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

PRG-1801 is a chimeric antigen receptor T-cell (CAR-T) therapy targeting BCMA. Participants will undergo leukapheresis to collect mononuclear cells for PRG-1801 manufacturing. Prior to infusion, patients receive lymphodepletion with cyclophosphamide (250-300 mg/m2/day) and fludarabine (25-30 mg/m2/day) for 3 days. PRG-1801 is then administered as a single intravenous infusion at one of three dose levels: 35×10\^6, 100×10\^6, or 300×10\^6 CAR-T cells. Premedication with antipyretics and antihistamines is given 30-60 minutes before infusion. The infusion rate is 2-5 ml/min. Patients are monitored for safety and efficacy for up to 24 months post-infusion. Some patients may be eligible for a second infusion if they respond initially but later relapse.