A Clinical Study on the Efficacy and Safety of HBM9161 in Patients With ITP

Study Overview
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Brief Summary
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To select a dose and to make a decision for Phase 3 study

Detailed Description
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The onset of primary immune thrombocytopenia is thought to be increased platelet destruction and decreased platelet production due to anti-platelet antibodies. HBM9161 is a fully human anti-FcRn monoclonal antibody that can effectively remove pathogenic IgG, thereby relieving platelet destruction and rapidly increasing platelet counts in patients. The study will be conducted in a Phase 2/3 operational seamless design, with group Dose A and Dose B of HBM9161 and a placebo group in Phase 2.

Official Title
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A Randomized, Double-blind, Placebo-controlled, Phase 2/3 Operational Seamless Designed Clinical Study to Evaluate the Efficacy and Safety of HBM9161 Weekly Subcutaneous Injection in Patients With Primary Immune Thrombocytopenia

Conditions
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Primary Immune Thrombocytopenic Purpura

Intervention / Treatment
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* Drug: HBM9161 Dose A
* Drug: HBM9161 Dose B
* Drug: Placebo


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: ≥ 18 years of age at the screening visit, male or female. Persistent or chronic ITP whose average number of platelet at the screening visit and pre-dose (at least 1 day apart) is < 30 × 10^9/L, and not > 35 × 10^9/L for any of two tests. No severe bleeding within 4 weeks prior to the screening visit. Patients who have received and failed at least 1 first line of ITP therapy (glucocorticoids and/or intravenous gamma globulin), or who are contraindicated, intolerable, or refuse standard therapy. Patients will be allowed to use a stable dose of concomitant drugs for the treatment of ITP. e.g., glucocorticoid, danazol, immunosuppressant (azathioprine, cyclosporine A, mycophenolate mofetil) and eltrombopag. Exclusion Criteria: Other autoimmune systemic diseases other than ITP. Multi-lineage immune cytopenias, such as Evan's syndrome, autoimmune pancytopenia. Secondary ITP. Received a vaccine within 4 weeks prior to the first dose of the study drug or planned during the study. Use of anticoagulants or any agents that have antiplatelet effect or can affect thrombopoiesis within 3 weeks prior to the first dose of the study drug. Received blood transfusion within 1 week prior to the first dose of the study drug. Received the intravenous gamma globulin, anti-D immunoglobulin, or plasmapheresis within 2 weeks prior to the first dose of the study drug. Received high-dose dexamethasone or high-dose methylprednisolone within 2 weeks prior to the first dose of the study drug. Received recombinant human thrombopoietin (rhTPO) within 4 weeks prior to the first does of the study drug. Received rituximab or other non-rituximab anti-CD20 drugs within 6 months prior to the first does of the study drug. Treated with splenectomy within 4 weeks prior to first dose of the study drug. Any thromboembolic or embolic events within 12 months prior to the first does of the study drug. Serum total IgG < 700 mg/dL at the screening visit.

Ages Eligible for Study
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Minimum Age: 18 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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No

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Treatment
Allocation: Randomized
Intervention Model: Parallel Assignment
Masking: Quadruple


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: HBM9161 Dose A<br>Patients will be randomized in a 1:1:1 ratio to HBM9161 (Dose A or Dose B) or placebo | Drug: HBM9161 Dose A<br>* HBM9161 (Dose A or Dose B) or matching placebo will be administered IV weekly<br>|
| Experimental: HBM9161 Dose B<br>Patients will be randomized in a 1:1:1 ratio to HBM9161 (Dose A or Dose B) or placebo | Drug: HBM9161 Dose B<br>* HBM9161 (Dose A or Dose B) or matching placebo will be administered IV weekly<br>|
| Placebo Comparator: Placebo<br>Patients will be randomized in a 1:1:1 ratio to HBM9161 (Dose A or Dose B) or placebo | Drug: Placebo<br>* HBM9161 (Dose A or Dose B) or matching placebo will be administered IV weekly<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Proportion of patients who achieve the early response. | The primary endpoint of phase 2 | 7 weeks | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Proportion of patients who achieve platelet count ≥ 50 × 10^9/L at least 2 times within 7 weeks. |  | 7 weeks | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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ITP