Lapatinib

Overview
Lapatinib (INN) or lapatinib ditosylate (USAN), also known as GW572016, is an anti-cancer drug developed by GlaxoSmithKline (GSK) as a treatment for solid tumours such as breast and lung cancer. It was approved by the FDA on March 13, 2007, for use in patients with advanced metastatic breast cancer in conjunction with the chemotherapy drug capecitabine (Xeloda TM). It is marketed by GSK in the U.S. as Tykerb. Once regulatory approval has been granted, it will be marketed as Tyverb in Europe.

Lapatinib is a once-daily oral drug indicated for women who have received prior treatment with the intravenous drug trastuzumab (Herceptin TM) and cancer drugs called taxanes and anthracyclines. 

Lapatinib is an ATP-competitive epidermal growth factor receptor (EGFR) and HER2/neu (ErbB-2) dual tyrosine kinase inhibitor. It inhibits receptor autophosphorylation and activation by binding to the ATP-binding pocket of the EGFR/HER2 protein kinase domain.

In patients with HER2/neu positive metastatic breast cancer that has progressed following treatment with previous chemotherapy regimens that included an anthracycline, a taxane, and trastuzumab, randomized clinical trial has demonstrated that the addition of lapatinib to capecitabine delayed the time of further cancer growth compared to capecitabine alone.