Macrophage inflammatory protein-1alpha (MIP-1alpha) is a protein produced by multiple myeloma (MM) cells, which induces proliferation of MM cells, formation of cells that resorb bone tissue, and is partly responsible for bone destruction. BX471 prevents binding of MIP-1alpha to receptors and inhibits the formation of these cells. PS-341 is effective at inhibiting replication of MM cells. We hypothesize that combining both drugs will exert profound anti-myeloma effects and result in inhibition of bone disease, and that targeting two regulators of cell growth will result in an anti-MM effect greater than the sum effect of both drugs, but less toxicity.