Stem cell transplantation prolongs survival in children with CML

Stem cell transplantation provides long-term leukemia-free survival in most children with chronic myeloid leukemia (CML), according to a report in the August 15th issue of Blood.

In adults with CML, leukemia-free survival ranges from 45% to 80% after treatment with stem cell transplantation, the authors explain, but few studies have specifically analyzed such outcomes in children.Dr. Irene A. G. Roberts from Imperial College, London, and colleagues in the Pediatric and Chronic Leukemia Working Parties of the European Group for Blood and Marrow Transplantation evaluated the outcomes of 314 children with Philadelphia-chromosome-positive CML undergoing stem cell transplantation from HLA-matched siblings or volunteer-unrelated donors.Almost all recipients (97% of siblings and 95% of volunteer-unrelated donor recipients) successfully engrafted after stem cell transplantation, the authors report, with cumulative 3-year transplant-related mortality reaching 20% for siblings and 31% for volunteer-unrelated donor recipients.Moderate to severe acute graft-versus-host disease was more common among volunteer-unrelated donor recipients (52%) than among siblings (37%), the report indicates, but there was no significant difference in the incidence or severity of chronic GVHD between the two groups.The overall 3-year leukemia-free survival was 55%, the researchers note, with siblings faring slightly better than volunteer-unrelated donor recipients both when transplanted in the first chronic phase (63% versus 56%, respectively) and when transplanted in advanced phase (35% versus 34%, respectively).The 3-year overall survival rate was also significantly higher among siblings (71%) than among volunteer-unrelated donor recipients (57%), the results indicate, and survival was twice as likely among children transplanted in first chronic phase than among those transplanted in advanced phase.The investigators observed poorer outcomes in children who received a T-cell-depleted graft, in CMV-negative recipients from CMV donors, and in children who did not receive methotrexate or interferon-alfa.”This is the largest reported series to specifically evaluate the outcome of allogeneic stem cell transplantation for CML in children,” the researchers write.”The outcome for children who undergo transplantation for CML is comparable to that observed for adults,” the authors conclude. ” Stem cell transplantation is curative for most children, but treatment related mortality remains a problem, particularly after volunteer-unrelated donor stem cell transplantation.””Further studies to better identify prognostic factors that predict stem cell transplantation outcome should prove invaluable in elucidating the clinical role of stem cell transplantation, particularly the timing of the procedure and the choice of alternative donors, when balanced against the results achieved with novel medical therapy such as tyrosine kinase inhibitors,” the investigators add.(Source: Blood 2003;102:1224-1231,1150: Reuters Health: September 9, 2003: Oncolink)