Background Immune thrombocytopenia (ITP) is an autoimmune disorder caused by increased platelet destruction and suboptimal platelet production. The fundamental treatment goal is to achieve a sustained hemostatic platelet count to minimize bleeding risk. Corticosteroids remain the mainstay for first-line management of ITP, but prolonged use is limited by adverse effects including mood and sleep disturbance, weight gain, hyperglycemia, osteoporosis and hypertension. Further, 20-30% of patients exhibit non-response to corticosteroid therapy and 80% of responders experience relapse when corticosteroids are reduced or stopped. Consequently, there is a critical need to identify alternative first-line therapies that yield higher initial response rates and reduced relapse rates. Romiplostim N01 is a recombinant human thrombopoietin mimetic peptide-Fc fusion protein and has been approved in China as second-line therapy for adult ITP. Recent studies have shown that Romiplostim exhibits considerable therapeutic potential in the first-line management of patients with ITP.

Study design and methods This single-arm, open-label study is designed to evaluate the efficacy and safety of romiplostim N01 combined with low-dose prednisone over a 6-month treatment period in treatment-naive, newly diagnosed elderly patients (≥60 years) with ITP (N=26).

The primary endpoints: The proportion of patients achieving the response criteria at 12 and 24 weeks after treatment initiation. (Overall Response Rate GR = CR+R; Complete Response (CR): platelet count≥100×10⁹/L with no bleeding symptoms; Response (R): platelet count between 30×10⁹/L and 100×10⁹/L, at least doubled from baseline, with no bleeding symptoms)

Secondary endpoint: The proportion of patients with sustained remission, sustained remission was defined as the maintenance of efficacy for at least 6 months from the beginning of remission, without additional ITP-specific treatment; The median time of platelet count≥50×10⁹/L; The proportion of patients with adverse events (AE), including severe adverse events (SAE) and laboratory safety parameters.

Inclusion Criteria: Patients with clinically confirmed ITP and platelet counts ≤30×10⁹/L for two consecutive times (or platelet counts >30×10⁹/L with bleeding); ECOG Performance Status score: 0–2; No prior systemic therapy for ITP; Age ≥60 years; Patients with hypertension or diabetes must have adequately controlled blood pressure or blood glucose; Bone marrow examination showing normal or increased megakaryocytic cells; Absence of active infection; Male patients of reproductive potential must practice effective contraception; Signed and dated written informed consent obtained.

Exclusion criteria : There are benign and malignant hematological diseases affecting thrombocytopenia, such as leukemia, myeloproliferative disorders, multiple myeloma, aplastic anemia, myelodysplastic syndrome, etc; Secondary thrombocytopenia caused by solid tumors; Secondary thrombocytopenia caused by infection; Drug-induced secondary thrombocytopenia (such as receiving immunosuppressive therapy within 1 month); Secondary thrombocytopenia caused by connective tissue disease; Autoimmune hemolytic anemia; Any of the results of human immunodeficiency virus antibody or syphilis antibody screening are positive; Hepatitis C antibody was positive and the detection of HCV-RNA exceeded the upper limit of laboratory examination in the research center; Hepatitis B surface antigen was positive and the detection of HBV-DNA exceeded the upper limit of laboratory examination in the research center. Fractures, gastrointestinal active ulcers or bleeding; Informed consent was not signed.

Treatment: Romiplostim N01 is initiated at a starting dose of 3µg/kg administered via subcutaneous injection once weekly for 3 months, with stepwise escalation in 1 µg/kg increments up to a maximum dose of 10 µg/kg, to maintain platelet counts within the range of 50-200×10⁹/L. Prednisone was administered at a low dose of 0.5 mg/kg for 1-2 weeks, and the effective dose was gradually reduced to discontinuation.

Disclosures:No relevant conflicts of interest to declare.

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2025
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