In vitro activity: BLU-554 is a novel potent, highly-selective, and orally bioavailable inhibitor of FGFR4 (fibroblast growth factor receptor 4) with an IC50 value of 5 nM in cell free assays. BLU-554 has the potential to be used for the treatment of hepatocellular carcinoma and cholangiocarcinoma. BLU-554 is well tolerated in these tumor models. Administration of BLU-554 induces tumor regression in liver cancer models. Upon oral administration, BLU-554 specifically binds to and blocks the binding of the ligand FGF19 to FGFR4. This prevents the activation of FGFR4, inhibits FGFR4-mediated signaling and leads to an inhibition of tumor cell proliferation in FGFR4-overexpressing cells. FGFR4 is a receptor tyrosine kinase and is involved in tumor cell proliferation, differentiation, angiogenesis, and survival. FGF19 is overexpressed by certain tumor cell types. Check for active clinical trials using this agent. (NCI Thesaurus).

Kinase Assay: BLU-554 is a novel potent, highly-selective, and orally bioavailable inhibitor of FGFR4 (fibroblast growth factor receptor 4) with an IC50 value of 5 nM in cell free assays.

Cell Assay: Fibroblast growth factor receptor 4 (FGFR-4) is a protein that in humans is encoded by the FGFR-4 gene. This protein is a member of the fibroblast growth factor receptor family, where amino acid sequence was highly conserved between members throughout evolution. FGFR family members 1-4 differ from one another in their ligand affinities and tissue distribution. A full-length representative protein consists of an extracellular region composed of three immunoglobulin-like domains, a single hydrophobic membrane-spanning segment and a cytoplasmic tyrosine kinase domain. The extracellular portion of the protein interacts with fibroblast growth factors, setting in motion a cascade of downstream signals, ultimately influencing mitogenesis and differentiation. The genomic organization of the FGFR-4 gene encompasses 18 exons. Although alternative splicing has been observed, there is no evidence that the C-terminal half of the Iglll domain of this protein varies between three alternate forms, as indicated for FGFR 1-3.