Anti CD19/BCMA CAR Gene Therapy for Relapsed/Refractory Immune Thrombocytopenia

Inclusion criteria

• 1. Age≥ 18 years old, regardless of gender. 2. Clinical diagnosis of primary immune thrombocytopenia for at least 6 months, platelet count < 30×10^9/L within 48 hours before participating in the study.

• Positive anti-platelet glycoprotein autoantibodies (such as GPIIb/IIIa). 4. Prior second-line ITP therapy (first-line treatment includes: corticosteroids or immunoglobulins; Second-line therapies include thrombopoietin receptor agonists (eg, eltrombopag, romiplostim) and/or rituximab, but are ineffective (platelet count < 30×10^9/L after treatment, or platelet count does not increase twice as much as baseline, or there is bleeding), or relapse after effective treatment (platelet count falls below 30×109/L after effective treatment, or falls below baseline, or bleeding symptoms) or is difficult to maintain after discontinuation of TPO agonists.

• Bone marrow examination shows megakaryocytosis or normal. 6. Basic normal functions of important organs:Echocardiography shows an ejection fraction of ≥50% and no significant abnormalities on ECG.Creatinine clearance (CrCl) (Cockcroft-Gault formula) ≥ 30 mL/min.Alanine aminotransferase (ALT) and aspartate aminotransferase (AST) ≤ 3.0 × upper limit of normal (ULN).Total bilirubin (TBIL) and alkaline phosphatase (AKP or ALP) ≤ 2.0× ULN (Gilbert's syndrome ≤3.0×ULN).Absolute lymphocyte count (ALC) ≥ 0.5×10^9/L; Absolute neutrophil count (ANC) ≥1×10^9/L; Hemoglobin (Hb) ≥ 60 g/L; Platelet count ≥ 10×10^9/L.Oxygen saturation > 92%.ECOG performance status ≤2 7. Males and women of childbearing potential must agree to use effective contraception from the time of signing the informed consent form until 1 year after the use of the study drug. Women of childbearing potential must have a negative blood pregnancy test at screening and prior to drug infusion and must not be breastfeeding.

Exclusion criteria

• 1. Thrombocytopenia caused by myelodysplastic syndrome, early aplastic anemia, atypical aplastic anemia, thrombotic thrombocytopenic purpura, etc.

• During the screening period, bone marrow examination showed myelofibrosis MF≥2 (European consensus scoring standard Thieleja 2005) or bone marrow examination showed the presence of a primary disease other than ITP that can lead to thrombocytopenia.

• History of hypersensitivity to any component of the therapeutic medication. 4. Major organs: NYHA class III to IV congestive heart failure. Myocardial infarction or coronary artery bypass grafting (CABG) or coronary artery stent implantation within 6 months. Ventricular arrhythmias, or history of unexplained syncope (excluding vasovagal syncope or dehydration). History of severe non-ischemic cardiomyopathy.

• Malignant disease within 3 years prior to screening, except for the following: malignant disease that has been curatively treated before enrollment and has no known active disease for 3 years ≥; or well-treated non-melanoma skin cancer with no evidence of disease.

• Symptomatic deep vein thrombosis or pulmonary embolism within the past 6 months or currently requiring anticoagulation.

• Participated in other interventional clinical studies within 1 month prior to screening.

• Vaccination of live attenuated vaccine within 4 weeks prior to screening. 9. Stroke or seizure within 6 months prior to signing the ICF (excluding old lacunar cerebral infarction).

• Positive for hepatitis B surface antigen (HBsAg) or hepatitis B core antibody (HBcAb) and peripheral blood hepatitis B virus (HBV) DNA titer test exceeds the normal range; Hepatitis C virus (HCV) antibody is positive and the hepatitis C virus (HCV) RNA titer in peripheral blood exceeds the normal range; positive for human immunodeficiency virus (HIV) antibodies; Positive syphilis test.

• Known history of bone marrow stem cell disease 12. Other conditions that the investigators consider unsuitable to participate in the study.