Japanese researchers have reported that umbilical cord blood transplants can be carried out more rapidly and achieve better results than unrelated donor stem cell transplants. The details of this report appeared in the December 1, 2004 issue of Blood .[1]
Allogeneic stem cell transplants are an important component of the treatment of adults with acute leukemia. The first choice for a donor of stem cells is an HLA-matched relative; however, such an ideal donor is only available for a minority of patients, resulting in the need to expand the donor pool. It has been determined that related donors who are mismatched for only one HLA antigen are also suitable stem cell donors. Over the past two decades, there has been a marked increase in the number of unrelated donor transplants, with outcomes similar to those achieved with related donor transplants. However, because of genetic disparity, unrelated matched donors cannot be found for many patients, especially for those with unusual HLA types, such as those found in many minority populations. In addition to the genetic problem, many patients die while seeking an unrelated donor, which can be a lengthy process. Umbilical cord blood offers an alternative source of stem cells that are immediately available and there is evidence that the degree of mismatching for HLA antigens is not as it is for marrow or blood stem cells. The major limitation of umbilical cord blood transplants is the low cell number with delayed or absent engraftment. There has been skepticism that single units of cord blood would be adequate for full engraftment in adults.
In a study carried out by the International Bone Marrow Transplant registry, it was reported that transplant-related mortality was similar between umbilical cord blood transplants and mismatched unrelated donor transplants, but worse for umbilical cord transplants when compared to HLA-matched, unrelated donor stem cell transplants. A similar effect was seen for leukemia-free and overall survival, with HLA-matched, unrelated transplants being superior.[2] Another study was reported by the Acute Leukemia Working Party of European Blood and Marrow Transplant Group and the Eurocord-Netcord Registry.[3] This analysis included 682 adults with acute leukemia, of whom 98 received an umbilical cord blood transplant and the remainder received a matched unrelated donor transplant. There were no statistically significant differences in chronic GVHD, transplant-related mortality, relapse, leukemia-free survival or overall survival between umbilical cord blood transplants and HLA-matched unrelated donor transplants.
There were 45 unrelated stem cell recipients and 68 cord blood recipients in this comparison. The median weight of the unrelated donor marrow recipients was 59.6 kg and the median weight of the cord blood recipients was 55.1 kg. Umbilical cord blood transplants were performed at a median of 2 months after initiating a search, compared to 10 months for unrelated marrow recipients. The one year treatment-related mortality was 9% for cord blood recipients and 29% for unrelated marrow recipients. Relapse rates were 16% for cord blood and 25% for unrelated bone marrow. Disease-free survival was 74% for cord blood and 44% for unrelated bone marrow.
Comments: The current study is the first to report survival advantages for umbilical cord blood transplants compared to unrelated donor stem cell transplants. These and other data support the concept that umbilical cord blood transplants are a viable alternative to unrelated donor stem cells. The most important aspect of umbilical cord blood transplants may not be in finding suitable donors, but may instead be the rapidity with which the stem cells can be obtained. Many patients die while a search for an unrelated donor is being carried out and this may change with these promising results.
[1] Takahashi S, Iseki T, Ooi J, et al. Single-institute comparative analysis of unrelated one marrow transplantation and cord blood transplantation for adult patients with hematologic malignancies. Blood. 2004;104:3813-3820.
[2] Laughlin MJ, Eapen M, Rubinstein P, et al. Outcomes after transplantation of cord blood or bone marrow from unrelated donors in adults with leukemia. New England Journal of Medicine . 2004;351:2265-2275.
[3] Rocha V, Labopin M, Sanz G, et al. Transplants of umbilical-cord blood or bone marrow from unrelated donors in adults with acute leukemia. New England Journal of Medicine . 2004;351:2276-2285.
Tigard Girl Recovering From Rare Procedure
|
4-Year-Old Only The 15th To Receive Procedure
|
Four-year-old Olivia Medici suffers from a disorder which causes her organs to shut down.Her only hope to live was a Cord Blood Stem Cell transplant. In a North Carolina hospital on Thursday, Olivia became the 15th child in the world to undergo the procedure. |
MSC type bone marrow transplant possible in India
Ahmedabad, Jan 8: The bone marrow stem cell transplant of mesenchymal stem cells (MSC) and hematopoietic stem cells (HSC) type are now possible in India, opening new avenues for treatment of incurable malignant or genetic disorders.
