Before each transplant, sickle cell patients received a "conditioning" regimen of low-dose immunosuppression drugs, low toxicity chemotherapy, and low-dose total body irradiation. Brodsky says this gentler approach to pre-transplant therapy has made transplant possible for sickle cell patients whose tissues and organs have been ravaged by the disease.
After the transplant, all patients received high doses of the chemotherapy drug cyclophosphamide, which kills remaining blood cells, including diseased sickled cells, and preserves the donor's stem cells responsible for making new, healthy cells.
Of the 17 patients, six transplants were not successful; however, because of the reduced intensity of the conditioning regimen, all of these patients recovered their own blood cells.
There were no deaths, some infections, and only slight skin-related graft versus host disease symptoms in one patient, which cleared without therapy, the researchers reported. Some brain swelling occurred in three patients during the conditioning period and resolved without neurologic damage.
The Johns Hopkins doctors say that while the majority of patients in the trial had successful transplants, about less than half did not.
"Sickle cell disease patients undergo multiple blood transfusions throughout their lives and may have acquired antibodies against many different blood types, making it more difficult than usual to give patients donated bone marrow." says Javier Bolaos-Meade, M.D., associate professor of oncology at the Johns Hopkins Kimmel Cancer Center and principal investigator of the study.
Improving the rate
|Contact: Vanessa Wasta|
Johns Hopkins Medicine