[Chimeric antigen receptors T cells for treatment of 48 relapsed or refractory acute lymphoblastic leukemia children: long term follow-up outcomes].

To evaluate the safety and efficacy of chimeric antigen receptors T cells (CAR-T) in childhood acute B lymphoblastic leukemia (B-ALL) to probe the prognosis-related factors. Forty-eight children, 29 boys and 19 girls, aged 3-17years old (median age was 8 years old) , with recurrent or refractory CD19 positive B-ALL, were treated by the CD19 specific CAR-T cells. A total of 48 cases received 61 infusions. Flow cytometry or real-time quantitative polymerase chain reaction method were used to monitor micro residual disease (MRD) . The follow-up period was from 16 to 1 259 days with the median follow-up of 406 days. SPSS software was used to statistical analysis. No adverse reaction was observed during 61 infusions. The most common adverse reaction after CAR-T cell infusions was cytokine-release syndrome (CRS) . Only 2 cases experienced level 3 CRS performance, including continuous high fever, convulsions, delirium, serous cavity effusion, and decreasing of blood pressure. Tocilizumab was given to release CRS performance. No treatment-related death occurred. Thirty-seven patients showed response during 7 to 28 days after infusions. The early response rate was 77.1%, with MRD before infusion less than 5% group higher than the MRD more than 5% group (87.1% 58.8%, =4.968, =0.036) . For the 37 patients who showed response to CAR-T cell infusions, univariate analysis identified that age, disease status at the time of treatment, MRD before infusion affected 2-year OS rate (<0.05) . Multivariate prognostic analysis for EFS disclosed that the MRD before infusion more than 5% (=3.433, 95% 1.333-8.844, =0.011) and not bridge to HSCT (=4.996, 95% 1.852-13.474, =0.001) were the independent risk factors. The fourth generation CAR-T cells directed against CD19 could effectively and safely treat relapsed and refractory B-ALL, which implicated that CAR-T therapy as a novel therapeutic approach could be useful for patients with relapsed or refractory B-ALL who have failed all other treatment options. Reducing MRD as far as possible by effective pretreatment chemotherapy was in favor of increasing the response rate. Bridging HSCT after CAR-T cell treatment might be a better therapeutic strategy for the patient with refractory or molecular relapsed B-ALL.