A real-world study of patient characteristics and clinical outcomes in EGFR-mutated lung cancer treated with first-line osimertinib.

Abstract

e21033 Background: Osimertinib is a third-generation mutation-specific covalent tyrosine kinase inhibitor of epidermal growth factor receptor ( EGFR) that is used for first-line therapy in EGFR-mutated non-small cell lung cancer (NSCLC) based on results of the FLAURA trial. We performed a retrospective analysis of baseline characteristics and clinical outcomes in real-world patients treated with osimertinib. Methods: We queried medical records at our NCI-designated cancer center hospital, Beth Israel Deaconess Medical Center (Boston, MA), for patients with unresectable EGFR-mutated NSCLC treated with first-line osimertinib. 56 patients were identified who initiated treatment with osimertinib from October 2017 to February 2021. Patient demographic information, treatment duration and next generation sequencing data were collected. Patients were determined to be FLAURA-eligible or FLAURA-ineligible based on published FLAURA trial inclusion and exclusion criteria. Time to discontinuation (TTD) of osimertinib was defined as months between osimertinib initiation and discontinuation. Median TTD and median OS were calculated. Results: Of the 56 patients included, 34 (61%) were female; 40 (71%) of patients were White, and 16 (29%) were Asian. 14 (25%) patients had an ECOG performance status of 2-4 at time of osimertinib initiation. Regarding EGFR mutation, 32 (57%) had exon 19 deletion and 16 (29%) had exon 21 L858R mutation. 8 (14%) patients had other EGFR mutations (not included in FLAURA) including: G719X, L861Q, and exon 20 insertion. In total, 25 (45%) patients were determined to be FLAURA-eligible, and 31 (55%) were FLAURA-ineligible. The most frequently occurring exclusionary comorbidities were concurrent active malignancy within two years (n = 9), baseline ECG abnormality (n = 9), and uncontrolled hypertension (n = 6). For clinical outcomes, the median TTD for all patients was 16.9 months (95% CI 12.6 – 35.1), whereas the median TTD was 31.1 months (95% CI 14.9 – NR) in the FLAURA-eligible cohort. Median OS for all patients was 32.0 months (95% CI 15.7 – NR) and not reached for the FLAURA-eligible cohort. No individual characteristic was associated with clinical outcomes using regression analysis. Conclusions: We report a single academic center’s experience with real-world osimertinib use in unresectable EGFR-mutated NSCLC – of which 55% of patients would have been ineligible for inclusion in the practice-changing FLAURA trial. Outcomes in the overall cohort (median TTD and OS) were comparable to the median PFS and OS, respectively, reported in the FLAURA study. Outcomes in our real-world FLAURA-eligible patients were better than previously reported. Our data supports the use of osimertinib in real-word settings and highlights the need for designing registration trials that are more inclusive of patient/disease characteristics seen in routine clinical practice.