Allogeneic transplantation for myelodysplastic syndrome (MDS)

Myeloablative hematopoietic stem cell transplantation improves survival but is not curative in a pre-clinical model of myelodysplastic syndrome

Allogeneic hematopoietic stem cell transplantation (A-HSCT) remains the only curative option for patients with myelodysplastic syndrome (MDS). We used the NUP98-HOXD13 (NHD13) murine model for MDS to study HSCT in a pre-clinical setting. NHD13 recipients transplanted with syngeneic bone marrow (S-HSCT) following myeloablative irradiation showed disease remission, with normalization of peripheral blood parameters and marked decrease in circulating leukocytes derived from the MDS clone. Despite the disease remission and improved survival compared to non-transplanted NHD13 controls, all mice eventually relapsed, indicating persistence of a long-lived radio-resistant MDS clone. In an effort to induce a graft versus leukemia (GVL) effect, A-HSCT with donor bone marrow that was mismatched at minor histocompatibility loci was compared to S-HSCT. Although recipients in the A-HSCT showed a lower early relapse rate than in S-HSCT, all mice in both groups eventually relapsed and died by 54 weeks post-transplant. To obtain a more significant GVL effect, donor splenocytes containing reactive T-cells were transplanted with allogeneic bone marrow. Although the relapse rate was only 20% at post-transplantation week 38, suggesting a GVL effect, this was accompanied by a severe graft versus host disease (GVHD) Taken together, these findings indicate that a myeloablative dose of ionizing radiation is insufficient to eradicate the MDS initiating cell, and that transplantation of donor splenocytes leads to decreased relapse rates, at the cost of severe GVHD. We suggest that NHD13 mice represent a feasible pre-clinical model for the study of HSCT for MDS.

Hematopoietic stem cell transplantation for myelodysplastic syndrome: a review

Allogeneic hematopoietic stem cell transplantation (HSCT) continues to be the only curative option for myelodysplastic syndrome (MDS). Since the majority of the patients with this disease are often older and frail, treatment-related mortality and morbidity remain major obstacles to be overcome. Reduced-intensity conditioning and continued lines of investigation in the field of allogeneic transplantation are expected to ultimately improve the overall therapeutic approach to MDS. In this review we summarize current recommendations and controversies surrounding HSCT for MDS, as well as the use of novel therapeutics in the peri-transplant period.

Update on the therapy for myelodysplastic syndrome

The myelodysplastic syndromes (MDS) are a diverse group of clonal hematopoietic stem cell disorders characterized by cytopenias. Patients have a risk of developing acute leukemia though most succumb to complications of low blood counts. Over the past decade many novel treatments have been developed and investigation of new agents is ongoing. In this article, we discuss the classification and prognostic systems that are used in MDS, the agents available for treatment of MDS as well as review supportive and palliative care options for patients who are not candidates for, or opt against, newer treatment strategies.

Allogeneic stem cell transplantation for myelodysplastic syndrome

Although it is only used to treat a minority of patients with myelodysplastic syndromes, stem cell transplantation (SCT) is the only proven curative treatment for this condition. Because MDS occurs in a population of older adults with significant comorbidities, reduced-intensity conditioning (RIC) regimens have been particularly important in extending safe SCT to the large MDS population over the age of 60 years. Extension of the unrelated donor pool together with the introduction of umbilical cord blood transplants in adults has extended the number of patients with suitable donors. Nevertheless overall mortality from SCT is greater than 50% because of relapse and non-relapse mortality (NRM). New developments to improve outcome include the tailoring of the transplant approach to the individual based on age and comorbidity, and the use of pretransplant chemotherapy to reduce disease bulk prior to transplant, as well as the introduction of post-transplant immunotherapy (pre-emptive donor lymphocyte infusions) and chemotherapy to prevent relapse. Further improvements in transplant outcome await better ways to reconstitute immunity and amplify the graft-versus-leukemia (GVL) effect without causing graft-versus-host disease (GVHD), as well as further extension of the donor pool and exploration of risk-adapted regimens for the population of MDS in their seventh to eighth decade.