Measurable residual disease dynamics holding prognostic significance in pediatric patients with RUNX1::RUNX1T1-positive AML: results from AML-CAMS serial trials.

Quantitative real-time PCR (qRT-PCR) enables measurable residual disease (MRD) monitoring in RUNX1::RUNX1T1-positive acute myeloid leukemia (AML), guiding treatment in patients with morphological remission. However, the optimal thresholds and timing for MRD assessment remain undefined, particularly in pediatric cases due to the rarity. Our analysis of 136 pediatric patients with RUNX1::RUNX1T1-positive AML revealed that less than a 3-log reduction after induction chemotherapy predicted an inferior prognosis (p < 0.05). However, patients with < 3-log reduction but MRD < 0.01% after two consolidations had outcomes comparable to those with ≥ 3-log reduction. Reduction < 3-log after induction chemotherapy plus MRD ≥ 0.01% after two consolidations was an independent adverse factor for both relapse-free (HR = 4.230, p = 0.016) and overall survival (HR = 5.128, p = 0.045). These findings highlight the prognostic value of early MRD dynamics and support MRD-guided risk stratification in pediatric AML.