Figure 1.

Fruquintinib is a highly selective and potent VEGFR1, 2, 3 kinase inhibitor. (A) Chemical structure of fruquintinib. (B) Kinome selectivity of fruquintinib at 1 μmol/L against 253 kinases using ³²p-ATP incorporation method generated at Millipore. The Kinome tree was downloaded from http://www.cellsignal.com. Percentage (%) denoted the inhibition of fruquintinib at 1 μmol/L to the recombinant kinases. Over 90% inhibition was observed for 3 VEGFR family members (1, 2, 3) and 70～90% inhibition on 4 other kinases, including Fms(Y969C), Ret, and FGFR1 and little effect on remaining kinases tested. IC₅₀s were generated for the kinases of interest and shown in Table 1.