SEATTLEA phase III study of 168 patients with hematologic
malignancies found that those receiving peripheral blood stem cells
(PBSC) had fewer relapses, fewer deaths, and faster engraftment than
those receiving bone marrow, without a greater risk of acute
graft-vs-host disease (GVHD). Both the PBSC and bone marrow
transplants were from HLA identical sibling donors. William
Bensinger, MD, a researcher in the Clinical Research Division at the
Fred Hutchinson Cancer Research Center reported the study at the ASH meeting.
Dr. Bensinger and his collaborators at the City of Hope Medical
Center and Stanford University started the prospective multicenter
trial in 1996 to compare two features of PBSC and bone marrow
transplantsengraftment time and acute GVHD. If it could be
shown that PBSC transplants worked as well for recipients as bone
marrow transplants do, then donors could be spared the pain as well
as the anesthesia required with bone marrow transplantation.
The study included 168 patients with hematologic cancers who had
human leukocyte antigenidentical relatives able to donate
either PBSC or bone marrow. Dr. Bensinger reported on the 138
patients who received their transplants by February 1999. These
patients had a median follow-up of 21 months.
No Major GVHD Variance
The course of the patients recovery varied significantly
between treatment groups. Neutrophil engraftment took place 6 days
earlier among PBSC recipients than among bone marrow recipients (15
days vs 21 days). Platelet engraftment also occurred earlier, in this
case, by 8 days (13 days for PBSC vs 21 days for bone marrow).
Relapse rates were higher among bone marrow recipients. Two-year
survival among patients receiving PBSC was 71%, significantly higher
than the 51% survival rate among marrow recipients. The gap in
survival rates between PBSC and marrow recipients was wider in
patients with advanced disease than in patients with less-advanced cancers.
One factor that did not differ significantly between treatment groups
was GVHD. Grade 3 or 4 acute GVHD occurred in 16% of PBSC recipients
and 13% of marrow recipients. Chronic GVHD had a cumulative incidence
of 38% in PBSC recipients and 28% in bone marrow recipients, which
was not considered statistically significant.
Dr. Bensinger concluded: the use of peripheral blood stem cells
was associated with significantly higher survival and disease-free
survival, more-rapid engraftment, and equivalent acute graft-vs-host disease.