Abstract 3400: TY-2136b, a next generation ROS1/TRK/ALK inhibitor, potently inhibits kinase and cell proliferation activities of tumor cells bearing drug-dependent acquired mutations
Authors: Niu Chengshan , Liang Apeng , Dou Yuge , Ji Kaige , Li Meihua , Zhao Yanchao , Zhang Yan , Guo Zhongwei , Gong Aishen , Jiang Mingyu , Chen Shaoqing , Chen Xiugui , Li Jun , Wu Yusheng 
Published: April 2023

Abstract
Although tyrosine kinase inhibitors (TKIs) with activity against ALK, ROS1, or TRKA-C have significantly improved clinical benefits in patients with diverse tumors harboring ALK, ROS1, or NTRKs rearrangements, drug resistance will be developed and subsequent therapy overcoming acquired resistance remains limited. The resistance is mainly caused by the adaptive mutations evolved in the structural region of ROS1/TRK/ALK kinases, especially solvent front substitutions such as ROS1 G2032R/TRKA G595R/ALK G1202R mutations. Next-generation TKIs targeting these mutations could potentially address this unmet medical need. Currently, several inhibitors, including TPX-0005, are under development in phase I/II clinical trials. Here, we report the finding of a novel small molecule, TY-2136b, which has been identified through a systemic approach against acquired ROS1/TRK/ALK mutations. Kinase assay results suggest that TY-2136b grants similar potency to TPX-0005 inhibiting ROS1 G2032R mutant activity (IC50 1.6 nM vs 2.4 nM ), confers significantly stronger potency than LOXO-101 inhibiting TRKA activity with G595R substitution (IC50 0.8 mM vs 460.1 nM ). The cell proliferation assay results with Ba/F3 cells suggest that TY-2136b is similar potent as TPX-0005 inhibiting cell proliferation of the Ba/F3 strain expressing mutant ROS1 bearing G2032R mutation, a major resistance mutation. TY-2136b also shows potent inhibition towards ROS1, ERK and AKT phosphorylation and downstream signaling in Ba/F3-CD74-ROS1-G2032R cells. Meanwhile, TY-2136b, TPX-0005, and TRK-selective second-generation LOXO-195 inhibitors had similar activity against TRKA G595R and TRKC G623R resistance mutations, but TY-2136b was better than TPX-0005 and LOXO-195 against TRKA G595R/F589L dual mutations in vitro. In vivo studies, TY-2136b showed dose-dependent anti-tumor effect at the dose of 5, 10, and 20 mg/kg, bid, in xenograft tumor models carrying ROS1 G2032R and TRKA G595R mutation, and was more effective than Crizotinib and LOXO-101 at testing dose, and showed better efficacy than TPX-0005 in higher dose. Next, in vivo activity of TY-2136b was examined with xenograft model of KM-12 expressing TPM3-NTRK1 fusion proteins. The results show that TY-2136b and TPX-0005 demonstrate more effectiveness than LOXO-195, and the animals tolerated TY-2136b better than TPX-0005. In the ALK-G1202R xenograft model, TY-2136b showed a significant anti-tumor effect in a certain dose-dependent manner. Taken together, our preclinical data demonstrate that TY-2136b can treat cancers caused by ROS1/TRK/ALK mutations and overcome drug resistance due to acquired solvent-front mutations. Currently, TY-2136b is under first-in-human clinical investigations in the US and China. * To Whom Correspondence should be addressed to: Jun Li, Chengshan Niu and Yusheng Wu
Citation Format: Chengshan Niu, Apeng Liang, Yuge Dou, Kaige Ji, Meihua Li, Yanchao Zhao, Yan Zhang, Zhongwei Guo, Aishen Gong, Mingyu Jiang, Shaoqing Chen, Xiugui Chen, Jun Li, Yusheng Wu. TY-2136b, a next generation ROS1/TRK/ALK inhibitor, potently inhibits kinase and cell proliferation activities of tumor cells bearing drug-dependent acquired mutations [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 3400.