SEATTLE--Early donor matching and transplant appear to be particularly
important in improving survival rates in chronic myeloid leukemia
(CML) patients receiving unrelated donor marrow, John A. Hansen,
MD, said at the plenary session of the American Society of Hematology
annual meeting. In fact, he said, in selected patients, survival
rates approach those of patients receiving marrow from HLA-identical
The anticipated 3-year survival rate for CML patients in chronic
phase who receive marrow from an HLA-identical sibling has been
about 80%, while 2-year disease-free survival in patients receiving
unrelated donor transplants has ranged from 36% to 45%.
The new study, conducted at the Fred Hutchinson Cancer Research
Center and the University of Washington, Seattle, showed 74% 3-year
survival in selected patients with HLA-matched unrelated donors
and early transplantation.
Dr. Hansen, professor of medicine at the University and head of
the Human Immunogenetics Program at Fred Hutchinson, said that
the study included 333 CML patients receiving non-T-cell-depleted
bone marrow cells following cyclophosphamide and total body irradiation.
Methotrexate and cyclosporine were administered after the transplant
for prevention of graft-versus-host disease (GVHD).
Although a majority of the patients in the study were HLA-A, B,
DRB1 identical with their donor (75%), the remaining 25% involved
at least one minor donor mismatch for HLA-A, B, or DR antigens,
Dr. Hansen said. Patient ages ranged from 5 to 55 years, with
a median of 36 years.
The study found that, for patients under age 50, the probability
of surviving 3 years post-treatment was 74% if transplantation
from an HLA-matched donor occurred less than 1 year after diagnosis
In comparison, the 3-year survival rate dropped to 57% if transplantation
was done more than 3 years following diagnosis. Survival dropped
even further, to 40%, if the marrow was from a mismatched donor
and transplantation was done more than 3 years after diagnosis.