Clinical Summary:

• Design/Population: This retrospective study evaluated adult patients with myelodysplastic syndromes who underwent allogeneic hematopoietic stem cell transplantation (allo-HSCT), examining disease- and transplant-related factors associated with post-transplant relapse. 
• Key Outcomes: Acute myeloid leukemia transformation was the strongest independent predictor of relapse following all-HSCT. Peripheral blood grafts were independently associated with a lower risk of relapse, while adverse cytogenic showed a trend towards increased relapse risk.
• Clinical Relevance: These findings suggest that underlying disease biology, particularly transformation to AML, is a major determinant of post-transplant relapse. Identifying these risk factors may help inform post-transplant risk assessment and surveillance strategies. 

Results from a retrospective analysis identified transformation to acute myeloid leukemia (AML) as the strongest independent predictor of relapse following allogeneic hematopoietic stem cell transplantation (allo-HSCT) in patients with myelodysplastic syndromes (MDS). 

These results were presented by Maria Krivitskaya, MD, RM Gorbacheva Research Institute, St Petersburg, Russia, at the Society of Hematologic Oncology (SOHO) Annual Meeting in Houston, Texas.

This retrospective analysis included 127 adult patients with MDS who underwent allo-HSCT between 2008 and 2024. Patients were classified according to the 2022 World Health Organization criteria, and disease risk was assessed using the Revised International Prognostic Scoring System (IPSS-R). 

Among 115 IPSS-R evaluable patients, 13% had low-risk, 24% had intermediate-risk, 36% had high-risk, and 27% had very high-risk disease. Cytogenic risk was favorable in 51% of patients, intermediate in 15% of patients, poor in 25% of patients, and very poor in 9% of patients. 

At the time of transplantation, 43% of patients were in complete remission, 35% of patients had experienced progression to secondary AML, and 22% of patients had clonal evolution. 

The median time to transplantation was 11 months, and median follow-up was 10 months. Matched related donors were used in 22% of patients, matched unrelated donors in 48% of patients, mismatched unrelated donors in 16%, and haploidentical donors in 14% of patients. Post-transplant cyclophosphamide was administered to 78% of patients, and peripheral blood was the graft source in 71% of patients. Engraftment was achieved in 87% of patients. 

The 2-year overall survival rate was 46%. Relapse occurred in 31% of patients at a median of 257 days, with a cumulative incidence of relapse of 29%. The non-relapse mortality rate was 27%.

In univariate analysis, clonal evolution (P = .013), adverse cytogenetics (P =  .028), AML transformation (P < .001), donor type (P = .027), and bone marrow graft source (P < .001) were associated with relapse. Chronic graft-versus-host disease was associated with a protective effect (P = .050).

In the multivariate analysis, AML transformation emerged as the strongest independent predictor of relapse, with approximately 10-fold increased risk (hazard ratio [HR], 9.97; P < .001). 

Peripheral blood grafts were independently associated with a 72% lower risk of relapse (HR, 0.28; P = .017). Adverse cytogenetics showed a trend toward increased relapse risk.

The findings suggest that relapse following allo-HSCT in MDS is strongly influenced by disease characteristics present before transplantation, particularly progression to AML. The observed association between peripheral blood grafts and reduced relapse risk also identifies graft source as a potentially relevant transplant-related factor.

Source:

Krivitskaya M, Rudakova T, Tsvetkov N, et al. Factors associated with relapse after allogeneic hematopoiehtic stem cell transplantation in myelodysplastic syndromes. Presented at the 2026 SOHO Annual Meeting; September 9-12, 2026; Houston, Texas. Abstract MDS-358.