TPO-RAs Combining Anti-CD 20 Monoclonal Antibody Versus TPO-RAs in the Management of Pediatric Primary Immune Thrombocytopenia (ITP)

Inclusion Criteria:

1. Age 6-17 years old (including both ends), male and female;

2. Patients aged 6-11 years (including values at both ends) were diagnosed with chronicITP, and patients aged 12-17 years (including values at both ends) were diagnosedwith persistent or chronic ITP, with platelet counts less than 20×109/L;

3. Patients did not respond to glucocorticoid therapy or relapsed. Previous ITPtreatment may include, but is not limited to, glucocorticoids, immunomodulators (IVIG), azathioprine, danazole, cyclophosphamide and immunomodulators.

4. Treatment for ITP (including but not limited to glucocorticoids, recombinant humanthrombopoietin, TPO agonist (TPO-RA), azathioprine, danazole, cyclosporin A,mycophenate) must be completed or dose stabilized before enrollment, and therapeuticdose should not be increased after enrollment (e.g. The glucocorticoid dose shouldbe stable for ≥14 days and the immunosuppressant dose should be stable for > 3months before the first administration of the study drug. TPO drugs should bestopped > 1 month, TPO-RA drugs should be stopped > 1 month).

5. No infectious fever (including but not limited to lung infection) in the past 1month.

6. Laboratory examination of coagulation function should show that the prothrombin time (PT) and activated partial thrombin time (aPTT) values did not exceed 20% of thenormal laboratory value range; No history of abnormal coagulation except for ITP.

7. WBC count, neutrophil absolute value and hemoglobin should be within the normalrange of laboratory values. No other abnormality except for ITP. Other exceptionsexcept the following:

• If the anemia is clearly caused by excessive blood loss associated with ITP.

• If the increase in WBC count/neutrophil absolute value was clearly due tosteroid therapy.

8. Understand the study procedure and voluntarily sign the informed consent.

• For subjects aged 6-7 (including both ends), parents/guardians understand thestudy procedure and voluntarily sign the informed consent in person, andsubjects are encouraged to participate in the informed process and voluntarilysign the informed consent in person;

• For subjects aged 8-16 (including both ends), parents/guardians and subjectsthemselves should understand the study procedure and voluntarily sign theinformed consent in person;

• For the minor subjects > 16 years old, if the subjects rely on their own incomeas the main source of living, they are regarded as persons with full capacityfor civil conduct and can independently carry out legal acts. The subjects cansign informed consent on the premise that they understand the researchprocedures and are willing to do so;

• For minor subjects > 16 years old, if the subjects do not rely on their ownincome as the main source of living, they cannot be regarded as persons withfull capacity for civil conduct and cannot independently carry out legal acts.Parents/guardians and subjects should understand the study procedures andvoluntarily sign the informed consent in person.

Exclusion Criteria:

1. Subjects who has any history of arterial/venous thrombosis and the following riskfactors including clotting factor V Leiden disease, ATIII deficiency,antiphospholipid syndrome, etc..

2. Subjects known to have failed all standard TPO-RAs treatments.

3. Subjects known to have taken anti-CD20 antibodytreatment within 3 months prior toinitial use of the study drug.

4. Within 2 weeks prior to the initial use of the study drug, subjects were treatedwith medications (including but not limited to aspirin, aspirin containingcompounds, clopidogrel, salicylate, and/or NSAIDs) or anticoagulants that had animpact on platelet function for > 3 consecutive days.

5. Subjects known to have participated in other investigational clinical trials within 3 months prior to first use of investigational drug.

6. Suffering from severe, progressive, uncontrolled kidney, liver, gastrointestinal,endocrine, lung, heart, nervous system, brain or psychiatric disorders.

7. HIV infection with laboratory or clinical diagnosis.

8. Previous history of hepatitis C, chronic hepatitis B infection, or evidence ofactive hepatitis. Laboratory tests at the screening stage indicate seropositivityfor hepatitis C or hepatitis B seropositivity (HBsAg positive). In addition, ifHBsAg is negative but HBcAb is positive (regardless of HBsAb status), HBV DNAtesting is required, and if positive, the subject should be excluded.

9. During the screening period, alanine aminotransferase (ALT), aspartateaminotransferase (AST) and alkaline phosphatase were more than 1.5 times of theupper limit of normal value, serum creatinine and bilirubin were more than 1.2 timesof the upper limit of normal value, and serum albumin was less than 10% of the lowerlimit of normal value.

10. Bone marrow biopsy results within 6 months before enrollment showed thatmyelofibrosis score MF≥2.

11. There is a history of abnormal platelet aggregation that may affect the reliabilityof platelet count measurements.

12. Any medical history or condition that the investigator deems unsuitable forparticipation in the study.