Similar Overall Survival and Toxicity After CB Transplanation with Co-Infusion of CD34+ Cells From a Third Party Donor Compared to Myeloablative MUD Stem Cell Transplantation In High Risk Patients

Abstract 3532 In the absence of an HLA matched sibling donor, an unrelated adult donor matched (MUD) at 8 of 8 alleles for HLA A, B, C, DRB1 is considered as first alternative. However, only 50% of patients in Europe have an available suitable donor in a median time of 4 months. For those patients without a suitable MUD, we have adopted CB (cord blood) stem cell transplantation with the co-infusion of CD34+ cells from a third party non HLA-identical donor (Dual transplantation). The objective of this study was to analyze toxicity and overall survival (OS) rates of patients who underwent this procedure and compare them with a cohort of patients who received a myeloablative MUD transplantation in a single centre and during a similar period of time. Patients: Between 2005 and 2010, 16 consecutive patients with high risk disease underwent a total of 18 dual transplants and 17 patients, with similar pre-SCT characteristics recieved a myeloablative MUD transplantation with 12/12 HLA identity in a single centre (Table 1). Transplants performed before 2005, those with manipulated grafts and with HLA mismatches were excluded. Results: There were no significant differences in age, gender, pre-SCT disease status and previous therapy lines between both groups. Three cases among the dual group showed primary graft failure (2 of them showing third party donor cells engraftment) who were rescued by a second CB transplant in two cases and a MUD in one case (succesfull in 2). There were no graft failures in the MUD group. GVHD rates are shown in table 1. OS was 50% in the dual group and 53% in the MUD group with a median follow-up of 33 (1-67) y 13 months (1,1-48,5) respectively (Figure 1). The cumulative relapse incidence at 2 years was 54% in the dual group and 53% in the MUD group. There were no relpses after 2 years in both groups. All the transplant related deaths (TRM) took place within the first year after transplantation with no significant differences in cumulative incidence between both groups (p=0,69). Conclusions: In our experience, CB transplantion together with the co-infusion of CD34+ cells from a third party HLA-mismatched donor offers OS and DFS rates comparable to those from myeloablative HLA 12/12 MUD trasnplantation with an acceptable TRM. Therefore, dual transplantion is still our first choice for patients without an available MUD or for whom trasplant is urgent. Disclosures: No relevant conflicts of interest to declare.