Effect of postremission therapy before reduced-intensity conditioning allogeneic transplantation for acute myeloid leukemia in first complete remission

The impact of pre transplant (HCT) cytarabine consolidation therapy on post HCT outcomes has yet to be evaluated after reduced intensity or non-myeloablative conditioning. We analyzed 604 adults with acute myeloid leukemia (AML) in first complete remission (CR1) reported to the CIBMTR who received a RIC or NMA HCT from an HLA-identical sibling, HLA-matched unrelated donor (URD), or umbilical cord blood (UCB) donor in 2000-2010. We compared transplant outcomes based on exposure to cytarabine post remission consolidation. Three year survival rates were 36% (29-43%, 95% CI) in the no consolidation arm and 42% (37-47%, 95% CI) in the cytarabine consolidation arm (p=0.16). Disease free survival was 34% (27-41%, 95% CI) and 41% (35-46%, 95% CI) (p=0.15), respectively. Three year cumulative incidences of relapse were 37% (30-44%, 95% CI) and 38% (33-43%, 95% CI), respectively (p=0.80).
Multivariate regression confirmed no effect of consolidation on relapse, DFS and survival. Prior to RIC/NMA HCT, these data suggest pre-HCT consolidation cytarabine does not significantly alter outcomes and support prompt transition to transplant as soon as morphologic CR1 is attained. If HCT is delayed while identifying a donor, our data suggest that consolidation does not increase transplant TRM and is reasonable if required.