Subjects who meet all the inclusion criteria will be randomized based on a computer-generated randomization schedule prepared by the Coordinating Centre. The first randomization will occur for the induction treatment: Arm A (Rd) or B (MPR) or C (CPR). Within each arm patients will be then randomized for the maintenance treatment(lenalidomide or lenalidomide and prednisone): Arms A1 (R) and A2 (RP); Arms B1 (R) and B2 (RP); Arms C1 (R) and C2 (RP). Randomization will be concealed until the end of the induction period for the maintenance treatment. Patients will be stratified at randomization according to the International Staging System (5) and age (< 75 years vs > 75 years).Treatment period includes induction and maintenance. During the induction and maintenance phases, all patients will attend periodic study center visits in order to asses the safety and efficacy of the treatment. This protocol also provides a substudy designed to observe asymptomatic patients excluded to the protocol that in any case could be inserted in the study . The asymptomatic patient is characterized by the absence of end-organ damage or tissue involvement, such as anemia, bone lesions, hypercalcemia, and renal failure, or by other relevant clinical conditions, such as hyperviscosity, amyloidosis, and recurrent infections (CRAB).