rhTPO Dose Escalation vs Eltrombopag Switch in ITP

Inclusion criteria

• Age 12-75 years, either sex;
• ECOG performance status 0-1;
• Diagnosis of ITP confirmed by bone marrow biopsy (valid within 3 months) or other relevant examinations;
• Patients who failed short-term rhTPO second-line treatment (≤14 days of medication) (PLT < 30×10⁹/L);
• Major organ function must meet the following requirements (based on normal values at the clinical trial center):

• Blood routine: absolute neutrophil count (ANC) ≥ 1.5×10⁹/L; no abnormalities other than ITP, except: a) PLT < 30×10⁹/L at Day 1 visit or within 48 hours of Day 1 is acceptable for enrollment; b) Hemoglobin: if anemia is clearly due to ITP (excessive bleeding related to thrombocytopenia), subjects with hemoglobin below the lower limit of normal may be enrolled based on investigator judgment;
• Blood biochemistry: total bilirubin (TBIL) ≤ 1.5×ULN; ALT, AST, or ALP ≤ 3×ULN; serum creatinine (Cr) ≤ 1.5×ULN with creatinine clearance ≥ 50 mL/min;
• Coagulation function: prothrombin time (PT) within ±3s of normal range; activated partial thromboplastin time (APTT) ≤ 1.5×ULN unless on medications known to alter INR and APTT; no history of coagulation abnormalities other than ITP;
• Previous ITP combination treatments including platelet transfusion, immunoglobulin, immunomodulators, and cyclophosphamide rescue therapy must have ended ≥2 weeks before enrollment; corticosteroids or TPO-class drug treatments must have ended ≥2 weeks before study start;
• Patients on immunosuppressants (including corticosteroids, azathioprine, danazol, cyclosporin A, mycophenolate mofetil) or platelet-elevating traditional Chinese medicine maintenance therapy must have stable therapeutic doses for at least the most recent month; patients receiving CD20 monoclonal antibody must have stopped treatment ≥6 months before enrollment; splenectomy patients may enroll ≥6 months after surgery;
• Women of childbearing potential must have negative serum pregnancy test within 24 hours before first dose; all subjects must agree to use effective contraception during the study and for 6 months after study treatment completion;
• No contraindications to rhTPO and eltrombopag use;
• Voluntary participation in this study, signed informed consent, good compliance, and willingness to cooperate with follow-up.

Exclusion criteria

• Refractory ITP patients (failure of first-line and second-line thrombopoietic drugs and CD20 monoclonal antibody treatment, or splenectomy failure/postoperative relapse);
• Pregnant or lactating patients;
• Evidence of secondary causes of ITP (e.g., untreated Helicobacter pylori infection, leukemia, lymphoma, autoimmune diseases such as SLE, Hashimoto's thyroiditis) or drug-induced (e.g., anticonvulsants, antibiotics, heparin), or bicytopenia/pancytopenia such as Evans syndrome, immune-related cytopenias, etc.;
• History or current presence of primary diseases other than ITP causing thrombocytopenia (e.g., primary myelodysplastic syndrome [MDS], congenital bone marrow failure diseases [e.g., Fanconi anemia, dyskeratosis congenita], aplastic anemia [AA]), and judged by investigator as unsuitable for this study;
• History of intracranial hemorrhage or other important organ severe bleeding (>CTC AE Grade 3), or history of symptomatic gastrointestinal bleeding (e.g., hematemesis, melena) within 6 months before screening (occult blood test positivity without symptoms/signs and hemorrhoids excluded);
• History of any arterial or venous thrombosis within 6 months before enrollment (including stroke, TIA, MI, DVT, or PE) AND presence of at least 2 of the following risk factors: hormone replacement therapy, oral contraceptives (including estrogen), smoking, diabetes, hypercholesterolemia, drug-controlled hypertension, hereditary coagulation disorders;
• Severe cardiovascular disease within 6 months before enrollment (NYHA Class III-IV), known arrhythmia increasing thromboembolic risk such as atrial fibrillation, coronary stent implantation, angioplasty, or post-CABG patients;
• Coexisting malignancy severely affecting survival;
• Continuous use of medications affecting platelet function (including but not limited to aspirin, clopidogrel, and/or NSAIDs) or anticoagulant therapy >3 days from 2 weeks after study start until study end;
• Use of any herbal medicine or nutritional supplements within 1 week before study start, except vitamin and mineral supplements;
• Currently having severe or uncontrolled infection (CTC AE Grade 2 infection);
• Laboratory or clinical evidence of HIV infection, previous hepatitis C clinical history, previous hepatitis B infection, or active hepatitis/active tuberculosis at screening. Screening laboratory tests indicating hepatitis C or hepatitis B infection (defined as positive HBsAg; additionally, if HBsAg negative but HBcAb positive, regardless of HBsAb status, HBV DNA testing is required, and if positive, subject should be excluded);
• Patients considered by investigator as unsuitable for this trial due to any other medical, social, or psychological factors that may affect safety or compliance with study procedures.