Inclusion Criteria:  Subjects who have completed or withdrawn from the HR-TPO-SAA-III study Subjects who have signed the informed consent form Female and male subjects of childbearing age who agree to take adequate contraceptive measures during the extension study period and within 28 days after the last dose Subjects who have completed the end-of-treatment evaluation in the original study  Exclusion Criteria:  Any unstable situation or situation that will compromise the safety of the subject Evidence of clonal cytogenetic abnormalities at the end-of-treatment examination of the HR-TPO-SAA-III study Subjects with uncontrollable hemorrhage and/or infection after standard treatment Subjects who have experienced deep vein thrombosis, myocardial infarction, stroke, or peripheral arterial embolism within 1 year Any situation that may compromise the subject and the safety or compliance thereof during the study