In vitro activity: Toceranib, also known as PHA-291639 and SU 11654, is an inhibitor of receptor tyrosine kinase (RTK) with Ki values of 6 nM and 5 nM for Flk-1/KDR and PDGFRβ, respectively. It is used in the treatment of canine mast cell tumor (also called mastocytoma). Toceranib is an veterinary drug that was approved for use in dog. Toceranib is likely to act mostly through inhibition of the kit tyrosine kinase, though it may also have an anti-angiogenic effect.

Kinase Assay: Toceranib (SU11654) is a selective inhibitor of the tyrosine kinase activity of several members of the split kinase RTK family, including PDGFR and Flk-1/KDR, with Kis of 5 and 6 nM, respectively.

Cell Assay: he BR, C2, and P815 cells were counted and resuspended in 24-well plates at a concentration of 0.5 × 106 cells/well (BR and C2) or 0.25 × 106 cells/well (P815) in complete medium. Cells were left untreated, or SU11652, SU11654, or SU11655 was added to a final concentration of 0.01 to 1 μM. Cells were collected after 24, 48, and 72 hours of culture and were counted to determine the number of cells surviving.