Abstract B135: Activity of Tegavivint in Hepatocellular Carcinoma with Aberrant Wnt/β-catenin Signaling and Evaluation of Biomarker Response

Abstract Aberrant Wnt/β-catenin signaling is a hallmark of hepatocellular carcinoma (HCC), with activating CTNNB1 mutations contributing to oncogenesis, immune evasion, and resistance to therapy. Up to 40% of HCC cases are driven by activating mutations in β-catenin or other components of the canonical Wnt pathway, which are associated with primary resistance to standard-of-care therapies. Transcriptional activation of Wnt target genes requires β-catenin recruitment via transducin beta-like protein 1 (TBL1). Tegavivint, an investigational small molecule currently in clinical studies for HCC (NCT05797805), inhibits the β-catenin–TBL1 interaction. While tegavivint has demonstrated selective activity in CTNNB1-mutant desmoid tumors, it is also known to disrupt both wild-type and mutant β-catenin interactions in other tumor contexts. Here, we evaluated how Wnt pathway mutation status shapes cellular phenotype and response to tegavivint using in vitro and in vivo HCC models. We profiled three HCC cell lines with distinct CTNNB1 statuses: HUH7 (wild-type), HUH6 (G34V), and HepG2 (exon 3 deletion). Baseline pathway activation, phenotypic features, and response to tegavivint were assessed. Apoptosis was measured by Annexin V staining, cell viability via CellTiter-Glo, and cell death kinetics using real-time Sytox Green imaging on the IncuCyte platform. Wnt target gene expression (AXIN2, GLUL, LGR5, NOTUM) was quantified by qPCR. In vivo, orthotopic HepG2 xenografts were established in NOD/SCID mice and treated with tegavivint (50 mg/kg BIW for 3 weeks). Tumor growth was monitored by ultrasound. Post-treatment analyses included serum alpha-fetoprotein (AFP) and serum protein profiling via Luminex, and immunohistochemistry for β-catenin, TBL1, and additional markers. Tegavivint treatment led to cell death in CTNNB1 mutant cell lines and a significant tumor growth inhibition in vivo, accompanied by transcriptional suppression of β-catenin targets (AXIN2, GLUL, LGR5, NOTUM) and re-expression of hepatic differentiation genes. Luminex analysis revealed upregulation of immune-modulatory proteins, suggesting a shift in the tumor immune microenvironment. In our ongoing clinical study, patient samples collected pre- and post-dosing with tegavivint were evaluated for mutational status using the FoundationOne® Liquid CDx assay and for changes in serum proteins using Luminex. Mutations in the Wnt/beta-catenin pathway were assessed for correlation with clinical activity, along with preliminary analyses of associations between clinical response and changes in serum protein biomarkers. These findings demonstrate that Wnt pathway mutation status shapes HCC phenotype and predicts sensitivity to tegavivint. CTNNB1-mutant models showed enhanced responses, including growth inhibition, differentiation, and transcriptomic reprogramming. These data support the use of Wnt/β-catenin pathway inhibitors as a precision medicine strategy in CTNNB1-mutant HCC and highlight the need for further studies in immune-competent models and biomarker-enriched clinical trials. Citation Format: Ciara Curran, Toshiyasu Suzuki, Aundrietta D. Duncan, Stephen K. Horrigan, Thomas G. Bird. Activity of Tegavivint in Hepatocellular Carcinoma with Aberrant Wnt/β-catenin Signaling and Evaluation of Biomarker Response [abstract]. In: Proceedings of the AACR-NCI-EORTC International Conference on Molecular Targets and Cancer Therapeutics; 2025 Oct 22-26; Boston, MA. Philadelphia (PA): AACR; Mol Cancer Ther 2025;24(10 Suppl):Abstract nr B135.