Allogeneic bone marrow transplantation for severe aplastic anemia: the Vancouver experience

We report a retrospective analysis of the experience of a single centre in treating severe aplastic anemia (SAA) with allogeneic bone marrow transplant (BMT). Between 1982 and 1992, we transplanted 21 patients with SAA (14 males, 7 females); median age at BMT was 15 y (range 2-40 y); median time from diagnosis of SAA to BMT was 29 d (range 6 d-5.5 y). Thirteen patients had received multiple transfusions before BMT. Patients were conditioned with cyclophosphamide 50 mg/kg for 4 d, +/- total body irradiation 300-500 cGy as a single fraction; 1 patient received total nodal irradiation (750 cGy) plus antithymocyte globulin. Sixteen patients received bone marrow from human leucocyte antigen (HLA)-identical siblings, 3 from haplo-identical parents, and 2 from unrelated volunteer donors; graft-versus-host disease (GVHD) prophylaxis was variable. Three patients failed to fully engraft following BMT; 2 achieved successful engraftment following a second BMT. Six of 20 evaluable patients (30%) developed grade II-IV acute GVHD, of whom 3 died; 3 patients developed limited and 5 patients (31%) developed extensive chronic GVHD, of whom 1 died. Fourteen patients (67%) are alive and well following BMT with a median follow-up of 6 y (range 2.1-11 y). Survival was superior in patients receiving sibling-donor BMT (75%) compared with those receiving parent- or unrelated-donor BMT (40%). We conclude that allogeneic BMT remains an important mode of treatment for SAA, but long-term survival remains limited by graft failure and GVHD.