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

- 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

- 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