The effect of PF-04691502 in the Eμ-TCL1 mouse model. Mice inoculated with Eμ-TCL1 tumor cells were treated by oral gavage with 5 or 10 mg/kg/d PF-04691502 or placebo control over 14 days of continual treatment after the emergence of a leukemic phase occurred at day 21 (depicted by the arrow in panel A). (A) Peripheral leukemic (CD5⁺CD220⁺) cell number was evaluated by flow cytometry in the presence of PF-04691502 or the vehicle control. (B) Illustration of the spleen sizes from mice treated with 10 mg/kg/d PF-04691502 or vehicle control as compared to the wild-type mouse C57BL/6. (C) Weights of the spleens depicted in panel B. (D) Leukemic cell number was also investigated in various organs, including spleen (SPL), lymph nodes (LN), and bone marrow (BM) after treatment with PF-04691502 or the vehicle control. Error bars represent SEM. *P < .02, **P < .004, ****P < .0001. PF, PF-04691502.