Study of AMG531(Romiplostim) in Patients With Aplastic Anemia

Inclusion criteria

• Voluntary signed informed consent to participate in the study;
• A diagnosis of AA confirmed by blood and bone-marrow examinations, etc.;
• Considered to require new treatment with ATG and CsA provided that NSAA must be platelet or erythrocyte transfusion-dependent.
• An Eastern Cooperative Oncology Group (ECOG) performance status (PS) score of 0 to 1at screening

Exclusion criteria

• Previously treated with ATG, CsA, or Alemtuzumab;
• Diagnosed as having congenital AA (Fanconi anemia, congenital dyskeratosis, etc.);
• Diagnosed as having AML or chronic myelomonocytic leukemia;
• Concurrent thrombocytopenia of other etiologies (e.g., MDS, ITP, cirrhosis);
• Concurrent active infection not adequately responding to appropriate therapy;
• Concurrent clinically significant illness(es) items which are deemed by the Investigator to be likely to affect the study conduct and assessments.
• Having active malignancies, or having a history of treatment of malignancies within 5 years prior to informed consent.
• Concurrent PNH
• Having Grade 2 or higher bone marrow reticulin based on Bone Marrow Pathology (2nd edition) ;
• History of chromosome aberrations discovered in bone marrow cells.
• Having blast cells > 2% in bone marrow;
• Positive for anti-human immunodeficiency virus (HIV) antibody;
• Receiving prophylactic or therapeutic treatment for hepatitis type B
• Positive for hepatitis C virus (HCV) antibody, and HCV infection being confirmed
• Planned hematopoietic stem cell transplantation during the study;
• Systemic treatment with any of the following medication for the treatment of AA within 4 weeks before Day 1, however, excluding their use as premedication:

• Anabolic steroids
• Corticosteroids;
• Pregnant or breastfeeding women, or women willing to become pregnant;
• Other conditions unsuitable for participation in the study in the opinion of the Investigator.