|There are currently
several different agents on the market or being tested in clinical trials
that target the ErbB signaling pathway.1 The full or partial
humanized monoclonal antibodies targeting ErbB1 (cetuximab) and ErbB2
(trastuzumab) bind to the extracellular domain of the respective receptors.
The small molecule inhibitors gefitinib and erlotinib, which target ErbB1,
work inside the cell and block receptor kinase activity. However, as
single-target agents, all of these agents work primarily against a single
family member. As a small molecule, lapatinib exerts its effect by blocking
the ATP binding site at the intracellular domain. Theoretically, lapatinib
may exhibit potent activity against both ErbB1 and ErbB2 receptors.
|1. Normanno N, Bianco C, De Luca A, et al. Target-based
agents against ErbB receptors and their ligands: a novel approach to cancer
treatment. Endocr Relat Cancer 2003; 10:1-21.