Efficacy and Safety of Thrombopoietin In Patients With Severe and Very Severe Aplastic Anemia

Inclusion Criteria: * Able to provide written informed consent * Have severe or very severe aplastic anemia Exclusion Criteria: * Have diagnosis of Fanconi anemia * Have infection not adequately responding to appropriate therapy * Have Paroxysmal Nocturnal Hemoglobinuria (PNH) clone size in neutrophils of greater than or equal to 50% * Have creatinine and/or blood urea nitrogen (BUN) ≥2 times the upper limit of normal * Have serum bilirubin ≥ 1.5 times the upper limit of normal, or ≥4.0 times the upper limit of normal if the patient has been treated with Anti-Thymocytes globulin（ATG） within three weeks of screening. * Have glutamic-oxaloacetic transaminase （AST） and/or glutamic-pyruvic transaminase （ALT） ≥ 3 times the upper limit of normal * Are female and are nursing or pregnant or are unwilling to take oral contraceptives or refrain from pregnancy if of childbearing potential * Have an Eastern Cooperative Oncology Group (ECOG) performance status of 3 or greater * Have had other Thrombopoietin (TPO-R) agonists medication in the previous 4 weeks.