Nintedanib

BIBF1120 inhibits PDGFR kinase activity of PDGFR alpha and PDGFR beta types with IC50 values of 59 nM and 65 nM, respectively. In addition, BIBF1120 suppresses the FGFR subtypes with IC50 of 60 nM, 37 nM and 108 nM for FGFR1, FGFR2, and FGFR3, respectively. BIBF1120 binds to the ATP-binding site in the cleft between the amino and carboxy terminal lobes of the kinase domain. The indolinone scaffold forms two hydrogen bonds with the backbone nitrogen of Cys⁹¹⁹ and the backbone carbonyl oxygen of Glu⁹¹⁷ in the hinge region. BIBF 1120 inhibits proliferation of PDGF-BB stimulated BRPs with EC50 of 79 nM in cell assays. BIBF1120 at concentrations as low as 100 nM blocks activation of MAPK after stimulation with 5% serum plus PDGF-BB. In cultures of human vascular smooth muscle cells (HUASMC), BIBF1120 prevents PDGF-BB stimulated proliferation with an EC50 of 69 nM. ^[1]