Totality Outcome of Afatinib Sequential Treatment in Patients With EGFR Sensitizing Mutation-positive NSCLC in South Korea

The T790M mutation is highly sensitive to osimertinib, which is approved in this setting following failure of gefitinib, erlotinib or afatinib. In contrast to first- and second-generation EGFR TKIs, no predominant resistance mechanism to first-line osimertinib has been clearly defined yet. The most common mechanisms of resistance were c-MET amplification only for 15% of patients and the emergence of the EGFR C797S mutation in 7%, while > 60% of patients were still with no identifiable mechanisms of resistance. As a result, targeted treatment options following first-line osimertinib failure remain limited. Thus, interest on sequential administration of EGFR TKIs in patients with EGFR mutation-positive NSCLC has been growing. So, here in this study, we intend to investigate treatment outcome (TOT) along with the several treatment options starting from the first line EGFR TKI treatment to various second line treatments including 3rd generation TKI and chemotherapy and others.