Fludarabine, arabinosyl cytosine and idarubicin (FLAI) for remission induction in poor-risk acute myeloid leukemia.

Progress in treatment of acute myeloid leukemia (AML) is slow and treatment intensification alone has limited effects, particularly in poor-risk cases. Poor-risk cases, that are identified mainly by prior history, leukemic cell mass and cytogenetic abnormalities, share multiple mechanisms of drug resistance that are responsible for treatment failure. Since Pgp-mediated resistance to anthracycline can be reduced with Idarubicin (IDA) and resistance to arabinosyl cytosine (AC) can be reduced with Fludarabine (FLUDA), we tested a combination of high dose AC (2000 mg/sqm, 5 doses), FLUDA (30 mg/sqm, 5 doses) and IDA (12 mg/sqm, 3 doses) for remission induction and consolidation in 45 consecutive cases of poor-risk AML. The complete remission (CR) rate was 71% after the first course and 82% overall, with a projected 2-year survival and relapse-free survival of 44% and 50% respectively. Non-hematologic toxicity was very mild, that is very important in elderly patients, but hemopoietic toxicity was substantial, with a time to hematologic recovery of 3 to 4 weeks and two cases of death in CR. Peripheral blood stem cells (PBSC) could be mobilized and collected successfully only in 11 cases. This three-drug combination is effective and has a limited non-hematologic toxicity, but FLUDA may increase the difficulty of obtaining PBSC early after remission induction.