Short-term blinatumomab for newly diagnosed pediatric MRD-positive B-ALL: A phase II study

Results from a phase II, prospective, non-randomized, controlled, open-label, single-center trial (ChiCTR2100053318) evaluating a short-term 14-day blinatumomab course (Blin-14d) in pediatric patients with newly diagnosed (ND) measurable residual disease (MRD)-positive B-cell acute lymphoblastic leukemia (B-ALL) at the end of induction (Day 46) were published in Annals of Hematology by Xue et al. Eligible intermediate- or high-risk patients received Blin-14d in combination with cyclophosphamide + cytarabine + mercaptopurine + vincristine + pegaspargase (CAMplus)-based early intensification (n = 30) or standard chemotherapy alone (n = 30). The primary endpoint was MRD complete remission (MRD-CR; MRD <0.01%) rate after Blin-14d.

Key data: Multiparameter flow cytometry (MFC)–MRD-negative remission was achieved in 100% of patients 1 week after Blin-14d vs 63% of patients in the control arm who received CAMplus (n = 27). Blin-14d independently predicted MFC–MRD-negative response after risk group adjustment (adjusted odds ratio [aOR], 28.92; 95% confidence interval [CI], 5.77–144.95; p < 0.001). Median time to first MRD negativity from Day 46 was shorter with Blin-14d vs standard chemotherapy (39 days vs 42.5 days; p = 0.0243). The 3-year event-free survival (EFS) was 73.9% with Blin-14d therapy vs 71.5% with standard chemotherapy (hazard ratio [HR], 0.50; 95% CI, 0.16–1.60; p = 0.2334); corresponding 3-year overall survival (OS) was 100% vs 85.9% (HR, 0.12; 95% CI, 0.02–0.87; p = 0.0360). Adverse events (AEs) occurred in 77% of patients in the Blin-14d arm, including Grade 3 AEs in 10%, with no Grade 4 or higher blinatumomab-related events.

Key learning: Blin-14d demonstrated rapid MRD clearance with manageable safety in ND pediatric MRD-positive B-ALL; however, the non-randomized design, absence of a standard 28-day blinatumomab comparator, and limited follow-up warrant further evaluation before routine practice change.