Dec. 9 (Bloomberg) -- Sickle cell disease, which affects 70,000 Americans, was reversed in 9 of 10 patients given bone marrow transplants using a new technique, according to a study that may expand the therapy to adults.

People with the disease have misshapen red blood cells. While doctors have long used transplants to replace those cells in children, the treatment has been too toxic for adults. A study in today’s New England Journal of Medicine found that replacing only a portion of the cells can work. Recipients were sickle cell-free 30 months later. None had a common reaction in which immune cells in the donor marrow attack the host’s body.

The inherited blood disorder affects 1 in 500 black Americans, causing symptoms that include wheezing, pain, stroke and organ failure, researchers said. The new regimen should be used only when patients can’t be treated in other ways, said Matthew Hsieh, the lead author and a researcher at the National Institutes of Health in Bethesda, Maryland.

“Sickle cell is a devastating illness that puts people in and out of hospitals their whole lives,” said Ira Bragg-Grant, executive director of the American Sickle Cell Anemia Association, in Cleveland. “For more adults to be freed of this chronic illness by transplants would be a phenomenal development.”

Red blood cells are typically smooth and disk-shaped. In sickle-cell disease, they take the form of a crescent and clump together, causing blockages in the vessels that carry oxygen- rich blood to limbs and organs.

A Better Regimen

Hsieh and colleagues at the National Institutes primed patients with radiation. To weaken the patients’ immune systems so their bodies wouldn’t reject the incoming cells, the researchers gave them Campath, a drug made by Cambridge, Massachusetts-based Genzyme Corp. that destroys certain white blood cells.

Patients received bone marrow containing stem cells, to make healthy red blood cells, from a sibling. After the transplant, the study participants went on an immunosuppressive medication called sirolimus, sold as Rapamune by New York-based Pfizer Inc.’s Wyeth unit.

Hsieh’s goal was to get a favorable mix of donor cells and recipient ones. The study’s results suggest they have the right mix, he said.

“Our study is important in two ways,” Hsieh said, “One, we were able to transplant adults and have them be sickle cell- free more than a year later. The other remarkable result was that none of the patients had graft-versus-host disease,” a common complication of bone marrow transplants.

More Choices

In stem-cell transplantation, the donor’s immune cells sometimes attack the organs in the patient’s body. These reactions are more common in adults than children. The high risk of graft-versus-host disease is one reason Hsieh sought to devise a less-toxic transplant regimen, he said.

Currently adult patients with severe sickle cell disease have two treatment choices, said Stuart Orkin, a pediatrics professor at the Harvard Medical School in Boston.

The first is hydroxyurea, an anti-tumor drug that is approved for treating pain in sickle cell disease. The problem with hydroxyurea, said Orkin, is that it doesn’t work in all patients. It can also cause infertility.

The other is blood transfusions to suppress the production of sickle cells. The trouble is, some people develop iron overload that makes further transfusion impossible.

No Cure

“Unlike transplantation, these options are purely supportive,” Orkin said. “They don’t cure anything.”

While stem-cell transplants are curative, doctors must weigh the risk of infection or even death, said Orkin. They must also consider the amount of existing organ damage and whether it’s reversible, he said.

Highly damaged organs can complicate a transplant. On the other hand, people who have had a stroke or organ failure “have more to lose if you don’t act,” said Hsieh, the study author.

According to Hsieh, the main drawback of transplantation is that it is hard to find a suitable donor. In his study, he was looking for patients who had siblings with matching white blood cells. Of the 112 eligible patients whose blood type was tested during recruitment, only 24 had qualifying siblings.

Furthermore, when doctors go to a bone marrow registry to find compatible donors, it turns out “African Americans are much harder to match because they’re underrepresented,” said Eugene Orringer, a professor of medicine at the University of North Carolina at Chapel Hill.

75,000 Hospitalizations

People with sickle cell disease have about 75,000 hospitalizations a year, for a total cost of $475 million, according to data gathered by the National Center for Health Statistics, a U.S. agency. The life expectancy can be as low as 42 years for males who inherit the sickle gene from both parents, according to a study out of the Harvard Medical School.

While scientists say that someday soon gene therapy may knock out the disease, transplantation offers the possibility of an immediate cure.

At this stage, Hsieh said he is reluctant to use the word “cured” to describe the patients in his study. Still, he is very encouraged by the number of them who are disease-free more than a year after their grafts. Said Hsieh: “We’ve had very good results so far. Our hope is that with more patients and longer follow-up, these patients will remain sickle cell-free.”

I just saw this on the news. Good news.

And donate blood if you can, folks! Sickle Cell patients will thank you!