Inclusion Criteria:
* Age 18 and above, male or female;
* Conform to the diagnostic criteria of immune Thrombocytopenia (ITP) ≥3 months;
* Failure to achieve response or relapse after corticosteroid therapy, and failure to achieve response or relapse after previous second-line treatments such as TPO/TPORAs therapy, or are unable to afford the cost of the treatment;
* The platelet count of \<30 X 10\^9/L measured within 2 days prior to inclusion (During the screening visit and/or before receiving the study drug, platelet counts must be less than 30×10\^9/L on at least two consecutive occasions, with a minimum interval of 1 day between the two tests.);
* ECOG physical state score ≤ 2 points;
* Subjects on stable dose maintenance therapy are allowed to be included (concomitant medications may include corticosteroids (≤0.5 mg/kg of prednisone or equivalent steroids) or TPO receptor agonists, etc.), but at the time of enrollment, only one concomitant medication with a stable dose is permitted. The concomitant medication must have been on a stable dose for at least 4 weeks prior to the first dose of the study drug;
* For female patients of childbearing potential, a negative pregnancy test result is required. Both female patients of childbearing potential and male patients must use highly effective contraception during the study and for 4 months/6 months after discontinuing treatment;
* Signed and dated written informed consent
Exclusion Criteria:
* Those who are allergic to Nicotinamide adenine dinucleotide or excipients, or who have previously received CD38 monoclonal antibody treatment with no efficacy.
* Those with autoimmune hemolytic anemia, or various types of secondary and genetic thrombocytopenia, such as leukemia, lymphoma, multiple myeloma, aplastic anemia, myelodysplastic syndrome, Evans syndrome, common variable immunodeficiency, systemic lupus erythematosus, cirrhosis, antiphospholipid antibody syndrome, pseudo-thrombocytopenia, drug-induced thrombocytopenia (e.g., quinine, heparin, antimicrobial drugs, anticonvulsants, etc.).
* A history of any thrombosis or embolism events within 12 months prior to the first dose, or the presence of extensive and severe bleeding, such as hemoptysis, upper gastrointestinal bleeding, intracranial hemorrhage, sepsis, or other irregular bleeding.
* Participation in any other clinical trial involving investigational drugs (including vaccine studies) or exposure to other investigational drugs within 4 weeks or 5 half-lives (whichever is longer) prior to the first dose.
* Use of anticoagulants or any drugs with antiplatelet effects (e.g., aspirin) within 2 weeks prior to the first dose.
* Receiving emergency treatment for ITP within 2 weeks prior to the first dose (e.g., methylprednisolone, platelet transfusion, intravenous immunoglobulin, or TPO receptor agonist treatment).
* Receiving azathioprine, danazol, cyclosporine A, tacrolimus, sirolimus, or similar drugs within 4 weeks prior to the first dose; receiving CD20 monoclonal antibodies such as rituximab, cyclophosphamide, vincristine, or similar drugs within 3 months prior to the first dose.
* Splenectomy within 6 months prior to the first dose.
* Receiving a live vaccine within 4 weeks prior to the first dose, or planning to receive any live vaccine during the study period.
* A history of undergoing allogeneic stem cell transplantation or organ transplantation.
* A history of clinically significant diseases that, in the investigator's opinion, may pose a risk to the subject's safety or affect the assessment of safety or efficacy during the study if the disease/condition worsens.
* Subjects who have had malignant tumors within the past 5 years prior to screening (excluding completely cured carcinoma in situ of the cervix and non-metastatic squamous cell carcinoma or basal cell carcinoma of the skin).
* Exhibiting clinically significant laboratory abnormalities at screening: a) Alanine aminotransferase (ALT) or aspartate aminotransferase (AST) ≥ the upper limit of normal (ULN); b) Total bilirubin ≥ 1.2 times ULN. ;c) Creatinine or blood urea nitrogen (BUN) ≥ ULN.
* Positive for HIV antibodies or syphilis antibodies.
* Positive for hepatitis B surface antigen (HBsAg) at screening, or positive for hepatitis B core antibody with a positive HBV-DNA result by polymerase chain reaction (PCR) testing, or positive for hepatitis C virus (HCV) antibodies.
* Women who are pregnant or breastfeeding, or planning to become pregnant or breastfeed during the study; and men whose partners are planning to become pregnant during the study.
* Subjects with mental disorders who are unable to provide informed consent or participate in the trial and follow-up properly.
* Subjects with unresolved toxicity symptoms caused by prior treatments before participating in the trial.
* Any other conditions deemed unsuitable for participation in this study as assessed by the investigator.
