Reduced intensity conditioning for allogeneic hematopoietic stem cell transplantation in myelodysplastic syndromes and acute myelogenous leukemia

Outcome of donor lymphocyte infusion after T cell-depleted allogeneic hematopoietic stem cell transplantation for acute myelogenous leukemia and myelodysplastic syndromes

Relapse occurs in 30%-50% of recipients of T cell-depleted (TCD) reduced-intensity conditioned (RIC) hematopoietic stem cell transplantation (HSCT) for acute myelogenous leukemia (AML) and myelodysplastic syndromes (MDS). Despite limited published supportive data, donor lymphocyte infusion (DLI) is used preemptively (pDLI) to improve donor chimerism and prevent relapse, and therapeutically (tDLI) after disease recurrence. We evaluated the efficacy and toxicity of pDLI and tDLI in 113 patients after TCD (alemtuzumab, n = 99; antithymocyte globulin, n = 14) RIC HSCT for AML or MDS. Recipients of pDLI (n = 62) had an estimated 5-year overall survival (OS) of 80% and an event-free survival of 65%. More than one-half (52%; n = 32) of the patients received pDLI within 6 months post-HSCT; despite this, the 5-year incidence of graft-versus-host disease was only 31% (95% confidence interval [CI], 19%-43%). Recipients of tDLI (n = 51) had an estimated 5-year OS of 40% and a 5-year relapse/progression rate of 69% (95% CI, 54%-81%). Recipients of tDLI at >6 months post-HSCT had a significantly superior 5-year OS after tDLI compared with those treated earlier (P = .008). The cumulative incidence of graft-versus-host disease at 5 years after tDLI was 45% (95% CI, 23%-65%). We demonstrate that pDLI safely promotes durable remission after TCD RIC HSCT for AML or MDS, and that tDLI salvages patients after late relapse with greater efficacy.

Allogeneic hematopoietic cell transplantation for MDS: for whom, when and how?

Hematopoietic cell transplantation (HCT) is currently the only treatment with curative potential for patients with myelodysplastic syndrome (MDS). However, treatment-related mortality and relapse have remained major barriers to uniform success. Therefore, important questions remain to be answered, such as whom to transplant, when and how. With reduced intensity conditioning (RIC) regimens, patients in their 70s and patients with comorbid conditions have been transplanted successfully, although the relapse incidence with this approach tends to be increased in comparison to high intensity regimens. Success rates are higher in patients transplanted at an early stage of their disease. Encouraging is the fact, that results with unrelated donors who are HLA-matched by high resolution typing are comparable to those achieved with HLA genotypically identical siblings. The establishment of cord blood as a source of stem cells, and the recent success with HLA-haploidentical related donors will allow the offering of HCT to virtually all patients. Dependent upon disease stage and characteristics, some 25% to 75% of transplanted patients will be cured. While 20%-30% of patients experience chronic medical problems after HCT, 70% report a "good to excellent" quality of life. New studies must focus on further reducing GVHD for all patients and on overcoming high relapse rates in patients with high risk disease.

Standard therapy for patients with myelodysplastic syndromes

The myelodysplastic syndromes (MDS) are a group of clonal hematopoietic stem cell disorders characterized by cytopenias, dysplastic changes in the hematopoietic precursors, and an increased risk of evolving into acute leukemia. Treatment for patients with MDS ranges from supportive care with blood products and/or growth factors up to allogeneic stem cell transplantation. Over the past decade, several novel therapeutic agents have been approved for clinical use. In this article, the current approach for the management of patients with MDS according to their risk category is described and mainly focuses on approved novel agents.

Reduced-intensity conditioning regimen combined with low-dose total body irradiation in the treatment of myelodysplastic syndrome

Although reduced-intensity conditioning (RIC) has been increasingly used in patients with myelodysplastic syndrome (MDS) to reduce transplant-related mortality, a high relapse rate in RIC remains an unresolved problem. Considering the additive antileukemic effect of low-dose total body irradiation (TBI), we evaluated the feasibility of combining RIC regimens with low-dose TBI in de novo MDS. The RIC regimen combined with low-dose TBI in this study consisted of fludarabine (150 mg/m(2)), intravenous busulfan (6.4 mg/kg), and TBI (400 cGy). Antithymocyte globulin was used to overcome HLA mismatching. A total of 31 subjects were recruited with a median age of 39 years (range 19-63). The patients received transplants from siblings (n = 20) or unrelated donors (n = 11). All patients rapidly achieved full-donor chimerism. At a median follow-up for survivors of 35 months (range 6.0-54.9), the 3-year overall survival, event-free survival, transplantation-related mortality, and relapse rates were 67.6, 63.2, 20.5 and 11.4%, respectively. The 3-year cumulative incidence of acute (grades II-IV) and chronic extensive graft-versus-host disease in patients who survived at least 100 days was 39.2 and 44.6%, respectively. These results suggest that an RIC combined with low-dose TBI may be a feasible therapeutic approach for treating de novo MDS.

Hematopoietic stem cell transplantation for MDS

Hematopoietic stem cell transplantation (HSCT) offers potentially curative therapy for patients with myelodysplastic syndromes (MDS). However, as the majority of patients with MDS are in the seventh or eighth decade of life, conventional transplant regimens have been used only infrequently, and only with the development of reduced-intensity conditioning has transplantation been applied more broadly to older patients. Dependent upon disease status at the time of transplantation, 30% to 70% of patients can be expected to be cured of their disease and survive long term. However, posttransplant relapse and graft-versus-host disease (GVHD) remain problems and further investigations are needed.

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.