Quantitative Mass Transfer of SFP-iron From Dialysate to Blood in CKD-HD Patients

Inclusion Criteria: 1. Adult subject ≥ 18 years of age undergoing chronic hemodialysis for chronic kidney disease (CKD) for at least 3 months, expected to remain on hemodialysis and be able to complete the study. 2. Screening Hgb ≥ 9.5 g/dL. 3. Screening transferrin saturation % (TSAT) ≥ 15% to ≤ 45%. 4. Screening serum ferritin ≥ 200 to ≤ 1200 µg/L. 5. Subject's standard dialyzer membrane is one of the 2 types, i.e. Baxter CT-190 or Gambro 17R or 21R. 6. The subject uses a reprocessed dialyzer for standard HD treatments. 7. Prescribed dialysis 3X/week. 8. Minimally adequate measured dialysis dose defined as URR (urea reduction ratio) ≥ 65%, or single-pool Kt/V (dialyzer clearance of urea multiplied by dialysis time, divided by patient's total body water) ≥ 1.2, or KIDt/V (online dialyzer clearance measured using ionic dialysance multiplied by dialysis time, divided by patients total body water) ≥ 1.2. 9. Stable dialyzer blood flow rate that is generally ≥ 350 mL/min and acceptable to the Investigator. 10. Stable dialysate flow rate that is generally ≥ 600 mL/min and acceptable to the Investigator. 11. Vascular access for dialysis that will be used upon enrollment with stable function in the judgment of the Investigator. 12. Female subjects must be either amenorrheic for ≥ 1 year or agree to not become pregnant by continuous use of an effective birth control method acceptable to the Investigator for the duration of their participation in the study. 13. Must be willing and able to provide written informed consent directly or through their authorized representative. Exclusion Criteria: 1. Subject has a living kidney donor identified or living-donor kidney transplant scheduled during study participation. (Note: Patients awaiting deceased-donor transplant need not be excluded.) 2. Vascular access for hemodialysis is a femoral catheter. 3. Known active bleeding from any site other than AV fistula or graft (e.g., gastrointestinal, hemorrhoidal, nasal, pulmonary, etc.). 4. Scheduled surgery during the study. 5. RBC or whole blood transfusion within 4 weeks prior to Screening. 6. Hospitalization in the month prior to Screening (except for vascular access surgery) that, in the opinion of the Investigator, confers a significant risk of hospitalization during the course of this study. 7. Evidence of current malignancy involving a site other than skin (except any melanoma, which renders the patient non-eligible). 8. History of drug or alcohol abuse within the last 6 months. 9. Regularly requiring hemodialysis more than three times per week. 10. Noncompliance with dialysis regimen in the opinion of the Investigator. 11. Pregnancy or intention to become pregnant before completing all study drug treatment. 12. Known ongoing inflammatory disorder (other than CKD), such as systemic lupus erythematosus, rheumatoid arthritis, or other collagen-vascular disease undergoing a disease flare. 13. Any current febrile illness (e.g., oral temperature \> 100.4°F, 38°C). (The patient may subsequently become eligible at least 1 week after resolution of the illness). 14. Known active bacterial, tuberculosis, fungal, viral, or parasitic infection requiring anti-microbial therapy or anticipated to require anti-microbial therapy during the patient's participation in this study. 15. Occult tuberculosis requiring prophylactic treatment with anti-tubercular drug(s) that overlaps with the patient's participation in this study. 16. Known positive status for hepatitis B surface antigen (hepatitis B testing is not required as part of this protocol). 17. Known human immunodeficiency virus (HIV) infection (HIV testing is not required as part of this protocol). 18. Cirrhosis of the liver based on histological criteria or clinical criteria (i.e., presence of ascites, esophageal varices, multiple spider nevi, or history of hepatic encephalopathy). 19. Active hepatitis with ALT and/or AST levels consistently greater than twice the upper limit of normal at any time during the two months prior to enrollment. 20. Participation in a study of an investigational drug or device within 30 days prior to randomization in this study.