Microtransplantation with Decitabine and Cytarabine Improves Patient Outcomes in Myelodysplastic Syndromes

Abstract Abstract 1709 The outcome of myelodysplastic syndromes (MDS) still remains unsatisfactory, with a low complete remission (CR) rate and a poor overall survival rate. Decitabine improved the overall responses of MDS as a hypomethylating agent, but CR rates remain low and prolonged pancytopenia. Our recently study showed that infusion of G-CSF mobilized HLA-mismatched peripheral blood stem cells (G-PBSC) can improve the outcome of chemotherapy for acute myeloid leukemia in elderly patients. However, whether G-PBSC combining decitabine and cytarabine chemotherapy will improve outcomes in MDS patients is unknown. Material and methods: Total of 72 patients with MDS, from 16 to 82 years of age, were assigned to receive decitabine 25–30 mg/m2daily for 4 days with cytarabine 150 mg/m2 daily for 7 days by intravenous followed to infusion of G-PBSC on 24 hours after each completion of the cytarabine therapy (Microtransplantation-group, n=28) or decitabine 20 mg/m2 daily for 5days (Decitabine group, n=27) or 15 mg/m2 daily for 5days (low decitabine group, n=17). The infused cells of mononuclear cells and CD34+ cells with HLA-mismatched in 3 loci (n=22) and 2 loci (n=5) and 1 loci (n=1) were 3.33(3.04–10.8)108/kg, 2.26(0.68–5.25)106/kg and no any GVHD prophylactic treatment was used in the Microtransplantation-group. Results: Total CR rate of was 42.9%#x2610;#x0025; A14.8% and 29.4% in the three groups, respectively. That of MST-group is significantly higher than that of B group (P=0.02). The CR rate after first course in MST group is 21.5% which was higher the other two groups (10% and 0%, P=0.14#x2610;#x0025; GP=0.04). The complete cytogenetic response rate in the Microtransplantation-group was 90.9% which is highest than the other two groups (10% and 11%, P<0.001,P<0.001). The progress free survival(PFS) of Microtransplantation-group in 12 months is 50.1% which is higher than other two group (9.9%,9.6%, P=0.01#x2610;#x0025; GP=0.008). Median times of neutrophil recovering over 1×109/L in three groups after 1 course therapy was 17,19 and 13 days and median times of platelet recovering over 50×109/L was 17,26 and 28days, respectively. These of MST group recovered more fastly than those of the other groups. The severe infection rate and early phase mortality rate in three groups had no differences. No donor chimerism, no graft-versus-host disease were observed in all of the patients in the MST group. Conclusion: Our clinical results suggested that decitabine with cytarabine and microtransplantation may improve clinical response CR rate early, especially on complete cytogenetic response and PFS, no increase infection rate and early phase mortality rate. The MST may provide an new method for MDS treatment. Further studies with much more patients and long-term follow-up should be conducted. Disclosures: No relevant conflicts of interest to declare.