Abstract 2174: Sirpiglenastat (DRP-104), a novel broad acting glutamine antagonist, has therapeutic potential in targeting KEAP1-mutant lung cancer

Abstract

Abstract Treating KRAS mutant lung adenocarcinoma (LUAD) remains a major challenge for clinical oncology. Approximately 20% of KRASmutant LUAD tumors carry loss-of-function mutations in KEAP1, a negative regulator of NRF2, which is the master transcriptional regulator of the endogenous antioxidant response. Emerging clinical studies demonstrate that KEAP1-mutant tumors are refractory to standard-of-care chemotherapy, immunotherapy, radiation and more recently KRASG12C inhibitors. Using a genetically engineered mouse model of KRAS-driven LUAD we demonstrated that loss of Keap1 hyper-activates Nrf2 and accelerates KRAS-driven LUAD. We observe that the ability of KEAP1 mutant tumors to divert their metabolism towards antioxidant production comes with a cost, generating multiple metabolic vulnerabilities, including a dependency on glutamine metabolism that can be therapeutically exploited through the pharmacological inhibition of glutaminase and other glutamine metabolizing enzymes. Using sirpiglenastat (DRP-104), a novel broad acting glutamine antagonist which inhibits all glutamine-consuming reactions, we demonstrate robust anti-tumor efficacy in multiple mouse and human pre-clinical KEAP1-mutant NSCLC models. Furthermore, we have characterized the metabolic mechanisms underlying DRP-104 sensitivity. Our studies demonstrate that DRP-104 has a distinct and broader mechanism of action compared to glutaminase selective inhibition, suggesting broader inhibition of glutamine metabolism may be a more effective therapeutic approach against KEAP1-mutant tumors. We have recently demonstrated that KEAP1-mutant tumors evade anti-tumor immune responses and do not respond to immune checkpoint blockade, which is also supported by clinical observations. We are currently assessing whether DRP-104 is able to promote anti-tumor immune responses as a single agent or in combination with immune checkpoint blockade in KEAP1-mutant tumors. Our studies will provide a rationale for sub-stratification of KEAP1-mutant patients with hyperactivation of the NRF2 pathway, which is a genetic subset of NSCLC with great clinical need, as treatment candidates for sirpiglenastat. A first-in-human clinical trial of sirpiglenastat (DRP-104) is currently ongoing and will further explore this hypothesis in a LUAD cohort (NCT04471415). Citation Format: Sarah LeBoeuf, Ray Pillai, Shih Ming Huang, Triantafyllia Karakousi, Warren Wu, Volkan Sayin, Robert Wild, Thales Papagiannakopoulos. Sirpiglenastat (DRP-104), a novel broad acting glutamine antagonist, has therapeutic potential in targeting KEAP1-mutant lung cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 2174.