EGFR/HER2

Class

small molecule

Notes

original target text: EGFR/HER2 inhibitor

EGFR and HER2 belong to the ErbB family of receptor tyrosine kinases, proteins embedded in the cell membrane that transmit growth signals from outside the cell to internal signaling cascades, chiefly the RAS-MAPK and PI3K-AKT pathways that drive cell proliferation and survival. In many cancers, these receptors become abnormally active through gene amplification, overexpression, or activating mutations, producing continuous growth signaling independent of normal regulatory cues. Because EGFR and HER2 frequently form heterodimers—pairing with each other rather than functioning strictly alone—and because tumors can shift dependence from one to the other under treatment pressure, agents designed to inhibit both kinases simultaneously aim to close off compensatory signaling routes that a single-target drug might leave open. This dual-inhibition strategy is particularly relevant in cancers driven by specific mutations in either gene, including insertions in a region of the kinase domain that can render some single-target agents less effective. Small molecules that bind the intracellular kinase domain and block its enzymatic activity are a common way to achieve this simultaneous blockade. Broadly, EGFR/HER2-directed therapy is relevant to lung, breast, and other epithelial cancers where these receptors act as principal growth drivers.