Cyclophosphamide and antithymocyte globulin to condition patients with aplastic anemia for allogeneic marrow transplantations: the experience in four centers.

This report summarizes the experience with a conditioning regimen of cyclophosphamide and antithymocyte globulin in patients with severe aplastic anemia given HLA-matched related marrow grafts at 4 transplantation centers. Enrolled were 94 consecutive patients, of whom 87 had received multiple transfusions and 38 had failed immunosuppressive therapy. Their ages ranged from 2 to 59 years. After transplantation, 89 patients received a methotrexate/cyclosporine regimen for graft-versus-host disease (GVHD) prevention. Cyclosporine with or without prednisone was given in 4 patients, and no immunosuppression was given in 1 patient. Ninety-six percent of patients had sustained grafts, whereas 4% rejected grafts between 2 and 7 months after transplantation. Of the 4 rejecting patients, 3 are alive with successful second engraftments. Acute grade II GVHD was seen in 21% of patients, grade III in 7%, and grade IV in 1% of patients. Chronic GVHD was seen in 32% of patients, most of whom responded completely to immunosuppressive therapy. With a median follow-up of 6.0 years (range, 0.5-11.6 years), the survival rate was 88%. No unusual long-term side effects have been seen with the regimen. We conclude that the cyclophosphamide/antithymocyte globulin regimen combined with methotrexate/cyclosporine after transplantation is well tolerated and effective in heavily pretreated patients with aplastic anemia.