LONG-TERM OUTCOME OF APLASTIC-ANEMIA IN ADULTS TREATED WITH ANTITHYMOCYTE GLOBULIN - COMPARISON WITH BONE-MARROW TRANSPLANTATION

The outcome of 155 adult aplastic anemia (AA) patients treated with an tithymocyte globulin (ATG, Upjohn, Kalamazoo, MI) at University of Cal ifornia, Los Angeles from 1977 to 1988 was evaluated. The median survi val of the 146 patients who did not undergo bone marrow transplantatio n was 5.6 years, with 49% +/-: 4% surviving more than 6 years. The mos t important predictor of survival was positive response to ATG (P < 0. 001), which was observed in 48% of patients. Among pretreatment variab les, disease severity was the best predictor of survival. Patients wit h moderate AA (MAA) had significantly better survival than those with severe (SAA) or very severe (VSAA) disease (P = 0.04). The 6-year actu arial survival rates of the three groups were 71% +/- 9%, 48% +/- 7% a nd 38% +/- 7%, respectively. Cox regression analysis found disease sev erity to be the only pretreatment variable significantly associated wi th survival (P = .02). Patient age, sex, disease etiology, concurrent treatment with androgens, or duration of ATG therapy were not associat ed with differences in survival or response to ATG. Late clonal hemato logic complications (ie, myelodysplasia, acute myelogenous leukemia) w ere observed in 5 of the 77 patients followed for more than 2 years af ter ATG treatment. In addition, one case of non-Hodgkin's lymphoma and three solid tumors occurred in the ATG-treated patients. The survival of 56 ATG-treated patients with SAA or VSAA between the ages of 16 an d 43 did not differ significantly from that of 55 adult AA patients wh o underwent bone marrow transplant (BMT) during the same time period ( P = 0.6). However, 6-year survival rates improved from 43% for patient s transplanted before 1984, to 72% for those who underwent BMT between 1984 and 1989. In contrast, there was no difference in the survival r ates of patients treated with ATG during these two time periods (46% v 45%, respectively). The results suggest a superior long-term outcome for adult patients with SAA treated with BMT rather than with ATG alon e, using current protocols. (C) 1995 by The American Society of Hemato logy.