Low Relapse without Excessive Transplant-Related Mortality Following Allogeneic Stem Cell Transplantation in Patients with High Risk Secondary Acute Myeloblastic Leukaemia and Myelodysplastic Syndromes, Long-Term Outcomes in a Single Centre Experience.

Abstract 4308

Allogenic stem cell transplantation (Allo-SCT) as a therapy for secondary acute myeloid leukaemia (sAML) and myelodisplastic syndromes (MDS) is the most powerful treatment option. However, (Allo-SCT) is also complicated by a high risk for treatment-related morbidity and mortality.

We analysed retrospectively the data of 70 patients transplanted at our institution from June 1995 to december 2008, 44 patients (63%) with sAML and 26 patients (37%) with MDS was treated with (Allo-SCT); median age at diagnosis was 41 years, (15-70), and the median age of 42, 5 years (16-70) at transplantation; The conditioning regimen was myeloablative combining (cyclophosphamide and TBI) in 16 patients (23%) and 54 patients (77%) was with a reduced intensity conditioning (RIC) regimens combining fludarabine, busulfan, and antithymocyte globulin; 11 patients (16%) were infused with bone marrow (BM), 55 patients (79%) peripherical blood stem cells (PBSC), and 4 patients (5%) cord blood cells; in 49 cases (70%) donor was a HLA identical sibling and in 21 (30%) was a matched unrelated donor;

41 patients (59%) carried high risk cytogenetic features, like (7q-, 5q-, > 3 alterations), while was normal in 24 patients (34%), and in 5 patients (7%) was unknown. Disease status at transplantation was as follow: CR in 24 patients (34%), 34 patients (49%) was refractory or in progression after treatment, and 12 patients (17%) was with a stable disease.

With a median follow-up of 55 months (3-150), 30 patients (43%) are alive, the overall survival OS at 2 years and 5 years was 48 % and 39% respectively, and after ten years of follow up, OS was 30%, 95%CI [17.8-50.8]. We observed also that 26 % of refractory patients and 54% of patients in CR are alive at five years of transplantation.

The probability of progression after transplantation at five and ten years was 31% with 95%CI [20.-46.5].

2 years and 5 years treatment related mortality (TRM) was 23% and 26% respectively, and no modification at ten year, 95%CI [14.3-37.3]. TRM occurred in 16 patients (23%). Cause of death was; infections in 5 patients (7%), GvHD in 3 patients (4%), GvHD and infection in 3 patients (4%), multi organ failure (MOF) in 5 patients (7%). In multivariate analysis; OS, PFS or TRM, were not influenced by donor type (HLA id sibling vs others), conditioning regimen (RIC vs MAC), and stem cell source (bone marrow vs PBSC).

Allogenic stem cell transplantation can be considered as a good option for the treatment of patients with high risk sAML and MDS when compared with the remission rate at five years of the other nonallogeneic SCT therapies.