An Clinical Study of CD19 CAR NK Cells for the Treatment of Refractory Primary Immune Thrombocytopenia

A single arm, open-label pilot study is designed to determine the safety and effectiveness of CD19 CAR NK cells (KN5501) in patients with refractory immune thrombocytopenia. 9 patients are planned to be enrolled in the dose-escalation trial (9×10\^9 cells, 13.5×10\^9 cells). The primary objective of the study is to evaluation of the safety and feasibility of KN5501 for the treatment of relapsed/refractory B-cell related autoimmune diseases. The secondary objective is to evaluate evaluation of KN5501 for the treatment of refractory immune thrombocytopenia. The exploratory objective is to evaluate expansion, persistence and ability to deplete CD19 positive B cells of KN5501 in patients with refractory immune thrombocytopenia.