Minimal residual disease-directed therapy in acute myeloid leukemia

Case 1: A 35-year-old man with a normal white blood cell (WBC) count (9.3 3 10(9)/L) was diagnosed with acute myeloid leukemia (AML) with a t(8;21)(q22;q22) translocation in 25/25 metaphases. The RUNX1-RUNX1T1 fusion gene was detected by real-time quantitative polymerase chain reaction (PCR), whereas studies for mutations involving KIT and FLT3 were negative. After 1 cycle of induction therapy with cytarabine/idarubicin according to the "7+3" schema, he achieved a morphologic complete remission (CR) with a 2-log reduction of RUNX1-RUNX1T1 transcript levels. The patient has anexcellent performance status and no comorbidities. Should you recommend allogeneic hematopoietic cell transplantation (HCT)? Case 2: A 43-year-old woman was diagnosed with cytogenetically normalAML; molecular studies for genemutations involving NPM1, CEBPA, and FLT3 were negative. After standard induction chemotherapy, she achieved a morphologic CR and then underwent 1 cycle of consolidation therapy with high-dose cytarabine. During the pre-HCT work-up in anticipation of matched related donor transplant, she is found to have evidence of minimal residual disease (MRD) by multiparameter flow cytometry (MFC); no prior MFC studies are available. She has no comorbidities other than arterial hypertension, and her performance status is excellent. Are you recommending additional cycle(s) of chemotherapy to attempt MRD eradication before HCT?