This is a randomized, open label, multicenter clinical trial to compare the efficacy and safety of Velcade (bortezomib) and dexamethasone versus Velcade, thalidomide, and dexamethasone versus Velcade, melphalan, and prednisone in patients with previously untreated multiple myeloma not considered candidates for high-dose chemotherapy and autologous stem cell transplantation.