Development of EGFR Family Small Molecule Inhibitors for Anticancer Intervention: An Overview of Approved Drugs and Clinical Candidates

The epidermal growth factor receptor (EGFR) family includes four structurally related receptor tyrosine kinases, termed as HER1 (EGFR, erbB1), HER2 (erbB2), HER3 (erbB3), and HER4 (erbB4). Given its intimate role in the development of several solid tumors, excessive HER signaling provides a unique opportunity for anticancer intervention. Along with extensive pharmacological studies validating the therapeutic potential of targeting the EGFR family for cancer therapy, kinase inhibitors of this family are continuously coming up and entering clinical studies. Herein, we review the EGFR family small molecule kinase inhibitors which have been approved or progressed into clinical studies, mainly focusing on their mechanisms of action, structure-activity relationships, binding modes, synthetic routes, and clinical status.