Dr Alok Shrivastava of the CMC Vellore, who is working on the bone marrow stem cells research said,“Our ability to collect and manipulate the HSC so as to purify them has allowed a novel type of transplantation where stem cells from half HLA matched donors, like parents, can be used for transplantation.”
The bone marrow stem cells therapy has enabled thousands of patients to be cured with bone marrow transplantation from HLA matched related donors since 1960. More recently, peripheral blood cells have been used with advantage for the same purpose.
He said, the major limitation in this process had been the lack of suitable donors. Search of alternatives had led to large donor registries being created and use of cord blood banks.
Dr Shrivastava, who is here to attend the 92nd Science Congress, said in recent years apart from the HSC, it had become apparent that the bone marrow had other stem cells that could be used for therapy. The best evaluated of these is the MSC.
Both HSC and MSC have been used for tissue repair and regeneration in different situations, he said adding their use for treatment of myocardium had really caught attention with multiple reports from different countries.
Novel applications also included treatment of brain and spinal cord injuries but more animal data is needed before wide clinical applications.
The possibility of treating inflammatory bowel diseases with such cellular therapy in the animal model was also being explored. Apart from the ability to regenerate damaged tissues, msc also seems to have immune modulatory effects.
He said work was also underway to explore whether this could also be used in organ transplantation such as kidney transplant. If successful it would make this modality of treatment more affordable for people as long term immuno-suppression.
He said the MSC which has the tendency to grow rapidly and extensively in culture system made it an attractive option for transduction with genes of interest that could be transferred into human beings lacking their function.Massachusetts State House News
Friday, January 7, 2005
BOSTON - State Sen. Scott Brown, along with Representative-Elect Richard Ross, recently filed legislation that instructs hospitals to inform patients about umbilical cord blood donation.
Recent studies have indicated new uses for donated umbilical cord blood. In addition to its traditional use as a treatment for children with leukemia, umbilical cord blood now appears to be an effective alternative to bone marrow treatment for adults with the disease who are unable to find a bone marrow match.
Donated umbilical cord blood can also provide stem cells for medical research, sidestepping the embryonic cell debate.
"Umbilical cord donation is a great alternative," said Brown. "It avoids the ethical debate over embryonic cells because these cells are obtained after the birthing process is complete."
Cord donation is free to the patient and a certified blood bank works with the hospital to collect the donation. Under current procedures, most umbilical cords are simply thrown away.
The bill instructs hospitals to offer a pregnant patient the option to donate her umbilical cord blood, except in cases where such a donation would contradict the religious doctrine of the hospital. The bill also provides an explicit exemption to a patient's right to donate if medical professionals feel the donation procedure could threaten the health of mother or baby.
"We want expectant mothers to know about this important option to help save lives," said Brown. "It's up to them if they want to participate, but it's important our medical community make the information available."
A constituent first brought this issue to Senator Brown's attention. The bill was then modeled after a similar law in Illinois.
It is a source of constant amazement that demonstrable progress in the use of adult stem cells to treat disease and injury in real people is virtually ignored, while embryonic stem cell research involving rodents gets headlines and editorials, such as the editorial [Jan. 3] trumpeting an experiment in which paralyzed rats were able to walk after being injected with human embryonic stem cells.
Adult stem cell research progress ignored
January 7, 2005
There were no headlines or editorials, for example, when Song Chang-Hoon, a professor at South Korea's Chosun University's medical school, told the story of Hwang Mi-Soon, a 37-year-old paraplegic who, after being paralyzed for 20 years, was able to rise from her wheelchair and is now shuffling back and forth with the aid of a walker after umbilical cord blood stem cells were injected into her spine.
Some of the studies that led to this virtually unreported Korean miracle were ironically funded by the Christopher Reeve Paralysis Foundation, and had Reeve sought the same therapy instead of obsessing about embryonic stem cells, he might have gotten out of his wheelchair as well.
The unreported problems with embryonic stem cells is that they suffer immune system rejection problems, they often cause tumors such as teratomas, and they are extremely difficult to convert to any specific type of cell.
Adult stem cells have been used therapeutically since the 1980s, and there are almost 80 therapies using them -- actual treatments, not theory or research. There have been more than 250 adult stem cell clinical trials. There are zero treatments using embryonic stem cells, and there have been zero clinical trials.
