No differences in patient survival rates between patients receiving transplantation with bone marrow or PBSC from unrelated donors, although the type and extent of complications were different.
Patients receiving PBSC engrafted faster than those receiving marrow
Chronic graft-versus-host disease (cGVHD) developed more often and was more severe in patients who received PBSC compared with those receiving marrow. Because cGVHD can cause significant disability in the post-transplant period, these findings may fuel a resurgence of interest in bone marrow as the favored graft source.
Access the full study in New England Journal of Medicine

-- October 17 2012

A large prospective, randomized study published in the New England Journal of Medicine (NEJM) compared outcomes of patients receiving transplantation with either peripheral blood stem cells (PBSC) or bone marrow from unrelated donors. While there was no difference in patient survival rates between these two major sources of donated blood cells, the study showed differences in the type and extent of complications.

Conducted by the Blood and Marrow Transplant Clinical Trials Network (BMT CTN), the study included patients who received a blood stem cell transplant from a donor outside of their family to treat leukemia and other blood diseases. Patients who received cells directly from a donor’s bone marrow, rather than from circulating PBSC, were more likely to have graft failure, but less likely to experience chronic graft-versus-host disease (cGVHD). Because cGVHD can cause significant disability in the post-transplant period, these findings may fuel a resurgence of interest in bone marrow as the favored graft source.

This study included nearly 50 transplant centers in the United States and Canada. It compared two-year survival rates for 273 patients receiving PBSC with 278 patients receiving bone marrow. Results showed PBSC resulted in better engraftment than bone marrow, but were associated with higher rates of cGVHD (53 percent compared with 40 percent in bone marrow), and the GVHD was also more severe. GVHD is a serious and often deadly post-transplant complication that occurs when the newly transplanted donor cells recognize the recipient’s own cells as foreign and attack them.

“This was an important study to conduct in a randomized, prospective manner. This new research confirms much of what we had suspected previously, but now gives patients, donors and physicians more concrete evidence to consider when deciding on the course of treatment,” said Dr. Dennis Confer, National Marrow Donor Program® (NMDP) chief medical officer, who co-authored the study.

“Our trial demonstrates that bone marrow and PBSC result in similar patient survival. While PBSC resulted in better engraftment, this did not lead to a survival benefit in our study follow-up period, but did show an increased risk for chronic GVHD,” said lead study author Claudio Anasetti, M.D., chair of the Department of Blood and Marrow Transplant at Moffitt Cancer Center in Tampa, Fla. “More effective strategies to prevent GVHD are needed to improve outcomes in these patients.”

The BMT CTN – a collaboration between the NMDP and its research arm CIBMTR (Center for International Blood and Marrow Transplant Research), the EMMES Corporation, and transplant centers throughout United States and Canada – performed the prospective, randomized study to determine if the source of the stem cell graft, whether PBSC or bone marrow, affects transplant outcomes in patients whose donors are unrelated. Approximately 70 percent of patients who need an allogeneic transplant do not have a matching donor in their family and depend on an unrelated donor.

This study was supported with funding from National Heart, Lung, and Blood Institute (NHLBI), National Cancer Institute (NCI), National Marrow Donor Program (NMDP), the Office of Naval Research, and Health Resources and Services Administration (HRSA).

PBSC are stem cells originally found in the bone marrow that have been moved, or mobilized, into the donor’s blood stream by the bone marrow-stimulating cytokine, filgrastim. Through a process called apheresis, a donor's blood is removed through a needle in one arm and passed through a machine that separates out the blood-forming stem cells. The remaining blood is returned to the donor through the other arm. Bone marrow, which contains blood and stem cells, is collected from the marrow cavity of the donor’s hipbones during a surgical procedure.

Visit http://www.nejm.org/doi/full/10.1056/NEJMoa1203517 to access the full study.