Safety and Efficacy of PRG-1801 in Recurrent/Refractory Primary Immune Thrombocytopenia (ITP)

This is a single center, open-label, 3+3 dose escalation, early phase 1 study to evaluate the safety, tolerability, and preliminary efficacy of PRG-1801 for patients with relapsed/refractory immune thrombocytopenia (ITP).

This investigator-initiated clinical study aims to evaluate PRG-1801, a BCMA-targeted CAR-T cell therapy, in patients with relapsed refractory immune thrombocytopenia (ITP). The study employs a dose-escalation design to assess safety, tolerability, and preliminary efficacy. Approximately 1 sites are planned to be selected for the clinical trial. The subjects, who sign the informed consent forms and been screened by inclusion/exclusion criteria, will be assigned into 100×10\^6, and 200×10\^6 CAR-T cells groups in order of sequence. And the subjects will undergo leukapheresis, lymphodepletion pre-treatment, and a single infusion of PRG-1801. Dose escalation will follow 3 + 3 design and 3-6 subjects in each group will complete a single dose. Within the same dose group, the next subject will be administered after the previous subject has completed at least 14 days of safety observation. After the last subject in each dose group has completed the dose-limiting toxicity (DLT) assessment window of 28 days after single dose, the enrollment and treatment for the next dose group may be initiated after the Safety Review Committee (SRC) agrees to enter the next dose group based on clinical safety data assessment. When DLT occurs in 1 of 3 subjects in a dose group, 3 additional subjects in the same dose group will be required (up to 6 subjects in the dose group have completed DLT assessment): if no DLT occurs in the additional 3 subjects, dose escalation will continue; if 1 of the 3 additional subjects experiences one DLT, dose escalation will be discontinued; if more than 1 of the 3 additional subjects experiences DLTs, dose escalation will be discontinued, and 3 additional subjects will be required to be enrolled at one lower dose level for DLT assessment. After the end of escalation for the maximum dose group, if no MTD is observed, the highest dose level is defined as the MTD