CCI-779 is efficacious in ALL xenografts. NOD/SCID mice were xenografted with human ALL from patient samples. After establishment of disease, defined as more than 5% blasts detected in peripheral blood, mice were randomized to treatment with 5 to 10 mg/kg/d of CCI-779 versus vehicle control. Disease was evaluated at weekly intervals by FACS analysis of peripheral blood, detecting human CD19⁺ and CD45⁺ cells. Graph depicts mean absolute blast counts (WBC × % blasts by FACS analysis) from mice generated from the 4 patient samples at weekly intervals, demonstrating statistically significant difference (P < .05) in all samples. Error bars depict standard error of the mean (SEM).