The COG evaluated the role of another novel agent, the anti-CD19 bispecific T cell–engaging antibody construct blinatumomab, by randomizing patients with first relapse of B-lineage ALL and high-risk features (any early relapse <36 months, or later relapse with MRD >0.1% by FCM following 4 weeks of intensive chemotherapy based on UK ALL R3 mitoxantrone Block 1 therapy) to receive two subsequent blocks of intensive chemotherapy modeled upon the remaining courses of UK ALL R3 re-induction chemotherapy or two courses of blinatumomab, prior to protocol-defined HSCT (35). The gene discussed is CD19; the disease is acute lymphoblastic leukemia.