Allogeneic stem cell transplantation for multiple myeloma: is there a future?

Despite remarkable progress in survival with the availability of novel agents, an overwhelming majority of patients with multiple myeloma (MM) relapse and the curability of MM remains limited. Genetically defined high-risk MM represents a subgroup with an aggressive disease course despite novel agents. Allogeneic hematopoietic cell transplantation (allo-SCT) is a potentially curative option in MM that has several advantages including a tumor-free graft, and the potential for sustained immune-mediated disease control. However, historically high treatment-related mortality (TRM) and conflicting reports from prospective studies in the United States and European Union have limited the utilization of this modality. Meanwhile, newer preparative regimens, planned maintenance strategies and improvements in supportive care have led to a decline in TRM and better survival in recent years. The allo-SCT platform also provides additional options of immunotherapy at relapse including donor lymphocyte infusions, immunomodulatory drug maintenance and withdrawal of immune suppression. In this article, we provide an in-depth review of literature for allo-SCT and other immunotherapy options, as well as the authors' approach to using allo-SCT in MM.