Extracellularly acting, small-molecule, allosteric inhibitor of FGF receptor signaling with oral bioavailability. SSR 128129E inhibits responses mediated by FGFR1-4 (IC50 values 15-28 nM for FGF2 induced FGFR stimulation), but not by other related RTKs.SSR 128129E does not inhibit all FGFR signaling pathways indiscriminatively but selectively blocks particular signaling pathways, dependent on the cellular context. Capable of inhibiting angiogenesis, inflammation, and bone resorption in arthritis, and delays tumor growth and metastasis.