Cladribine Added to Idarubicin and Cytarabine as an Induction Regimen for Patients with De Novo Acute Myeloid Leukemia: A Multicenter, Randomized Phase III Trial

PURPOSE: To assess the efficacy and safety of an induction regimen composed of idarubicin, cytarabine, and cladribine (IAC) in patients with de novo acute myeloid leukemia (AML). PATIENTS AND METHODS: Adult patients with newly diagnosed AML were randomized to the IAC group (cladribine 5 mg/m2/day for 5 days, idarubicin 8 mg/m2/day for 3 days, and cytarabine 100 mg/m2/day for 7 days) and the IA group (idarubicin 12 mg/m2/day for 3 days and cytarabine 100 mg/m2/day for 7 days) at a 1:2 ratio. The primary endpoint was complete remission (CR) after induction. Secondary endpoints included 2-year overall survival (OS), disease-free survival, and cumulative incidence of relapse. RESULTS: A total of 618 adult patients with newly diagnosed AML were enrolled. The overall CR rate was 80.5% in the IAC group compared with 72.4% in the IA group (P = 0.029). The 2-year OS was 81.3% in the IAC group compared with 70.0% in the IA group (P = 0.011). Patients on the IAC regimen achieved a higher CR rate compared to those on the IA regimen, particularly in those with adverse risk (69.8% vs. 49.1%, P = 0.008), 2-year OS (80.1% vs. IA 58.1%, P = 0.014), and disease-free survival (78.8% vs. 51.3%, P = 0.009). In the subgroup of patients older than 45 years of age, the IAC regimen exerted better CR (77.1% vs. 62.6%, P = 0.033) and 2-year OS (74.7% vs. IA 55.0%, P = 0.019). There were no differences in chemotherapy-related toxicities between the groups. CONCLUSIONS: Cladribine added to the IA regimen was safe and effective in de novo AML. Patients with adverse risk or those between 45 and 60 years of age might benefit significantly on both response and survival with the IAC regimen.