RET testing and treatment patterns among patients with aNSCLC in US clinical practice.

Abstract

9091 Background: Biomarker testing, including for rearrangement during transfection (RET), is recommended and important in selecting efficacious targeted therapy for patients with advanced non-small cell lung cancer (aNSCLC). This retrospective cohort study characterized RET testing and treatment patterns among aNSCLC patients in clinical practice. Methods: We used the nationwide Flatiron Health electronic health record-derived de-identified database to select patients diagnosed with aNSCLC (stage ≥IIIB) from 2017-2022. We measured rates of RET testing (test result ≤90 days after advanced diagnosis). We used logistic regression to identify baseline characteristics predictive of timely testing. Finally, we described treatment patterns for patients with RET+ aNSCLC before and after the US approval of RET inhibitors. Results: Among 26,329 aNSCLC patients, rates of RET testing ≤90 days after advanced diagnosis increased from 25% (2017 Q1) to 73% (2022 Q1). Patients were less likely to receive RET testing within 90 days if they were Black (multivariate odds ratio [OR] 0.8) or Hispanic (OR 0.8) compared to White, or had Medicare (OR 0.9; all p<0.001) compared to commercial insurance. Patients were more likely to receive RET testing within 90 days if they were in the highest socioeconomic quintile (OR 1.4), had de novo disease (OR 2.1), or no history of smoking (OR 1.3; all p<0.001). Between 2017 and 2022, there were increases in the use of next-generation sequencing (66% to 89%) and blood samples for biomarker testing (25% to 49%) and a decrease in mean days from diagnosis to test result (33 to 28) for the first RET test among those who had testing within 90 days. Among all patients with aNSCLC tested within 90 days (n=12,275), 73 were RET+ and received 1L treatment ≤90 days after advanced diagnosis. The most common 1L treatments before (n=35) and after (n=38) RET inhibitor approval were chemotherapy (40%) and RET inhibitor (42%), respectively (Table). Conclusions: RET testing has increased over time, but certain patient subgroups are less likely to receive timely RET testing and therefore may not be optimally treated. Among patients with RET+ aNSCLC identified after RET inhibitor approval, only 42% were treated with a RET inhibitor in the 1L setting. These results suggest both disparities in access to RET testing and unmet medical need among patients with RET+ aNSCLC. [Table: see text]