The purpose of this study is to evaluate the efficacy and safety of AMG 531 compared with
placebo in thrombocytopenic Japanese subjects with immune (idiopathic) thrombocytopenic
purpura (ITP) .
Minimum age: 20 Years.
Maximum age: N/A.
Gender(s): Both.
Inclusion Criteria:
- Japanese patients with diagnosis of ITP according to the diagnostic criteria proposed
by Research Committee for Idiopathic Hematopoietic Disorders of the Ministry of
Health, Labour and Welfare [MHLW] (revised in 1990) at least 6 months before the
first screening visit
- The mean of the 3 scheduled platelet counts taken at the scheduled visits during the
screening period must be ≤ 30 x 10^9/L, with no individual count > 35 x 10^9/L
- Eastern Cooperative Oncology Group (ECOG) performance status of 0 to 2
- Subjects must be ≥ 20 years of age at the time of obtaining the informed consent
- Have received at least 1 prior treatment for ITP
- If known Helicobacter pylori positive, having completed one course of Helicobacter
pylori eradication therapy at least 12 weeks before the first screening visit
- A hemoglobin value taken at scheduled visit during the screening period must be ≥ 10
g/dL
- A serum creatinine concentration taken at scheduled visit during the screening period
must be ≤ 2 mg/dL
- Adequate liver function, as evidenced by a total bilirubin taken at scheduled visit
during the screening period ≤ 1. 5 times of the upper limit of the normal range
(except for patients with a confirmed diagnosis of Gilbert's Disease) or an alanine
aminotransferase and aspartate aminotransferase taken at the screening visit ≤ 3
times of the upper limit of the normal range
Exclusion Criteria:
- Any known history of bone marrow stem cell disorder. Any abnormal bone marrow
findings other than those typical of ITP.
- Any active malignancy. If prior history of cancer other than basal cell carcinoma or
cervical carcinoma in situ, no treatment or active disease within 5 years before the
first screening visit.
- Documented diagnosis of arterial thrombosis (eg, stroke, transient ischemic attack,
or myocardial infarction); history of venous thrombosis (eg, deep vein thrombosis,
pulmonary embolism) and receiving anticoagulation therapy at the first screening
visit.
- Documented diagnosis of anti phospholipid antibody syndrome
- Currently receiving any treatment for ITP except oral corticosteroids, azathioprine
and/or danazol administered at a constant dose and schedule from at least 4 weeks
prior to the first screening visit
- Received intravenous immunoglobulin, anti D immunoglobulin, or any drug administered
to increase platelet counts (eg, immunosuppressants except azathioprine) within 2
weeks before the first screening visit
- Have had a splenectomy for any reason within 12 weeks before the first screening
visit
- Past or present participation in any study evaluating pegacaristim (polyethylene
glycol-conjugated recombinant human megakaryocyte growth and development factor,
KRN9000), Eltrombopag (SB 497115), recombinant human thrombopoietin, AMG 531, or
other Mpl stimulation product
- Received hematopoietic growth factors (eg, granulocyte colony stimulating factor,
macrophage colony stimulating factor, erythropoietin, interleukin 11) for any reason
within 4 weeks before the first screening visit
- Received any anti malignancy agents (eg, cyclophosphamide, 6 mercaptopurine,
vincristine, vinblastine, Interferon alfa) for any reason within 8 weeks before the
first screening visit
- Received any monoclonal antibody drugs (eg, rituximab) for any reason within 14 weeks
before the first screening visit
- Less than 4 weeks since receipt of any therapeutic drug or device that is not MHLW
approved for any indication before the first screening visit
- Pregnant or breast feeding
- Subjects of reproductive potential who are not using adequate contraceptive
precautions, in the judgment of the investigator
- Known severe drug hypersensitivity
- Concerns for subject's compliance with the protocol