Hetrombopag or Placebo in Treatment-Naive Severe Aplastic Anemia

Inclusion criteria

1.15 Years to 75 Years (weight greater than 50 kg if Age < 18 years old). 2.Severe aplastic anemia characterized by Bone marrow cell proliferation less than 25 percent (If ≥25% but <50%, the remaining hematopoietic cells should be <30%) AND At least two of the following: Absolute neutrophil count <0.5×109/L; Platelet count <20×109/L; Absolute reticulocyte count <20×109/L.

3.Unsuitable or unwilling to perform hematopoietic stem cell transplantation (HSCT).

4.Signed informed consent.

Exclusion criteria

• Diagnosis of whole blood cell reduction due to other causes or bone marrow hypoproliferative diseases.
• Subjects who have previously received immunosuppressive therapy with mycophenolate mofetil, sirolimus, high dose cyclophosphamide (≥45mg/kg/d), alemtuzumab, etc；or have treated with thrombopoietin receptor agonist (eg, eltrombopag, romiplostim, rhTPO, etc.) prior to randomization.
• Previous history of hematopoietic stem cell transplantation.
• Subjects who is known or suspected of contraindications or hypersensitivity to Hetrombopag's API (Active Pharmaceutical Ingredient).
• Evidence of clonal cytogenetic abnormalities at the time of screening.
• Bleeding and/or Infection not adequately responding to appropriate therapy.
• Any laboratory or clinical evidence for HIV infection. Any clinical history for hepatitis C infection; chronic hepatitis B infection; or any evidence for active hepatitis at the time of subjects screening.
• ALT> 2.5 x upper limit of normal (ULN), AST> 2.5 x upper limit of normal (ULN) DBLI> 1.5 x upper limit of normal (ULN), Scr> upper limit of normal (ULN).
• Subjects with uncontrolled hypertension (>180/100mmHg), severe arrhythmia (such as complete left bundle branch block, QT interval prolongation (Bazetts formula), torsade ventricular tachycardia, etc.), unstable angina, pulmonary hypertension at the time of screening.
• Subjects diagnosed with cirrhosis or portal hypertension.
• Subjects with malignant solid tumors of any organ system within 5 years prior to screening, with or without treatment, metastasis or recurrence, except for local cutaneous basal cell carcinoma; subjects with hematological tumors found previously or during screening.
• Subjects with deep vein thrombosis, myocardial infarction, stroke or peripheral arterial embolization within 12 months prior to randomization.
• Female subjects who are nursing or pregnant.
• Subjects cannot comply with effective contraception.
• Subjects have participated in other clinical trial within the 3 months prior to study entry.