Presentation (CTI)

OBJECTIVES: B-cell precursor acute lymphoblastic leukemia (ALL) is the most common childhood cancer. In Colombia, ALL accounts for 35.5% of new pediatric cancer cases and contributes to approximately one in three deaths from malignant neoplasms in individuals <18 years. Although therapeutic advances have improved survival, major challenges persist in middle-income settings, and evidence on blinatumomab in Latin American pediatric populations remains limited. We aimed to characterize the experience with blinatumomab for first relapse of pediatric B-cell precursor ALL in an oncology service of a high complexity hospital in Cartagena, Colombia.
METHODS: We conducted an ambispective observational cohort study (2015-2025) including 31 patients aged 1-18 years with first relapse of ALL. Patients were grouped according to relapse treatment: blinatumomab (n=14) or systemic chemotherapy (n=17). Outcomes included overall survival, second relapse, access to hematopoietic stem cell transplantation, and adverse events. Comparisons were performed using contingency tables and Fisher’s exact test.
RESULTS: Patients receiving blinatumomab had a mean age of 8.21 years (SD 4.9) and 21.4% were female, while those receiving chemotherapy had a mean age of 10.0 years (SD 4.8) and 35.0% were female. Blinatumomab was associated with higher overall survival (71.4% vs. 17.6%; p=0.003) and greater access to transplantation (92.8% vs. 58.8%; p<0.001), along with lower second relapse rates (n=1, 7% vs n=8, 47%). Adverse events occurred in 5 out of 14 blinatumomab-treated patients, all grade I. In the chemotherapy group, 2 adverse events were recorded (one grade I and one grade IV), both leading to treatment discontinuation.
CONCLUSIONS: In this single-center cohort of pediatric patients with first relapse of ALL, blinatumomab was associated with improved survival and higher access to transplantation compared with systemic chemotherapy, with predominantly mild adverse events.