Lapatinib is the generic name for Tykerb, an investigational oral drug that is being developed as a treatment for women with certain types of HER-2-positive breast cancer (i.e., breast cancer cells that produce excess amounts of HER-2 protein receptor, which is present mainly on the surface of the cells). The way that lapatinib may work as a medication for breast cancer is by sticking to the portion of HER-2 protein that is inside the breast cancer cells. As lapatinib also can bind to epidermal growth factor receptor (EGFR), which is present on other types of cancer cells, the drug has potential as a therapy for certain other types of solid tumors.
A recent Phase III clinical trial studied treatment of 321 patients with HER-2 positive, advanced or metastatic breast cancer that had progressed (i.e., got worse) or recurred (i.e., re-occurred) after therapy with an anthracycline drug, a taxane drug, and Herceptin (generic name, trastuzumab, which is a special type of antibody called a monoclonal antibody). In the study, use of the combination of lapatinib and the standard drug, capecitabine (the generic name of the brand-name drug, Xeloda), resulted in no observable growth or spread of the breast cancer for an average of 8.5 months, which is approximately 4 months longer than the cessation of growth or spread following treatment with just Xeloda (which resulted in no observable growth or spread for an average of 4.5 months).[1, 2] Furthermore, recurrence of breast cancer in the brain developed in fewer patients who received a combination of lapatinib and capecitabine than in those who received only capecitabine.
Side effects of combination treatment with lapatinib and capecitabine observed in some patients in the study included diarrhea and rashes.
Because of the encouraging results of the study, lapatinib is expected to be available soon through a compassionate use program for selected patients via application by medical oncologists to the manufacturer, GlaxoSmithKline (GSK). Later in 2006, it is anticipated that GSK will submit a new drug application (NDA) for approval of lapatinib for treatment of breast cancer to the U.S. Food and Drug Administration (FDA).
1. E. R. Winstead. National Cancer Institute. NCI Cancer Bulletin. 2006; 3(23):1-2.
2. M. Marchione. Drug brings new hope in breast cancer fight. Associated Press. 06/04/06.