Efficacy and Safety of Romiplostim N01 Combined With Rituximab in Patients With Oral TPO-RA-Refractory Primary Immune Thrombocytopenia

An Open-label, Single-arm, Single-center Study to Evaluate the Efficacy and Safety of Romiplostim N01 in Combination With Rituximab in Patients With Primary Immune Thrombocytopenia Refractory to Oral TPO-RAs

The primary objective of this trial is to assess the efficacy and safety of combining Romiplostim N01 with Rituximab for the treatment of adult patients with primary immune thrombocytopenia (ITP) whose disease is refractory to oral TPO-RAs.

All participants in this study will receive the same combination treatment:

Rituximab: Given once a week through an intravenous infusion for 4 weeks. Romiplostim N01: Given as a weekly injection，the dose may be adjusted each week based on the patient's platelet count.

Participants will be asked to:

Visit the clinic regularly for check-ups, blood tests (to monitor platelet counts), and safety assessments.

Report their bleeding symptoms for evaluation. This is an open-label, single-arm trial, meaning that all participants will receive the investigational treatment, and both the research team and participants will be aware of the treatment assigned. The study aims to enroll approximately 30 adult patients aged 14 years or older who have been diagnosed with ITP and have not responded adequately to prior oral TPO-RAs (eltrombopag/hetrombopag).

Inclusion Criteria:

Confirmed diagnosis of primary immune thrombocytopenia (ITP).

Age ≥14 years.

Prior exposure to at least one ITP-directed therapy (e.g., corticosteroids, intravenous immunoglobulin, recombinant human thrombopoietin, TPO-RAs, immunosuppressants, or splenectomy), including a minimum 4-week course of an oral TPO-RA (hetrombopag or eltrombopag) that was discontinued due to insufficient response.

Platelet count < 30 × 10⁹/L at screening, OR platelet count < 50 × 10⁹/L with concurrent clinically significant bleeding.

Stable glucocorticoid dose (e.g., prednisone or methylprednisolone, not exceeding 4 tablets daily) for at least 2 weeks, and stable dosing of any other immunosuppressants for at least 4 weeks prior to enrollment.

No receipt of intravenous immunoglobulin within 2 weeks before the first dose of study treatment.

No platelet transfusion within 1 week before the first dose of study treatment.

Exclusion Criteria:

Secondary ITP due to underlying conditions such as other autoimmune disorders, viral infections, or drug exposure.

Presence of active malignancy, pregnancy, significant cardiovascular or cerebrovascular disease, or history of arterial/venous thrombosis.