PURPOSETo investigate the impact of prior-to-transplantation azacitidine (AZA) on patient outcome after allogeneic stem-cell transplantation (alloSCT) for myelodysplastic syndrome (MDS). PATIENTS AND METHODSOf the 265 consecutive patients who underwent alloSCT for MDS between October 2005 and December 2009, 163 had received cytoreductive treatment prior to transplantation, including induction chemotherapy (ICT) alone (ICT group; n = 98), AZA alone (AZA group; n = 48), or AZA preceded or followed by ICT (AZA-ICT group; n = 17). At diagnosis, 126 patients (77%) had an excess of marrow blasts, and 95 patients (58%) had intermediate-2 or high-risk MDS according to the International Prognostic Scoring System (IPSS). Progression to more advanced disease before alloSCT was recorded in 67 patients. Donors were sibling (n = 75) or HLA-matched unrelated (10/10; n = 88). They received blood (n = 142) or marrow (n = 21) grafts following either myeloablative (n = 33) or reduced intensity (n = 130) conditioning.ResultsWith a median follow-up of 38.7 months, 3-year outcomes in the AZA, ICT, and AZA-ICT groups were 55%, 48%, and 32% (P = .07) for overall survival (OS); 42%, 44%, and 29% (P = .14) for event-free survival (EFS); 40%, 37%, and 36% (P = .86) for relapse; and 19%, 20%, and 35% (P = .24) for nonrelapse mortality (NRM), respectively. Multivariate analysis confirmed the absence of statistical differences between the AZA and the ICT groups in terms of OS, EFS, relapse, and NRM. CONCLUSIONWith the goal of downstaging underlying disease before alloSCT, AZA alone led to outcomes similar to those for standard ICT.