Prognostic impact of the conditioning intensity on outcomes after allogeneic transplantation for MDS with low blasts: A nationwide retrospective study by the adult MDS working group of the Japan Society for Transplantation and Cellular Therapy

Abstract

Abstract Poor prognostic factors, such as transfusion dependency and chromosomal risk, need to be considered in the indication of allogeneic hematopoietic stem cell transplantation (allo-HSCT) for patients harboring myelodysplastic syndromes with less than 5% marrow blasts (MDS-Lo). We conducted a nationwide retrospective study to clarify the optimal conditioning intensity for MDS-Lo. Among 1,229 patients, 651, 397, and 181 with MDS-Lo received myeloablative (MAC), reduced-intensity (RIC), and non-myeloablative conditioning (NMAC) regimens, respectively. The multivariate analysis revealed that the RIC group had better graft-versus-host disease (GVHD) and relapse-free survival (GRFS) than the MAC group (HR 0.75, 95% CI 0.63–0.89, P = 0.001), while no significant differences were observed between the NMAC and MAC groups. Furthermore, overall survival, chronic GVHD- and relapse-free survival, and the incidence of relapse and non-relapse mortality did not significantly differ among three groups. The RIC group had a lower incidence of acute (HR 0.81, 95% CI 0.68–0.97, P = 0.019) and chronic GVHD (HR 0.79, 95% CI 0.63–0.99, P = 0.045) than the MAC group. In conclusion, the RIC and NMAC regimens are promising options for MDS-Lo patients in addition to the MAC regimen. The careful management of GVHD in MDS-Lo patients receiving the MAC regimen needs to be considered.