FLAG-IDA Regimen (Fludarabine, Cytarabine, Idarubicin and G-CSF) in the Treatment of Patients with High-Risk Acute Myeloid Leukemia and Myelodysplastic Syndromes.
Authors: Montesinos Pau , de la Rubia Javier , Orti Guillermo , Sanz Jaime , Martinez David , Mendoza Ninotchka , Scaff Miguel , Paciello Mariliz , Romero Monica , Martin Guillermo , Lorenzo Ignacio , Martinez Jesus , Algarra Lorenzo , Jarque Isidro , Perez-Sirvent Mariluz , Sanz Guillermo , Sanz Miguel A. 
Published: October 2019

Background: Preliminary results with the combination of fludarabine, cytarabine, idarubicin, and granulocyte colony-stimulating factor (G-CSF) (FLAG-IDA), reported complete response (CR) rates of 47–95% in patients with high-risk acute myeloid leukemia (AML) and myelodysplastic syndromes (MDS), with acceptable toxicity. These results lead to a generalized use of FLAG-IDA regimen in this set of patients. However, these studies have been made in small series and the long-term outcome of patients have not been described.

Objectives: Analyze the results of FLAG-IDA regimen, in terms of CR rate and long-term outcome, in a large series of patients with high-risk AML and MDS treated in a single institution.

Methods: From 1997 to 2007, 158 adult patients (median age 60 years, range 16–79) received FLAG-IDA regimen (Fludarabine, 30 mg/m2 intravenous (iv) for 4 days, cytarabine 2 g/m2 iv for 4 days, idarubicin 10 mg/m2 iv for 3 days and glycosylated G-CSF at a daily dose of 300 mcg/m2, from day -1 until day 5). Post-remission therapy consisted of allogeneic transplantation (Allo-HSCT) in eligible patients, or consolidation (idarubicin, 10 mg/m2 iv for 3 days and cytarabine, 200 mg/m2 iv for 5 days), followed by intensification with Auto-HSCT or one cycle of carboplatin (300 mg/m2 for 4 days, as a 24 h continuous infusion). Patients were diagnosed with high-risk MDS (11%), treatment related AML (10%), AML secondary to MDS (29%), primary refractory AML (17%), AML in first relapse (27%), and AML in second or subsequent relapse (6%). Median follow-up of the cohort was 40 months (range 2–104). We calculated the Kaplan-Meier estimates curves for overall survival (OS), disease-free (DFS) and relapse-free survival (RFS).

Results: CR and partial remission (PR) was achieved in 84 patients (53%) and in 19 patients (12%), respectively. Twenty-three patients (15%) died during induction, mostly due to infection (19 patients). The CR rates according to the disease status were the following: high-risk MDS 61%, treatment related AML 73%, AML secondary to MDS 52%, primary refractory AML 54%, AML in first relapse 49%, and AML in second or subsequent relapse 30%. Post-remission therapy consisted of Allo-HSCT in 16 patients (8 related and 8 unrelated), Auto-HSCT in 15 patients, and chemotherapy alone in 53 patients. The 1 and 5 year OS, DFS and RFS of the entire cohort were 36% and 11%, 40% and 11%, and 51% and 23%, respectively. The 1 and 5 year OS in patients achieving CR, PR and resistance were 64% and 22%, 26% and 7%, and 4% and 0%, respectively (p<0.0001). The 5 year RFS of patients treated with chemotherapy alone, Auto-HSCT and Allo-HSCT were 13%, 16% and 64%, respectively (p=0.09). The 5 year RFS of patients aged >55 years and ≤55 years were 4% and 53%, respectively (p=0.0005). The 5 year DFS of patients treated with chemotherapy alone, Auto-HSCT and Allo-HSCT were 7%, 13% and 35%, respectively (p=0.22).

Conclusion: Our results confirm the acceptable toxicity and high response rate observed with FLAG-IDA regimen in this very high-risk subgroup of patients. This regimen can be a bridge towards Allo-HSCT, that appear to be the most curative therapy in this setting.