Lapatinib is a selective dual inhibitor of epidermal growth factor receptor (EGFR, ERBB1) and human epidermal growth factor receptor 2 (HER2, ERBB2), each with an IC50 of about 10 nM (Rusnak et al.) It binds reversibly, but with a very slow off-rate, to the ATP binding pocket in an inactive-like conformation, thus preventing autophosphorylation
Binding is very potent, with Ki values of 3 and 13 nM to EGFR and HER2 respectively (Wood et al.)
Induces apoptosis in cells overexpressing EGFR and/or HER2, and inhibits tumor growth in a mouse xenograft model (Xia et al.)
