26P Prognostic factors and outcomes of patients (Pts) with advanced NSCLC while on osimertinib (Osi) treatment (Tx): A retrospective database study

Osi is a 3rd-generation EGFR TKI indicated for 1st- (1L) and 2nd-line (2L) treatment of adult pts with advanced NSCLC with common EGFR mutations (cEGFRm; exon 19 deletions ex19del or exon 21 L858R mutations). Not all patients benefit from osi Tx, and most eventually develop resistance. There are currently few approved targeted Tx for cEGFRm NSCLC. Here we characterise pt profiles with cEGFRm NSCLC to describe the population and existing unmet medical need. This retrospective study uses data from the Epidemiological Strategy and Medical Economics (ESME; France) and the Rigshospitalet (RH; Denmark) databases. Eligible pts were adults with histologically confirmed primary cEGFRm NSCLC who were prescribed 1L or 2L osi. The primary objective was to describe pt profiles and outcomes and identify characteristics that are potential prognostic factors for overall survival (OS), progression-free survival (PFS), time to next therapy (TNT), and time to treatment discontinuation (TTD). Current results are from 624 pts from ESME; analysis of 127 pts from RH is ongoing: median age at diagnosis, 68.5 y; 73.4% female; 42.0% and 58.8% had L858R and ex19del, respectively. Of the 198 pts that received 1L osi, 24% died before 2L and 34% had subsequent Tx. Of the 426 who received 2L osi, 30% died before 3L and 47% had subsequent Tx. Among pts receiving subsequent Tx after 1L or 2L osi, the most common Tx was platinum-based chemo (1L, 34%; 2L, 45%). For 1L osi, median OS, PFS, TNT, and TTD were 27.0, 12.4, 19.5, and 17.6 mo, respectively. For 2L osi, median OS, PFS, TNT, and TTD were 18.6, 7.4, 11.9, and 11.5 mo, respectively. In both 1L and 2L, OS and PFS are substantially lower than those reported in clinical trials. While different sets of prognostic factors were observed for different outcomes and lines, ECOG performance and presence of L858R mutation were consistently prognostic across all settings. This retrospective analysis based on real-world data on 1L and 2L osi efficacy confirms the poor outcomes with osi shown in clinical trials, with 24% of pts with 1L osi dying before receiving a 2L Tx. These results highlight the unmet need for new Tx options in cEGFRm NSCLC.