Study of Erythropoietin (EPO) Administration Schedule

Inclusion Criteria: * Patients aged between 18 and 80. * Dialysis for at least 3 months. * Epoetin treatment for the last 3 months. * Baseline hemoglobin (Hb) value of \>= 9.0 g/dL and \< 13.0 g/dL. * Baseline mean weekly epoetin maintenance dose ≤ 12,000 IU * Patients who agree to participate in this study in writing. Exclusion Criteria: * Hemoglobinopathies, i.e. sickle cell disease, thalassemia of all types. * Hemolysis as defined * Gastrointestinal bleeding necessitating treatment (medication, transfusion) within the last 3 months. * Patients with uncontrolled hypertension. * Acute infection of unstable systemic inflammatory disease. * Current malignant disease. * High likelihood of early withdrawal or interruption of the study (e.g. severe diseases within the last 3 months, such as myocardial infarction, unstable angina, stroke, deep venous thrombosis). * Life expectancy below 12 months. * Planned elective surgery during the study period. * Blood transfusions within the last 3 months. * Pregnancy and lactation. * Other conditions regarded as unsuitability by investigator.