Stem cells derived from umbilical cords are a viable and effective transplant source for thousands of leukemia patients

Nov 24 2004

A new study published in 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.

"As many as 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," says Mary J. Laughlin, MD, lead author on the study and hematologist oncologist at Case Comprehensive Cancer Center and University Hospitals of Cleveland Ireland Cancer Center. "Umbilical cords that are normally discarded after birth could provide real hope for these patients."

Dr. Laughlin led an international team of researchers in collaboration with the International Bone Marrow Transplant Registry and the New York Blood Center National Cord Blood Program. They conducted an analysis and comparison of treatment results in more than 500 adult leukemia patients undergoing transplant.

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 patient's ages 16 to 60 years who underwent transplants in the United States during a six-year period ending in 2001.

Survival rates were highest (33 percent) for those bone marrow transplants with matched unrelated donors. Survival rates were the same (22 percent) 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. "Dr. Laughlin's 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 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 (the afterbirth), and the cord blood it contains, is discarded. Now a trained technician can collect the cord blood which 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 percent 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."

University Hospitals of Cleveland collaborates with the New York Blood Center National Cord Blood Program (a public cord blood bank that was the source of most of the cord blood units reported in the study) to collect cord blood donated for future patients. Recently, cord blood donated by the mother of a newborn baby at UHC proved a lifesaving option for a two-year-old leukemia patient.