Mejstrikova E, Klinger M, Markovic A, et al. - Most patients who had one cycle of blinatumomab retained CD19 expression and would thus be eligible for further anti-CD19 CAR T-cell therapy.

• Blinatumomab is a BiTE (bispecific T-cell engager) immuno-oncology therapy that has shown significant activity in patients with relapsed or refractory B-cell precursor acute lymphoblastic leukemia (R/R B-ALL); a subset of patients, however, relapse.

• Monitoring CD19 expression in relapsed patients is crucial for informing the sequencing of subsequent therapy.

• The expression of CD19 was examined in 59 pediatric patients with R/R B-ALL on the day of diagnosis, as well as on days 15 and 29 of cycle 1 of blinatumomab.