WASHINGTON — A new method of bone marrow transplantation has effectively reversed sickle cell disease, a researcher from the National Institutes of Health said Wednesday on Capitol Hill.
Complete bone marrow transplants have been successful for children but have traditionally not worked for adults, who are less tolerant of complete transplantation because of years of organ damage from sickle cell disease. A new method of partial replacement, however, has been successful in adults in nine out of 10 cases, according to Dr. John Tisdale of NIH, who spoke at the Congressional Biomedical Research Caucus.
After two and a half years of follow up, all 10 recipients are alive and the disease was eliminated in nine of the patients. Tisdale is hopeful that this method will become more widely used.
“There’s still a lot that needs to be worked out,” Tisdale said.
Sickle cell disease is an inherited condition that causes bouts of severe pain and organ damage and sharply limits life expectancy. People with the disease have unusually formed blood cells, shaped like sickles or crescent moons, which can get stuck and block blood vessels. Over time, the damage can lead to stroke and severe pain in the chest, arms, legs and stomach.
Sickle cell disease also damages the kidneys, liver and spleen, leaving people, especially children, more susceptible to infection. The disease is especially common among African-Americans, Tisdale said.
In trials, nearly 200 children with severe sickle cell disease were cured with the complete bone marrow transplants after undergoing a regimen in which their own marrow was completely destroyed with chemotherapy. Usually this treatment was reserved for more resilient children who haven’t suffered as much damage from the disease.
In the past, adults weren’t candidates because they were considered to be too sick to handle the high doses of chemotherapy and radiation necessary to prep the body for the procedure, said Tisdale.
But the new method allows for a less demanding pre-transplantation routine, one that even adults with severe sickle cell can tolerate. In separate trials, Tisdale and others only partially replaced adult patients’ bone marrow, believing that the healthy cells would outlast and completely replace the disease-causing cells.
In the U.S., more than 70,000 people suffer from sickle cell, Tisdale said.
“One of the things we’ve been very careful to do is make our procedures as simple as possible to make them exportable,” Tisdale said.