[Clinical Analysis of Blinatumomab in the Treatment of 21 Children with Relapsed/Refractory B-Cell Acute Lymphoblastic Leukemia].

[OBJECTIVE] To evaluate the efficacy and safety of blinatumomab in the treatment of children with relapsed/refractory B-cell acute lymphoblastic leukemia (R/R B-ALL), and to explore the factors affecting the efficacy of blinatumomab.

[METHODS] The clinical data of 21 children with R/R B-ALL who received treatment with blinatumomab in the Department of Pediatrics, Peking University People's Hospital from April 2021 to December 2023 were retrospectively analyzed.

[RESULTS] Among the 21 children, there were 10 boys and 11 girls, with a median age of 4(2-17) years. There were 5 cases of isolated bone marrow relapse, 1 case of bone marrow combined with central nervous system relapse, 3 cases of isolated minimal residual disease (MRD) relapse, 5 cases of isolated molecular relapse, 2 cases of MRD combined with molecular relapse, and 5 cases of refractory disease. In 8 children with baseline blasts ≥5% before blinatumomab treatment, 7 cases (87.5%) achieved complete remission (CR) after treatment, and 3 cases (37.5%) achieved MRD negativity. There were 13 children with positive MRD and/or molecular markers (with bone marrow CR) before blinatumomab treatment, of whom 12 cases (92.3%) achieved MRD and/or molecular negativity after treatment. The median follow-up time of the 21 children was 13.1(6.5-34.9) months, with a 1-year overall survival (OS) rate of (92.3±7.4)%. The factors affecting the short-term efficacy of blinatumomab included the baseline blasts ( =0.026) and MRD level ( =0.026) before treatment. No grade 3 or higher cytokine release syndrome (CRS) occurred, and no neurological events were observed.

[CONCLUSION] The short-term efficacy of blinatumomab in pediatric R/R B-ALL is excellent, particularly in children with low tumor burden. The clinical adverse events are controllable, and the safety profile is favorable.