Allogeneic Stem Cell Transplantation for Advanced Myelodysplastic Syndrome: Comparison of Outcomes between CD34 ⁺ Selected and Unmodified Hematopoietic Stem Cell Transplantation

In this study, we compared transplantation outcomes of allogeneic hematopoietic stem cell transplantation (HSCT) in patients with advanced myelodysplastic syndrome (MDS) who received a CD34 ⁺ cell-selected and those who received an unmodified allograft. This analysis initially included 181 patients, 60 who received a CD34 ⁺ cell-selected transplant and 121 who received an unmodified transplant. Owing to significant differences in disease characteristics, the analysis was limited to patients with <10% blasts before HSCT (n = 145). Two groups were defined: low risk, with low- and intermediate-risk cytogenetics (CD34 ⁺ , n = 39; unmodified, n = 46), and high risk: poor and very poor risk cytogenetics (CD34 ⁺ , n = 19; unmodified, n = 41). In the low-risk group, the incidence of grade II-IV acute graft-versus-host disease (aGVHD) at 1 year post-transplantation was 18% in the CD34 ⁺ subgroup versus 41.3% in the unmodified subgroup (P =.015). There were no differences between the subgroups in the incidence of grade III-IV aGVHD. The incidence of chronic graft-versus-host disease (cGVHD) at 3 years in the 2 subgroups was 5.3% and 56%, respectively (P <.001). At 3 years post-transplantation, relapse, overall survival (OS), and relapse-free survival (RFS) were similar in the CD34 ⁺ and unmodified subgroups: 8.1% versus 19.4% (P =.187), 58.5% versus 53.7% (P =.51), and 59.5% versus 52.4% (P =.448). However, the composite outcome combining extensive cGVHD-free status and relapse-free status (CRFS) at 3 years was 59.5% in the CD34 ⁺ group versus 19.2% in the unmodified group (P <.001). In the high-risk group, grade II-IV aGVHD at 1 year was 31.6% in the CD34 ⁺ subgroup versus 24.4% in the unmodified subgroup (P =.752). There were no differences between the subgroups in the incidence of grade III-IV aGVHD. The incidence of cGVHD at 3 years in the 2 subgroups was 0% versus 27.6% (P =.013). At 3 years post-transplantation, relapse, OS, RFS, and CRFS in the 2 subgroups were 31.6% versus 69.3% (P =.007), 35.5% versus 14.5% (P =.068), 31.6% versus 10.7% (P =.045), and 31.6% versus 6.1% (P =.001), respectively. Cytogenetic abnormalities at diagnosis and transplant type had significant univariate associations with RFS in the high-risk cohort. Only cytogenetics (P =.03) remained associated with this outcome in a multivariate model. OS was similar in the 2 transplant groups; however, CRFS was superior in the CD34 ⁺ cell-selected transplant group.