Radioimmunotherapy in the Transplant Setting

High-dose chemotherapy (HDC) conditioning regimens with autologous stem cell transplantation (ASCT) or reduced intensity conditioning (RIC) with allogeneic stem cell transplantation (allo-SCT) are consolidate approaches for patients with chemotherapy-sensitive, relapsed, aggressive, or indolent non-Hodgkin’s lymphoma (NHL). These approaches have been shown to be the only curative option for the majority of patients. Despite results that can be achieved with SCT combined with HDC, there are some problems that may limit the utility of this approach for a broad patient population, for example, older age or comorbidities. Furthermore SCT has limited success in chemorefractory disease or in heavily pretreated patients; recurrent disease is the major cause of treatment failure and the majority of patients relapsed. Consequently, there is the need for other effective and well-tolerated modality that will eradicate disease thus improving outcomes for both unfit patients and younger with refractory disease. Because lymphomas are highly sensitive to radiation, radioimmunotherapy (RIT) has been used with great success in consolidation therapy, and there is great interest in exploring the use of RIT, either as a single agent or as part of a conditioning regimen for autologous SCT. RIT was also considered as part of RIC to reduce the toxic effects of HDC. The data so far suggest that the use of RIT in the autologous setting can improve clinical outcome with no added toxicity, whereas similar positive findings have been reported in studies of yttrium-90-ibritumomab tiuxetan combined with RIC and allograft SCT in high-risk patients.