French researchers say stem cell transplants successful in sickle cell patients




December 08, 2002




In an apparent advance of earlier research, French doctors believe they can now cure children with severe sickle cell disease through stem cell transplants without risking serious complications or death.
The French researchers, who have performed 69 transplants since 1988, reported an 85 percent disease-free survival rate _ and even better results since revising their mix of anti-rejection drugs in 1992.


Six patients died in the earlier phase _ four after rejecting the new stem cells _ but there were no deaths in the last 30 transplants, said lead researcher, Dr. Francoise Bernaudin of The Hopital Intercommunal de Creteil outside Paris.


The findings, which have not yet been published, were presented Sunday at the annual meeting of the American Society of Hematology in Philadelphia.


"It's going to change the way we treat individuals with this disorder," said Dr. Ronald Hoffman of the University of Illinois, the society's president. "If they're truly cured ... they're going to be freed of the consequences of a chronic disease."


Sickle cell disease is an inherited blood disorder that affects about 70,000 Americans, most of them black, as well as some people from the Mediterranean, Africa and elsewhere.


Researchers are pursing several cures and treatments for sickle cell disease, including gene therapy, drug therapies and stem cell transplants.


The transplants have been conducted at several sites in the United States, but the French study is the largest by any one team and has produced the best results to date, Hoffman said.


The disease causes a deformity in a person's red blood cells that prevents the blood from carrying enough oxygen and nutrients to the heart, brain and other organs. Patients often suffer chronic, painful conditions including anemia and kidney and lung damage and are prone to heart attacks and disabling strokes.


Most sickle cell patients used to die in childhood, but better treatments now enable them to live into their 40s and 50s. However, doctors have been frustrated in their attempts to improve the patients' quality of life.


"Maybe if a new drug appears which seems efficacious, we will stop again, but for the moment, sickle cell transplant remains the only treatment offering the cure," Bernaudin said Sunday at the Pennsylvania Convention Center, where about 20,000 people are attending the five-day conference.


Patients in the study had a median age of 8.9 years. In a bone marrow transplant, a patient's own bone marrow is destroyed through radiation or chemotherapy before the procedure.


Bone marrow was used in 60 of the transplants and umbilical cord blood in seven. A mix of cord blood, which is rich in stem cells, and bone marrow was used in one remaining case and blood stem cells in the other.


After four of the initial 12 patients rejected the transplant, Bernaudin and her team in 1992 added an immunosuppressant, anti-thymocyte globulin, to the drugs patients receive before surgery. There were no rejections afterward.


"That was her big innovation, and that led basically to a 100 percent success rate," Hoffman said.


One patient in the later phase required a second transplant, which proved successful. Three showed the continued presence of the disease, but its severity declined, Bernaudin said.


Given the strong results, and the small number of complications, Bernaudin believes children with severe sickle cell disease _ about half of all sickle cell patients _ should get transplants by age 2 or 3, before suffering organ damage.


"I think the cost-effectiveness is a no-brainer. Because what you really have to integrate into that equation is the ability of these folks to become productive members of society," Hoffman said.


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On the Net:


American Society of Hematology: http://www.hematology.org/


Sickle Cell Disease Association of America: http://www.sicklecelldisease.org/


©NEPA News 2002