Efficacy and Safety of QL0911 in Adult Patients With Chronic Primary Immune Thrombocytopenia

Inclusion Criteria: * Aged ≥18 years old; * Diagnosed primary ITP for at least 12 months; * Had received at least one first-line ITP treatment with no response or recurrence after treatment; * Had a platelet count \<30×10\^9/L within 48 hours before the first dose; * Eastern Cooperative Oncology Group (ECOG) performance status of 0, 1, or 2; * Fully understand and comply with the requirements of this study, and voluntarily sign the informed consent form. Exclusion Criteria: * Had a history of bone marrow stem cell abnormalities or myelodysplastic syndrome other than ITP-specific changes. * Had arterial thrombosis, or venous thromboembolism; severe cardiovascular diseases; malignant tumors; secondary thrombocytopenia caused by autoimmune diseases. * Underwent splenectomy within 12 weeks before the first dose; * Had received ITP treatments (including rescue treatment) within 2 weeks before the first dose; * Had received romiplostim (Nplate®) or eltrombopag (Revolade®), rhTPO or other agents that stimulate TPO receptors (also known as c-Mpl), and hematopoietic growth factors (HGFs) within 4 weeks before the first dose; * Had received antineoplastic agents within 8 weeks before the first administration, but when treating ITP with hypomethylating agents (HMA) such as decitabine, a 4-week washout period was acceptable, as judged by the investigator; * Had received antibody-based therapies within 14 weeks before the first dose; 8) had serum creatinine or total bilirubin \>1.5 upper limit of normal (ULN), alanine transaminase (ALT) or aspartate transaminase (AST) \>3 ULN, hemoglobin \< 100g/L, absolute neutrophil count \<1.5x10\^9/L; * Had prothrombin time (PT) or prothrombin time-international normalized ratio (PT-INR) or activated partial thromboplastin time (APTT) exceeded 20% of the reference range of normal values.