WIKIMEDIA, OPENSTAX COLLEGEDespite the fact that they carried another’s stem cells in their blood, some participants of a clinical trial testing a modified blood stem-cell transplant for severe sickle cell disease have safely terminated their immunosuppressant medication that most stem-cell recipients take all their lives. The results of the study, conducted at the National Institutes of Health (NIH) Clinical Center in Bethesda, Maryland, were published this week (July 1) in JAMA.
“That the patients who discontinued this medication were able to do so safely points to the stability of the partial transplant regimen,” lead author Matthew Hsieh of the NIH’s National Institute of Diabetes and Digestive and Kidney Diseases said in a press release.
“Side effects caused by immunosuppressants can endanger patients already weakened by years of organ damage from sickle cell disease,” added coauthor John Tisdale of the National Heart, Lung, and Blood Institute. “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.”
In addition to allowing half of the trial participants to stop taking immunosuppresants without experiencing rejection or graft-versus-host disease, the experimental therapy “reversed sickle cell disease in nearly all the patients,” according to the release.
Currently, a blood stem-cell, or bone marrow, transplant is the only cure for sickle cell disease, in which sickle-shaped cells block blood flow, causing pain, organ damage, and stroke. The new therapy involves replacing only some of the patients’ marrow, which is less damaging than a full transplant procedure, which involves high doses of chemotherapy. Moreover, the partial transplant used donor stem cells from healthy siblings. In the end, 26 of 30 patients saw their symptoms disappear, and 15 of 30 patients stopped taking their immunosuppressant medication. Now, nearly three-and-a-half years later, none of these 15 patients have suffered any rejection or graft-versus-host disease.
“It’s an exciting advancement for adults with sickle cell disease,” Allison King, an assistant professor of pediatrics at Washington University School of Medicine in St. Louis who wrote an accompanying editorial in JAMA, told the Chicago Tribune. “It really offers adult patients with sickle cell disease with matched siblings hope that they can be cured from this disease and have great outcomes.”