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

Aims: This study describes real-world outcomes of pretreated EGFR T790M-positive (T790M(+)) advanced non-small-cell lung cancer patients progressing after first- or second-generation tyrosine kinase inhibitors and receiving osimertinib, compared with T790M-negative (T790M(-)) patients. We have also described progression patterns and treatment sequences. Patients & methods: This is a retrospective multicenter Italian observational study including consecutive Caucasian patients referred between 2014 and 2018. Results: 167 patients were included. Median progression-free survival was 9.8 months (95% CI: 8.3-13.3) for T790M(+) and 6.0 months (95% CI: 4.9-7.2) for T790M(-) patients, respectively. Median overall survival was 20.7 months (95% CI: 18.9-28.4) for T790M(+) and 10.6 months (95% CI: 8.6-23.6) for T790M(-) patients, respectively. The T790M mutation correlated with absence of new sites of disease. After progression, most T790M(+) patients continued osimertinib, whereas most T790M(-) patients received a different treatment line. Conclusion: Better outcomes were shown in patients receiving osimertinib. A more limited progression pattern for T790M(+) was suggested.Lay abstractOsimertinib 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