The simple truth is that most progress in stem cell research is being made using the adult rather than the embryonic variety. And the truth is that a biased media is largely ignoring that fact, while portraying opponents of embryonic stem cell research as heartless Bible-thumpers prolonging human suffering.
Daniel John Sobieski, Garfield Ridge
Family with cancer history banks umbilical cord blood
Two weeks after Cindy Aggson returned from her honeymoon, her mother passed away from non-Hodgkins
With a history of cancer in the family -- Cindy's husband, Roger Aggson, also had lost relatives to cancer -- the Washington County couple decided to bank their youngest son's cord blood, an increasingly popular practice that capitalizes on the ability of special cells in the umbilical cord to treat a variety of life-threatening diseases.
"It's like insurance," said Cindy Aggson, who paid $1,700 to bank her now-3-month-old son's cord blood with a private company, the San Bruno, Calif. -based Cord Blood Registry (CBR). "You pay into it, but you don't know if you're going to need it."
Cord blood refers to the blood that remains in the umbilical cord after it is separated from the newborn following childbirth. (Like the placenta, the umbilical cord is usually discarded after childbirth.) Because cord blood is rich in stem cells, a special type of cell that generates blood cells, said Janice Olson, medical director of the Cancer and Blood Disorders Program at Legacy Emanuel Hospital & Health Center, it is useful in treating leukemia and other malignancies of the bone marrow as well as some immune deficiencies and sickle cell anemia.
Cord blood stem cells, which regenerate blood, differ from the more controversial embryonic stem cells, which have the ability to differentiate into any cells in the body.
Families who want to bank their child's stem cells have several options. Since CBR's launch 10 years ago, more than 80,000 families have stored cord blood with the company, said spokeswoman Amy Seirer. During that same period, CBR has released 35 samples for client use. In one case, a child's stored cord blood was used in a bone marrow transplant to cure a sibling with sickle cell anemia.
From the mom's perspective, said Aggson, cord blood banking is a simple process. Before her son's birth, Aggson contacted CBR, which mailed a collection kit overnight. In the delivery room, after the umbilical cord was severed, a nurse used a syringe to extract the blood. The Aggsons then used a courier service to ensure the kit would arrive at CBR within 24 hours.
"It was so easy," Aggson said. "Everybody was super friendly and super nice." In addition to the up-front cost, CBR charges a $95 annual storage fee to maintain the cord blood at the requisite minus 180 degrees Celsius.
Despite Aggson's positive experience, most doctors encourage parents to bank cord blood with public agencies rather than private companies.
"I heartily recommend that parents bank cord blood with the Red Cross," Olson said. "I would recommend against banking cord blood privately." Her concerns have less to do with the legitimacy of private-sector practices -- there are several companies that offer the service -- than with the slim chance that a child would actually use his or her own cord blood. Parents who give cord blood to the Red Cross do so with the understanding that it is a donation and that the agency may release the stem cells to others. Over the past year the Red Cross has collected and stored 350 cord blood donations for transplant use and has sent out 100 units.
Over the past 10 years, Olson said, autologous cord blood transplants -- in which the patient receives stem cells that have come from her own blood -- have rarely been used. Research suggests that allogenic cord blood transplants -- in which blood comes from someone other than the patient -- are more effective in treating diseases, she said.
Parents should weigh the relatively high expenses of private storage against the small possibility that a child will actually develop a life-threatening disease, said Alfred Ono, Aggson's obstetrician at Legacy Good Samaritan Hospital and Medical Center. "It's similar to people saying, 'What if I get testicular cancer? Should I save my sperm now?' The question is, do you really want to spend that money?"
For Aggson, the answer is a definite yes, "even if there's just a slight chance I will use this," she says. "I would never forgive myself if I decided not to pay the money and something happened."
Besides, she adds: "Who knows what they might be able to do with cord blood in the future? I believe in technological advances."
SAN BRUNO, Calif., Dec. 30 /PRNewswire/ -- Coming to the end of a year of
geometric growth, Cord Blood Registry (CBR), the world's leading newborn stem
cell bank, has won a second decisive victory against PharmaStem Therapeutics,
Inc.'s claims of patent infringement relating to CBR's newborn stem cell (cord
blood) preservation business.
U.S. District Judge Gregory M. Sleet, who had already overturned a multi-
million dollar jury verdict awarded to PharmaStem Therapeutics, Inc., dealt a
further setback when he denied PharmaStem a second trial in the patent case.
