Acute lymphoblastic leukemia (ALL) is the most common childhood cancer; adults account for just under half of cases.1 While frontline chemotherapy induces long-term remission in approximately 80–85% of children and 40–50% of adults with newly diagnosed ALL, outcomes remain poor for patients with relapsed or refractory (R/R) disease.2 The CD3/CD19-directed bispecific T cell engager (TCE) blinatumomab, FDA-approved since 2014, has shown substantial activity in both adult and pediatric patients with relapsed or refractory B-cell ALL (R/R B-ALL). The gene discussed is CD19; the disease is acute lymphoblastic leukemia.