An Umbilical Cord for Adults With Leukemia

Umbilical-cord blood, now used mostly to treat children with leukemia, could save thousands of adults a year who cannot find bone marrow donors, two research studies indicate.

A European study found that patients who received cord blood were as likely to be free of leukemia two years later as those who received bone marrow. A U.S. study looking at three-year survival yielded results almost as promising.

The studies were published in Thursday’s New England Journal of Medicine.

To Dr. Mary M. Horowitz of the Medical College of Wisconsin, senior author of the U.S. study, the message is clear: Umbilical-cord blood can save adults.

Leukemia patients often undergo radiation or chemotherapy to kill their cancerous white blood cells -- a treatment that wipes out their immune systems too. To restore their immune systems, doctors give these patients an infusion of bone marrow or umbilical-cord blood, both of which contain stem cells capable of developing into every kind of blood cell.

Cord blood offers an important advantage over marrow that makes it particularly valuable for use in transplants: Its stem cells are less likely to attack the recipient’s body. That allows a wider margin of error in matching donors and recipients.

Until now, cord blood had been considered suitable only for children because each donation has only about one-tenth the number of stem cells of a marrow donation.

In the European study, involving 682 patients, about one-third of both those who got matched marrow and those who got cord blood that did not quite match their own tissues were alive after two years. In the U.S. study of 601 patients, about one-third of those who got matched marrow remained leukemia-free compared with about one-fifth of those who got cord blood or unmatched marrow.

Both studies were based on records from transplants in the late 1990s and early 2000s.

Using cord blood could improve the odds of eventually getting a transplant for the 16,000 U.S. adult leukemia patients each year who cannot find a compatible marrow donor, said the U.S. study’s leader, Dr. Mary J. Laughlin of Case Comprehensive Cancer Center in Cleveland.

Still, Dr. Nancy Kernan, assistant chief of marrow transplantation at Memorial-Sloan-Kettering Cancer Center in New York, said cord blood transplants in adults should be done only as part of studies to look at and improve their effectiveness.

Public cord blood banks -- where blood drawn from umbilical cords and placentas at birth is kept frozen -- would need to quadruple their supply to find a match for every leukemia patient who needs one. With 4 million births a year in this country, and most cord blood thrown away, that should not be a problem after additional public money becomes available, doctors said.

A federal Institute of Medicine committee is looking into the best way to set up a national cord blood supply, and is scheduled to complete its report in March.

“I know our committee will consume this study avidly,” said Kristine Gebbie, chairman of the group.

The first bone marrow transplants were done in the 1960s; cord blood transplants started in the 1990s. Stem cell transplants save 20% to 30% of patients who hope to grow new immune systems. But without the treatment, virtually all of them would die.