Half of patients in a trial who have severe sickle cell disease were able to safely stop immunosuppressant medication following a modified blood stem-cell transplant, according to a study in the July 1 issue of the Journal of the American Medical Association.
Immunosuppressant medication reduces immune system strength and can cause serious side effects such as infection and joint swelling. In this study, 15 of 30 adults stopped taking the medication under careful supervision one year after transplant and still had not experienced rejection or graft-versus-host disease, in which donor cells attack the recipient, at a median follow up of 3.4 years, according to a news release. The partial transplant done in the study also effectively reversed SCD in 26 of 30 patients and allowed them to achieve stable mixed donor chimerism, a condition in which a person has two genetically distinct cell types in the blood.
The trial was conducted by researchers from the National Institutes of Healths National Institute of Diabetes and Digestive and Kidney Diseases and the National Heart, Lung and Blood Institute.
Typically, stem-cell recipients must take immunosuppressants all their lives, Matthew Hsieh, MD, lead author on the paper and staff clinician at NIH, said in the release. That the patients who discontinued this medication were able to do so safely points to the stability of the partial transplant regimen.
The partial transplant performed in the study used donor stem-cells from healthy siblings and is much less toxic than the standard transplant, which uses high doses of chemotherapy to kill all of the patients marrow before replacing it with donor marrow. Several patients in the study had less than half of their marrow replaced.
Side effects caused by immunosuppressants can endanger patients already weakened by years of organ damage from sickle cell disease, John F. Tisdale, MD, the papers senior author and a senior investigator at NIH, said in the release. Not having to permanently rely on this medication, along with use of the relatively less-toxic partial stem-cell transplant, means that even older patients and those with severe sickle cell disease may be able to reverse their condition.
More than 90,000 people in the U.S. have SCD, according to the release. Worldwide, millions of people have the disease.
One of the most debilitating effects of sickle cell disease is the often relentless pain, Hsieh added. Following the transplant, we saw a significant decrease in hospitalizations and narcotics to control that pain.
Patients with SCD interested in joining NIH blood stem-cell transplant studies may call (800) 411-1222 or visit http://www.clinicaltrials.gov for more information.