Abstract 932: Discovery of D-1553, a novel and selective KRas-G12C Inhibitor with potent anti-tumor activity in a broad spectrum of tumor cell lines and xenograft models

Abstract KRas mutations are frequently seen in solid tumors such as lung (~25%), colorectal (~40%) and pancreatic (~90%) cancers. The G12C mutation accounts for ~50% of all KRas mutations in lung cancer and to a lower percentage in other tumor types. Recently, selective inhibitors targeting the KRas-G12C mutation through covalent link to the cysteine of the mutated protein have been advanced to early clinical development and exhibited encouraging response in patients with lung cancer. Here, we present a novel small molecule compound that specifically inhibits KRas-G12C in vitro (cell lines) and in vivo (cell line-derived xenograft tumor models). The anti-tumor activity of D-1553 is evaluated across a panel of cancer cell lines including lung, pancreatic and colorectal cancers and shown to be active only in cancer cells with KRas-G12C mutation. In addition, D-1553 is highly potent in vivo in various cell line-derived xenograft tumor models with KRas-G12C mutation as a single agent. When D-1553 is combined with MEK inhibitor, SHP2 inhibitor or cytotoxic agents, further tumor growth inhibition or regression was observed in tumor xenograft models. These data suggest that D-1553 has anti-tumor activity in a broad spectrum of cancers and is suitable for tissue-agnostic clinical development targeting cancers with KRas-G12C mutation. D-1553 is currently in a Phase 1/2 clinical trial evaluating safety, tolerability, PK and efficacy in patients with advanced solid tumors harboring KRasG12C mutation (NCT04585035). Citation Format: Zhe Shi, Jifang Weng, Xiaochong Fan, Emma Wang, Qingqing Zhu, Liangshan Tao, Zixing Han, Zhenwu Wang, Haotao Niu, Yueheng Jiang, Ling Zhang, Xing Dai, Yaolin Wang. Discovery of D-1553, a novel and selective KRas-G12C Inhibitor with potent anti-tumor activity in a broad spectrum of tumor cell lines and xenograft models [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr 932.