Abstract 3323: Novel Pan-RAS inhibitor ADT-007: A unique mechanism of antitumor selectivity in pancreatic and colorectal carcinoma models

Abstract Multiple types of RAS mutations activate RAS isoforms, HRAS, NRAS, or KRAS, that drive oncogenic signaling leading to uncontrolled cell proliferation and tumor development. RAS mutations occur de novo in approximately one-third of all human cancers, and are especially prevalent in pancreatic, colorectal, and lung tumors. Where RAS mutations are less frequent in other cancers, such as breast cancer, RAS can be pathologically activated by growth factor receptors that engage numerous downstream effectors. The currently FDA-approved KRAS-targeted drugs are designed to covalently inactivate only G12C KRAS mutants, however, this mutation is only prevalent in lung cancer. The most common mutations in pancreatic ductal adenocarcinoma (PDAC) are KRAS-G12D, KRAS-G12V, and KRAS-G12R. Our novel class of pan-RAS inhibitors, exemplified by ADT-007, addresses the urgent need for pan-RAS inhibitors with antitumor activity in cancers harboring these common mutations. These pan-RAS inhibitors have unique pharmacological properties that allow for selective killing of cancer cells harboring RAS mutations. ADT-007 inhibited growth of an array of carcinoma tumor cell lines in vitro with single digit nM IC50 values regardless of RAS mutant allele, and inhibited RAS activation and MAPK/AKT signaling. Because it is a pan-RAS inhibitor, ADT-007 may not be susceptible to commonly reported mechanisms of resistance to covalent KRAS inhibitors, such as activation of wild type (WT) alleles or secondary RAS mutations. Differentiated normal epithelial or hepatic cells, and tumor cells with WT RAS were insensitive to ADT-007 due to enzymatic detoxification of ADT-007 via glucuronidation, representing a novel mechanism of tumor selectivity. An orally bioavailable prodrug of ADT-007 (ADT-1004) is well tolerated in vivo, and produced sustained concentrations of ADT-007 well above IC50 values in plasma and even higher levels in tumors. Daily oral administration of ADT-1004 significantly inhibited RAS signaling and tumor growth in orthotopic and PDX mouse models of pancreatic cancer. Citation Format: Junwei Wang, Adam B. Keeton, Sindhu Ramesh, Peyton Johnson, Yulia Y. Maxuitenko, Jeremy B. Foote, Chung-Hui Huang, Kristy L. Berry, Khalda Fadlalla, Bandi D. Reddy, Ganji P. Nagaraju, Elmar Nurmemmedov, Ivan Babic, Vadim Gaponenko, Xi Chen, Bassel F. El-Rayes, Donald J. Buchsbaum, Gary A. Piazza. Novel Pan-RAS inhibitor ADT-007: A unique mechanism of antitumor selectivity in pancreatic and colorectal carcinoma models [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 3323.