Comparison of toxicity and outcome in patients with acute myeloid leukemia treated with high-dose cytosine arabinoside consolidation after induction with a regimen containing idarubicin or daunorubicin.

The toxicity and outcome after high-dose ara-C/daunorubicin (HDara-C/DNR) consolidation therapy in de novo AML was compared in 11 patients who received an idarubicin-containing induction therapy (IDA; from June 1995 to March 1997) and 16 patients pretreated with daunorubicin (DNR; from July 1990 to May 1995) for induction. The DNR group consisted of two cohorts, one (n = 6) of patients who had received, as had the IDA group, two induction and one intermediate-dose ara-C consolidation courses, and another (n = 10) of patients who had been pretreated with one induction and one consolidation course prior to HDara-C/DNR. There was no difference in the relative dose between the three cohorts. Following HDara-C/DNR, the IDA-pretreated patients experienced a more prolonged myelosuppression during consolidation therapy compared with the DNR group. Duration of neutropenia (< 500 neutrophils/microl) following HDara-C/DNR was 31.2 +/- 16 days (mean +/- SEM) in the IDA group compared with 18.7 +/- 5 days in the DNR group (p < .001 Mann-Whitney U-test). The duration 'of thrombocytopenia (platelets < 25000/microl) was 34.8 +/- 20 days in the IDA group vs. 18.5 +/- 6 days in the DNR group (p < .005). The more prolonged myelosupression was associated with a longer duration of fever (18.9 +/- 24 vs. 6.9 +/- 5.2 days). A greater incidence, length (11 +/- 8 vs. 1.2 +/- 2 days), and severity of diarrhea were observed in the IDA-pretreated group. Three of 11 IDA patients experienced WHO grade III-IV diarrhea. In the IDA group two patients developed severe enterocolitis with Candida septicemia, and one of these patients died. One patient in the IDA group died during prolonged aplasia. In the DNR group 6/16 patients experienced grade I-II diarrhea. Two patients in each group died during consolidation therapy. The CR rate was 87% in the IDA group and 79% in the DNR group. Relapse-free survival after HDara-C is 50% at a median follow-up of 60 months in the DNR group and 45% after a median follow-up of 17 months in the IDA group. Whether the advantage of the superior response rate in the IDA-treated patients may be lost during HDara-C consolidation treatment due to increased toxicity remains to be proven in larger trials.