P76.94 Survival Analyses and Molecular Predictors of Outcomes in Patients Treated with Osimertinib for Metastatic NSCLC Harboring EGFR Mutation

Tyrosine kinase inhibitors (TKI) are the cornerstone targeted therapy for metastatic non-small cell lung cancer (NSCLC). This retrospective study was undertaken to investigate impact of third generation epidermal growth factor receptor (EGFR)-TKI, Osimertinib, on two most frequent EGFR mutations, exon 21-L158R and 19-deletion, encountered in NSCLC. The primary objective evaluate potential differences overall survival (OS) disease-free (DFS) between patients harboring 21-L858R mutation 19 deletion when treated with Osimertinib. From January 2010 December 2018, consecutive NSCLC-EGFR Osimertinib 80 mg once daily, were analyzed. Retrospective data extracted through electronic medical records located at Sunnybrook Health Sciences Centre. All had positivity by cytology, plasma or tissue sampling. A total 56 included. median age initial diagnosis 65 years old (range 27 – 85 years). similar percentage 46.42% (n=26) an 19-deletion. 7.1% (n=4) either uncommon type location gene modification unknown. majority, 76.7% (n=43), T790m positive, 8.9% (n=5) negative, 14.2% (n=8) unknown status. For those who mutation, 46.4% (n=24) positive 28.5% biopsy. Only 16% (n=9) received first-line setting 84% (n=47), as second-line beyond. 50% (n = 28) this cohort brain metastases. Among DFS 15.2 months (95% confidence interval [CI] 11.3 - 19.0 months) 14.2 19-deletion [CI], 6.0 22.4 months); p= 0.25. OS 52.6 group 35.4 69.7 49.6 25.6 73.6 0.58. Although is a heterogeneous disease variable responses EGFR-targeted drugs, our did not show difference common mutations larger population further investigation needed.