Comparison of a Combination of Vosaroxin (VOS) and Intermediate-Dose Cytarabine (IDAC) with Idac for the Consolidation Therapy of Younger Patients with Favorable- and Intermediate-Risk Acute Myeloid Leukemia (AML) in First Complete Remission (CR): Preliminary Results of a Randomized Phase 2 R4-VOS Study of the French ALFA-Filo AML Intergroup

In spite of CR rates of 75-80% currently achieved with anthracycline-cytarabine regimens in younger patients with favorable and intermediate-risk AML, relapse remains a major issue. The French AML intergroup launched the BIG-1 trial in 2015 in order to test different strategies aiming at reducing relapse rate and improving survival. All patients with previously untreated non-APL and non-CBF AML aged 18-60 years are eligible for trial participation which is still ongoing. The trial design includes several randomizations (R): Idarubicin vs daunorubicin for induction (R1), HDAC vs IDAC for consolidation (R2), post-transplant GVHD prophylaxis modalities (R3). R4 consists of nested randomized phase 2-3 trials testing the addition of new drugs to the IDAC or HDAC backbones during the consolidation phase. The protocol was designed to allow the sequential evaluation of several new agents over the trial period. Vosaroxin (VOS) has shown antileukemic activity (Advani, Clin Cancer Res 2010). The combination of VOS and IDAC showed higher CR rate and a non-significant OS benefit as compared to a placebo-IDAC arm in a large phase 3 trial in patients with refractory/relapsed AML (Ravandi Lancet Oncol 2015). We hypothesized that the addition of VOS to IDAC would improve LFS as compared to IDAC alone when given during the consolidation phase. Methods. Eligibility criteria in the BIG-1 trial include: previously untreated AML according to WHO 2016 classification (AML secondary to an untreated myelodysplastic syndrome allowed), age 18-60, ECOG PS 0-2, no cardiac contra-indication to anthracyclines. Patients with APL and patients with CBF-AML are excluded. Eligibility criteria for R4 randomization were: Patients in first CR/CRp/CRi following 1 or 2 courses of induction chemotherapy according to the BIG-1 protocol; ELN2010 favorable- and intermediate-risk groups; ECOG PS ≤ 3; Absence of severe uncontrolled infection. Patients were scheduled to receive Cytarabine: 1.5 gr/m² twice daily on D1, 3, 5 with or without Vosaroxin: 70 mg/m² on D1 and D4 per cycle for a maximum of three cycles at 4-6 weeks intervals. Patients scheduled for allo-SCT or those who had reached CR after 2 induction cycles were to receive only 2 cycles of VOS-IDAC/IDAC. R4-VOS sub-trial was designed to detect an increase of the 18-month LFS from 55% to 75% using a two-step phase 2-3 study. With type I and II errors set at 20% and using a one-sided test, 70 patients had to be randomized. If the predefined stati