Allogeneic hematopoietic cell transplantation with reduced-intensity conditioning following FLAMSA for primary refractory or relapsed acute myeloid leukemia.

Patients with primary refractory or relapsed acute myeloid leukemia (AML) have a dismal prognosis. We report a retrospective single center analysis of aplasia-inducing chemotherapy using fludarabine, cytarabine, and amsacrine (FLAMSA) followed by reduced-intensity conditioning (RIC) for allogeneic hematopoietic cell transplantation (HCT) in 62 consecutive primary refractory or relapsed AML patients. Two-year event-free survival and overall survival (OS) were 26 and 39%, respectively. Risk stratification according to cytogenetic and molecular genetic markers showed superior survival in patients in the intermediate-1 risk group (2-year OS 70%) compared to the intermediate-2 risk (2-year OS 34%, p = 0.03) and adverse risk (2-year OS 38%, p = 0.06) group. The use of HLA-matched versus HLA-mismatched donors had no significant influence on survival (p = 0.98). Two-year OS in the elderly subgroup defined by age ≥60 years was 31% compared to 46% in the group of younger patients <60 years (p = 0.19). Cumulative incidence of non-relapse mortality at 2 years adjusted for relapse as competing risk was 20% for patients <60 years and 26% for older patients (p = 0.55). Chronic graft-versus-host disease was associated with a statistically significant superior survival (p < 0.01). FLAMSA-RIC followed by allogeneic HCT enables long-term disease-free survival in primary refractory or relapsed AML even in the elderly patient population.