Stem Cells Show Advantage over Marrow Transplants

A large, multicenter study involving 172 patients with hematologic malignancies has found that transplants of allogeneic peripheral blood stem cells significantly increased cell production compared to marrow transplants, with 45% of marrow transplant patients and 65% of stem cell transplant patients surviving disease-free after two years. Conducted by researchers at the Fred Hutchinson Cancer Research Center (Seattle, WA, USA), the study was reported in the January 18 issue of The New England Journal of Medicine.

The incidence of acute graft-versus-host disease (GVHD) was 57% in marrow patients and 64% in stem cell patients, while the incidence of chronic GVHD was 34% in marrow patients and 46% in stem cell patients. The data offer promising news for many patients with high-risk blood cancers, say the researchers. These include patients with advanced-stage leukemia and those who have suffered one or more relapses as well as patients with lymphomas that did not respond to treatment. The advantage of stem cells over marrow transplants for low-risk patients is less clear because there is not yet sufficient data to draw conclusions.

Dr. William Bensinger, who led the study, noted that there are several reasons to be cautious about the results. Other studies suggest that stem cell patients have higher rates of chronic GVHD, which may not occur until three to five years after transplant. In a delayed reaction, the donor immune cells attack the patient's skin, liver, eyes, mouth, and joints and must be controlled with immune suppression drugs. "We won't know for another year or two if chronic GVHD shows up among these patients,” said Dr. Bensinger.



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