Judge Sleet ruled that CBR did not infringe on either of the two patents that
the jury relied on in their October 2003 verdict. "There was no legally
sufficient evidentiary basis for a reasonable jury to find that the companies
infringed the patents," Sleet wrote in an eight-page opinion. Both PharmaStem
patents are currently under re-examination by the Patent and Trademark Office.
"We are pleased that the court recognizes the overwhelming evidence
presented and has denied a new trial," says Stephen Grant, VP and co-founder
of CBR. "The decision enables us to keep our focus on the rapidly expanding
market demand and the high quality, lifesaving service that we provide."
CBR's 35th transplant is scheduled to take place this week in California.
As of December 2004, CBR had provided more clients with stem cells for medical
therapies than all other family cord blood banks combined. Studies have shown
that survival rates can more than double when genetically related newborn stem
cells are used for patients compared to unrelated newborn stem cells. "Our
service is a critical part of giving families access to the best medical
treatments available," says Grant. "The PharmaStem patents threatened to
require a licensing fee for each unit stored, which would have increased costs
to families."
Derived from the blood remaining in the umbilical cord following birth,
newborn stem cells are used to treat serious diseases such as leukemia,
lymphoma, and sickle cell anemia. Because it can only be collected at birth, a
growing number of expectant parents are arranging to store their newborns'
stem cells as both "biological insurance" in case of future illness and as a
"biological resource" to take advantage of new treatments using their
regenerative power for treating diseases like diabetes and Alzheimer's, and
repairing damage from heart attack, stroke, and even spinal cord injury.
Recently, newborn stem cells made headlines in the highly publicized story
of a paralyzed 37-year-old South Korean woman who was able to walk for the
first time in 20 years after being treated with newborn stem cells. (Visit
http://www.cordblood.com to see more about this story.) This and other news about
emerging therapies has lead to an increase in demand for CBR's cord blood
banking service. "Our enrollments are up more than 100% over this time last
year," says Johnnie Domingue, CBR's CFO and COO.
About Cord Blood Registry
Cord Blood Registry is the leader in newborn stem cell processing and
cryopreservation for familial use in transplantation and regenerative
medicine. The stem cells preserved by CBR are collected immediately after the
birth of a newborn and are then available to be used in treatments for the
newborn, siblings, and any compatible genetic family member. Once
transplanted, the cells have the ability to repair damaged or diseased tissues
with little risk of rejection and increased long-term survival. The company's
research and development is focused on advancing the collection, processing,
and storage methods to optimize quality and cell yield. Additionally, CBR
facilitates collection of donated research samples, available for the nearly
200 research programs worldwide that are focused on stem cell expansion and
cell-based therapies. For more information visit http://www.cordblood.com, or
call 1-888-CORD BLOOD. Cord Blood Registry is a registered trademark of Cbr
Systems, Inc.
Media Relations Contact: Rita Kennen, Cord Blood Registry
1-800-588-6377, Ext. 239
rkennen@cordblood.com
Website: http://www.cordblood.com/
SOURCE Cbr Systems, Inc.Web Site: http://www.cordblood.com
South Dakota Bill would set up cord-blood donation system
PIERRE - New mothers in South Dakota would be able to donate the medically valuable blood from their babies' umbilical cords and placentas under a bill to be offered by Rep. Elizabeth Kraus, R-Rapid City.
The state has no system under which to donate cord blood, Kraus said. Cord blood, which contains stem cells and can be used in place of bone-marrow transplants, is currently discarded as medical waste.
"Something that is normally wasted can be used to save and improve lives without taking a life," Kraus said.
Kraus will introduce her bill when the Legislature convenes its 2005 session on Tuesday, Jan. 11.
The stem cells in cord blood are less controversial than embryonic stem cells, Kraus said.
Kraus's bill would require hospitals to offer each new mother the option of donating the cord blood. The expense of collecting, transporting and storing the blood would be borne by the cord-blood bank that takes the donation, she said.
Kraus's bill will follow federal legislation passed in 2001 that helped establish a national registry of cord blood, according to the Web site for the National Marrow Donor Program, www.marrow.org. The registry helps match patients suffering from blood diseases such as leukemia and others who would otherwise need a bone-marrow transplant. Earlier this year, Illinois became the first state to require hospitals to give new mothers the option of donating cord blood.
Scientists are studying the blood-forming cells from cord blood as a new method for treating patients with life-threatening diseases, including leukemia, lymphomas, immune-system disorders and inherited metabolic diseases.
