The pivotal ELIANA Phase II trial (NCT02435849) (25), which led to the approval by the Food and Drug Administration and European Medicines Agency of tisagenlecleucel as the currently only CD19 CAR T-cell therapy for R/R BCP-ALL, enrolled 75 patients in the age range 3–23 years (25). This evidence concerns the gene OPN1SW and acute lymphoblastic leukemia.