Allogeneic Stem Cell Transplantation from Unrelated Donors after Reduced Intensity Conditioning in Patients with MDS/sAML. A Report from the Chronic Leukemia Working Party (CLWP) of the EBMT.

We analysed the results of 67 patients with MDS/sAML who were transplanted with allogeneic stem cell transplantation from unrelated donors after a reduced intenisity conditioning and reported to the EBMT. The median age was 52 years (range 17–70 years) and stem cell source was bone marrow (n = 30) or peripheral blood progenitor cells (n = 33).. The graft was HLA matched in 57 patients while 8 patients received SCT from HLA-mismatched donor. The MDS classification was as follows: RA/RARS: n=8, RAEB/CMML: n = 14, RAEB-t/sAML: n = 22. The conditioning regimen consisted of fludarabine/busulfan (n=15), fludarabine/melphalan (n=6), fludarabine and TBI (n=8) or fludarabine and others (n=36)At time of transplantation only 12 (18%) were in first complete remission. The Kaplan-Meier estimates of the probability of 2 years overall and disease free survival were 33 % (95% CI: 21–45 %) and 24 % (95% CI: 12–36 %), respectively. The probability of relapse at two years was 58 % (95% CI: 40–76 %) and of one year treatment-related mortality 37 % (95% CI %: 23–51 %).

In an univariate analysis assessing source of stem cells, age, disease type, T-cell depletion, and HLA-matching no factor was significant for OS, EFS, TRM and Relapse. Allogeneic stem cell transplantation after a reduced intensified conditioning followed by unrelated SCT seems to be a feasible approach in those patients who were no candidates for a standard conditioning but is associated with a considerable number of relapses.