BACKGROUND
Randomized trials have shown that the transplantation of filgrastim-mobilized peripheral-blood stem cells from HLA-identical siblings accelerates engraftment but increases the risks of acute and chronic graft-versus-host disease (GVHD), as compared with the transplantation of bone marrow. Some studies have also shown that peripheral-blood stem cells are associated with a decreased rate of relapse and improved survival among recipients with high-risk leukemia.
METHODS
We conducted a phase 3, multicenter, randomized trial of transplantation of peripheral-blood stem cells versus bone marrow from unrelated donors to compare 2-year survival probabilities with the use of an intention-to-treat analysis. Between March 2004 and September 2009, we enrolled 551 patients at 48 centers. Patients were randomly assigned in a 1:1 ratio to peripheral-blood stem-cell or bone marrow transplantation, stratified according to transplantation center and disease risk. The median follow-up of surviving patients was 36 months (interquartile range, 30 to 37).
RESULTS
The overall survival rate at 2 years in the peripheral-blood group was 51% (95% confidence interval [CI], 45 to 57), as compared with 46% (95% CI, 40 to 52) in the bone marrow group (P = 0.29), with an absolute difference of 5 percentage points (95% CI, −3 to 14). The overall incidence of graft failure in the peripheral-blood group was 3% (95% CI, 1 to 5), versus 9% (95% CI, 6 to 13) in the bone marrow group (P = 0.002). The incidence of chronic GVHD at 2 years in the peripheral-blood group was 53% (95% CI, 45 to 61), as compared with 41% (95% CI, 34 to 48) in the bone marrow group (P = 0.01). There were no significant between-group differences in the incidence of acute GVHD or relapse.
CONCLUSIONS
We did not detect significant survival differences between peripheral-blood stem-cell and bone marrow transplantation from unrelated donors. Exploratory analyses of secondary end points indicated that peripheral-blood stem cells may reduce the risk of graft failure, whereas bone marrow may reduce the risk of chronic GVHD. (Funded by the National Heart, Lung, and Blood Institute–National Cancer Institute and others; ClinicalTrials.gov number, NCT00075816.)
Summary:Treatment options for persons with leukemia relapsing after allogeneic transplantation are limited. We analyzed the outcome of 279 patients with acute and chronic leukemia, who relapsed after HLA-identical sibling transplantation and received a second allogeneic transplant. The influence of potential risk factors on treatment-related mortality (TRM), relapse, treatment failure (relapse or death) and overall survival after second transplantation were assessed using proportional-hazards regression. The cumulative incidences (95% confidence interval) of relapse and TRM at 5 years were 42 (36-48)% and 30 (24-36)%, respectively. The 5-year probabilities of both overall and leukemia-free survival were 28 (23-34)%. In multivariate analyses, risks of treatment failure and mortality were lower in younger patients (p20 years) and patients who relapsed after 6 months from first transplantation. Risks of relapse were lower in patients who relapsed after 6 months from first transplantation and in complete remission prior to second transplantation. Risks of relapse were higher after reduced-intensity conditioning regimens. Any potential advantage of using a different matched related donor for a second transplantation is not supported by these data. Although age, disease status and conditioning regimen are important, duration of remission after first transplantation appear to be the most important determinant of outcome.
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