Erlotinib is an orally-available, ATP-competitive, aminoquinazoline-based inhibitor of EGFR at an IC50 of 2 nM. EGFR autophosphorylation is inhibited by Erlotinib at 20 nM. [1]

In DiFi human colon cells, Erlotinib inhibits proliferation at submicromolar concentrations and also blocks the cell cycle in G1, resulting in significant accumulation of the cell cycle inhibitor p27KIP1. Erlotinib induces apoptosis in vitro. [2]