Feasible Outcomes of T Cell–Replete Haploidentical Stem Cell Transplantation with Reduced-Intensity Conditioning in Patients with Myelodysplastic Syndrome

• We analyzed the outcomes of haploidentical stem cell transplantation in myelodysplastic syndrome or secondary acute myeloid leukemia from in myelodysplastic syndrome.
• Our strategy using T cell–replete grafts with reduced-intensity conditioning contributed to a low incidence of nonrelapse mortality (23.3% at 4 years).
• Disease-free and overall survival rates of our cohort were 46.8% and 41.9% at 4 years, respectively.
• Our T cell–replete haploidentical stem cell transplantation using reduced-intensity conditioning may be a feasible option for patients with myelodysplastic syndrome and secondary acute myeloid leukemia.

Even with the recent optimization of haploidentical stem cell transplantation (SCT), its role for patients with myelodysplastic syndrome (MDS) or acute myeloid leukemia evolving from MDS (sAML) should be validated. We analyzed the outcomes of consecutive 60 patients with MDS or sAML who received T cell–replete haploidentical SCT after reduced-intensity conditioning with fludarabine, busulfan, and rabbit antithymocyte globuline ± 800 cGy total body irradiation. Patients achieved a rapid neutrophil engraftment after a median of 12 days (range, 8 to 23) and an early immune reconstitution without high incidences of acute graft-versus-host disease (GVHD) II to IV and chronic GVHD (36.7% and 48.3%, respectively). After a median follow-up of 4 years, incidence of relapse and nonrelapse mortality and rate of overall survival and disease-free survival was 34.8%, 23.3%, 46.8%, and 41.9%, respectively. In multivariate analysis, the disease status at peak was a significant predictor for relapse (lower-risk MDS versus higher-risk MDS or sAML; hazard ratio [HR], 5.69; 95% confidence interval [CI], 1.45 to 22.29; P = .013) and disease-free survival (HR, 4.44; 95% CI, 1.14 to 17.34; P = .032). Chronic GVHD was an additional significant predictor for relapse (no versus yes; HR, 2.87; 95% CI, 1.03 to 7.51; P = .043). Our T cell–replete haploidentical SCT may be a feasible option for patients with MDS and sAML without conventional donors.