According to the National Marrow Donor Program, blood in the umbilical cord and placenta is unique because it contains large numbers of blood-forming cells. Cord blood does not contain the antigens that cause the human body to attack blood cells taken from another person's body, a trait that makes them easier to match from donor to recipient.
The national registry allows doctors to match donors and patients in the same way they match organ donors and recipients.
When cord blood is donated, the blood — usually 3 to 5 ounces — is drained from the umbilical cord and placenta, tested and stored in a liquid nitrogen freezer at a cord-blood bank, according to the National Marrow Donor Program.
Some families pay a fee to store their cord blood in case it is needed by the child whose birth it came from or by a sibling. Studies have shown that cord blood remains useful for as long as 10 years.
Health Alert: Cord blood for leukemia patients
Chicago-NBC) Dec. 23, 2004 - Charles Ford says blood from an umbilical cord helped him survive leukemia, "Without this I probably would have died."
Charles knows he is not out of the woods yet, but at least now he has a fighting chance against the killer disease, "I have a leukemia that's very aggressive, one if the worst types."
He is only the third adult patient at the University of Chicago Hospitals to undergo what's called a cord blood stem cell transplant.
His body was flooded with chemotherapy and radiation that killed both his cancer and his immune system. Then he got a fresh immune system from the rich source of stem cells: the donated blood of a baby's umbilical cord.
Doctor Koen Van Besien, the director of stem cell transplantation at the University of Chicago, says, "The major advantage's that it allows us to find the source of donor stem cells for patients who otherwise don't have a donor."
Doctor Van Besien offers cord blood transplants, because there are not enough of the standard bone marrow donors to go around, especially for minority communities. As a result about one in two patients die because they can't get a bone marrow transplant in time to save their lives.
Still, until now, cord blood transplants were considered inferior to bone marrow, at least for adults. That's changed thanks to two new studies published in "The New England Journal of Medicine." Both show that cord blood is just as good a source as the bone marrow that comes from unrelated donors.
Doctor Van Besien says, "This has the potential over time to save thousands of lives."
Charles says, "It's looking good. If it is working like it is supposed to, all the cancer will be gone."
The success rate, even for a fully-matched bone marrow. is about one in three, so while stem cell transplants are not a sure thing.
Researchers Set New Standard Of Care For Adult Cord Blood Transplant Patients
University of Minnesota researchers will present the promising results from adult umbilical cord blood studies for patients with cancers of the blood and bone marrow. These studies' findings provide solutions to the problems outlined in recently published studies in the New England Journal of Medicine (NEJM).
 |
|
||
|
|||
|
|||
"The results of our studies are a triumph in a treatment that has been largely viewed as only possible in children and adolescents," said John Wagner, M.D., professor of pediatrics and scientific director of clinical research, Blood and Marrow Transplantation Program and Stem Cell Institute.
A major limitation of adult cord blood transplantation highlighted in the NEJM articles is the high likelihood of patients dying early after transplant. This likelihood is due to: poor recovery of the patient's blood cell counts as a result of the relatively low number of cells in cord blood compared to bone marrow, or toxicity from the high doses of chemotherapy and radiation used in conventional transplant regimens.
The University of Minnesota Blood and Marrow Transplant Program have addressed these issues in two separate studies. In the first study, the combined use of two cord blood units from different donors was investigated as a way to increase the number of cord blood cells given to the patient on transplant day. Thirty-one patients were given high-dose chemotherapy and radiation, in which all the patient's bone marrow is destroyed, and then transplanted with two partially matched umbilical cords. The matching criteria is less stringent in cord blood than bone marrow. All of the patients engrafted successfully with cord blood cells with a low incidence of serious transplant complications and very promising survival compared to the previous studies.
In the second study, a group of 59 patients who were not eligible for high doses of chemotherapy and radiation (due to their older age, extensive prior chemotherapy treatment, or other serious co-existing diseases) were treated with a "reduced intensity" regimen involving lower doses of chemotherapy and radiation. These patients were then transplanted with cord blood from either one or two donors. In this study, 89 percent of the patients engrafted successfully overall with 98 percent of patients engrafting if they had recent chemotherapy before the transplant or a prior transplant. Despite the high-risk nature of this patient group, the risk of life-threatening transplant complications was relatively low even in older patients or those with a prior transplant.
