Although many patients with acute myeloid leukemia (AML) can be cured with stem cell transplantation (SCT), approximately 30% to 40% will experience relapse of their cancer after the transplantation. Relapsed AML is much more difficult to treat and cure, particularly if relapse occurs within the first 6 months after transplantation, and post-transplant relapse is a leading cause of death in this patient population. Prevention of relapse is critical for improving outcomes in AML.
In a review published in the American Journal of Hematology, Jonathan Webster, MD, and Cole Sterling, MD, of the Sidney Kimmel Comprehensive Cancer Center at Johns Hopkins University of Medicine in Baltimore, Maryland, summarized literature on current and emerging approaches for the prevention of AML relapse following allogeneic SCT.1
“We used to think that the biggest problem for patients who have a bone marrow transplant were complications of the transplant,” Dr Webster told Hematology Advisor. “We’ve managed to move past that, and now the biggest issue is that those patients have a reasonably high risk [for] relapse after the transplant.”
In the United States, the most common type of bone marrow transplantation for AML is allogeneic SCT, which involves collecting and infusing stem cells from a matched donor. Occasionally, the donor immune cells will recognize and attack leukemia cells in the patient’s body after transplantation in a process known as the graft-versus-leukemia (GVL) effect.
Before allogeneic SCT, patients receive chemotherapy to weaken their immune system in order to reduce risk of rejection of the transplanted donor cells. Two types of regimens can be used: myeloablative (high-dose) chemotherapy and nonmyeloablative (low-dose) chemotherapy. Myeloablative chemotherapy is associated with lower risk for relapse (40% vs 30%) but higher risk of transplant-related death (20% vs 10%) compared with nonmyeloablative chemotherapy.
Who Is at Risk for Relapse?
Aside from type of pretransplantation chemotherapy regimen, other factors may help predict which patients are at increased risk of experiencing relapse. Pretransplant risk factors include complex karyotype at diagnosis (number and type of chromosomal abnormalities) and presence of FLT3 mutations. After transplant, assessing chimerism, the percentage of donor-derived T cells in the transplant recipient, may inform selection of patients for relapse prevention therapies, such as donor lymphocyte infusion and azacitidine.1,2