Abstract 592: A novel pMEK inhibitor ABM-4095 for the treatment of pancreatic cancer

Abstract

Abstract The MEK-ERK pathway is often activated in tumors by mutations of upstream BRAF- or RAS-proteins. The RAS is frequently mutated in several cancers, especially in pancreatic cancer with an about 95% rate. Pancreatic cancer has the highest mortality rate with a 5-year survival rate of 8% and a median survival of 6 months. Targeted therapies have been extensively evaluated in pancreatic cancer, however, survival improvement of this aggressive disease using a targeted strategy has been minimal. The only currently approved targeted therapy is erlotinib in combination with the chemotherapy drug gemcitabine. To date, four MEK inhibitors that block RAF-activation have been approved by the FDA, but their ability to inhibit ERK signal activated by RAS-mutations is limited due to the induction of MEK phosphorylation by relief of ERK-dependent feedback inhibition of RAF. Here, we report a novel small molecule, ATP-uncompetitive, pMEK inhibitor ABM-4095 that potently prevents phosphorylation of MEK by RAF with moderate inhibition of MEK kinase activity. Most of MEK inhibitors approved by FDA or in clinical trials increase pMEK levels instead. ABM-4095 has a good cell permeability. Its anti-cancer efficacy has been demonstrated both in the in vitro cancer cell line proliferation assay and in vivo xenograft models. ABM-4095 showed a synergy effect with erlotinib in pancreatic cancer cells. In a Miapaca-2 xenograft model, ABM-4095 showed good dose-dependent tumor inhibition as a single agent or combining with the KRAS G12C inhibitor AMG-510, and tumor regressions were observed. In summary, ABM-4095 is a potent pMEK inhibitor with a high activity against the RAS-mutant pancreatic cancer in vitro and in vivo. Detailed preclinical results will be presented. Citation Format: Min Xu, Yong Hu, Lanjiao Zhao, Xiuquan Chen, Youqin Chen, Chen Yang, Jizhi Li, Chen Chen, Xiaobing Lv. A novel pMEK inhibitor ABM-4095 for the treatment of pancreatic cancer [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 592.