Phase I Trial Promising for Cord Blood Transplant "Booster"
MIAMI, FL -- Adding a dose of slightly more mature stem cells to an umbilical cord blood transplant shows promise for increasing the success of transplants in children, Duke researchers reported Friday.
In results of a phase I trial prepared for presentation at the annual conference of the American Society of Hematology, Dr. Joanne Kurtzberg, who directs Duke's pediatric bone marrow and cord blood transplant program, said laboratory expansion of stem cells appears to be a safe and effective step in enhancing cord blood transplant.
In the trial, a small sample of umbilical cord blood was drawn from the transplant material at the time of transplant. Stem cells were placed in media within a special cell production system, similar to an incubation system, and allowed to grow for 12 days. After the 12 days of ex vivo growth, the "booster" cells were given to the transplant recipient by intravenous infusion.
Of the 28 patients enrolled in the initial phase of the ex vivo expansion trial, 19 had successful cord blood booster transplants. The remaining patients lacked sufficient cells in the transplant material for expansion.
Before this trial, researchers had shown that the system developed by Aastrom Biosciences was successful in growing cells in the laboratory setting. However, the Duke trial marked the first time ex vivo expansion of cord blood stem cells had been infused in patients.
"We are pleased with the Aastrom system for growing the stem cells, and know it is working well," Kurtzberg said. "In our next step, we will be looking at increasing effectiveness by growing the cells prior to transplant and giving the mature cells at the same time the patient receives the transplant unit."
Allowing some of the stem cells to mature, Kurtzberg said, may provide added protection against infection for the patients by boosting the number of white cells in their system. While it's too early to say, Kurtzberg said she thinks the boost of mature stem cells may lead to swifter engraftment.
"One of the concerns with cord blood transplant is the effect of the lower volume of transplant material," she said. "We know transplant can be done with less cord blood than bone marrow, but we think that patients have a better chance of engrafting, and engrafting more quickly, when the amount of transplant material is greater. Knowing that we can expand the unit could lead to cord blood transplant being more available to more people."
Kurtzberg said another factor to be studied is the type of growth media used in the expansion process.