Abstract
Allogeneic hematopoietic transplantation following nonmyeloablative preparative conditioning (also know as “mini-dose transplantation”) is frequently applied to patients who, on the basis of prior therapy, organ dysfunction, or co-morbid conditions may be considered ineligible for full, dose-intenstive treatment. This approach assumes that early regimen-related toxicity can be averted by the nonmyeloablative approach. We present the results obtained in a group of consecutive, unselected older adults with advanced hematologic neoplasia who underwent allogeneic transplantation from fully histocompatible siblings or unrelated donors after dose-reduced preparative conditioning in a single center. Thirty-four patients, median age 57 years (range 26–66) underwent allogeneic transplantation from siblings (14 patients) or unrelated donors (20 patients) following preparative conditioning consisting of chemotherapy only (typically fludarabine, cytarabine, and cyclophosphamide) or those drugs plus antithymocyte globulin, respectively. One recipient of a related allograft and one recipient of an unrelated allograft received preparative fludarabine/melphalan and busulfan/fludarabine/ATG, respectively. Diagnoses prior to transplantation included advanced acute leukemia and myelodysplasia (17 patients), nonHodgkin’s or Hodgkin’s lymphoma (11 patients), and CLL or Multiple Myeloma (6 patients). Allogeneic transplantation followed previous autologous transplantation in 17 patients. Time from previous autologous transplantation to nonmyeloablative allogeneic transplantation varied. Prior autograft conferred a significant adverse risk on recipients of allogeneic transplants following nonmyeloablative conditioning. Only two of 17 patients with a history of prior autograft enjoyed long-term survival as opposed to seven of 17 who had not undergone prior autologous transplant. Mortality before day + 100, typically attributed to treatment-related toxicities, occurred in 11 patients; nine of these patients had had prior autologous transplantation. Prior autologous transplantation typically was done for acute myelogenous leukemia in first complete remission and referral for allotransplant may have been an indicator of more aggressive disease biology. In conclusion, allogeneic transplantation following a nonmyeloablative preparative regimen may be associated with significant risk of early mortality in patients who undergo this treatment after prior autologous transplantation, especially for acute leukemia, suggesting that criteria for allogeneic transplantation after nonmyeloablative condition should take this risk into account. Further studies from multiple centers will be required to confirm this observation.
