Real-world EGFR testing patterns among U.S. patients with advanced NSCLC.

Abstract

298 Background: Guidelines recommend mutation testing prior to initiating first-line therapy (L1) for patients with advanced non-small cell lung cancer (aNSCLC), including testing for epidermal growth factor receptor (EGFR) mutations. Guidelines also recommend further testing after patients progress on targeted therapy to identify possible resistance mutations and inform selection of subsequent treatment. The present study characterized real-world (RW) EGFR testing patterns in aNSCLC patients. Methods: This retrospective observational cohort study evaluated an aNSCLC cohort (stage IIIB or higher) from the Flatiron Health database. Eligible patients were newly diagnosed, ≥18 years old, and received at least one line of therapy (LOT) during 2015-2020. Patients were followed to last activity, death, or end of the study period, whichever came first. Results: The final study cohort included a total of 22,726 patients. Of these, 17,165 (75.5%) had ≥1 EGFR test and 2,611 (15.2% of the tested study population) tested positive for EGFR mutations at any time during the study. The proportion of aNSCLC patients receiving EGFR testing prior to L1 initiation increased from 45.2% in 2015 to 56.6% in 2020. Among 11,791 patients who had an EGFR test prior to initiation of L1, 1,944 (16.5%) had positive results. Of these, the cumulative proportion of patients receiving a second EGFR test prior to L2, L3, and L4 (contingent on receiving the following LOT) was 36.3% (322 out of 888), 55.4% (241 out of 435), and 67.0% (146 out of 218), respectively. From 2015-2020, the median time from sample collection to EGFR test results decreased from 26 to 16 days for next generation sequencing (NGS) tests and from 17.5 to 12 days for polymerase chain reaction (PCR) tests. During this same period, the proportion of NGS EGFR tests increased from 27.6% to 75.0%. In addition, use of plasma samples for EGFR tests increased substantially (6.3% to 36.5%). Conclusions: The proportion of aNSCLC patients tested for EGFR mutations has increased over time (2015-2020). Median time to available EGFR test result has decreased for both NGS and PCR tests. NGS testing has become increasingly more common as has use of plasma samples. However, opportunities for improvement exist, including further increasing the proportion of patients tested prior to initiation of L1 therapy, as well as testing prior to the selection of subsequent therapy when indicated. As more targeted therapies emerge and resistance mutations to current therapies are further characterized, continued refinement of RW testing practices is required to optimize patient care.