1001P Epidermal growth factor receptor (EGFR) testing and treatment patterns associated with diagnosis of non-small cell lung cancer (NSCLC) with EGFR exon 20 insertions (ex20ins) in the US

Abstract

With new targeted therapies approved for patients with NSCLC with EGFRex20ins, it is important to understand real-world diagnosis and treatment choice, as these mutations are associated with poor prognosis and require tailored treatment. The Flatiron Health electronic health record database was used to identify 75,067 patients with advanced NSCLC from 01/01/2011 to 12/31/2021. EGFR testing rates and proportion of tests done with next-generation sequencing (NGS) were described for all patients. First-line (1L) treatments were described for patients with EGFRex20ins(+) results in the last 5 years (2017-2021), stratified by initiation of 1L before or after EGFRex20ins(+) testing result. Overall, 67% of patients were tested for EGFR mutations (n=51,470). EGFR testing rates and the proportion of tests done with NGS increased from 2011 to 2021 (44.4 to 80.7% and <1.0 to 81.0%, respectively). Among patients with EGFRex20ins(+) results 2011-2017 (n = 250), 59 (24%) started 1L treatment prior to and 141 (56%) started 1L after their first EGFRex20ins(+) (50 were unknown). A higher proportion of patients received EGFR TKIs or were enrolled in clinical trials, and a lower proportion received chemotherapy if they started 1L treatment after their first EGFRex20ins(+) result, when compared to patients who started 1L treatment before. Similar proportions of patients were treated with IO monotherapy or IO + chemotherapy regardless of when treatment was started (table).Table: 1001P1L treatments in patients with EFRex20ins 2017-2021Started treatment before EGFRex20ins (+) result n (%)Started treatment after EGFRex20ins (+) result n (%)n = 59n = 141Chemotherapy27 (45.8)36 (25.5)IO monotherapy5 (8.5)16 (11.3)IO + chemotherapy21 (35.6)44 (31.2)EGFR TKI4 (6.8)32 (22.7)Clinical Trial1 (1.7)12 (8.5)Other1 (1.7)1 (0.7) Open table in a new tab EGFR testing increased over time; however, 20% of patients still remained untested in 2021. Among patients with EGFRex20ins mutations, a high proportion of patients started IO or EGFR TKIs after genetic testing despite limited effectiveness in this population. With the recent approval of therapies targeting EGFRex20ins mutations, increased testing and awareness of treatment outcomes in this population are needed.