These findings corroborate earlier studies; in a phase 1/2 trial conducted in children with CD19-positive BCP-ALL that were in second or later relapse, any relapse after allogeneic HSCT, or refractory to other treatments and with > 25% bone marrow blasts at screening, complete hematologic responses were observed in 27 of the 70 patients (median [range] age of 8 [< 1–17] years) who received the recommended dose of blinatumomab. This evidence concerns the gene CD19 and acute lymphoblastic leukemia.