High-dose idarubicin and busulphan as conditioning for autologous stem cell transplantation in acute myeloid leukemia: a feasibility study.

Introduction: Between 30 and 50% of patients with acute myeloid leukemia still relapse after autologous stem cell transplantation. We investigated the feasibility of a new conditioning regimen consisting of high dose IDA plus oral busulphan in patients undergoing autologous transplantation.

Materials And Methods: Patients (n = 13) were given three days continuous infusion IDA, followed by four days conventional dose oral busulphan as conditioning. Peripheral blood stem cells were used in all cases. Eleven patients were in CR1. Patients with t(8;21) and inv(16) as well as those with acute promyelocytic leukemia were excluded from the study. The median of CD34+ cells infused was 6.2 x 10(6)/l (2.6-16.1).

Results: No case of transplant-related mortality occurred. The median number of days to neutrophil (>0.5 x 10(9)/l) and platelet (>20 x 10(9)/l) recovery was 10 (7-21) and 20 (9-26), respectively. Patients needed a median of 3 platelet units (1-6) and 3 blood units (0-12), respectively. Left ventricular ejection fraction remained unmodified after ASCT. Twelve out of 13 patients (92%) had variable grade of mucositis (two grade 2, five grade 3 and five grade 4). Total parenteral nutrition was needed in nine patients (69%). After a median follow-up of 14 months from ASCT, 11 patients out of 13 (85%) are alive in continuous CR; the other two patients experienced relapse at 12 and 14 months.

Conclusion: Our data demonstrate the feasibility of a conditioning regimen based on high-dose IDA plus Busulphan in AML. Results concerning antileukemic efficacy are promising, but need confirmation on larger series with longer follow-up.