Abstract 1963: BB102, a highly selective and potent reversible-covalent FGFR4 inhibitor effective in multiple xenograft tumor models

Abstract

Abstract Introduction: Fibroblast growth factor receptor 4 (FGFR4) belongs to the FGFR family which interact with fibroblast growth factors (FGFs) to regulate cell proliferation, differentiation and apoptosis. Due to unique structural domain, FGFR4 is specifically bound by FGF19 with high affinity in the presence of co-receptor β-Klotho. Hyperactivated FGF19/FGFR4 signaling, induced by FGF19/FGFR4 overexpression and FGFR4 mutation, was reported to be associated with the growth, metastasis and invasion of various cancer. Thus, FGFR4 is considered as a novel target to treat cancer with hyperactivated FGF19/FGFR4 signaling. Here we report BB102 as a highly selective and potent reversible-covalent FGFR4 inhibitor. Methods: BB102 was developed through structure-based drug design, and optimized by SAR analysis and medicinal chemistry iteration. Biochemical and cell assays were applied in evaluation of BB102 inhibitory activity. Preclinical studies including pharmacokinetic (PK) and toxicity were performed in rats and dogs. Xenograft tumor models in mice were conducted to demonstrate the in vivo efficacy of BB102. Results: As a reversible-covalent FGFR4 inhibitor, about half compound of BB102 dissociated from FGFR4 kinase within 24 h, which was conducive to overcome the fast re-synthesis rate of FGFR4 (< 2 h) in hepatocellular carcinoma cells. BB102 only inhibited kinase activity of FGFR4WT, FGFR4N535K and FGFR4V550L at nanomolar levels in 207 kinase panel screening. BB102 completely blocked the phosphorylation of the downstream protein ERK at 16.7 nM. BB102 exhibited strong inhibitory effects on the cell proliferation in vitro and tumor growth in mouse models inoculated with the high expression of both FGF19 and FGFR4, or FGFR4 mutated tumor cells. PK profile of BB102 showed good oral bioavailability (F>70%) with a nearly linear dose-dependent exposure. The compound had no effects on the respiratory and central nervous systems in rats, cardiovascular system in Beagle dogs or hERG liability in vitro. In comprehensive safety evaluation, the Severely Toxic Dose in 10% (STD10) in rats was 300 mg/kg/day and the Highest Non-Severely Toxic Dose (HNSTD) in dogs were 100 mg/kg/day. Conclusion: BB102 is a highly selective and potent reversible-covalent FGFR4 inhibitor with promising efficacy in high expression of both FGF19 and FGFR4, and/or FGFR4 mutated tumor models and good safety in preclinical studies. The phase I study of BB102 is in progress. Citation Format: Qi Wang, Gongping Duan, Wei Hua, Xianglong Wei, Min Li, Junheng Wang, Xingmin Zhang. BB102, a highly selective and potent reversible-covalent FGFR4 inhibitor effective in multiple xenograft tumor 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 1963.