Embargoed until: 5 p.m. (CST) on December 7, 1998
Contact: Michael Maggio, Director, Media Relations, [email protected]
Heidi Diedrich, Manager, Media Relations
CORD BLOOD CELLS GROWN IN LABORATORY AND USED SUCCESSFULLY IN ADULT BONE MARROW TRANSPLANTS
For the first time, physicians have been able to grow sufficient numbers of umbilical cord blood cells employing automated technology and use these cells for successful bone marrow transplants in adults. By doing so, they have opened the door to greater patient survival rates and the possibility that almost any patient in search of a bone marrow donor will be able to find one, according to a report presented today (Dec. 7) by the lead investigator from Loyola University Medical Center, Maywood, Ill.
Until now, bone marrow transplants with cord blood cells have been a treatment option only for children and those few adults weighing about 85 pounds or less because umbilical cords yield a limited cell supply that is insufficient for treating most adults with larger body sizes.
The transplants using the laboratory-grown cord blood cells were performed in extremely high-risk leukemia and non-Hodgkins lymphoma patients who had run out of treatment options and for whom a suitable bone marrow donor could not be found, said Dr. Patrick Stiff, director of the bone marrow transplantation program at Loyola=s Cardinal Bernardin Cancer Center.
Although this phase of the research was limited to the treatment of leukemia and non-Hodgkins lymphoma, transplantation of umbilical cord blood cells grown in the laboratory could eventually prove successful in treating such blood disorders as sickle cell anemia and thalassemia, breast cancer, and other cancers for which bone marrow transplantation is an option, Stiff said.
"With our ability to expand cord blood cells, not only might most patients have a donor somewhere in the world, but mortality rates may drop significantly -- a real breakthrough," Stiff said.
Presenting the study results at the annual meeting of the American Society of Hematology in Miami, Stiff and colleagues from Hackensack University Medical Center in Hackensack, N.J., reported that four of 10 patients receiving the laboratory-grown umbilical cord cells responded favorably and were currently disease-free.
"We are encouraged by these results, especially considering that all the patients in the study had advanced disease and were otherwise unlikely to survive," Stiff said.
Among the key study findings were that a perfect umbilical cord donor match was not necessary for a successful transplant to occur and that the engraftment rate -- the rate at which newly transplanted cells begin functioning as part of the immune system -- was about the same for the adults receiving the laboratory-grown cord cells as it has been for children who undergo bone marrow transplantation and are much more tolerant of any new cells.
As part of their study, researchers at the Loyola and Hackensack university medical centers tested the efficacy of new, automated technology, developed by Aastrom Biosciences
Inc., of Michigan, that promotes the expansion of marrow cells in the laboratory. The cells removed from an umbilical cord are put into a bioreactor, along with growth-promoting nutrients. The bioreactor is then placed in an incubator where the cells are nourished and allowed to expand during a 12-day period. As much as a 50-fold increase in some cells can occur during this time span.
The number of cells grown and harvested during this process proved sufficient to allow transplantation to occur in the study participants, including one patient who weighed approximately 200 pounds.
"The ability to increase the supply of umbilical cord cells in the laboratory will significantly enhance physicians= ability to treat leukemia and lymphoma in adults who have no related or unrelated marrow donor," Stiff said. "In fact, umbilical cord cells may even prove more desirable and effective than marrow cells from unrelated donors."
Like bone marrow, umbilical cord blood contains the "mother cells" that can endlessly produce the cells that the body needs to fight disease.
"The advantage of cord blood cells, however, is that they are still immunologically naive. They have not learned to identify with a particular host (body) and, therefore, are more adaptable than mature marrow cells to new environments," Stiff said. "For this reason, we do not require a perfect donor match in order to use these cells for transplantation."
Because a "perfect match" is not necessary, a supply of umbilical cord cells can be found for almost any patient, he added. Donated umbilical cord blood cells are frozen and stored in banks throughout the world.
For every five adults who develop leukemia, four are expected to die because they are either too old to undergo bone marrow transplantation or cannot find a matching donor. Only 10 percent of candidates for bone marrow transplantation have a sibling with matching marrow cells. The remainder currently must turn to the National Bone Marrow Registry to find a match.
The first-year mortality rate for patients with a related donor match is 20 percent. That jumps to 40 percent for patients who have received marrow cells from an unrelated donor and are considered a good risk. For patients with a poorer prognosis, the first-year mortality rate after an unrelated-donor transplant is as high as 70 percent due to imperfect matching.
Although autologous bone marrow transplants -- in which a small portion of a patient's own marrow cells are cleansed of disease and returned to the patient -- are sometimes an option, the mortality rate is 80 percent or more, Stiff said.
Bone marrow is the tissue inside bones where blood cells are manufactured. These cells include white blood cells, which are responsible for fighting infection and disease. The development of leukemia, lymphomas and other cancers occurs when these disease fighters lose their ability to recognize and destroy the abnormal cancer cells.
Patients with cancers for which bone marrow transplantation may be an option first undergo standard chemotherapy treatment to put their disease into remission. Because relapse of the cancer occurs in as many as 80 percent of the cases, a matching bone marrow donor is often sought while the patient remains free of the cancer.
When the disease reoccurs, patients who have matching donors and are eligible for a bone marrow transplant receive a combination of high-dose chemotherapy and radiation to kill all their diseased bone marrow, including the cancer cells. In effect, their entire immune system is destroyed. New, disease-free bone marrow cells from a matching donor are then transplanted into the patient in the hope that the patient's body will not reject these transplanted cells and that the cells will accept their new environment, expand and take over the person's normal immune function.
"We are excited because our study results open up the possibility of using umbilical cord blood cells to treat many more patients and achieve higher survival rates," Stiff added.
The federal Food and Drug Administration has approved expansion of the study to include more leukemia and lymphoma patients.
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