Abstract
Hepatocellular carcinoma (HCC) is an aggressive liver malignancy that is difficult to treat with no approved biomarker based targeted therapies. FGF19-FGFR4 signaling blockade has been recently identified as a promising avenue for treatment of a subset of HCC patients. Using HCC relevant xenograft and PDX models, we show that Lenvatinib, an approved multi-kinase inhibitor, strongly enhanced the efficacy of FGFR4 inhibitor H3B-6527. This enhanced combination effect is not due to enhanced FGFR4 inhibition and it is likely due to cell non-autonomous VEGFR activity of Lenvatinib. This cell non-autonomous mode of action was further supported by strong in vivo combination efficacy with the mouse specific VEGFR2 antibody, DC101, which cannot cell-autonomously inhibit pathways in human xenografts. Mechanistic studies showed that the combination resulted in enhanced efficacy through increased anti-angiogenic and anti-tumorigenic activities. Overall, our results indicate that this combination can be a highly effective treatment option for FGF19 driven HCC patients, and provide preclinical validation of a combination that can be readily tested in the clinical setting.