Measurable Residual Disease (MRD) in Elderly Acute Myeloid Leukemia (AML): Results from the Pethema-Flugaza Phase III Clinical Trial

Background: AML is the most common acute leukemia in adults and its prevalence significantly increases in the elderly. The 5-year survival rate for adults younger than 60 is around 40% and decreases to 10% in patients above this age. Even those patients who tolerate intensive induction chemotherapy and achieve complete remission (CR) have poor outcome. Detection of MRD in younger AML refines outcome prediction of patients in CR after intensive chemotherapy. However the value of MRD in elderly patients is inconsistent between those treated with intensive vs hypomethylating drugs, and unknown after semi-intensive therapy. Aim: Define the role of MRD assessment by multidimensional flow cytometry (MFC) for therapeutic decision making in elderly AML patients treated with semi-intensive chemotherapy vs hypomethylating agents (HMA). Methods: Two-hundred eighty-three elderly AML patients were included in the PETHEMA phase III FLUGAZA clinical trial and randomized to receive three induction cycles with fludarabine and cytarabine (FLUGA) followed by six consolidation cycles with reduced intensity FLUGA, or three induction cycles with 5-azacitidine (AZA) followed by 6 consolidation cycles with AZA. After consolidation, patients continued with the same treatment if MRD ≥0.01% or stopped if MRD