Graft-versus-Host Disease–Free, Relapse-Free Survival after Allogeneic Stem Cell Transplantation for Myelodysplastic Syndrome

Graft-versus-host disease–free, relapse-free survival (GRFS) is a composite endpoint that measures survival free of relapse or significant morbidity after allogeneic hematopoietic stem cell transplantation (HSCT). Consecutive adult patients (N = 324) who received HSCT with fludarabine and busulfan–based conditioning for myelodysplastic syndrome (MDS) or secondary acute myeloid leukemia evolved from MDS were retrospectively analyzed. One-year and 3-year GRFS rates were 47.8% and 34.5%, respectively. Three fixed factors (circulating blast > 3%, high cytogenetic risk, and high comorbidity index) and 2 factors (which are) modifiable by clinicians (myeloablative conditioning [MAC] and low-dose [<7.5 mg/kg] antithymocyte globulin [ATG]) were independent factors for poor GRFS. Based on these 5 factors, 3 groups (3-year GRFS: 64.9% in low risk, 33.6% in intermediate risk, and 6.6% in high risk; P <.001) were identified. Fixed factor–adjusted GRFS in patients receiving reduced-intensity conditioning (RIC) plus high-dose ATG (≥7.5 mg/kg) was superior (P <.001) to those receiving MAC and/or low-dose ATG. Favorable influences of RIC plus ATG ≥ 7.5 mg/kg were evident in the low-risk group defined by fixed factors (3-year GRFS, 38.9% versus 4.4%; P <.001) but were not evident in the high-risk group (3-year GRFS,.0% versus 5.3%; P =.678). Conclusively, this study suggests that risk-adapted selection of conditioning intensity and ATG could improve qualified HSCT outcomes.