High-dose idarubicin plus busulfan as conditioning regimen to autologous stem cell transplantation: promising post-remission therapy for acute myeloid leukemia in first complete remission?

The optimal post-remission therapy (PRT) for acute myeloid leukemia (AML) remains uncertain. We reported 32 AML patients in first complete remission (CR1) undergoing autologous hematopoietic stem cell transplantation (ASCT) with a characteristic conditioning regimen, termed I-Bu, based on high-dose idarubicin plus busulfan, which considerably strengthened antileukemic activity. Most patients were in better or intermediate-risk group except that cytogenetic or molecular risk information was missing for 18.7 % of the patients. Unpurged peripheral blood stem cells were used in all the cases. The adverse effects were mild and reversible. Only one case of transplant-related mortality was observed. All the patients in this study acquired hematopoietic reconstitution after ASCT. After a median follow-up of 30 (6-119) months, 24 patients (75.0 %) were alive in which 20 (62.5 %) patients were in continuous CR. There were 11 (34.4 %) patients who relapsed after HSCT. Cumulative relapse probability was about 40 % after 24 months. Median OS and DFS have not been reached. Patients in the better and intermediate-risk group had different clinical outcomes, but the differences were not statistically significant. ASCT with I-Bu regimen is possibly promising PRT for better and intermediate-risk AML patients in CR1.