Continuous infusion idarubicin and oral busulfan as conditioning for patients with acute myeloid leukemia aged over 60 years undergoing autologous stem cell transplantation

There is growing interest in autologous stem cell transplantation (ASCT) for elderly patients with acute myeloid leukemia (AML). While mortality and toxicity from ASCT have been reduced, relapse rate is still high. In a prospective study, we investigated the feasibility of a new conditioning regimen consisting of high-dose idarubicin plus busulfan in AML patients aged over 60 years undergoing ASCT. A total of 14 patients (median age: 64 years) received 2 days continuous infusion of idarubicin at 20 mg/m2/day, followed by 3 days of oral busulfan (4 mg/kg/day) as conditioning. 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 11 and 12, respectively. Cardiac toxicity was absent, while 12 patients (86%) had grade 3-4 mucositis. After a median follow-up of 9 months from ASCT, nine of 14 patients are alive in continuous complete remission (CR), four have relapsed at 3, 6, 8 and 9 months, and one died in CR1 from gastric cancer. Our data demonstrate the feasibility of a conditioning regimen based on high-dose idarubicin plus busulfan in elderly AML patients. Results concerning reduction of relapse rate need confirmation in a larger series with longer follow-up.