Abstract 4502: Design, synthesis, and evaluation of next-generation EGFR degraders to overcome osimertinib-resistance

Abstract The occurrence of C797S mutation in epidermal growth factor receptor (EGFR) is a leading mechanism of clinically acquired resistance to third-generation EGFR inhibitors, including Osimertinib. L858R/T790M/C797S and del19/T790M/C797S are commonly observed tertiary EGFR mutants identified in Osimertinib-resistant tumors. As of now, no clinically approved treatment exists that specifically targets these mutants. Here, we report the design and synthesis of a series of highly effective next-generation EGFR degraders effectively degrading EGFR C797S-containing triple mutants. Most compounds demonstrated antiproliferation activity in the subnanomolar range when tested on Ba/F3L858R/T790M/C797S and del19/T790M/C797S cells. Not only C797S but our designed degraders also degraded a wide range of EGFR mutants, including Exon19Del and L858R/T790M (DC50 <100nM). One representative Compound, HDBNJ2812, strongly degrades L858R/T790M/C797S and del19/T790M/C797S with DC50 of 34 nM (Dmax 88.5%) and 14 nM (Dmax 99.7%), respectively. This compound potently inhibits the proliferation of Ba/F3L858R/T790M/C797S (GI50 64 nM) and del19/T790M/C797S (GI50 40 nM). HDBNJ2812 demonstrated high inhibitory potential on HCC827 (del19) and H1975 (L858R/T790M) cell lines (GI50 18.9 and 85 nM, respectively). Furthermore, this degrader demonstrates weak cytotoxicity on non-mutant EGFR-expressing cells, such as A431, WI-26 (human lung fibroblast cells), and CHO-K1 (Chinese hamster ovary cells). Additionally, the in vivo PK/PD findings complement this compound's potential to be considered further. HDBNJ2812 may serve as a lead compound to render the greater therapeutic window for treating resistant non-small cell lung cancer patients with EGFR C797S mutants. Citation Format: Mohammad Hassan Baig, Juhan Bok, Dongmin Kim, Sagar Dattatraya Nale, Yun Sung Jo, Changjoong Kim, Taehhwan Park, Jaejune Dong, Byoung Gon Moon. Design, synthesis, and evaluation of next-generation EGFR degraders to overcome osimertinib-resistance [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 4502.