Role of reduced intensity conditioning in allogeneic hematopoietic cell transplantation for patients with multiple myeloma

High-dose chemotherapy followed by autologous hematopoietic cell transplantation continues to play an integral role in the treatment strategy in patients with newly diagnosed multiple myeloma. Incorporation of newer potent anti-myeloma agents has further improved outcomes. However, disease relapse or progression remains a challenge after autologous transplantation. Allogeneic hematopoietic cell transplantation remains the only potentially curative modality for some patients due in part to graft-versus-myeloma effect. High transplant-related mortality, in the range of 30% to 40%, previously seen with myeloablative conditioning regimens including total body irradiation plus cyclophosphamide has been significantly reduced by introducing less ablative preparative regimens, so called reduced-intensity conditioning. Cumulative evidence suggests encouraging prospects for allogeneic transplantation through improved outcomes of myeloma patients (overall survival exceeding 70% at 2 years in some studies); however, which patient population would benefit most from this treatment remains to be defined. Newer strategies to augment graft-versus-myeloma effect and minimize post transplant toxicities are in need of further improvement in patients with myeloma.