Treatment with EGFR-tyrosine kinase inhibitor (TKI) shows a durable response against NSCLC harboring EGFR mutation; however, treatment resistance occurs within 1-1.5 years following first-line EGFR-TKIs [first- and second-generation (G) TKIs]. When resistant NSCLC exhibits T790M mutations, osimertinib is the standard therapy. However, intratumoral heterogeneity and clonal evolution may occur in NSCLC. Afatinib may overcome tumor heterogeneity, leading to T790M colonal purity. We aimed to determine whether NSCLC treatment with afatinib followed by osimertinib (afatinib group) provides higher therapeutic efficacy than other 1st-G EFGR-TKIs followed by osimertinib (1st-G group).
This multicenter retrospective study evaluated outcomes between afatinib group and 1st-G group. We analyzed clinical data from NSCLC patients receiving osimertinib after progression following 1st- or 2nd-G EGFR-TKIs between March 28, 2016 and March 31, 2018. Patients with performance status (PS) 0-2 were enrolled to reduce bias of patients' conditions.
We enrolled 111 patients treated with osimertinib. The median age was 69 (range: 39-88) years. Out of 111 patients, 33 (29.7%) were men, 100 (90%) had PS 0-1, and 35 (31.5%) were in the afatinib group. The objective RR and DCR were significantly higher in the afatinib group than in the 1st-G group [82.9% vs. 53.9% (p=0.0065); 91.4% vs. 71.1% (p=0.032)]. The median PFS tended higher in the afatinib group than in the 1st-G group (15.6 vs. 8.9 months, p=0.195).
Afatinib followed by osimertinib may provide better outcomes for T790M-positive NSCLC than 1st-G EGFR-TKIs. Afatinib followed by osimertinib may be a therapeutic option for NSCLC harboring EGFR mutation.