[The Short-Cycle Blinatumomab Therapy for MRD-Positive and Chemotherapy-Intolerant Pediatric ALL: Analysis of...

To evaluate the short-term efficacy and safety of a short-course blinatumomab regimen in children with acute lymphoblastic leukemia (ALL) who were minimal residual disease (MRD)-positive or chemotherapy-intolerant.

We retrospectively analyzed pediatric ALL patients treated with short-course blinatumomab (5 μg/m²/day on days 1-7; 15 μg/m²/day on days 8-14) at the Department of Hematology, The Second Hospital of Lanzhou University, from August 2023 to March 2025. The primary endpoints were the MRD conversion-to-negativity rate and adverse events.

A total of 16 children were enrolled (12 boys and 4 girls), with a median age of 7 (range, 3-11) years. Four patients had relapsed ALL, eight were newly diagnosed with MRD positivity on day 19 of induction therapy, and four were newly diagnosed but chemotherapy-intolerant with baseline MRD negativity. All 12 patients with MRD positivity before blinatumomab achieved MRD negativity (12/12). Common adverse events were fever (9/16), abnormal liver function (3/16), infection (2/16), abdominal pain (2/16), and neurologic toxicity (1/16), all grade 1-2. One patient experienced grade 1 cytokine release syndrome (CRS) and one experienced grade 1 immune effector cell-associated neurotoxicity syndrome (ICANS); no grade ≥3 CRS or ICANS occurred. With a median follow-up of 5 (3-6.5) months, the proportion remaining event-free during follow-up was 10/12 (95%CI : 51.6%-97.9%) in the baseline MRD-positive group.

Short-course blinatumomab demonstrated favorable short-term efficacy with acceptable safety in pediatric ALL patients with relapse, early MRD positivity during initial induction, or chemotherapy intolerance.