This is a single arm, open-label, non-randomized, dose-escalation, phase I study to determine the safety and efficacy of ssCART-19 in the treatment of patients with CD19 positive relapsed or refractory acute lymphoblastic leukemia.~Primary objectives:~Determine the safety and tolerability of ssCART-19 cells in patients with refractory or relapsed acute lymphoblastic leukemia.~Secondary objectives:~Observe the anti-tumor response of ssCART-19 cells to refractory or relapsed acute lymphoblastic leukemia.~Overall remission rate (ORR) assessment during the 3 months after ssCART-19 administration，ORR includes CR and CRi~Duration of response (DOR)~Progression-free survival (PFS)~Overall survival (OS)~To characterize the in vivo cellular pharmacokinetic (PK) profile of ssCART-19 cells.~To characterize the pharmacodynamic (PD) profile of ssCART-19 cells.
This is a single arm, open-label, non-randomized, dose-escalation, phase I study to determine the safety and efficacy of ssCART-19 in the treatment of patients with CD19 positive relapsed or refractory acute lymphoblastic leukemia.