Real-world data on treatment outcomes in EGFR-mutant non-small-cell lung cancer patients receiving osimertinib in second or further lines.

Lay abstract Osimertinib is an oral drug that inhibits the growth of non-small-cell lung cancer (NSCLC) tumors with a specific mutation in EGFR. Osimertinib is given to patients with advanced EGFR-mutant NSCLC as initial therapy or after the failure of prior first- or second-generation tyrosine kinase inhibitors in patients who develop the EGFR T790M resistance mutation. Real-world data about the efficacy of EGFR-mutant NSCLC patients receiving osimertinib are needed to confirm the findings of large randomized clinical trials. Most real-world studies have investigated outcomes in Asian populations. This study aims to describe outcomes in EGFR T790M-positive patients receiving osimertinib after the failure of first- or second-generation tyrosine kinase inhibitors, compared with T790M-negative patients receiving a systemic treatment, in a Caucasian population. In addition, the study aims to describe how the disease spreads once it starts progressing again and any subsequent treatment lines. 167 patients were included. The results of this study suggest that EGFR T790M-positive patients receiving osimertinib as second- or further-line treatment had better outcomes and a more limited progression compared with T790M-negative cases.