Targeting T Cells
Multicenter study reduces transplant risk in AML patients
Patients with acute myeloid leukemia (AML) who were treated as part of a multicenter study by the Blood and Marrow Transplant Clinical Trials Network had excellent survival and a low risk of graft-vs.-host disease, the major complication of transplantation. Steven Devine, MD, director of the Blood and Marrow Transplant Program at the OSUCCC – James, was co-chair and first author of the study.
During the three-year study at eight centers, 44 AML patients received allogeneic stem cell transplants from related donors whose immune system markers were identical to those of the patients. This type of transplant is the most effective means of preventing relapse in AML patients who are in complete remission but at high risk for relapse.
Graft-vs.-host disease occurs in 30-40 percent of patients who receive transplants from related donors, limiting the use of this otherwise curative procedure. The disease is most effectively prevented by removing the T cells that cause it from the donor graft via T-cell depletion. However, Devine says T-cell depletion is not often used because there is no FDA-approved method for it.
“We designed a clinical trial for adult AML patients that used a single processing method for depleting T cells that did not require post-transplant graft-vs.-host disease prophylaxis,” Devine says. Since the T cells were removed ahead of time, none of the patients had to be on drugs to prevent rejection or graft-vs.-host disease.
After six months, 81 percent of patients in the study had achieved disease-free survival, and 64 percent maintained disease-free survival at one year. The results are close to what is observed using other current transplant procedures, but with fewer complications related to graft-vs.-host disease. Devine says the study confirms the feasibility of using a uniform method of T-cell depletion.
Presented at the 51st Annual Meeting of the American Society of Hematology, December 2009.