Comparison of matched unrelated and matched related donor myeloablative hematopoietic cell transplantation for adults with acute myeloid leukemia in first remission

Hematopoietic cell transplantation (HCT) from a matched related donor (MRD) benefits many adults with acute myeloid leukemia (AML) in first complete remission (CR1). The majority of patients do not have such a donor, however, requiring use of an alternative donor if HCT is undertaken. We retrospectively analyzed 226 adult AML CR1 patients undergoing myeloablative unrelated donor (URD) (10/10 match, n=62; ≤9/10, n=29) or MRD (n=135) HCT from 1996–2007. Five-year estimates of overall survival (OS), relapse, and non-relapse mortality (NRM) were 57.9%, 29.7%, and 16.0%, respectively. Failure for each of these outcomes was slightly higher for 10/10 URD than MRD HCT, although statistical significance was not reached for any endpoint. The adjusted hazard ratios (HR) were 1.43 (0.89–2.30, p=0.14) for overall mortality, 1.17 (0.66–2.08, p=0.60) for relapse, and 1.79 (0.86–3.74, p=0.12) for NRM, respectively, and the adjusted odds ratio (OR) for grades 2–4 acute graft-versus-host disease was 1.50 (0.70–3.24, p=0.30). Overall mortality among 9/10 and 10/10 URD recipients was similar (adjusted HR=1.16 [0.52–2.61], p=0.71). These data indicate that URD HCT can provide long-term survival for CR1 AML; outcomes for 10/10 URD HCT, and possibly 9/10 URD HCT, suggest that this modality should be considered in the absence of a suitable MRD.