Abstract 6754: Clinical characteristics, real-world treatment patterns, and clinical outcomes among patients with previously treated metastatic or unresectable EGFR-mutated non-small cell lung cancer in the United States

Abstract Background: A consensus on preferred treatment for patients with EGFR-mutated (EGFRm) advanced or metastatic non-small-cell lung cancer (a/mNSCLC) who have progressed on osimertinib and platinum-based chemotherapy (PBC) has yet to be established. The study objectives were to describe patient characteristics and treatment patterns in this context and assess corresponding clinical outcomes in the US real-world setting. Methods: This study was a retrospective analysis of data sourced from Flatiron’s de-identified database, which included electronic health records and curated cancer data from approximately 280 US cancer clinics (~800 US sites of care). The index line of therapy (LOT) was defined as initiation of a new treatment regimen after osimertinib and PBC. Adults were eligible for inclusion if they: 1) were diagnosed with a/mNSCLC on or after January 1, 2011; 2) had evidence of an activating EGFR mutation (exon 19 or L858R); 3) initiated a new LOT between November 13, 2015, and June 30, 2021, after treatment with osimertinib and PBC. Treatment regimens in the index LOT were summarized, and real-world overall survival (rwOS, defined as the time from initiation of index LOT to death) and real-world progression-free survival (rwPFS, defined as the time from initiation of index LOT to disease progression or death) were assessed. Results: Among 273 study patients included, the majority were ≥65 years (57%), female (67%), Caucasian (65%; Asian, 17%; Black or African American, 6%), with no history of smoking (58%), performance status 0-1 (82%), and >2 prior LOT (64%). Median follow-up duration was 7.3 months. Index treatment regimens were classified as tyrosine kinase inhibitor (TKI) monotherapy (15%) or TKI in combination with non-immuno-oncologic agents (12%), non-platinum-based chemotherapy (23%), immuno-oncologic monotherapy (17%) or combination therapy (15%), PBC (12%), a regimen containing a clinical study drug (4%), or other NSCLC therapy (1%). Deaths occurred in 203 patients (74%) during follow-up; median rwOS was 8.6 months (95% confidence interval [CI], 7.4-9.8). Real-world progression occurred in 235 patients (86%); median rwPFS was 3.3 months (95% CI, 2.8-4.4). Conclusions: For patients with EGFRm a/mNSCLC, third-generation EGFR TKIs such as osimertinib can provide disease control, however progression is common. After disease progression, chemotherapy is often the next treatment of choice. Results of this real-world study show that treatment patterns after EGFR TKI and PBC are highly variable and suggest poor clinical outcomes, highlighting the need for more efficacious treatments among patients with previously treated a/mNSCLC. Citation Format: Jyoti D. Patel, Jie Meng, Sudarshan Phani, Aaron Crowley, Summera Zhou, Maribel Salas, Yoko Tanaka, Hoa Le, Jeffrey Anderson, Karen L. Reckamp. Clinical characteristics, real-world treatment patterns, and clinical outcomes among patients with previously treated metastatic or unresectable EGFR-mutated non-small cell lung cancer in the United States. [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 6754.