Relapsed Pediatric ALL

The purpose of this study is to learn more about newer methods of transplanting blood cells donated by a partially matched family member to children with high-risk CD19 positive leukemia ALL. Primary Objective: \- To assess the safety and feasibility of combining CD19-CAR(Mem) T cells after TCRαβ+/CD19 depleted haploidentical donor transplantation for pediatric patients with relapsed/refractory CD19+ B-cell malignancies. Secondary Objectives: * To estimate 1-year post-transplant overall survival, event-free survival, and GVHD-free relapse-free survival (GRFS). * To estimate cumulative incidence of engraftment, acute and chronic GVHD, and immune-related adverse events, including CRS and ICANS.

Autologous, unselected CD3+ lymphocytes collected from apheresis, transfected with a lentiviral vector containing a 2nd generation chimeric antigen receptor (CAR) consisting of a scFv recognizing CD19 and dual co-stimulatory intracellular signaling domains (4-1BB and CD3ζ).

Traditional salvage chemotherapy has low efficacy and poor long-term prognosis for relapsed or refractory (R/R) B-cell acute lymphoblastic leukemia (B-ALL). Targeted CD19 CAR-T cell immunotherapy is an effective means of treating R/R B-ALL. Several clinical studies have shown that its remission rate for R/R B-ALL can reach 68-93%. However, long-term follow-up found that the remission time after CD19 CAR-T treatment is short and the relapse rate is high. Therefore, how to ensure the long-term survival of R/R B-ALL patients after remission by CAR-T therapy is an urgent problem to be solved. Some studies have shown that timely bridging allo-HSCT after CAR-T treatment can overcome the risk of relapse and further improve the long-term survival of patients. However, there is currently no randomized controlled study on whether to bridge transplantation after CAR-T. The purpose of this study is to evaluate the efficacy and safety of S1904 in the treatment of relapsed or refractory CD19-positive B-cell acute lymphoblastic leukemia with or without bridging to allogeneic hematopoietic stem cell transplantation after remission.

This is a phase II clinical study to evaluate the safety and efficacy of pCAR-19 B cell autologous infusion preparation in the treatment of CD19-positive relapsed/refractory B-cell acute lymphoblastic leukemia.