A comparative trial of posttransplant immunosuppression in patients transplanted for thalassemia. Cyclosporine alone versus cyclosporine, cyclophosphamide, and methotrexate.

This study compares the efficacy of 2 posttransplant immunosuppressive regimens for prevention of graft-versus-host disease (GVHD). Forty-four patients, ages 8-15 years, with homozygous beta thalassemia received marrow allografts from HLA-identical siblings following an ablative regimen of busulfan and cyclophosphamide. Twenty-two patients received cyclosporine (CsA) alone and 22 received cyclosporine, cyclophosphamide, and methotrexate for prophylaxis against GVHD. Two who received CsA alone have died (1 of graft rejection and 1 of acute GVHD) as did 4 patients who received 3 drugs (1 of rejection, 1 of acute GVHD, 1 of infection and cardiac failure before engraftment, and 1 of acute respiratory failure before engraftment). One patient in each group rejected the transplant and survives with thalassemia. The probability of developing acute GVHD was 41% for the CsA group and 15% for the 3-drug group (P = less than 0.05). Patients receiving CsA alone had a probability of event-free survival of 86% compared to 77% in the group receiving 3 drugs (P = 0.40) with a followup of 209-706 days. Although the study showed a decrease in the incidence of GVHD in recipients of the more intensive prophylactic regimen, this study was terminated since it was apparent that even if larger numbers of patients were studied it would be difficult to demonstrate a significant survival advantage with the use of this drug regimen.