Pediatric patients with acute lymphoblastic leukemia treated with blinatumomab in a real‐world setting: Results from the NEUF study

Background Prior to regulatory approval of blinatumomab in pediatric patients with relapsed/refractory Philadelphia chromosome‐negative B‐cell precursor acute lymphoblastic leukemia (R/R Ph− BCP‐ALL), blinatumomab was made available via an expanded access program (EAP). Procedure This retrospective observational study included patients receiving blinatumomab in the EAP between January 1, 2014 and June 30, 2017 who were followed until death, entry into a clinical trial, end of follow‐up, or end of the study period (December 31, 2017), whichever occurred first. Results Among 113 children enrolled, 72 were diagnosed with R/R Ph− BCP‐ALL and 41 were minimal residual disease positive (MRD+, either Ph− or Ph+). In the R/R group, 38 (53%) patients achieved hematological response within two cycles. Of these, 19 (50%) proceeded to hematopoietic stem cell transplantation (HSCT) without bridging myelosuppressive therapy. Of 36 patients in the R/R group evaluable for MRD, 30 (83%) had an MRD response. In the R/R group, median relapse‐free survival was 5.4 months and median overall survival (OS) was 8.2 months. Of 36 patients in the MRD+ group who were evaluable for MRD after two cycles, 27 (75%) had an MRD response. Overall, 24 (59%) of the MRD+ patients proceeded to HSCT without other bridging therapy. Median disease‐free survival was 13.6 months; median OS was not reached. Conclusions In this real‐world pediatric cohort, blinatumomab was effective within two cycles. Over half of patients with R/R Ph− BCP‐ALL achieved hematological response and most achieved MRD response in the MRD+ group, confirming the efficacy of blinatumomab in pediatric trials.