u3-1784

U3-1784 is a fully human monoclonal antibody that specifically targets fibroblast growth factor receptor 4 (FGFR4). Developed using phage display technology, it binds with high affinity to FGFR4 and acts as an antagonist by blocking the binding of various fibroblast growth factors (FGFs) to the receptor. This inhibition prevents activation of downstream signaling pathways such as FRS2 and Erk, which are implicated in tumor cell proliferation and survival. The FGFR4/FGF19 axis is overactivated in approximately 20% of liver tumors, making it a promising therapeutic target for hepatocellular carcinoma (HCC) and other solid tumors. Preclinical studies demonstrated that U3-1784 significantly slowed tumor growth in models overexpressing FGF19 but had no effect on tumors lacking FGF19 expression. However, clinical development was discontinued after phase I trials due to business reasons. The drug was originally developed by U3 Pharma and later by Daiichi Sankyo[1][2][5][7][8].