Median TOTs on afatinib and osimertinib were 15.0 months (95% CI:14.0 - 16.1) and 11.9 months (95% CI:8.9 - 14.6), respectively. The median OS in the osimertinib group was 54.3 months (95%CI:46.7 - 61.9), much longer than that in the comparator group. In patients who received osimertinib, the OS was longest with Del19+ (median 59.1, 95% CI:48.7 - 69.5)...This is one of the largest real-world studies reporting the encouraging activity of sequential afatinib and osimertinib in Asian patients with EGFR+ NSCLC who acquired the T790M mutation, particularly Del19+.

...patients with EGFRm+ (Del19, L858R) NSCLC who had T790M+ disease after first-line afatinib and then received osimertinib...median TTF was 37.1 months (90% CI: 28.1–40.3) and median OS was 44.8 months (90% CI: 37.0–57.8) in Asian patients (overall global study population: median TTF 27.7 months [90% CI: 26.7–29.9], median OS 37.6 months [90% CI: 35.5–41.3]). Clinical benefit was particularly encouraging in Asian patients with Del19-positive disease (n=31): median TTF 40.0 months (90% CI: 36.4–45.0), median OS 45.7 months (90% CI: 38.2–57.8). Median TTF and OS were 38.2 months (90%: 28.9–40.3) and 44.8 months (90% CI: 38.2–57.8), respectively, in Asian patients who received a starting dose of afatinib 40 mg (n=46), and 36.4 months (90% CI: 28.1–41.7) and 41.3 months (90% CI: 36.9–57.8),...sequential afatinib and osimertinib is effective, particularly in Asian patients with EGFRm+ NSCLC who develop T790M. Median OS was nearly 4 years in those with Del19+ disease...

Sequential afatinib/osimertinib was associated with encouraging OS/TTF in patients with EGFR T790M-positive non-small-cell lung cancer, especially in patients with Del19-positive tumors.