TYRA-430: First reversible FGFR4/3 inhibitor designed to overcome current challenges in FGF19-driven hepatocellular carcinoma treatment.

Abstract

583 Background: Hepatocellular carcinoma (HCC) is an aggressive malignancy that accounts for approximately 80-90% of all primary liver cancers and is projected to become the third leading cause of cancer-related mortality by 2030. Previous work demonstrated that human Fibroblast Growth Factor 19 (FGF19) was overexpressed in 20-30% of HCC, thereby exerting an oncogenic effect via signaling through its cognate receptors FGFR4, FGFR3, and the co-receptor Klotho b (KLB). Multiple selective covalent FGFR4 inhibitors have been clinically evaluated in FGF19-overexpressing HCC. However, selective inhibition of FGFR4 alone was insufficient and resulted in low response rates and limited duration, likely due to redundant signaling through FGFR3. Here we describe the first report on the preclinical profile of TYRA-430, a first-in-class reversible FGFR4/3 inhibitor. Methods: The preclinical profile of TYRA-430 was assessed in vitro in HCC cellular assays and in vivo in mouse xenograft models. The in vitro potency was assessed by measuring cell viability using Cell Titer-Glo 2.0 Luminescent assay. Percentage of tumor growth inhibition (TGI) was used as a measure to evaluate in vivo efficacy of TYRA-430. Results: TYRA-430 exhibited potency against Ba/F3 cells dependent on wildtype FGFR3 and FGFR4, as well as the known Cys552 and Val550 gatekeeper (GK) resistance mutations in FGFR4. In vitro data showed that TYRA-430 displayed superior potency over the reversible multi-kinase inhibitors sorafenib and lenvatinib, and the covalent FGFR4 inhibitors fisogatinib (BLU-554) and roblitinib (FGF401) in KLB/FGF-19/FGFR3/4 driven models of HCC (Hep3B, HuH-7, and JHH-7 cells). Furthermore, in a human HuH-7 HCC xenograft model in nu/nu mice, TYRA-430 achieved 96% tumor growth inhibition (TGI), compared to 75% TGI for lenvatinib and 86% TGI for FGF401. Additionally, in the GA180 FGF19-driven gastric cancer PDX model, TYRA-430 demonstrated superior efficacy with 93% tumor growth inhibition (TGI), compared to 56% TGI achieved by roblitinib. Conclusions: TYRA-430 was active and potent in multiple KLB/FGF-19/FGFR3/4 models of human hepatocellular carcinoma in vitro and in vivo . Moreover, TYRA-430 displayed potent activity against known FGFR4 resistance mutations compared to covalent FGFR4-specific inhibitors in the clinic. TYRA-430 will be investigated in a Phase 1 clinical trial in hepatocellular carcinoma and other advanced solid tumors.