Long-term outcomes in patients with relapsed/refractory acute myeloid leukemia and other high-risk myeloid malignancies after undergoing sequential conditioning regimen based on IDA-FLAG and high-dose melphalan.

Allogeneic hematopoietic cell transplantation (alloHCT) remains the only curative option for relapsed/refractory acute myeloid leukemia and other high-risk myeloid malignancies. To improve alloHCT results in this setting, sequential regimens were designed as a strategy to lower tumor burden and quickly induce the graft-versus-leukemia effect. We analyzed long-term outcomes of a sequential regimen based on IDA-FLAG and high-dose melphalan, as set forth by the CETLAM cooperative group. This protocol yielded a high complete response rate (89%) and a lower cumulative relapse incidence (30% at five years) compared to other regimens. Five-year non-relapse mortality, however, reached 45%, with grade 3-4 acute graft-versus-host disease being the most frequent adverse event (a 100-day incidence of 29%). Altogether, 5-year overall survival was 25% in this group of patients with otherwise dismal prognosis. Long-term survivors enjoyed a good quality of life after a median follow-up of 68 months.