Targeting non-small cell lung cancer with small-molecule EGFR tyrosine kinase inhibitors.

Epidermal growth factor (EGFR) tyrosine kinase inhibitors (TKIs), such as gefitinib and erlotinib, show excellent clinical efficacy for patients with non-small cell lung cancer (NSCLC) with EGFR mutations, including Exon 19 deletion and single-point substitution, and L858R of exon 21. The reason for the reduction in effectiveness of these EGFR TKIs is the T790M gatekeeper mutation in the ATP-binding pocket of Exon 20, which increases the affinity of EGFR for ATP. Newer EGFR TKIs, such as afatinib, osimertinib, rociletinib, EGF816 and ASP8273, selectively target T790M mutants, sparing wild-type EGFR. EGFR TKIs have fewer adverse effects than chemotherapy and also improve progression-free survival. Combination therapy of EGFR TKIs with anti-EGFR antibodies is recommended for overcoming the problem of resistance to some extent. This review could help medicinal chemists to design novel EGFR TKIs against NSCLC.