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

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.