Umbilical Cord Blood Provides New Hope for Leukemia Patients

A study published in the Nov. 24, 2004 issue of the New England Journal of Medicine confirms that stem cells derived from the umbilical cords of newborn babies are a viable and effective transplant source for thousands of leukemia patients who have no other treatment option.

Nearly 16,000 leukemia patients diagnosed each year require a bone marrow transplant, but have no matched relative or can't find a match in the national bone marrow registry, according to Mary Horowitz, MD, senior author of the study and the Robert A. Uihlein Jr. Professor of Hematologic Research at the Medical College of Wisconsin. She practices at Froedtert Hospital, a major teaching affiliate of the Medical College.

Dr. Horowitz, who is scientific director of the Center for International Blood and Marrow Transplant Research (CIBMTR), points out that "umbilical cords that are normally discarded after birth could provide real hope for these patients." CIBMTR is a joint program of the Medical College and the National Marrow Donor Program.

This study was coordinated at the CIBMTR Statistical Center in Milwaukee and made use of large databases of transplant outcomes maintained by the CIBMTR and the New York Blood Center National Cord Blood Program. Working with Dr. Horowitz is a team of researchers led by Mary J. Laughlin, MD, hematologist/oncologist at Case Comprehensive Cancer Center and University Hospitals of Cleveland Ireland Cancer Center and Drs. Cladd Stevens and Pablo Rubinstein of the New York Blood Center. They conducted an analysis and comparison of treatment results in more than 500 adult leukemia patients undergoing transplant.

Transplant Outcomes Analyzed
Researchers directly compared patients who had cord blood stem cell transplants with two groups: patients who had fully-matched unrelated bone marrow transplants and patients who had one antigen-mismatched unrelated bone marrow transplants. The study included patients age 16 to 60 who underwent transplants in the United States during a six-year period ending in 2001.

Survival rates were highest (33%) for those bone marrow transplants with matched unrelated donors. Survival rates were the same (22%) for cord blood and one antigen-mismatched unrelated bone marrow transplant patients - results that clearly indicate the efficacy of cord blood stem cells when bone marrow donors are unavailable, according to Dr. Laughlin, an associate professor of medicine at Case Western Reserve University School of Medicine.

"These are very high-risk patients who undergo cord blood transplants only as a last resort effort to stay alive," Dr. Laughlin says. "Even with a cord blood transplant, these patients often suffer from life-threatening infections. But the fact is, without attempting this innovative therapy, none of them would survive."

"Techniques that extend the availability of stem cell transplantation to those patients in desperate need are an important and valuable step in the right direction," said Marshall Lichtman, MD, The Leukemia & Lymphoma Society's Executive Vice President. "The study gives renewed hope to adult patients without a sibling stem cell donor. Continued research is needed, however, to improve the outlook for the large proportion of patients who do not yet benefit from these approaches." The Society helped fund the study.

Cord Blood Provides Stem Cells
Cord blood transplantation provides leukemia patients with stem cells, enabling them to produce healthy blood cells in a procedure previously shown to be highly effective in children with the disease. As a stem cell source, umbilical cord blood is not controversial and readily available; in fact, cord blood is normally discarded after a baby's birth.

New mothers can donate cord blood immediately after delivery. Ordinarily, the placenta, and the cord blood it contains, is discarded. Now, a trained technician can collect the cord blood that remains in the placenta after the baby is born and the cord is cut. The donated cord blood is processed and frozen and stored for any patient in the future that might need a transplant.

The availability of cord blood makes it a logical choice for doctors and their patients when a matching bone marrow donor cannot be found. A patient's best chance for survival comes from a bone marrow donor who is related to the patient and matches the patient's tissue type. A bone marrow transplant from an unrelated donor may be an option when there is no donor available in the family, but offers a poorer chance for survival, even when fully matched.

"The fact is, approximately 20,000 leukemia patients nationwide need transplants but only 20% of them have a sibling match, so there remains a large group - about 16,000 patients - who are forced to seek donors from a marrow donor registry in hopes of finding a match from donors who aren't related to them," Dr. Laughlin says. "But only a small percentage of patients are lucky enough to find a transplant match at the registry, which is why the cord blood transplant is so important."

The study was funded by the National Cancer Institute, the National Institute of Allergy and Infectious Diseases, the National Heart Lung and Blood Institute, the Abraham and Phyllis Katz Foundation, The Leukemia & Lymphoma Society, American Society of Clinical Oncology and the Children's Leukemia Research Association.

For more information on this topic, see the HealthLink article Leukemia Patients Treated with Cord Blood Face Lower Risk of Complications.

MCW Health News presents up-to-date information on patient care and medical research by the physicians of the Medical College of Wisconsin.