Dose-Reduced Allogeneic Stem Cell Transplantation After Autologous High-Dose Chemotherapy in Patients With Multiple Myeloma

Inclusion Criteria: * Multiple Myeloma Stadium II / III acc. to Salmon and Durie * signed informed consent * adequate organ function prior autologous respectively allogeneic SCT * availability of HLA-identical related or unrelated donor * availability of at least 2 x 10\^6 CD34+ cells per kg BW of recipient for the autologous SCT and at least 3 x 10\^6 CD34+ cells for allogeneic SCT * for MRD-SCT: 18-66 years; for MUD-SCT: 18-55 years * at age \<55 years existence of risk factors that make an myeloablative allogeneic transplantation to risky * consent of donor to give DLI Exclusion Criteria: * severe heart insufficiency * cardiovascular diseases or severe concomitant diseases * active infections that need antibiotic therapy * positive for HIV or hepatitis * malign secondary disease * limited liver function with total bilirubin \> 1.5 ULN * increased transaminase \> 3 ULN * increased serum creatinine \> 2 mg/dl * pregnant or lactating women * known hypersensitivity to Fludarabine or Melphalan * participation in another trial