Matched Unrelated Donor Stem Cell Transplantation (MUD-SCT) After Dose-reduced Conditioning for Patients With Multiple Myeloma and Relapse After Autologous SCT

Inclusion Criteria: * Multiple Myeloma stage II or III acc. to Salmon and Durie (chemosensitive or refractory) and relapse or progression after high dose chemotherapy with autologous stem cell support * Age 18-60 years * ECOG-performance status 0-1 * Availability of a HLA-compatible unrelated donor (HLA-A, -B, -DRB1, -DQB1) Exclusion Criteria: * Serious concomitant medical disease that would limit life span or ability to tolerate chemotherapy * Severe cardiac failure (ejection fraction \< 40%) * Severe impairment of renal function (Creatinine clearance \< 50ml/min) * Severe impairment of liver function (bilirubine \> 2 fold of upper limits of normal) * Pregnant or lactating women * Other major organ or system dysfunctions(GI, neurological, psychiatric dysfunctions that would impair tolerance of chemotherapy or prolonged haematological recovery) * Positivity for HIV