Outcomes of alemtuzumab-based reduced intensity conditioning stem cell transplantation using unrelated donors for myelodysplastic syndromes

This prospective study evaluated the outcomes of 75 successive patients receiving a FBC (fludarabine, busulphan, alemtuzumab) reduced-intensity conditioning (RIC) regimen for myelodysplastic syndromes (MDS) using volunteer unrelated donors(VUD). The prognostic significance of a variety of clinical variables including the recently described haematopoietic cell transplantation co-morbidity index (HCT-CI) was assessed. The median age of the cohort was 52.0 years (range: 19-68 years) with a median follow-up of 1038.5 d. Forty-nine patients (65%) had an International Prognostic Scoring System stage of >= Intermediate-2, 35 (46%) had intermediate or poor risk cytogenetics, and 23 patients(31%) were human leucocyte antigen-mismatched. The actuarial 3-year overall survival (OS) and disease-free survival (DFS) was 43% [95% confidence interval (CI): 37-49] and 41% (95%CI: 35-47) respectively, and the cumulative incidence of extensive chronic graft-versus-host disease was 22%. On multivariate analysis, presence of either one class II mismatch or a two-antigen mismatch adversely influenced transplant-related mortality, DFS and OS. In addition, disease status at transplantation and the haematopoietic cell transplantation-specific comorbidity index were independent variables for overall survival. In contrast, both advanced age and pre-transplant cytogenetic status did not significantly affect overall outcomes. RIC regimens using VUD was associated with durable long-term survival even in older patients with MDS, and the use of a pre-transplant comorbidity index may help to improve patient selection for transplantation.