Real-world efficacy of osimertinib in previously EGFR-TKI treated NSCLC patients without identification of T790M mutation

The efficacy of osimertinib in previously EGFR-TKI-treated NSCLC without identification of T790M mutational status remains unclear in real-world practice.

417 patients had stage III–IV NSCLC harboring EGFR mutation and 154 out of 417 patients receiving osimertinib as ≥ second-line EGFR-TKI were identified. The time to treatment failure and risk of death were analyzed.

Higher risk of death was found in EGFR-mutant patients with age ≥ 65 years, non-adenocarcinoma, no surgery or radiation, non-exon 19 deletion/exon 21 L858R, higher ECOG PS (2–4), PD-L1 expression ≥ 50%, and bone/liver/adrenal metastasis (all p < 0.05). Osimertinib as ≥ second-line TKI in patients with/without identification of T790M revealed lower risk of death compared to first-line first/second generation TKI without subsequent osimertinib (p = 0.0002; 0.0232, respectively). However, osimertinib-treated patients with T790M did not have superior survival than those without (p = 0.2803). A higher risk of treatment failure for osimertinib was found in males, patients with first-line TKI duration ≤ 12 months, BMI drop > 10%, and PD-L1 expression ≥ 50% (All p < 0.05). Nonetheless, osimertinib as ≥ second-line TKI in patients without identification of 790 M did not have higher risk of treatment failure than those with T790M (p = 0.1236).