Salvage therapy for acute myeloid leukemia with fludarabine,cytarabine, and idarubicin with or without gemtuzumab ozogamicin and with concurrent or sequential G‐CSF

The current salvage therapies for relapsed/refractory acute myeloid leukemia (AML) are unsatisfactory. Over the past 7 years, we have used two salvage regimens: fludarabine, cytarabine, and idarubicin with (FLAG‐IM) or without gemtuzumab ozogamicin (GO) (9 mg/m² on Day 8) (FLAG‐I) in relapsed/refractory AML. Three‐quarters of patients also received concurrent G‐CSF. Seventy‐one patients were treated, 23 with FLAG‐I and 48 with FLAG‐IM. The median duration of follow‐up was 30.6 months. The treatment groups were well balanced with median ages of 48 years (range 18–70) and 47 years (range 20–68), unfavorable cytogenetics in 57% and 35%, prior allogeneic stem cell transplant in 43% and 42%, and CR1 duration <1 year in 60% and 67%, respectively, for FLAG‐I and FLAG‐IM. The complete remission (CR) rate in the FLAG‐I group was 39% with an additional 13% achieving a CRp overall response rate (ORR) 52%]; the CR rate in the FLAG‐IM group was 29% with an additional 27% achieving a CRp (ORR 56%). The median duration of response (DOR; 16.8 vs. 8.3 months), event‐free survival (EFS; 7.4 vs. 4.1 months), and overall survival (OS; 8.8 vs. 5.0 months) trended to favor FLAG‐I over FLAG‐IM. The patients who received G‐CSF concurrent with chemotherapy had superior overall response rate (ORR; 62% vs. 29%, P = 0.026), median EFS (6.2 vs. 3.4 months, P = 0.010), and OS (8.8 vs. 3.9 months, P = 0.004) when compared with those who sequentially received G‐CSF and chemotherapy, regardless of chemotherapy regimen. The addition of GO, at this dose and schedule, to FLAG‐I failed to improve the outcomes in patients with relapsed/refractory AML. The patients who received G‐CSF concurrently with chemotherapy had improved outcomes. Am. J. Hematol., 2009. © 2009 Wiley‐Liss, Inc.