Real-World Implementation, Feasibility, and Early Clinical Effectiveness of Blinatumomab for Children with B-ALL in Lower Middle-Income Countries

In 2025, blinatumomab was added to the WHO Essential Medicines List for Children for treating B-cell acute lymphoblastic leukemia (B-ALL), yet access remains limited in many low-and middle-income countries (LMICs). Consequently, real-world experience in these settings, particularly where access, supportive care, and delivery infrastructure differ substantially from those in high-income countries, remains poorly characterized. To evaluate the early clinical effectiveness and implementation challenges of blinatumomab administration for pediatric B-ALL in lower-middle-income countries, an observational cohort study was conducted at 6 pediatric oncology centers participating in a blinatumomab drug-access program in India, Pakistan, and Vietnam. A consecutive sample of 106 children aged 1-18 years with relapsed/refractory B-ALL (n = 60, 56.6%) or minimal residual disease (MRD) > 0.1% (n = 46, 43.4%) were treated with blinatumomab. Across 192 treatment cycles, 54 unplanned interruptions occurred, primarily due to adverse events. Severe (grade 3+) cytokine release syndrome occurred in 2 patients during cycle 1; severe neurotoxicity occurred in 4 patients in cycle 1 and 1 in cycle 2. Among 71 patients with follow-up data, 26 patients (36.6%) subsequently received a hematopoietic stem cell transplant (HSCT), including 14 for relapsed/refractory disease. Six-month EFS and OS were 61.5% ± 5.8% and 89.9% ± 3.6%, respectively, and 12-month EFS and OS were 58.1% ± 7.1% and 82.8% ± 5.5%, respectively. Survival did not differ significantly between patients who received an HSCT and those who did not. MRD-negative status after cycle 1 was associated with superior 12-month EFS (P < 0.0001) and OS (P = 0.0366). With implementation support, blinatumomab was safely and effectively delivered in pediatric referral centers in lower-middle-income countries, supporting strategies to broaden immunotherapy access globally.