Peripheral blood stem cell transplant may change practice
Peripheral blood stem cell and bone marrow transplantation from unrelated donors produced similar survival outcomes in a cohort of more than 500 patients, according to results of a phase 3 study.
Previous research has indicated that transplantation of filgrastim-mobilized peripheral blood stem cells from HLA-identical siblings is linked to accelerated engraftment at the cost of increased risk for acute and chronic graft-versus-host disease when compared with bone marrow transplant.
The current multicenter, randomized trial included 551 patients from 48 centers.
Claudio Anasetti, MD, department chair of the blood and bone marrow transplantation program at Moffitt Cancer Center, and colleagues used an intention-to-treat analysis to compare 2-year survival outcomes among patients who had been randomly assigned in a 1:1 ratio to peripheral blood stem cell or bone marrow transplantation from unrelated donors.
The trial, conducted between March 2004 and September 2009, included a median follow-up period of 36 months.
Researchers reported a 2-year OS rate of 51% (95% CI, 45-57) among patients assigned to the peripheral blood group compared with 46% (95% CI, 40-52) among patients assigned to the bone marrow group (P=.29). The researchers noted that this was an absolute difference of five percentage points (95% CI, −3 to 14).
Graft failure occurred in 3% (95% CI, 1- 5) of patients in the peripheral blood group and 9% (95% CI, 6-13) of patients in the bone marrow group (P=.002).
At the 2-year mark, chronic graft-versus-host disease occurred in 53% (95% CI, 45-61) of patients in the peripheral blood group compared with 41% (95% CI, 34-48) of patients in the bone marrow group (P=.01).
The researchers reported no significant differences in incidence of acute graft-versus-host disease or relapse between the two groups.
In an accompanying editorial, Frederick R. Appelbaum, MD, of the Fred Hutchinson Cancer Research Center and the University of Washington in Seattle, noted the study was not large enough to examine effects among certain patient subsets. Follow-up was limited, and quality-of-life data for patients and donors were missing, as was an analysis of resource utilization, Appelbaum said.
“Still, the results provide data that should change current practice,” he wrote. “Instead of being the default choice for most unrelated-donor transplants, mobilized peripheral-blood stem cells should be used in only the minority of patients for whom the benefits outweigh the risks.”
These include patients in need of rapid engraftment, such as those with life-threatening infections, and patients at high risk for graft rejection, including those undergoing reduced-intensity conditioning without prior exposure to intensive chemotherapy, Appelbaum said.
“However, for the majority of unrelated-donor transplantations performed after the patient has undergone a standard, high-dose preparative regimen, bone marrow should be used, since survival is equivalent with the two transplant sources but the incidence of chronic GVHD — which can be a debilitating complication — is significantly lower with bone marrow,” Appelbaum wrote.
“While this study should change practice, it will be interesting to see if it really does,” he added. “The benefits of peripheral blood are seen early, under the watchful eyes of the transplantation physician, whereas the deleterious effects occur late, often after the patient has left the transplantation center.”
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