Abstract 4904: Glutamine antagonist DRP-104 enhances anti-tumor responses in KEAP1 mutant lung cancer

Abstract

Abstract KEAP1 is mutated in approximately 20% of non-small cell lung cancer (NSCLC) and is associated with poor response rates to checkpoint blockade. Given the therapeutic challenge presented by KEAP1 mutant tumors and the great potential held by immunotherapeutic approaches, there is an urgent need to identify the mechanisms that mediate immune evasion in patients with KEAP1 mutant lung adenocarcinoma. We previously demonstrated that metabolic rewiring in KEAP1 mutant tumors leads to increased dependency on glutamine as a substrate for multiple anabolic pathways. DRP-104 (Sirpiglenastat) is a novel glutamine antagonist which inhibits all glutamine consuming reactions. Using pre-clinical mouse models and patient derived xenograft models we demonstrate that DRP-104 robustly impairs the growth of KEAP1 mutant tumors. Furthermore, using an immunocompetent orthotopic lung adenocarcinoma mouse model we find that treatment with DRP-104 increases survival of Keap1 mutant tumor bearing mice treated with anti-PD1 therapy. We have dissected the mechanism by which DRP-104 impacts KEAP1 mutant tumors and the surrounding immune microenvironment. Notably, DRP-104 impairs nucleotide synthesis in KEAP1 mutant tumors and thereby inhibits cancer cell growth. In addition, DRP-104 reduces exhausted T cell and T regulatory populations within the tumor microenvironment as well as increases effector T cell function. Overall, we find that DRP-104 impairs the growth of KEAP1 mutant tumors through both targeting of tumor intrinsic metabolic vulnerabilities and through tumor extrinsic immunostimulatory mechanisms such as promoting the expansion of functional anti-tumor T cell populations. This data provides additional rationale for the ongoing phase I/II clinical trial (NCT04471415) using DRP-104 in NSCLC with mutations in KEAP1 as well as for combining DRP-104 with checkpoint blockade. Citation Format: Ray Pillai, Sarah LeBoeuf, Ali Rashidfarrokhi, Shih Ming Huang, Triantafyllia Karakousi, Anastasia-Maria Zavitsanou, Warren Wu, Volkan Sayin, Robert Wild, Sergei Koralov, Thales Papagiannakopoulos. Glutamine antagonist DRP-104 enhances anti-tumor responses in KEAP1 mutant lung cancer. [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 4904.