Trial design This multicenter, randomized, controlled trial is conducted by the French Myeloma Intergroup(IFM) in elderly patients with previously untreated multiple myeloma. The primary objectives of the study are to compare the efficacy and safety of MP with MP-Thalidomide or with MEL100 (intermediate-dose melphalan 100 mg/m2 - based treatment). The secondary objective is to compare the efficacy of MP-Thalidomide vs MEL100.