ONX-0914 is synergistic with FDA-approved inhibitors. (A-B) ONX-0914 is synergistic with bortezomib (Btz), carfilzomib (Cfz), and ixazomib (Ixa) in MM1.S (A) and RPMI-8226 (B) cells (n = 2). Numbers on the graph are CIs. (C) ONX-0914 and bortezomib have synergistic activity in orthotopic mouse model of MM. NSG mice (6 per group) were injected intravenously with MM1.S cells and then treated as shown. Weight at euthanasia is not included on the right graph because animals lose weight as a result of disease progression. Error bars indicate standard error of the mean. Bottom: 1 µL of serum samples was assayed for human Igλ by western blot. The latest sample was taken at euthanasia. *P < .05 when compared with vehicle group; **P < .005 when compared with vehicle group; ##P < .005 when compared with bortezomib only group. PI, proteasome inhibitor.