RELAPSE OF APLASTIC-ANEMIA AFTER IMMUNOSUPPRESSIVE TREATMENT - A REPORT FROM THE EUROPEAN BONE-MARROW TRANSPLANTATION GROUP SAA WORKING PARTY

This study was designed to determine the incidence of relapse and fact ors predictive for relapse in 719 patients with severe aplastic anaemi a (SAA) after immunosuppressive treatment (IS). Patients developing my elodysplasia or acute leukaemia after IS, and patients receiving a tra nsplant, were excluded from this analysis. Response was defined as rea ching complete independence from transfusions, relapse was defined as becoming again transfusion dependent. This criteria was validated by s imilar figures when using other 'relapse criteria' such as drop in neu trophil or platelet counts. Of 358 patients responding to IS, 74 patie nts relapsed after a mean time of 778 d after treatment. The actuarial incidence of relapse is 35.2% at 14 years after IS. The risk for rela pse was higher in patients responding within 120 d from IS (48%) compa red to patients responding between 120 and 360 d (40%) and only 20% fo r slow responders (> 360 d from IS) (P < 0.00001). In multivariate ana lysis this factor still proved significant (P < 0.0001). The mean time between diagnosis and treatment was significantly longer in patients relapsing compared to patients who did not relapse (260 v 134 d. P = 0 .037). Relapse was not predicted by the severity of the disease, age, and sex. In 39 of the 74 relapsing patients a second response could be achieved. Responses after relapse were associated in univariate analy sis with early response to previous IS and early occurrence of relapse . The actuarial survival of patients not relapsing is significantly be tter than survival of patients relapsing (79.8% v 67.1%, P = 0.0024). However, the actuarial survival of 39 relapsing patients who responded again to IS was similar to patients not relapsing (86%) and significa ntly better than in 35 patients not reaching a second response after r elapse (49.3%, P = 0.0015). This study indicates that relapse is a rel evant problem in the treatment of aplastic anaemia, and does have an i mpact on overall survival. Prospective studies of immunosuppressive re gimens, looking at responses, should also address this problem in the future.