"These remarkable results represent a significant advance in the practice of adult cord blood transplantation. These approaches allow us to offer potentially life-saving transplant therapy to many patients who have previously been denied such treatment," said Juliet Barker, MBBS(Hons), assistant professor of medicine, Adult Blood and Marrow Transplant Program.
###
The studies were funded by the National Institutes of Health. The study on transplants from two partially HLA-matched umbilical cord blood units is being published in the February print edition of the journal Blood and is currently available online at www.bloodjournal.org.
The Academic Health Center is home to the University of Minnesota's six health professional schools and colleges as well as several health-related centers and institutes. Founded in 1851, the University is one of the oldest and largest land grant institutions in the country. The AHC prepares the new health professionals who improve the health of communities, discover and deliver new treatments and cures, and strengthen the health economy.
| Country, INDIA, ahead in stem cell research, say scientists | ||
| Ashok Bagariya | ||
|
Ahmedabad, January 5: While scientists around the world debate the ethical issues surrounding use of stem cells for medical treatment, India has already taken lead in this direction and has conducted the world’s biggest and most successful adult stem cell experiment, say scientists. Dr D Balasubramaniam, director of Hyderabad’s L V Prasad Eye Institute, who is in Ahmedabad to attend the 92nd Indian Science Congress, says, ‘‘The LV Prasad Eye Institute has been into adult stem cell research for the last six years and doctors at the hospital have successfully reconstructed over 160 damaged retinas using stem cells.’’ Scientists have been successful in taking adult stem cells from the limbus of the eye and using them to reconstruct the damaged outer surface of the eye, he says. Dr Balasubramaniam also claims this is the largest and the most successful stem cell trials in the world. Similar efforts using stem cells for treating cardiac ailments are being carried out at Christian Medical College (CMC), Vellore. Dr Aloke Srivastava from CMC, also here for the Congress says, “The institute is currenlty engaged in trials wherein stem cells from patient’s bone marrow are taken and injected into the damaged portion of his heart. After implant these adult bone marrow cells take over the function of heart muscles.” Dr Deepika Mohanty, director of Institute of Immuno-Haematology in Mumbai says, “While ethical issues surround the use of embryonic stem cells, we have found a way out and are currently engaged in research on stem cells obtained from the umbilical cord. The umbilical cord blood stem cells have emerged as an ethical and safe option to embryonic stem cells research. And we are also looking at establishing umbilical cord banks in Mumbai and other parts of the country.” The subject has excited researchers across the world after they knew how to differentiate these stem cells (embryonic stem cells and adult stem cells) into a variety of other cells in the human body. Doctors soon started believing that these ‘blank cells’ can be developed into cells of the heart, brain, skin and bones and go a long way in finding cures for many serious diseases. “There is the ethical issue of raising expectations of patients when we ourselves are uncertain of the results with stem cells. We do not want to go around claiming that the technique is perfected unless we get positive and replicable results in clinical trails,” said Dr Willam Wijns who heads the stem cell research programme in Belgium. But according to Dr Balasubramaniam the issue is not disturbing scientists here. “There are no ethical issues in the work. We have proved that it works.” |
Umbilical-cord blood, now used mostly to treat children with leukemia, could save thousands of adults with the disease each year who cannot find bone marrow donors, two big studies indicate.
A European study found that those who got cord blood were just as likely to be free of leukemia two years later as those who got marrow. A U.S. study looking at three-year survival yielded results almost as promising.
To Dr. Mary 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 up donors and recipients.
But up to now, cord blood has been considered suitable only for children, because each donation has only about one-tenth the number of stem cells in a marrow donation.
The two new studies, published in Thursday's New England Journal of Medicine, suggest that is not a serious impediment.
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 were leukemia-free after two years, 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 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 - 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 once more public money comes into play, doctors said.
A federal Institute of Medicine committee is already 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 only 20 percent to 30 percent of the patients who hope to grow new immune systems. But without the treatment, virtually all of them would die.
Some researchers said techniques they have developed in the past two years, since the study ended, already have boosted their success.
Most doctors consider cord blood more appropriate for smaller people, because it contains fewer stem cells than marrow. In the two studies, cord blood recipients tended to weigh less than those who got marrow - an average of 22 pounds less in the U.S. research, about 18 in the European study.
There are two competing U.S. public cord bank systems, one holding about 38,000 vials, the other 27,000. Together, they do not add up to the supply kept by just one of the 20 or so private banks kept for paying families.