The impact of end-of-consolidation measurable residual disease in the era of novel pediatric leukemia therapy.

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Background: The introduction of blinatumomab (BLINA) has improved event-free survival (EFS) and overall survival (OS) in pediatric patients with high-risk B-cell acute lymphoblastic leukemia (ALL). In patients with post-induction measurable residual disease (MRD) positivity, BLINA may serve as a safe bridging therapy to hematopoietic cell transplantation (HCT). However, little is known about the impact of end-of-consolidation (EoC) MRD on outcomes in high-risk pediatric ALL in the current BLINA-incorporated treatment era. Methods: We retrospectively enrolled pediatric patients diagnosed with high-risk B-cell ALL between February 2022 and December 2024 at Chang Gung Memorial Hospital. Patients were categorized into EoC MRD-negative and EoC MRD-positive groups. Outcomes of interest included EFS, OS, and BLINA-related adverse events (AEs). Results: The cohort consisted of 15 patients. With a median follow-up of 24 months, the observed 2-year EFS and OS rates were 71.5% and 86.7%, respectively. Based on EoC MRD status, 8 patients were classified as EoC MRD-negative and 7 as EoC MRD-positive. Baseline characteristics were comparable between the two groups. Higher relapse (57.1% vs. 0%, P = 0.0256) and mortality (28.6% vs. 0%, P = 0.2) rates were observed in the EoC MRD-positive group. The 2-year EFS was significantly higher in the EoC MRD-negative group (100% vs. 42.9%, P = 0.02). No high-grade short-term or long-term BLINA-related AEs were observed in either group. Conclusions: Achieving EoC MRD negativity was associated with sustained remission and improved survival in high-risk pediatric B-cell ALL treated with early intensification chemotherapy and BLINA. EoC MRD assessment may help identify patients who can maintain disease control without HCT.

Comparisons between EoC MRD-positive and EoC MRD-negative groups.