Determination of Safe Dose of Romiplostim (AMG 531) in Patients With Myelodysplastic Syndromes (MDS)

Inclusion Criteria: Diagnosis of MDS using the World Health Organization classification Low or Intermediate-1 risk MDS using the International Prognostic Scoring System (IPSS) The mean of two platelet counts taken during the screening period must be ≤ 50 x 10^9/L, with no individual count > 55 x 10^9/L (The mean platelet counts of 5 subjects enrolled at the maximum tolerated dose (MTD) must be ≤ 20 x 10^9/L). Standard of care platelet assessments taken prior to Informed Consent may be used as 1 of the 2 counts taken within 3 weeks prior to study day 1. Must be ≥ 18 years of age at the time of obtaining informed consent Eastern Cooperative Oncology Group (ECOG) performance status of 0-2 at the time of screening Adequate Liver Function, as evidenced by a serum bilirubin ≤ 1.5 times the laboratory normal range (except for patients with a confirmed diagnosis of Gilbert's Disease), alanine aminotransferase (ALT) ≤ 3 times the laboratory normal range, and aspartate aminotransferase (AST) ≤ 3 times the laboratory normal range A serum creatinine concentration ≤ 2 mg/dL (≤ 176.6 µmol/L) Before any study-specific procedure, the appropriate written informed consent must be obtained (see Section 12.1) Exclusion Criteria: Currently receiving any treatment for MDS other than transfusions and erythropoietic growth factors. If granulocyte growth factors are currently being received, they cannot be used on or after study day 1 Clinically significant bleeding within 2 weeks prior to screening (eg, gastrointestinal (GI) bleeds, intracranial hemorrhage) Prior malignancy (other than controlled prostate cancer, in situ cervical cancer or basal cell cancer of the skin) unless treated with curative intent and without evidence of disease for ≥ 3 years before screening Prior history of bone marrow transplantation Persistent peripheral blood monocytosis (≥ 3 months with an absolute monocyte count > 1,000/µL) Unstable angina, congestive heart failure (New York Heart Association [NYHA] > class II), uncontrolled hypertension (diastolic > 100 mmHg), uncontrolled cardiac arrhythmia, or recent (within 1 year) myocardial infarction Received Anti-Thymocyte Globuline (ATG) within 6 months of screening Received hypomethylating agents, immunomodulating agents, histone deacetylase inhibitors, cyclosporine or mycophenolate within 6 weeks of screening Received interleukin (IL)-11 (oprelvekin) within 4 weeks before screening Concurrent use of granulocyte growth factors (i.e. granulocyte-colony stimulating factor [G-CSF; Neupogen, Granocyte], pegfilgrastim [Neulasta], granulocyte macrophage-colony stimulating factor [GM-CSF; Leukine, Prokine, Sargramostim]) Have ever previously received recombinant thrombopoietin (rTPO), pegylated recombinant human megakaryocyte growth and development factor (PEG-rHuMGDF), eltrombopag, or romiplostim Less than 4 weeks since receipt of any therapeutic drug or device that is not Food and Drug Administration (FDA) approved for any indication Other investigational procedures are excluded History of arterial thrombosis (eg, stroke or transient ischemic attack) in the past year History of venous thrombosis that currently requires anti-coagulation therapy Untreated B12 or folate deficiency Subject is evidently pregnant (eg, positive human chorionic gonadotropin [HCG] test) or is breast feeding Subject is not using adequate contraceptive precautions Subject has known hypersensitivity to any recombinant E coli-derived product Subject previously has enrolled in this study Subject will not be available for follow-up assessment Subject has any kind of disorder that compromises the ability of the subject to give written informed consent and/or to comply with study procedures