Which Patients Should Undergo Allogeneic Stem Cell Transplantation for Myelodysplastic Syndromes, and When Should We Do It?

Fludarabine and Melphalan Compared with Reduced Doses of Busulfan and Fludarabine Improve Transplantation Outcomes in Older Patients with Myelodysplastic Syndromes

Reduced-intensity conditioning (RIC) regimens developed to extend the use of allogeneic hematopoietic stem cell transplantation (HSCT) to older patients have resulted in encouraging outcomes. We aimed to compare the 2 most commonly used RIC regimens, i.v. fludarabine with busulfan (FluBu) and fludarabine with melphalan (FluMel), in patients with myelodysplastic syndrome (MDS). Through the Center for International Blood and Marrow Transplant Research (CIBMTR), we identified 1045 MDS patients age ≥60 years who underwent first HSCT with a matched related or matched (8/8) unrelated donor using an RIC regimen. The CIBMTR's definition of RIC was used: a regimen that incorporated an i.v. busulfan total dose ≤7.2 mg/kg or a low-dose melphalan total dose ≤150 mg/m². The 2 groups, recipients of FluBu (n = 697) and recipients of FluMel (n = 448), were comparable in terms of disease- and transplantation-related characteristics except for the more frequent use of antithymocyte globulin or alemtuzumab in the FluBu group (39% versus 31%). The median age was 67 years in both groups. FluMel was associated with a reduced relapse incidence (RI) compared with FluBu, with a 1-year adjusted incidence of 26% versus 44% (P ≤ .0001). Transplantation-related mortality (TRM) was higher in the FluMel group (26% versus 16%; P ≤ .0001). Because the magnitude of improvement with FluMel in RI was greater than the improvement in TRM with FluBu, disease-free survival (DFS) was better at 1 year and beyond with FluMel compared with FluBu (48% versus 40% at 1 year [P = .02] and 35% versus 27% at 3 years [P = .01]). Overall survival (OS) was comparable in the 2 groups at 1 year (63% versus 61%; P = .4) but was significantly improved with FluMel compared with FluBu at 3 years (46% versus 39%; P = .03). Our results suggest that FluMel is associated with superior DFS compared with FluBu owing to reduced RI in older patients with MDS patients. © 2021 American Society for Transplantation and Cellular Therapy. Published by Elsevier Inc.

Cytogenetics and comorbidity predict outcomes in older myelodysplastic syndrome patients after allogeneic stem cell transplantation using reduced intensity conditioning

BACKGROUND

Allogeneic hematopoietic stem cell transplantation (allo-HSCT) is the only treatment with a curative potential for myelodysplastic syndrome (MDS) patients. Allo-HSCT has substantial risks, particularly in the elderly, and its role for older MDS patients has yet to be defined.

METHODS

We analyzed 88 MDS patients aged ≥ 60 years with allo-HSCT after reduced intensity conditioning regimens over the last decade. The study cohort had high risk features; 47 of 88 (53.4%) patients were > 65 years of age, 24 (27%) patients had cytogenetic abnormalities consistent with monosomal karyotype (MKpos), 33 (38%) patients had histological subtype of RAEB-1 and RAEB-2 at diagnosis, and 45 (51%) patients had a hematopoietic cell transplantation-comorbidity index (HCT-CI) of ≥ 3.

RESULTS

The 3-year incidence of progression, transplant-related mortality (TRM), and overall survival (OS) were 26% (95% confidence interval [CI], 18%-37%), 35% (95% CI, 26%-47%), and 41% (95% CI, 30%-52%), respectively. MKpos was the only prognostic factor that increased the risk of disease progression compared with good-risk cytogenetics (hazard ratio [HR] = 9.5, P = .003) as well as MKneg (HR = 3.3, P = .01). For TRM, HCT-CI ≥ 3, but not age >65 years, was associated with worse outcomes (HR = 3.1, P = .007). Cytogenetics and HCT-CI enabled us to identify prognostic groups for OS. MKpos patients had the worst 3-year OS (17%), whereas patients with good-risk cytogenetics and HCT-CI < 3 had the best OS (92%).

CONCLUSION

Our results confirm that allo-HSCT can provide long-term survival in older MDS patients. Cytogenetics and HCT-CI identify prognostic risk groups and guide selection of older MDS patients who are candidates for allo-HSCT. Cancer 2017;123:2661-70. © 2017 American Cancer Society.