CI-1033 (Canertinib) is an orally bioavailable irreversible Pan-erbB tyrosine kinase inhibitor, targeting EGFR with IC50 of 0.8, 19 and 7 nM for EGFR, HER-2 and ErbB-4, respectively. It effectively inhibits the growth of esophageal squamous cell carcinoma which co-expresses both EGFR and HER2 with the inhibition of phosphorylation of both MAPK and AKT. inhibitor, is a clinically promising agent that is active against all four members of the erbB receptor tyrosine kinase family. In vitro studies of human cancer cell lines indicate that CI-1033 results in prompt, potent, and sustained inhibition of tyrosine kinase activity. This inhibition is highly selective for erbB1 (epidermal growth factor receptor), erbB2, erbB3, and erbB4 without inhibiting tyrosine kinase activity of receptors such as platelet-derived growth factor receptor, fibroblast growth factor receptor, and insulin receptor, even at high concentrations. [1][2]