Combination of cytarabine and topotecan in patients treated for acute myeloid leukemia with persistent disease after frontline induction

After a first course of induction chemotherapy, 30-40% of patients with acute myeloid leukemia (AML) do not achieve a complete response (CR). A second course of an anthracycline and intermediate-dose cytarabine (IDAC) allows a significant number of patients with persistent AML at day 14 to finally achieve a CR. We hypothesized that use of a topotecan and cytarabine combination in this setting might improve tolerance and efficacy. Cytarabine (1000 mg/m(2)/12 h days 1-4) was combined with topotecan (TA, 1.25 mg/m(2)/day by continuous intravenous infusion [CIV] days 1-4) in 31 consecutive patients with >= 5% marrow blasts by day 14 of induction. The median follow-up was 36 months. The CR rate was 81%, and the 2-year probability of overall survival and cumulative incidence of relapse were 66% and 38%, respectively. No unexpected toxicity was observed. Comparison with historical controls treated with the combination of a similar schedule of cytarabine and an anthracycline showed a better CR rate (p = 0.054), overall survival (p = 0.03) and cumulative incidence of relapse (p = 0.03). These results were confirmed in a multivariate analysis model. This work shows that the substitution of an anthracycline by topotecan is feasible and associated with significant efficacy for patients with AML with persistent leukemia at day 14 after standard-dose anthracycline induction.