MINIALO-VELCADE2005: A Study of Bortezomib (Velcade) Treated Multiple Myeloma Patients Pre and Post Allogeneic Haematopoietic Progenitor Cell Transplant With no Myeloablative Conditioning

Inclusion Criteria: * Patient is, in the investigator's opinion, willing and able to comply with the protocol requirements. * Patient has given voluntary written informed consent before performance of any study-related procedure not part of normal medical care, with the understanding that consent may be withdrawn by the patient at any time without prejudice to their future medical care. * Age over 18 and under 67 years old. * Patient diagnosed with symptomatic Multiple Myeloma based on standard criteria with bad prognosis. This factor is associated with at least one of the clinical alterations defined as follows: Patient who displayed a Monosomy of chromosome 13 or other adverse cytogenetic abnormality. Patient in first relapse. Patient with relapsed multiple myeloma after autologous transplantation. * Patient has a ECOG performance status \<= 2. * Patient has a life-expectancy \>3 months. * Patients who are candidates for autologous transplantation. * Patients must have HLA-identical sibling donors. * Patient has the following laboratory values before Baseline visit: Platelet count ≥ 30000/mm3 (transfusion allowed), hemoglobin ≥ 8 g/dl (transfusion allowed) and absolute neutrophil count (ANC) ≥ 0.750/mm3. Lower values are accepted if they are caused by bone marrow infiltration. Aspartate transaminase (AST): ≤ 2.5 x the upper limit of normal. Alanine transaminase (ALT): ): ≤ 2.5 x the upper limit of normal. Total bilirubin: ≤1.5 x the upper limit of normal. Serum creatinine value ≤ 2mg/dl Exclusion Criteria: * Patient present serious pathologies that make impossible chemotherapy treatments: 1. Congestive heart failure, angina or heart attack during last 12 months. 2. Uncontrolled arterial hypertension. 3. Uncontrolled supraventricular arrhythmias during last 3 last months. 4. Ventricular arrhythmia. 5. Hepatic disease (Cirrhosis). * Patient has Grade 2 peripheral neuropathy within 14 days before enrollment. * Patient with serious psychiatric disorders that make impossible comply satisfactorily with the protocol requirements. * Personal medical history of neoplasia of other type, except: carcinoma in situ, other curatively treated malignancy in complete remission for more than 10 years. * Patient has hypersensitivity to bortezomib, boron or mannitol. * Fertile patient is not going to use a medical effective contraceptive method during the trial. * Patient has received other investigational drugs within 30 days before enrollment * Patient is known to be seropositive for the human immunodeficiency virus (HIV), Hepatitis B surface antigen-positive or active hepatitis C infection. * Patient had a myocardial infarction within 6 months of enrollment or has New York Heart Association (NYHA) Class III or IV, heart failure, uncontrolled angina, severe uncontrolled ventricular arrhythmias, or electrocardiographic evidence of acute ischemia or active conduction system abnormalities. * Patient is enrolled in another clinical research study and/or is receiving an investigational agent for any reason. * Patient participated in clinical study VISTA. * Pregnant or breast-feeding women.