Fludarabine, cyclophosphamide, and antithymocyte globulin for matched related and unrelated allogeneic stem cell transplant in severe aplastic anemia

Twenty severe aplastic anemia (SAA) patients underwent allogeneic stem cell transplantation (allo-SCT) with fludarabine (FLU), cyclophosphamide and antithymocyte globulin from a matched related (n=7, age ≥ 40) or unrelated donor (n=13, any age). Median age was 34 years (range 1–59). Median time from diagnosis to allo-SCT was 12 months (range 2–244). Seventeen out of 19 evaluable patients engrafted (90%). There were two secondary graft failures (10%). Median time to neutrophil recovery was 15 days (range 8–30). Chimerism studies indicated ≥90% donor-derived engraftment in 16/19 evaluable patients (75%). Four out of 20 patients (20%) developed acute (grade II–IV) GVHD, and 6/16 evaluable patients (37%) developed chronic GVHD. We observed EBV reactivation and viremia in seven patients, which was successfully treated with rituximab in all but one instance (where it was self-limiting). Thirteen patients (62%) are alive (including eight of the last nine treated) with a median follow-up of 30 months (range 3–112). Seven patients expired (graft rejection n=1, GVHD n=1, multiorgan failure n=1, infection n=2, EBV post-transplant lymphoproliferative disorder/PTLD n=2). Total body irradiation-free, FLU-based conditioning for matched related and unrelated allo-SCT is feasible with high engraftment rates. EBV PTLD remains a drawback of this approach.