Value of Precision Medicine in AdvancedNon-SmallCell Lung Cancer:Real-WorldOutcomes Associated with the Use of Companion Diagnostics

Background Companion diagnostic (CDx) testing for patients with advanced non-small cell lung cancer (aNSCLC) identifies patients more likely to benefit from biomarker-driven treatments. Methods Patients with nonsquamous cell (non-Sq) aNSCLC from the Flatiron Health database (diagnosed January 1, 2011-May 31, 2018) who had CDx testing were compared with those who had no reported evidence of testing. The association between CDx testing and overall survival was evaluated by unadjusted and adjusted Cox proportional hazards regression models. Logistic regression analysis identified characteristics associated with CDx testing. The revised modified Lung Cancer Prognostic Index and other factors identified a priori were included in the adjusted models. Results A total of 17,555 patients with non-Sq aNSCLC (CDx,n= 14,732; no CDx,n= 2,823) with mean +/- SD age of 67.2 +/- 10.0 years were included. Most were insured (91.7%) and white (67.1%). Asian patients and those who were never-smokers were more likely to undergo CDx testing. Those with CDx testing lived longer than those without (median [95% confidence interval (CI)] survival, 13.04 [12.62-13.40] vs. 6.01 [5.72-6.24] months) and had a decreased mortality risk (adjusted hazard ratio [95% CI], 0.72 [0.69-0.76]). A survival advantage was also seen for patients with CDx testing who received biomarker-driven first-line therapy. Conclusion Patients with non-Sq aNSCLC who had CDx testing had a greater survival benefit than those without, supporting broader use of CDx testing in routine clinical practice to identify patients more likely to benefit from precision medicine. Implications for Practice Companion diagnostic (CDx) testing coupled with biomarker-driven treatment offers a greater survival benefit for patients with advanced non-small cell lung cancer (aNSCLC). In this study, patients with nonsquamous aNSCLC from Flatiron Health, a large, real-world oncology database, with CDx testing had a reduced mortality risk and lived longer than patients without reported evidence of CDx testing; those who received biomarker-driven therapy as their first line of treatment were likely to survive three times longer than those who did not. These results demonstrate the clinical utility of CDx testing as the first step in treating nonsquamous aNSCLC in real-world clinical practice.