Incidence of T790M in Patients With NSCLC Progressed to Gefitinib, Erlotinib, and Afatinib: A Study on Circulating Cell-free DNA

Epidermal growth factor receptor (EGFR) tyrosine kinase inhibitors (TKIs) are characterized by different pharmacologic profiles, potentially affecting the development of resistance mutations, which were investigated in the present study. We retrospectively included patients with EGFR-mutant non–small-cell lung cancer who had received EGFR TKIs as first-line therapy. Circulating cell-free DNA was analyzed at disease progression to investigate the incidence of T790M. We found a greater occurrence of T790M in patients with progression during gefitinib or erlotinib versus afatinib therapy, although the time to progression was comparable. We found that EGFR TKIs behave differently with respect to the development of the T790M resistance mutation, and this finding could have implications in the choice of second-line treatment.