Anti-CD19 chimeric antigen receptors T cells for the treatment of relapsed or refractory E2A-PBX1 positive acute lymphoblastic leukemia: report of three cases.

Patients with relapsed or refractory E2A-PBX1 positive acute B lymphoblastic leukemia (B-ALL) receiving anti-CD19 chimeric antigen receptor T cells (CAR-T) were retrospectively assessed to evaluate the efficacy and safety of disease burden on outcomes and to identify predictive variables. Of the three case patients, case 1 relapsed after hematopoietic stem cell transplantation. After being treated with anti-CD19 CAR-T, the patient showed minimal residual disease (MRD), and his fusion genes turned negative. Case 2, who suffered refractory leukemia, received anti-CD19 CAR-T treatment in an attempt to remove the MRD before transplantation. She showed MRD, and her fusion genes turned negative. Case 3 received anti-CD19 CAR-T treatment because of relapse after allo-SCT at the molecular level. After infusion, she developed severe pneumonia accompanied with the indication that the leukemia had progressed. Our findings suggest that anti-CD19 CAR-T cells therapy with a remarkable MRD eradicating ability might be an effective option for patients with relapsed and refractory E2A-PBX1 positive B-ALL.