Timing of Peripheral Leukemic Blast Clearance in Patients with Acute Myeloid Leukemia Undergoing Induction Therapy at an Urban University Cancer Center

Background. Gajjar noted that patients with Acute Lymphoblastic Leukemia who had early peripheral leukemic blast clearance during induction chemotherapy experienced improved relapse-free survival (1995). Elliot described that for individuals with Acute Myeloid Leukemia (AML) treated with Cytosine Arabinoside (100 mg/m2/day by continuous infusion for 7 days) and Daunorubicin 45 mg/m2 IV or Idarubicin 12 mg/m2 IV daily for 3 days, time to clearance of peripheral leukemic blast clearance correlated with relapse-free survival (2007). Methods. In this retrospective study of our patients seen/treated between November, 2019 and July 2024, seventeen patients with Acute Myeloid Leukemia with evidence of leukemic blasts detected by automated hematology analyzer and confirmed by visual examination on peripheral smear, were treated with curative intent with Cytosine Arabinoside 100 mg/m2/day by continuous intravenous infusion for 7 days and Daunorubicin 90 mg/m2 IV (one patient over concern about potential cardiomyopathy received Mitoxantrone 12 mg/m2 IV) daily for 3 days or for the two patients with myelodysplasia-related AML, liposomal Daunorubicin 44 mg/m2 and liposomal Cytosine Arabinoside 100 mg/m2 intravenously on days 1, 3, and 5. Results. Patient characteristics: 9 males/8 females, median age-62 (range: 21-76), African-American (8), Caucasian/Latin American (7), Asian (2); median circulating absolute peripheral blast count-6107/mm³, median white blood count-11.8/mm³, and median LDH-473 IU/L. ELN risk categories: favorable-3 (18%), intermediate-7 (41%), adverse-7 (41%). On post-induction bone marrow examination on day 28, nine patients achieved morphologic complete response (CR). Patients experiencing CR had median peripheral leukemic blast clearance on day 3 (2-6) compared to those experiencing other than CR who had median blast clearance on day 6 (3-9); p=0.049 (Mann Whitney test). Conclusion. Early clearance of blasts from peripheral blood during induction therapy of patients with AML treated with high-dose Daunorubicin (90 mg//m2) may serve as a predictor of complete response.

No relevant conflicts of interest to declare.