Long-Term Results of Non- Fludarabine Versus Fludarabine-Based Conditioning Regimens in Severe Aplastic Anemia Patients

BACKGROUND AND OBJECTIVE: Allogenic hematopoietic cell transplantation (AHSCT) is the best therapeutic modality capable of correcting the hematologic manifestations of severe aplastic anemia (SAA), here in this study we have compared the results of well-tolerated fludarabine-based conditioning regimens for SAA patients who are heavily transfused undergoing AHSCT.

DESIGN AND SETTINGS: This is a retrospective study consist of 25 patients diagnosed with SAA who underwent AHSCT between February 2002 and March 2015 at the Bone Marrow Transplantation Unit of Hacettepe University. All patients gave written informed consent for the procedure.

PATIENTS AND METHODS: We analyzed the outcome of 25 SAA patients who had undergone AHSCT between 2002 and 2015. the median age at transplantation was 27(16-55) years. Patients received transplants from an HLA-identical sibling (n=24) and mismatched allogeneic related HSCT (n=1). Hematopoietic Stem Cells (HSC) were collected from the donors via apheresis. Eight patients underwent standard CY 50 mg/kg plus ATG-Fresenius^R 5-10 mg/kg as conditioning fort he transplantation procedure and 13 patients conditioned with CY(50 mg/kg for 2 days) plus fludarabine 25 mg/m2 for 5 days and ATG-Fresenius^R 5-10 mg/kg as AHSCT conditioning and received GvHD (Graft-vs-Host Disease) prophylaxis was standard CsA 3 mg/kg IV inf. plus Methotrexate(MTX) 10mg/m2 on day 1,and MTX 5 mg/m2 on days 3.,6. and 11.

RESULTS: The median follow-up period for all the survivors was 117 months [minimum 3 and maximum 159 months]. The 5-year overall survival (os) for patients who did or did not receive fludarabine-based preparative regimens for the allograft was 93%, and 87%, respectively. However, there were no statistically significant differences in os rates between these two groups (P=0,58). Median neutrophil engraftment time was 11 days and median platelet engraftment time was 13 days. Primary graft failure occurred in 1 patients (4%) who received fludarabine-based conditioning regimens.

CONCLUSION: Fludarabine-Based (Flu-CY-ATG) conditioning is a safe and viable option when compared to the standard CY-ATG conditioning in heavily-transfused SAA patients who undergo Allogeneic hematopoietic stem cell transplantation (allo-HSCT).