OBJECTIVETo compare the efficacy and toxicity of 10 mg/m² or 8 mg/m² idarubicin (Ida) combined with cytarabine (IA"3+7"regimen) as induction chemotherapy for adult patients with newly diagnosed acute myeloid leukemia (AML).

METHODSFrom June 2004 to October 2013, 335 adult AML (non acute promyelocytic leukemia) patients receiving the IA regimen as induction chemotherapy were enrolled, including 198 cases with 10 mg/m² Ida and 137 cases with 8 mg/m² Ida for 3 days. We compared the hematologic response, hematologic side effects and prognosis between the two regimens.

RESULTSExcept for 4 early deaths, the complete remission (CR) rate after the first cycle of induction chemotherapy was 72.5%, 10.0% partial remission (PR) and 82.5% overall remission (OR) rate. The CR and OR rates were higher in the 10 mg/m² Ida group than the 8 mg/m² Ida group (CR: 78.9% vs 63.5%, P=0.003; OR: 88.2% vs 75.4%, P=0.007). Multivariate analysis showed that female, HGB≥100 g/L, FLT3-ITD mutation negative and 10 mg/m² Ida were favorable factors for CR. All patients presented cytopenias of grade Ⅳ. There was no differences on the recovery time of ANC≥0.5×10⁹/L and PLT≥20×10⁹/L after induction chemotherapy. Within a median follow-up of 14 (1-118) months, 98 (29.3%) patients relapsed, 92 (27.5%) died. The disease-free survival (DFS) and overall survival (OS) at 3 years were 53.2% and 58.9%, respectively. DFS and OS at 3-year were 34.2% and 37.4% in the chemotherapy cohort, 74.5% and 81.2% in the transplant cohort. 10 mg/m² Ida was an independent favorite factor for DFS (P=0.040) and OS (P=0.007).

CONCLUSIONAs compared to 8 mg/m², 10 mg/m² Ida significantly improved the CR, with the same extent of hematological side effects, and was an independent favorite factor for DFS and OS.