Allogeneic Stem-Cell Transplantation in Patients With Waldenstrom Macroglobulinemia: Report From the Lymphoma Working Party of the European Group for Blood and Marrow Transplantation.

PURPOSE Allogeneic stem-cell transplantation (alloSCT) is a curative therapeutic option for patients with low-grade lymphoid malignancies. Information regarding alloSCT in Waldenström macroglobulinemia (WM) is limited. This study presents the long-term outcome of a large series of patients with WM treated with alloSCT. PATIENTS AND METHODS A total of 86 patients received allograft by using either myeloablative (MAC; n = 37) or reduced-intensity conditioning (RIC; n = 49) regimens and were retrospectively studied. The median age was 49 years (range, 23 to 64 years); 47 patients had received three or more previous lines of therapy, and eight patients had experienced failure on a prior autologous stem-cell transplantation. A total of 59 patients (68.6%) had chemotherapy-sensitive disease at the time of alloSCT. Median follow-up of the surviving patients was 50 months (7 to 142 months). Results Nonrelapse mortality (NRM) at 3 years was 33% for MAC and 23% for RIC. The overall response rate was 75.6%. The relapse rates (RRs) at 3 years were 11% for MAC and 25% for RIC. Fourteen patients received donor lymphocyte infusions (DLIs) for disease relapse. PFS and OS at 5 years were 56% and 62% for MAC and 49% and 64% for RIC, respectively. The occurrence of chronic graft-versus-host disease (cGVHD) was associated with a higher NRM and a lower RR, leading to an improvement in PFS. CONCLUSION alloSCT can induce durable remissions in a selected population of young and heavily pretreated patients with WM. The low RR, the achievement of additional disease responses after DLIs, and the lower RR in patients developing cGVHD suggest the existence of a clinically relevant graft-versus-WM effect