Abstract:

Objective To explore the efficacy and safety of CD19 chimeric antigen receptor T cells (CAR-T) in the treatment of refractory/relapsed B-cell acute lymphoblastic leukemia (B-ALL) in children and adolescents. Methods The clinical data of refractory/relapsed B-ALL patients<25 years old who received CD19 CAR-T therapy from June 2017 to March 2021 were retrospectively analyzed and the efficacy and safety of this therapy was evaluated. Results A total of 64 patients (35 boys and 29 girls) with refractory/relapsed B-ALL were included, and the median age was 8.5 (1.0-17.0) years old. One month following CD19 CAR-T infusion, a short-term effectiveness assessment of all 64 patients showed minimal residual disease (MRD) negative in 62 of them, and complete remission (CR) or complete remission with incomplete hematologic recovery (CRi) in all 64 patients. The incidence rates of cytokine release syndrome (CRS) and immune effector cell-associated neurotoxicity syndrome (ICANS) were 78.1 % and 23.4 %, respectively. Twenty-two patients experienced recurrence after infusion, with a median recurrence time of 10.1 months. The 4-year overall survival (OS) rate was 66.0 %±6.0 %, and the 4-year leukemia free survival (LFS) rate was 63.0 %±6.0 %. Long-term follow-up results demonstrated superior LFS and OS in patients bridged to allogeneic hematopoietic stem cell transplantation (allo-HSCT) compared to those who were not bridged to transplantation (4-year LFS: 81.8 %±6.2 % vs. 24.0 %±9.8 %, 4-year OS: 81.4 %±5.9 % vs. 44.4 %±11.2 %; both P<0.01). Conclusions CD19 CAR-T therapy can effectively treat refractory/relapsed B-ALL, and bridging to HSCT after infusion can further improve the long-term survival outcomes in patients.

Key words: chimeric antigen receptor, CD19, refractory, relapsed, B-cell acute lymphoblastic leukemia