Role of CD19 and specific KIT‐D816 on risk stratification refinement in t(8;21) acute myeloid leukemia induced with different cytarabine intensities

High‐dose cytarabine (Ara‐C) has been reported with increased treatment‐related mortality, whereas few data are available concerning intermediate‐dose Ara‐C for induction of acute myeloid leukemia (AML) with t(8;21) translocation. We retrospectively analyzed factors impacting complete remission (CR), event‐free survival (EFS), cumulative incidence of relapse (CIR), and overall survival (OS) in 197 adults with t(8;21) AML, of whom 107 cases were induced with intermediate‐dose and 90 with standard‐dose Ara‐C (as part of 3 + 7 protocol). After a single induction course, the overall CR rate was 87.6% (170/194), with a significant difference between the standard‐dose (83/105, 79.0%) and intermediate‐dose (87/89, 97.8%) groups (p < 0.001). Rather than general KITmut, the specific KIT‐D816 independently led to a lower probability of achieving CR (HR = 3.29 [1.18–9.24], p = 0.023), worse EFS (HR = 3.53 [1.82–6.84], p < 0.001), and OS (HR = 5.45 [1.77–16.84], p = 0.003) in the standard‐dose group, but not in the intermediate‐dose group. CD19(+) represented the only independent factor predicting lower CIR both in the standard‐dose group (HR = 0.32 [0.10–1.00], p = 0.050) and in the intermediate‐dose group (HR = 0.11 [0.03–0.40], p = 0.001). When combined, KIT(+) plus CD19(−) conferred the most increased relapse risk (3‐year CIR 60%; SE 0.12). Specific KIT‐D816, instead of general KITmut, may be incorporated in prognostication model for t(8;21) AML. Combination of CD19 with KIT provides a more definite risk stratification profile for t(8;21) AML.