speak with their doctor; it is not known if lapatinib passes into breast milk or what effects it can have on a developing child. Some drugs may interact with lapatinib. Your doctor needs to know what prescription or nonprescription (supplements) drugs you are on to decide the correct dose of lapatinib.⁽⁴⁾

References for this page:

1. NU Lin, LA Carey, MC Liu, et al. Phase II trial of lapatinib for brain metastases in patients with HER2+ breast cancer. Proceedings of the American Society for Clinical Oncology. 2006; 24:18S.
2. Karen E. Lackey, Lessons from the drug discovery of lapatinib, a dual ErbB1/2 tyrosine kinase inhibitor. Current Topics in Medicinal Chemistry. 2006; 6: 435-460. [PUBMED]
3. ER Wood, AT Truesdale, OB McDonald, et al. A unique structure for epidermal growth factor receptor bound to GW572016 (Lapatinib): Relationships among protein conformation, inhibitor off-rate, and receptor activity in tumor cells. Cancer Research. 2004; 64(18): 6652-6659. [PUBMED]
4. TYKERB Package Insert. GlaxoSmithKline. Research Triangle Park, NC 27709. 2007. [http://www.tykerb.com/about_tykerb.html]