Purpose@#Although osimertinib is the standard-of-care
treatment of
epidermal growth factor receptor (EGFR) T790M
mutation –positive non–
small cell lung cancer , real-world evidence on the
efficacy of osimertinib is not enough to reflect the complexity of the entire
course of
treatment . Herein, we
report on the use of osimertinib in
patients with EGFR T790M
mutation –positive non–
small cell lung cancer who had previously received EGFR
tyrosine kinase inhibitor (TKI)
treatment in
Korea . @*Materials and
Methods @#
Patients with confirmed EGFR T790M after
disease progression of prior EGFR-TKI were enrolled and administered osimertinib 80 mg daily. The primary
effectiveness outcome was
progression-free survival , with
time-to-treatment discontinuation,
treatment and
adverse effects leading to
treatment discontinuation, and overall
survival being the
secondary endpoints. @*Results@#A total of 558 individuals were enrolled, and 55.2% had
investigator -assessed responses. The median
progression-free survival was 14.2 months (95%
confidence interval [CI], 13.0 to 16.4), and the median
time-to-treatment discontinuation was 15.0 months (95% CI, 14.1 to 15.9). The median overall
survival was 36.7 months (95% CI, 30.9 to not reached). The benefit with osimertinib was consistent regardless of the age,
sex ,
smoking history , and primary EGFR
mutation subtype. However, hepatic
metastases at the
time of
diagnosis , the presence of
plasma EGFR T790M, and the shorter duration of prior EGFR-TKI
treatment were poor predictors of osimertinib
treatment . Ten
patients (1.8%), including three with
pneumonitis , had to discontinue osimertinib due to severe
adverse effects . @*Conclusion@#Osimertinib demonstrated its
clinical effectiveness and
survival benefit for EGFR T790M
mutation –positive in Korean
patients with no new
safety signals.