Marrow transplantation in patients with thalassemia responsive to iron chelation therapy.

BACKGROUND: Patients with homozygous beta-thalassemia, who have a good prognosis during treatment with conventional therapy, appear to have an especially high probability of hematologic cure with bone marrow transplantation, although the morbidity and mortality associated with such treatment are not established.

METHODS: The records of all patients with thalassemia who received bone marrow transplants from HLA-identical donors in Pesaro, Italy, were examined from October 1982 through May 1992. Detailed evaluation of the outcome was conducted in the 89 patients identified as being in class 1 according to the Pesaro classification, in which hepatomegaly, portal fibrosis, and the inadequacy of iron chelation therapy are considered independent risk factors, and the patients are classified as being in class 1 if none of these factors are present, class 2 if one or two of the factors are present, and class 3 if all three factors are present. Sixty-four of the patients had been prepared for transplantation with a drug regimen in current use that includes busulfan and cyclophosphamide followed by cyclosporine as prophylaxis against acute graft-versus-host disease (protocol 6).

RESULTS: There were seven deaths, all within 101 days of transplantation. Two of the 64 patients treated according to protocol 6 died. The probabilities of survival, rejection-free survival, death from causes unrelated to rejection, and rejection were 0.92, 0.85, 0.06, and 0.08, respectively, in the total group and 0.97, 0.93, 0.03, and 0.04 in the 64 patients treated according to protocol 6. Preliminary evidence suggests that there was useful unloading of tissue iron deposits.

CONCLUSIONS: The high probability of cure with little early or late morbidity and mortality suggests that patients with class 1 thalassemia who have HLA-identical donors available should be treated by bone marrow transplantation. However, this was not a controlled trial, so we cannot directly compare the outcome with that of conventional treatment.