The Role of Stem Cell Transplant in the Therapy of Acute Myeloid Leukemia (AML)

Acute myeloid leukemia (AML) is the most common indication for allogeneic hematopoietic stem cell transplant (HSCT). Decision-making around allogeneic HSCT for AML patients in first remission should be based on the estimated risks of relapse and non-relapse mortality (NRM). Risk of relapse is most strongly informed by testing for cytogenetics, somatic mutations, and minimal residual disease (MRD) testing. Several risk scores based on the Hematopoietic Cell Transplant-Co-morbidity Index are available to estimate the risk of NRM using patient comorbidities, and these should be calculated prior to HSCT to inform decision-making. Conditioning chemotherapy should be individualized based on patient comorbidities. In younger fit patients, high-intensity or myeloablative conditioning is generally preferred to reduce relapse. In older (>65 years) patients or those with significant comorbid conditions, reduced intensity conditioning regimens are likely preferred. In vivo T-cell depletion with anti-thymocyte globulin and post-transplant cyclophosphamide reduces the risk of chronic graft-versus-host disease without a significant increase in risk of relapse. HLA-matched related relatives are preferred as donors although unrelated, haploidentical, and umbilical cord blood donors are all possible alternatives for patients without this option. Relapse remains a major problem following alloHSCT and use of chimerism monitoring and MRD testing can be used to inform treatments to prevent relapse including withdrawal of immunosuppression, donor lymphocyte infusion, and hypomethylating agents.