The purpose of this study is to investigate the efficacy of ferumoxytol for the repletion of iron stores and correction of iron deficiency anaemia in patients with severe chronic kidney disease or end-stage chronic kidney disease on peritoneal dialysis, and to assess the impact of the administration of a ferumoxytol dose on various markers for iron stores, as well as on various markers for inflammation and oxidative stress.

Inclusion Criteria:

• For women of childbearing age, negative serum pregnancy test at screening.
• Severe chronic kidney disease (TFGe lower than 30 ml/min) OR end-stage kidney disease on peritoneal dialysis.
• Anaemia, as defined by haemoglobin (Hb) < 120 g/L, within 14 days prior to screening, in a patient with or without an Erythropoiesis-stimulating agent (ESA).
• Iron depletion, as defined by transferrin saturation (TSAT) < 20% and/or a ferritin assay (FERR) < 200, within 14 days prior to screening.
• If an ESA is used, stable dose over the past 60 days.

Exclusion Criteria:

• Allergy to ferumoxytol or another intravenous iron formulation.
• Administration of ferumoxytol or any other intravenous, intramuscular or oral iron formulation within 30 days of enrolment.
• Patient who have received a blood transfusion within 2 weeks prior to enrolment, or are planned to receive a blood transfusion over the duration of the study.
• Patient currently participating in a clinical trial with another investigational drug or device or who have received an investigational drug or device within 30 days of enrolment in this study.
• Hb < 90 g/L at the time of screening.
• Existing or clinically suspected bleeding of digestive, gynaecological or other origin.
• Patient who have another cause of anemia, other than iron deficiency (for example, but not limited to, systemic lupus erythematosus, rheumatoid arthritis, multiple myeloma, myelodysplastic disorder, etc.).
• Patients who are not responding to ESA or who are receiving in excess of 30000 units/week of erythropoietin (EPO), or 150 mcg/week of darbepoietin alfa.
• Major surgery within one month prior to enrolment in the study or planned surgery, other than vascular access creation, while the patient is in on the study.
• Patient who have had a malignancy (except for non-melanoma cancer of the skin) unless the patient has received curative treatment and has been disease-free for > 2 years.
• Patient who are considered by the Investigator to have a medical status that would preclude the patient's participation in this protocol.
• Patient due to have a magnetic resonance imaging examination or in whom such an examination is planned, in the next three months.
• Woman who plans to become pregnant in the next three months.
• Woman that is breastfeeding.
• Ongoing or recent (< 2 weeks) bacterial infection requiring treatment.
• Patient unable to give informed consent.
• Patient refuses to give informed consent.