P364: donor-derived cd19 car-t cells and chemotherapy plus donor lymphocyte infusion in the treatment of recurrent cd19+ b-all after allogeneic hematopoietic stem cell transplantation

Background: Donor derived CD19 car T cells plus donor lymphocyte infusion is rarely used in the treatment of recurrent CD19 positive B-ALL after allogeneic hematopoietic stem cell transplantation (allo-HSCT) Aims: To compare the efficacy of donor derived CD19 car T cells and chemotherapy plus donor lymphocyte infusion in the treatment of recurrent CD19 positive B-ALL after allogeneic hematopoietic stem cell transplantation (allo-HSCT) Methods: We retrospectively analyzed 43 patients with B-ALL who relapsed after allo-HSCT from March 2016 to November 2019，including 22 patients treated with donor derived CD19-CAR-T cells (CAR-T group) and 21 patients treated with chemotherapy plus donor lymphocyte infusion (Chemo-DLI group). Results: The rates of complete remission (77.3%) in the CAR-T group were significantly higher than those in the Chemo- DLI group (38.1%); The 1- and 2-year leukemia-free survival(LFS) in the CAR-T group and Chemo-DLI group were 54.5% vs 9.5%, 45.5% vs 4.8%, respectively. The 1- and 2-year overall survival(OS) in the CAR-T group and Chemo-DLI group were 68.2% vs 19%, 63.6%vs 9.5%, respectively. Six patients (28.6%) in the Chemo-DLI group developed grade II-IV acute graft-versus-host disease (aGVHD). Two patients (9.1%) with grade I-II aGVHD were found in the CAR-T group. The incidence of CRS in the CAR-T group was 86.4%, the grade I-II CRS was59.1%, the grade III CRS was 27.3%. There was no grade 4 CRS. Two subjects developed ≤grade-2 immune effector cell-associated neurotoxicity syndrome (ICANS). Summary/Conclusion: Compared with chemotherapy plus DLI, donor-derived CD19 CAR-T is more effective and safe in the treatment of recurrent B-ALL after allogeneic HSCT.