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Stephanie Feher (sfeher@pcipr.com)
Erin Duncomb (eduncomb@pcipr.com)
Public Communications Inc.
312-558-1770

EMBARGOED UNTIL FEBRUARY 17, 2006

AT A GLANCE - Umbilical cord blood transplant gaining in acceptance; provides new hope for children with severe leukemia who have no other options. - Cord blood expands transplant for patients who otherwise face near-certain death. - Data presented by Duke University researchers, who performed world’s first unrelated donor cord blood transplant in 1993.

EMBARGOED UNTIL 12:01 A.M. FRIDAY, FEB. 17, 2006 (EST) [7:01 P.M. HST]

Umbilical Cord Transplant Increases Odds of Finding Suitable Transplant Donor, Improves Survival for High-Risk Children with Leukemia

HONOLULU (February 17, 2006) – Transplant with stem cells harvested from umbilical cords is improving survival for some children with leukemia who otherwise face near-certain death. Results with the technique in 97 children with acute myeloid leukemia (AML) who did not have a suitable family donor were reported here today at the BMT Tandem Meetings.

Overall, approximately 40 percent of the children survived after transplant.

"The use of umbilical cord blood stem cells has greatly increased the reach of transplant for many patients who cannot find or do not have time to wait for a transplant from an unrelated donor," said Vinod K. Prasad, M.D., assistant professor, division of pediatric blood and marrow transplantation, department of pediatrics, Duke University Medical Center, Durham, N.C.

Umbilical cords are rich in hematopoietic stem cells, undifferentiated cells that can divide and become different types of blood cells. Because umbilical cord blood cells have not been exposed to many foreign agents such as bacteria and viruses, they are more immunological "naïve" and less likely to cause complications such as severe life-threatening graft vs. host disease (GVHD), an attack on the recipient by immune cells from the donor. GVHD was not a primary factor in the deaths of any of the children in the study, Dr. Prasad said.

The children were treated from 1995 – 2005, and represented a subset of AML patients with severe disease who were referred to Duke University after chemotherapy and in some cases a transplant had failed. Fifteen of 51 patients with relapsed or refractory disease (leukemia that was resistant to chemotherapy or recurred and then did not respond) survived, and 24 of 46 patients whose disease was in remission but had a high probability of recurrence survived, Dr. Prasad said.

"Although the death rates were higher in the relapse patients in comparison to the overall population of children with leukemia, the results are very promising. These children represent the most severe cases, and nearly all would have died within weeks or months without transplant," he said.

Before transplant, patients were pre-treated with conditioning regimens consisting of chemotherapy and/or total body irradiation to kill the body's stem cells and white blood cells, including the cancerous leukemia cells. Cord blood infused into the blood stream after conditioning regimens to replace the blood cells destroyed by these treatments develop into new and healthy blood and immune system cells.

"Our results were especially promising when the conditioning regimen included a chemotherapy drug called Melphalan. The three-year probability of survival in relapsed or refractory patients who received this conditioning regimen was 39 percent – a significantly higher survival rate than would be expected for such desperately ill children," he said.

Finding a Transplant Donor
There are as many as 7 million adults registered as potential stem cell donors in the United States and elsewhere, compared to approximately 50,000 umbilical cords available for transplant. Yet the chances of finding a suitable donor, harvesting the stem cells and performing transplant in time to save the child's life are much greater when umbilical cord blood is used, Dr. Prasad said. Umbilical cord transplant also offers hope to many non-Caucasian children because other ethnic groups are under-represented in the available pool of volunteer donors. More than one-third of the children in the Duke study were of African-American, Latino, Asian-Indian, Asian, or Middle Eastern descent. Duke University, which performed the world's first unrelated donor umbilical cord blood transplant in 1993 under the direction of Dr. Joanne Kurtzberg, treats patients from throughout the United States and other nations.

"The best chance for survival is when the child has a family donor, usually a sibling, whose blood is a good match for the patient," said Dr. Prasad. The chance that a brother or sister's blood will match that of the patient is 25 percent. "In these cases, survival is as high as 60-80 percent. But when there is no family donor, it can sometimes be very difficult or impossible to find a good match despite the large number of registered donors."

Donor-recipient matching is primarily based on the compatibility of molecules on the blood called human leukocyte antigens (HLA). With adult donors, you must have a very stringent matching for 8-10 antigens to make transplant feasible, and success is more likely with a perfect match. "In many cases, you can search the databases of millions of available donors and not find a suitable match," said Dr. Prasad. With umbilical cord blood, a less stringent match is acceptable and a successful transplant can be performed because the donor cells are less reactive against the recipient's immune system.

"Umbilical cord transplant also can be performed much more quickly than transplanted cells from a living donor, a process that can take up to two months or more. In this group of critically ill children, there is not enough time to wait that long. Because umbilical cord blood is frozen and readily available, transplant can be performed within two to three weeks," he said. The umbilical cord and the placenta connect the unborn baby to its mother and supplies the needed blood and nutrients during pregnancy. Cord and the placenta is often discarded after birth. Instead, without risk to the mother or the baby, it can be collected, tested and stored in public cord blood banks and made available to patients in need of a transplant donor.

"Umbilical cord transplantation is rapidly gaining acceptance as an advance in transplantation. Ours and other studies show that this technique holds great promise for improving survival for children with the most severe forms of leukemia for whom there is no other hope," said Dr. Prasad. The technique has also shown success in treating some inborn metabolic diseases such as Krabbe, Hurler, and SanFilippo syndromes.

AML is a particularly virulent form of leukemia, and up to 50 percent of patients will need transplant to have a chance for survival. Other types of the disease, such as acute lymphoid leukemia (ALL), more often can be successfully treated with chemotherapy alone and only approximately 25 percent require transplant.

In the children who died, death was caused by uncontrolled disease, infection and toxicity related to treatment. "Many of these patients had previously undergone multiple courses of chemotherapy and in some cases even transplants, which have a cumulative effect, putting them at high risk for treatment-related death," according to Dr. Prasad.

Co-authors of Dr. Prasad's presentation at the BMT Tandem Meetings are J. Wu, S.H. Parikh, T.A. Driscoll, P. Szabolcs, P.L. Martin, S. Carter and J. Kurtzberg.

The BMT Tandem Meetings are the joint annual meetings of two leading professional organizations dedicated to research, education and patient care in the field of blood and marrow transplantation and cellular therapy. The Center for International Blood and Marrow Transplant Research (CIBMTR), based in Milwaukee, is an affiliation of the International Bone Marrow Transplant Registry (IBMTR) of the Medical College of Wisconsin and the research arm of the National Marrow Donor Program, which collects, analyses and disseminates clinical data on blood and marrow transplantation and conducts original research to determine the most effective BMT strategies. The American Society for Blood and Marrow Transplantation, based in Arlington Heights, Ill., is a professional association of clinicians, investigators and other health personnel promoting blood and marrow transplantation research, education, scholarly publication and clinical standards. For more information on the BMT Tandem Meetings, visit www.asbmt.org/annualmeet.