Ki: Flk-1trans-phosphorylation (2.1 mM), FGFR1 trans-phosphorylation (1.2 mM), and PDGFR autophosphorylation (0.008 mM).

Vascular endothelial growth factor, fibroblast growth factor (FGF), and platelet-derived growth factor (PDGF) and their cognate receptor tyrosine kinases are strongly implicated in angiogenesis associated with solid tumors. TSU-68 is a novel inhibitor of these receptors.

In vitro: Biochemical kinetic studies using isolated Flk-1, FGF receptor 1, and PDGF receptor β kinases revealed that TSU-68 has competitive inhibitory properties with respect to ATP. In cellular systems, TSU-68 inhibited receptor tyrosine phosphorylation and mitogenesis after stimulation of cells by appropriate ligands [1].

In vivo: Oral or i.p. administration of TSU-68 in athymic mice resulted in significant growth inhibition of a diverse panel of human tumor xenografts of glioma, melanoma, lung, colon, ovarian, and epidermoid origin [1].

Clinical trial: Phase I clinical study indicated that TSU-68 can be safely combined with standard doses of carboplatin-paclitaxel, with the combination manifesting promising antitumor activity [2].

References:
[1] Laird AD, Vajkoczy P, Shawver LK et al.  SU6668 is a potent antiangiogenic and antitumor agent that induces regression of established tumors. Cancer Res. 2000 Aug 1;60(15):4152-60.
[2] Okamoto I, Yoshioka H, Takeda K et al.  Phase I clinical study of the angiogenesis inhibitor TSU-68 combined with carboplatin and paclitaxel in chemotherapy-naive patients with advanced non-small cell lung cancer. J Thorac Oncol. 2012 Feb;7(2):427-33.