Ascertain the Optimal Starting Dose of Mircera Given Subcutaneously for Maintenance Treatment of Anemia in Pediatric Patients With Chronic Kidney Disease on Dialysis or Not Yet on Dialysis.

Inclusion criteria

• Pediatric participants 3 months to 17 years of age with clinically stable chronic renal anemia
• CKD with estimated glomerular filtration rate (eGFR) of < 45 mL/min/1.73 m2 (determined by the Bedside Schwartz formula) or dialysis treatment for at least 8 weeks before the first dose of Mircera
• For participants on peritoneal dialysis (PD): a weekly Kt/V≥ 1.8
• For participants on hemodialysis (HD): adequate HD, urea reduction ratio (URR) > 65% or Kt/V > 1.2 for participants on HD three times per week.

Participants with fewer than or more than three HD sessions per week should have a weekly Kt/V≥ 3.6.

• Baseline Hb concentration 10.0-12.0 g/dL determined from the mean of two Hb values measured at Visit 1 (Week -3) and Visit 2 (Week -1)
• Stable SC maintenance treatment with epoetin alfa, epoetin beta, or darbepoetin alfa with the same dosing interval for at least 6 weeks before the first dose of Mircera
• Stable dose of epoetin alfa, epoetin beta, or darbepoetin alfa treatment with no weekly dose change > 25% (increase or decrease) for at least 4 weeks before the first dose of Mircera
• Adequate iron status defined as ferritin≥100 ng/mL or transferrin saturation (TSAT)≥ 20% (or percentage of hypochromic red cells < 10%); mean of two values measured during screening.

Exclusion criteria

• Overt gastrointestinal bleeding within 8 weeks before screening or during the screening period
• RBC transfusions within 8 weeks before screening or during the screening period
• Hemoglobinopathies (e.g., homozygous sickle-cell disease, thalassemia of all types) Hemolytic anemia, Active malignant disease
• PD subjects with an episode of peritonitis within the past 30 days prior to screening and/or during the screening period
• Uncontrolled or symptomatic inflammatory disease (e.g., systemic lupus erythematosus)
• Uncontrolled hypertension as assessed by the investigator
• Epileptic seizures within 3 months prior to screening and during the screening period
• Administration of any investigational drug within 4 weeks prior to screening or planned during the study
• Severe hyperparathyroidism (intact parathyroid hormone [PTH]≥ 1000 pg/mL or whole PTH≥ 500 pg/mL) or biopsy-proven bone marrow fibrosis
• Kidney transplant with use of immunosuppressive therapies known to exacerbate anemia
• Known hypersensitivity to recombinant human erythropoietin (EPO), polyethylene glycol, or any constituent of the study drug formulation
• Anti-EPO antibody (AEAB)-mediated pure red cell aplasia (PRCA) or history of AEAB mediated PRCA or positive AEAB test result in the absence of PRCA
• High likelihood of early withdrawal or interruption of the study (e.g., planned living donor kidney transplant within 5 months of study start)
• Planned elective surgery during the entire study period