Patients achieving confirmed CR, R, or PR who reach a plateau prior to receiving the maximum 8 courses of induction therapy OR who achieve confirmed CR, R, or PR after receiving the maximum 8 courses of induction therapy proceed to maintenance therapy. Patients achieving stable disease after receiving the maximum 8 courses of induction therapy either proceed to maintenance therapy or receive further treatment with bortezomib, thalidomide, and dexamethasone off-study.