WT161 exhibited adequate PK exposure and efficacy in mice. (A) Male CD-1 mice (n = 3) were injected i.v. with WT161 at 5 mg/kg. Mean plasma concentration–time profiles were used to calculate drug exposure [area under the curve (AUC) = 3,049 ng⋅L−1⋅h−1], t1/2 = approximately 1.4 h, and Cmax = 18,663 ng/L. CLz, clearance; MRT, mean residence time extrapolated to infinity; t1/2z, terminal elimination half-life; Tmax, time to maximum concentration; Vz, volume of distribution at terminal phase. (B) Quantitative analysis of Ac-α-tubulin–positive cells in MM1.S xenograft tumors from two control and two WT161-treated mice. Data represent the mean ± SD.