Short-term blinatumomab for B-cell acute lymphoblastic leukemia pediatric patients results in measurable residual...

Blinatumomab (Blin) effectively eradicates measurable residual disease (MRD) in pediatric B-cell acute lymphoblastic leukemia (B-ALL), but standard 28-day regimens face high costs and compliance challenges. A phase 2 trial assessed a shortened 14-day Blin protocol in pediatric patients with newly diagnosed B-ALL who were MRD-positive (≥ 0.01%, < 5%) at the end of induction therapy (ChiCTR2100053318). This non-randomized trial included 60 pediatric patients with CD19⁺ B-ALL. Post-induction (day 46), the Blin-14d group (n = 30) received Blin (14-day infusion) only, while the Non-Blin-14d group (n = 30) continued standard chemotherapy. Primary endpoint: MRD complete remission (CR) rate post-Blin. Secondary endpoints: safety and long-term outcomes. After Blin-14d-therapy, all Blin-14d group (100%) achieved MRD negativity (MFC-MRD-neg) within one week. Median time to MRD negativity was shorter in Blin-14d vs. Non-Blin-14d (39 days vs. 42.5 days, p = 0.0243). Predicted 3-year OS, but not EFS, favored Blin-14d (OS 100% vs. 85.9%, p = 0.0360; EFS 73.9% vs. 71.5%, p = 0.2334). Treatment deviations occurred in 10% (Blin-14d) vs. 50% (Non-Blin-14d). Adverse events (AEs) affected 77% of Blin-14d patients, mostly grade 1-2; two had grade 3 AEs. No grade 4 or higher Blin-related events occurred. With the limitations of a non-randomized study, short-term Blin was highly effective in inducing MRD remission with a favorable safety profile, representing a promising and efficient treatment strategy for MRD-positive B-ALL.