Comparable outcomes between younger (≤40 years) and older (>40 years) adult patients with severe aplastic anemia after HLA-matched sibling stem cell transplantation using fludarabine-based conditioning

Allogeneic stem cell transplantation from HLA-matched siblings (MSD-SCT) for elderly patients with severe aplastic anemia (SAA) is not a widely accepted first-line treatment. Recently, fludarabine, lower-dose cyclophosphamide and antithymocyte globulin conditioning (Flu/lower-dose Cy/ATG) with lower toxicities has been investigated. To determine whether this regimen can overcome the negative effects of age, we analyzed 117 adult patients with SAA who received MSD-SCT using Flu/lower-dose Cy/ATG, and compared outcomes between 63 younger age group (YAG; <= 40 years) and 54 older age group (OAG; > 40 years) patients. No primary graft failure was observed. Neutrophil engraftment was significantly faster in the YAG compared with the OAG (12 vs 13 days; P = 0.04). The incidences of acute grade II-IV (9.5% vs 9.3% at day 100; P = 0.42) and chronic GVHD (8.1% vs 9.5% at 5 years; P = 0.80), secondary graft failure (20.8% vs 7.9% at 5 years; P = 0.11) and transplant-related mortality (5.4% and 11.1% at 5 years; P = 0.91) were not significantly different between the YAG and OAG. In addition, failure-free (73.7% vs 81.0% at 5 years; P = 0.73) and overall survival rates (93.7% vs 88.9% at 5 years; P = 0.20) were comparable. Our results suggest that MSD-SCT using Flu/lower-dose Cy/ATG may be a feasible first-line treatment even in older patients with SAA.