In the first part of the study (phase I component), different doses of oral Melphalan (0.18-0.25 mg/Kg) associated with Prednisone (MP) will be combined with escalating doses of Revlimid (from 5 mg/day) and administered together. This phase will define the MTD of the association. In the second part of the study (phase II component), 30 patients will be treated with MPR at dose/s defined from phase I component to verify data of response and toxicity.