After the first three induction cycles, and in the absence of progression or unacceptable toxicity, peripheral blood hematopoietic stem cells will be mobilized and collected using G-CSF for later autologous transplantation. Patients will be randomized in a 1:1 allocation ratio to receive conditioning treatment with MEL-200 versus BUMEL. Randomization will take place at the beginning of the study, once the screening is complete and the patient's eligibility verified. Three months after transplantation, patients will receive two cycles of consolidation treatment with VRD-GEM at the same doses administered during induction treatment.