OUTLINE: This is a randomized, controlled, multicenter study. Patients are stratified according to type of disease (resistant vs refractory vs relapsed vs adverse cytogenetic), age (under 15 vs 15 to 29, vs 30 to 49 vs 50-59 vs 60-69 vs 70 and over), performance status, and de novo and secondary leukemia. Patients with relapsed disease are further stratified according to duration of first remission (less than 6 months vs 6 to 12 months vs 12 months and over), and prior transplantation (yes vs no).