Sixty-two patients with high-risk acute leukemia were treated with the FLAD regimen [3 days of treatment with fludarabine 30 mg/m(2), cytarabine (AraC) 2 g/m(2), and liposomal daunorubicin 80 mg/m(2)]. The acute myeloid leukemia (AML) patients were either refractory to standard induction regimens (8), were in first or second relapse (13), or received therapy as first-line treatment [21 patients, 16 were above 60 years of age and 5 had post-myelodysplastic syndrome (MDS) AML]. The acute lymphoblastic leukemia (ALL) patients were treated for relapsed (7) or refractory disease (10). Three patients had chronic myeloid leukemia (CML) in the blastic phase. FLAD was well tolerated by most patients. Ten major infectious complications were recorded while no signs of cardiac toxicity were observed. Five patients (8%) died before day 28 with hypocellular marrow, mainly of infection or hemorrhage, and response could not be evaluated. Complete response rate was 62% and 69% among AML patients treated at diagnosis or for relapsed disease, respectively, and 59% among the ALL patients. Furthermore, FLAD managed to overcome the negative impact of poor prognosis karyotype in ALL patients, since five of the seven patients with t(9;22) or complex karyotype achieved complete remission (CR). Nine patients underwent bone marrow transplantation (BMT). Among the AML patients who were treated at diagnosis or for relapse, the median duration of CR was 7 months (range: 2-18) and 8 months (range: 2-26), respectively. Median survival among these patients was 8 (range: 1-40) and 12 (range: 1-30) months, respectively. Similar values were found in ALL patients. In conclusion, FLAD may be an effective alternative treatment for patients with relapsed AML and for patients with ALL who failed first-line therapy.