Mobilization of HSPC by ixazomib in mice. Mice were analyzed for peripheral blood (PB) CFU-C at various time points. (A) Mice were treated with vehicle (Veh) or ixazomib (Ixa) IV at 2, 4 , 8, or 14 mg/kg. Mice were analyzed for PB CFU-C at baseline and 12, 15, 24, and 48 hours (hr; n = 5 mice/group). (B) Mice were treated with IV ixazomib (n = 5) vs o.g. of ixazomib (n = 10). Mice were analyzed for PB CFU-C at baseline and 12, 15, and 24 hours (P = .025 comparing oral vs IV ixazomib; P = .0003 comparing oral ixazomib vs Veh). (C) Peak mobilization of each mouse treated with ixazomib o.g. vs IV. (D) Ixa o.g. vs bortezomib (Bor) HSPC mobilization. PB CFU-C were analyzed at baseline and 12, 15, and 24 hours after ixazomib and bortezomib (*P > .07 comparing peak oral ixazomib mobilization vs peak IV bortezomib mobilization). (E) CFU-C subtypes after ixazomib o.g. plerixafor SC, and G-CSF SC, CFU-erythroid (CFU-E), CFU-granulocyte and monocyte (CFU-GM), and CFU-granulocyte and erythrocyte and monocyte, and megakaryocyte (CFU-GEMM). (F) Mobilization of HSPC in response to ixazomib in combination with G-CSF and plerixafor. Mean PB CFU-C in G-CSF + ixazomib vs GCSF alone: 11 320/mL; SE, 1760/mL vs 3420/mL; SE, 915/mL, respectively; P = .01. Mean PB CFU-C in plerixafor plus ixazomib vs plerixafor: 1190/mL; SE, 361/mL vs 810/mL; SE, 180/mL, respectively; P = .34. Data are mean ± SE.