From 1983 to 1994 two types of trials were performed. Between 1983 and 1987 a modified VAPA protocol (post-remission therapy with intensive sequential blocks for 12-16 months) was given to 40 patients from two institutions. CR was attained in 75% and 5-year EFS was 35%. In 1988 a post-remission protocol based on intensification chemotherapy (two high-dose Ara C treatments combined with mitoxantrone in the first and amsacrine in the second) followed by BMT was initiated. Remission induction was DAE combination (1 or 2). Patients in CR or PR with HLA-compatible donor received an allogeneic transplant (al-BMT) and those without an autologous transplant (ABMT) with "purged" marrow. Pre-BMT therapy was fractionated TBI and CYCLO in patients over 3 years and Busulfan + CYCLO + VP-16 in those under 3. Between April '88 and December '94, 51 patients (aged 3 months to 15 years) were enrolled. 80% attained CR, 14% were failures or partial responses and 6% died before the 30th day. During the intensification phase, 5 patients attained CR and one relapsed and died. 47 patients (45 in CR and 2 in PR) proceeded to the BMT phase. 16 patients (14 in CR and 2 in PR) received al-BMT and 31 (all in CR) ABMT. Both group characteristics were comparable.