Clinical Evaluation of Eltrombopag in Chronic Idiopathic Thrombocytopenic Purpura (ITP)

Inclusion Criteria: * Subject has signed and dated written informed consent. * Subject (\>=20 years) diagnosed with ITP. * Subject previously enrolled in TRA108109 (NCT00540423) must have completed the treatment and follow-up periods as defined in that protocol. * Subject has no intercurrent medical event at risk of thrombosis such as thrombophilia. * Prolongation of prothrombin time and activated partial thromboplastin time (aPTT) must be within 1.2 times the upper limit of the normal range with no history of hypercoagulable state. * A complete blood count (CBC), within the reference range, with the following exceptions: * Hemoglobin: patients with haemoglobin level \< the lower limit of normal are eligible for inclusion if hemorrhage is present. * Neutrophil count \>= 1,500/L (1.5x10E9/L) is required for inclusion. * The following clinical chemistries MUST NOT exceed 1.2 times the upper limit of the normal reference range: creatinine, total bilirubin and alkaline phosphatase. * The following clinical chemistries MUST NOT exceed 2 times the upper limit of the normal reference range: ALT and AST. * Albumin must be not less than 80% of the lower limit of normal. * Female subjects must either be: * of non-childbearing potential (hysterectomy, bilateral oophorectomy, bilateral tubal ligation or post-menopausal \> 1 year), or * of childbearing potential and have a negative pregnancy test and agree to use contraceptive methods specified in the GSK List of Highly Effective Methods for Avoidance of Pregnancy from two weeks prior to administration of study medication, throughout the study, and 28 days after completion or premature discontinuation from the study: * Reticulocyte count within the reference range or elevated in case of bleeding. Exclusion Criteria: * Any severe medical condition (cardiac, hepatic or renal disorder) other than chronic ITP. (Note: "Severe" is defined as \>= Grade 3 as a rule according to the "Classification of the Severity of Adverse Experiences (PAB/SD Notification No.80, dated 29 June 1992) * History of suspected or confirmed arterial or venous thrombosis (e.g., myocardial infarction, deep vein thrombosis) within the last 1 year. * History of drug/alcohol abuse or dependence within the last 1 year. * Suspected blood disorder other than ITP. * Suspected platelet aggregation abnormality. * Suspected cyclic thrombocytopenia. * Suspected Evans Syndrome. * Subjects who met the GSK Liver Stopping Criteria in the previous eltrombopag study TRA108109 (NCT00540423). * Current or history of HIV infection or hepatitis B virus or hepatitis C virus infections. * Current malignancy or history of malignancy that was treated with chemotherapy or radiotherapy. * Female subjects who are nursing or pregnant, who may be pregnant, or who contemplate pregnancy during the study period. * Subjects who are deemed unsuitable for the study by the investigator (or subinvestigator). * Treatment with an investigational drug within 30 days preceding the first dose of study medication. * Pre-existing cardiovascular disease, or arrhythmia known to increase the risk of thromboembolic events (e.g. atrial fibrillation).