Inhibition of FLT3-ITD phosphorylation by SU11248 is time- and dose-dependent.

(A) Athymic mice carrying established MV4;11 tumor xenografts were given a single oral dose of SU11248 (20 mg/kg) or citrate buffer vehicle; predose animals received no treatment. Tumors were harvested at the indicated times, and FLT3 was analyzed by IP/W for phosphotyrosine, followed by total FLT3. Each lane represents a separate animal, and plasma drug concentrations are indicated below for each. ND indicates not detectable. (B) Experiment performed as in panel A except that mice received SU11248 at either 20, 5, or 1 mg/kg for the indicated times.