Study to Evaluate Darbepoetin Alfa in Pediatric Subjects With Anemia Due to Chronic Kidney Disease

Inclusion Criteria: * Girls and boys between birth and \< 1 year of age at the time of enrollment * Body weight ≥ 3 kg at screening and enrollment * Diagnosis of chronic kidney disease stage 3 to 5 with an estimated Glomerular Filtration Rate \< 60 mL/min/1.73m2 without dialysis using the updated Schwartz Equation at screening; OR on dialysis at screening * Hemoglobin ≤ 9.0 g/dL within 7 days prior to enrollment * Transferrin saturation ≥ 20% at screening Exclusion Criteria: * Premature girls and boys (\< 37 weeks of gestation, counting from the first day of the mother's last menstrual period) * Peritoneal dialysis subjects with an episode of peritonitis within 30 days prior to enrollment * History of cardiovascular events or thromboembolism * History of upper or lower gastrointestinal bleeding * History of seizures * Active liver disease or history of liver disease * Uncontrolled hypertension defined as stage 2 hypertension or greater. This is defined as a systolic or diastolic blood pressure value greater than the 99th percentile + 5 mmHg for a subject's age * Major surgery 12 weeks prior to enrollment * Red blood cell transfusions 12 weeks prior to enrollment * Use of any erythropoiesis-stimulating agent within 12 weeks prior to enrollment * Currently receiving antibiotic therapy for systemic infection within 4 weeks prior to enrollment * Current or prior use of immunosuppressants (excluding low-dose corticosteroids, defined as ≤ 0.5 mg/kg per day prednisone or equivalent for ≤ 5 days) * Subject is receiving a dose higher than 0.5 mg/kg per day of prednisone (or equivalent dose of another corticosteroid) for \> 5 days within 4 weeks prior to enrollment * Receiving or has received any investigational drug (or is currently using an investigational device) within the 30 days or 5 half-lives (whichever is longer) prior to enrollment * Subject has known hypersensitivity to darbepoetin alfa, r-HuEPO, or to any of the excipients