Patients with end-stage kidney disease on maintenance hemodialysis frequently require iron supplementation to compensate for ongoing iron losses, and to maintain hemoglobin levels with or without additional use of erythropoiesis-stimulating agents (ESA).

The investigators aim to compare two different intravenous iron preparations, ferric carboxymaltose and iron sucrose in 140 hemodialysis patients. The investigators primary objective is to assess whether both agents are equally effective to maintain a target haemoglobin within 10-12 mg/dl. The investigators will also measure ferritin, transferrin, transferrin saturation, and how much ESA therapy is administered.

Patients will be randomly assigned to either treatment group and followed in parallel over an active study period of 40 weeks.

Inclusion Criteria:

• Signed informed consent
• Male and female patients aged ≥ 18
• Patients with anemia and end stage kidney disease on dialysis
• Hemoglobin ≥ 8,5g/dl
• Ferritin < 1000mg/dl
• TSAT < 50%
• CRP < 5mg/dl

Exclusion Criteria:

• Hemoglobin < 8,5g/dl
• Pregnancy or Nursing
• Known allergic reaction to i.v. iron supplementation or to ingredients of Investigational Medicinal Product (IMP)
• Chronic infections (HIV, Hep B, Hep C)
• Acute infections (CRP>5mg/dl; Antibiotic therapy except for prophylactic use)
• Malignant tumor disease
• Oral iron supplementation at study inclusion
• Participation in a different study at the same time
• Active bleeding issues
• Surgical intervention within the last 4 weeks before study inclusion
• Mental diseases
• Bronchial asthma
• Atopic allergy
• Eczema
• Receipt of red blood cell (RBC) concentrate within the last 4 weeks before study inclusion