1558P - Biomarker status as a mediator of age-related overall survival (OS) in advanced non-small cell lung cancer (aNSCLC)

Abstract

BackgroundRisk models for NSCLC have identified age as a prognostic factor, but the relevance of molecular biomarkers to age-related outcomes is undefined. We explored the prevalence of biomarkers by age group and the impact of biomarker status on age-related differences in OS among aNSCLC patients (pts) in a real-world population. MethodsPts with stage IIIB, IV or recurrent metastatic NSCLC (diagnosed 1/1/11 to 11/30/18) were identified in a US-based, EHR-derived, deidentified database (Flatiron Health). Cox proportional hazard regressions evaluated OS by age at aNSCLC diagnosis (dx) (< vs≥50 years), controlling for gender, histology, race, stage, dx year, smoking status, visit site, region and PDL1 status. Sequential and subgroup regressions modeled ALK+, EGFR+ and ROS1+ biomarker status as mediators of the age effect on OS. ResultsOur sample included 41,024 pts (median age 69 years); median OS was 11 months. Pts <50 years lived longer than pts ≥50 years (HR: 0.83; p<0.001). Molecular testing and positive results for ALK, EGFR and ROS1 were higher in age <50 (Table); this finding was maintained for non-squamous pts (p≤0.001). Within ALK+, EGFR+ or ROS1+ subgroups, age was not associated with OS. Sequential variable analysis found 35% of the association between age and OS may be explained by ALK, EGFR and ROS1 biomarker status. ConclusionsYoung aNSCLC pts have longer OS than older pts; this benefit is significantly mediated through biomarker status. Pts with mutations had similar OS regardless of age group. As older pts are tested less often and have a lower prevalence of mutations, future work should explore whether increased testing in older pts may mitigate the age-related OS disparity.Table1558P Baseline characteristics by age at aNSCLC Dx*TableAll, n (%) N=41,024< 50 y, n (%) n=1381≥50 y, n (%) n=39,643Female19,301 (47)716 (52)18,585 (47)Non-squamous histology28,203 (69)1092 (79)27,111 (68)Non-smoker4723 (12)323 (23)4400 (11)ALK tested23,618 (58)948 (69)22,670 (57)ALK+†625 (2.6)106 (11)519 (2.3)EGFR tested25,276 (62)1000 (72)24,276 (61)EGFR+†3009 (12)162 (16)2847 (12)ROS1 tested12,310 (30)514 (37)11,796 (30)ROS1+†113 (0.92)12 (2.3)101 (0.86)*All age comparisons p<0.001;†among tested Legal entity responsible for the studyFlatiron Health. FundingFlatiron Health. DisclosureA.B. Cohen: Shareholder / Stockholder / Stock options, Full / Part-time employment: Flatiron Health, an independent subsidiary of Roche; Shareholder / Stockholder / Stock options: Roche. B.D.A.P. Neri: Shareholder / Stockholder / Stock options, Full / Part-time employment: Flatiron Health, an independent subsidiary of the Roche group. B.J.S. Adamson: Full / Part-time employment, Provisional patent filed: Flatiron Health, an independent subsidiary of Roche; Non-remunerated activity/ies, Provisional patent filed: University of Washington; Research grant / Funding (self): American Foundation for Pharmaceutical Education; Research grant / Funding (institution): PhRMA Foundation; Leadership role: International Society for Pharmacoeconomics and Outcomes Research; Advisory / Consultancy: Salutis Consulting; Advisory / Consultancy: Fred Hutchinson Cancer Research Center; Advisory / Consultancy: Institute for Disease Modeling, Intellectual Ventures; Advisory / Consultancy: Boston Scientific; Shareholder / Stockholder / Stock options: Roche. C.M. Scanlon: Shareholder / Stockholder / Stock options, Full / Part-time employment: Flatiron Health, an independent subsidiary of Roche. C. Gross: Honoraria (self), Travel / Accommodation / Expenses: Flatiron Health, Inc., which is an independent subsidiary of the Roche Group; Research grant / Funding (institution): Pfizer; Research grant / Funding (institution): Johnson & Johnson. N.J. Meropol: Shareholder / Stockholder / Stock options, Full / Part-time employment: Flatiron Health, Inc., which is an independent subsidiary of the Roche Group; Shareholder / Stockholder / Stock options: Roche. R.A. Miksad: Shareholder / Stockholder / Stock options, Full / Part-time employment: Flatiron Health, Inc., which is an independent subsidiary of the Roche Group; Shareholder / Stockholder / Stock options: Roche; Advisory / Consultancy: De Luca Foundation.