MB-CART19.1 in Patients With R/R ALL

This is an open-label, non-randomized phase II paediatric study. In this study, eligible patients will receive autologous T cells transduced with the lentiviral vector pLTG1563 (MB-CART19.1) at a doesage of 2x10e6 \~2x10e7 CAR-transduced T cells/kg. Upon enrollment, leukapheresis will be performed for MB-CART19.1 generation. Patients with high disease burden at screening (e.g. ALL with M3 marrow and 10.000/L blasts in peripheral blood) may receive bridging chemotherapy after leukapheresis, to avoid critical tumor lysis syndrome and cytokine release syndrome (CRS) by subsequent lymphodepleting chemotherapy and CAR transfer. All patients will receive lymphodepleting chemotherapy with fludarabine 30 mg/m2/d intravenously (iv) on days -5,-4,-3 and -2 cyclophosphamide 500 mg/m2/d iv on day -3,-2 before CAR T cell transfer to enhance the in vivo expansion of CAR T cells. Patients will receive freshly prepared MB-CART19.1 on day 0, corresponding to day 12 (48 hours) of manufacturing, at a dose of 2x10e6 \~2x10e7/kg MB-CART19.1 T cells as defined in the study design section. The appropriate volume for the target cell dose will be drawn up and given as an IV injection over 30 minutes through a large vein peripherally or centrally. The primary objectives are: * To assess the safety and tolerability of MB-CART19.1. * To evaluate the biological activity of adoptive transfer of autologous MB-CART19.1 in patients with R/R CD19-positive B cell lymphoblastic leukemia. The primary endpoint is Overall response rate (ORR):ORR in ALL patients is defined as the rate of complete remission (CR, CRh) on day 28.