The primary objective of the present clinical study aims to demonstrate the superiority of allogeneic stem cell transplantation (allo SCT) compared to conventional therapy for the difference in overall survival (OS) at 5 years in patients with multiple myeloma who have relapsed or progressed after first-line autologous hematopoietic stem cell therapy.~The secondary objectives are to show an improvement of progression free survival and relapse free survival after allo SCT compared to conventional therapy.~In addition, quality of life, toxicities, recurrence rates, non-relapse mortality (NRM), remission rates including minimal residual disease (MRD) and incidence of severe or life-threatening infection between the two arms are compared. Acute and chronic graft-versus-host disease (GvHD) after allo SCT are evaluated.
Allogeneic stem cell (allo SCT) transplantation for multiple myeloma is a potential curative treatment, but is associated with morbidity and treatment related mortality. Approved drug combinations or another autologous stem cell transplantation (auto-SCT) can be used for relapsed patients resulting in a median progression free survival up to 2-3 years.~In the current trial after first-line treatment relapsed or progressed myeloma patients with an HLA compatible donor will be randomized after 3 cycles of salvage therapy to allogeneic stem cell transplantation or to continuous conventional salvage therapy.