Allogeneic Stem Cell Transplantation vs. Conventional Therapy as Salvage Therapy for Relapsed / Progressive Patients With Multiple Myeloma After First-line Therapy

Inclusion Criteria:

Patients eligible for study inclusion must meet criteria 1- 7 at registration and all of the following criteria before randomization:

1. Multiple Myeloma
2. Age 18 - 65 years
3. A signed informed consent form must be obtained before participation in the study
4. Age 66 - 70 years, if comorbidity index according to Sorror score = 0 and ECOG ≤ 1
5. 1st relapse/ progression according to IMWG criteria after first-line therapy (consisting of induction therapy followed by autologous transplantation once or twice and maintenance therapy), Additionally: meeting the need for treatment based on the SLiM-CRAB-criteria
6. Negative pregnancy test in female patients
7. Maximum of 1 cycle salvage therapy prior to study inclusion
8. Availability of a fully compatible stem cell donor (HLA-ident. Sibling or 10/10 MUD or 9/10 MMUD if mismatch affects DQB) after 3 cycles salvage therapy
9. CR/PR or SD according to IMWG-criteria after 3 cycles salvage therapy within the study

Exclusion Criteria:

Patients are excluded from the study if any one of criteria 1-6 are met at registration and if criterion 7 is met before randomization:

1. Non-sufficient organ function defined as:

   Bilirubin (in the absence of Meulengracht's disease), SGPT or SGOT ≥3 higher than normal values Cardiac ejection fraction ≤ 50% GFR \< 30 ml/min DLCO \< 35 % or continuous oxygen dependency
2. Active hepatitis B or C infection or uncontrolled HIV infection
3. Other, active malignant disease
4. Prior treatment with allogeneic stem cells
5. Participation in a clinical trial or taking an IMP within 30 days or five times the half-life of the IMP, whichever is longer, prior to registration
6. Positive serum pregnancy test at screening and before first treatment or breastfeeding
7. PD under salvage therapy