CD19 and acute lymphoblastic leukemia: The combination of TKIs (imatinib or ponatinib) with CX-4945 significantly extended the survival and reduced the tumor burden in the IKZF1 deletion (Ik6<sup>+</sup>) Ph+ ALL patient-derived xenograft (PDX) mouse model; particularly, the patient died of relapse shortly after treatment with the third-generation TKI and the CD19/CD3 bispecific antibody blinatumomab.