SAN FRANCISCOUmbilical cord blood transplants provide
new hope for children with leukemia and genetic diseases requiring
transplantation, Joanne Kurtzberg, MD, said at the 42nd Annual Meeting of the
American Society of Hematology (ASH). She reported that 53% of pediatric
patients treated with cord blood transplant at Duke University are surviving.
In this single-institution study, the largest ever conducted
using cord blood, 208 patients under the age of 18 received umbilical cord
blood transplants from unrelated donors between 1993 and 2000 at Duke
University Medical Center. Patients had hematologic malignancies, genetic
disorders, immune deficiencies, and metabolic disorders, all of which were
incurable without a marrow replacement. Life expectancy was less than 1 year.
The transplants were successful in 108 patients, who are alive
at a median follow-up of 2.3 years, said Dr. Kurtzberg, director of the
Pediatric Stem Cell Transplantation Program at Duke.
For patients with acute lymphocytic leukemia (ALL), 3-year
event-free survival is 46%, while those transplanted in first remission have an
event-free survival rate of 80%. ALL patients treated before the age of 1 had
the best survival rates, with 22 of 25 (90%) still alive and free of disease at
Event-free survival at 3 years was 80% in patients with chronic
myelogenous leukemia (CML) in chronic or accelerated phase and 88% in patients
with myelo-dysplastic syndromes.
"Diseases that in the past have been incurable can now be
cured if patients are referred early for treatment with umbilical cord blood
transplants from an unrelated donor," Dr. Kurtzberg said.
Transplants of cord blood, taken from a baby’s umbilical cord
and the placenta, can be used successfully in patients because the HLA antigens
do not need to match those of the recipient as closely as in bone marrow
Only seven patients (3%) in the Duke study received transplants
in which all six antigens matched exactly; 185 patients (89%) received cord
blood transplants in which only four or five of six antigens matched (59% and
30%, respectively). Sixteen (7%) children received haplo-identical umbilical
Chronic GVHD Reduced
HLA disparity had no adverse effect on survival, the
researchers concluded, adding that this may be due to the fact that fetal blood
cells are immunologically immature and do not trigger rejection of tissue.
The rate of chronic graft-versus-host disease (GVHD) is only 9%
in umbilical cord blood transplant patients vs 100% in unrelated bone marrow
transplant patients, Dr. Kurtzberg said in an interview with ONI. Chronic GVHD
causes significant morbidity and is responsible for half of the late deaths in the marrow
"This means a lot of bone marrow transplant patients are
really sick and can’t have a normal quality of life," Dr. Kurtzberg
said, "whereas these kids receiving cord blood have a rough first 3
months, but after that, they recover and don’t have late complications from
their transplants. In pediatrics, that is our goalwe’re not looking at
buying somebody a year, we’re looking at buying somebody decades."
Dr. Kurtzberg said that 95% of patients can find a two-antigen
mismatched umbilical cord blood donor. Such mismatched transplant patients
experience no significant differences in time to engraftment, compared with
related donor transplant groups. In multivariate analysis, she said, the cell
dose/kg was the only statistically significant variable predictive of a
Possibilities and Options
Physicians must learn about these possibilities for children,
Dr. Kurtzberg told ONI. "The family of a child who doesn’t have a bone
marrow donor shouldn’t be told that there are no options," she said.
"Ninety percent of the time you can find a mismatched, but suitable, cord
blood donor, and the outcomes are at least comparable to those with unrelated
bone marrow transplants, and may be better."