Patients with acute myeloid leukemia undergoing allogeneic hematopoietic cell transplantation: trends in survival during the past two decades

It remains unclear how specific innovations in allogeneic hematopoietic cell transplantation (HCT) attained over the past decades have contributed to improvement in transplantation outcomes. To address this question, we conducted a registry-based study of adults with acute myeloid leukemia in first or second complete remission who underwent allogeneic HCT between 1994 and 2013 from a sibling (N = 1600) or unrelated (N = 2113) donor matched at the antigen level for HLA-A, -B, and -DR. Preliminary analysis led us to focus on comparisons between the 1994–2006 and 2007–2013 periods. Significant improvement in survival was observed in the later cohort compared to the earlier cohort for unrelated HCT (P = 0.004), but not for related HCT (P = 0.767). The improvement in unrelated HCT was solely due to diminished non-relapse mortality (P = 0.001), while incidence of relapse did not change over time (P = 0.934). The percentage of patients receiving transplants from 8/8-matched unrelated donors was significantly higher in the later cohort (P < 0.001), and their survival was significantly better than that of those undergoing mismatched unrelated HCT (P = 0.022). These findings suggest that advances in HLA-typing technology have been vital for improvement in transplantation outcomes.