Endexo™ is an additive that is blended into the fiber solution during manufacturing of the hemodialyzer hollow fibers. The intended purpose of the additive is to increase blood compatibility in the finished dialyzer, which is referred to as the "dialyzer with Endexo."

This is a prospective, sequential, multi-center, open-label study with subjects on thrice-weekly (in-center) hemodialysis (HD). After a Screening Period, there will be 12 hemodialysis treatments on the Optiflux dialyzer (Optiflux Period), followed by 38 HD treatments on the dialyzer with Endexo (Endexo Period), and then a Follow-up Visit. The study population will consist of End-Stage Renal Disease ESRD subjects who are a minimum of 22 years of age. The primary objective of the study is to collect data on the performance of the dialyzer with Endexo when used to perform hemodialysis (HD) in End-Stage Renal Disease (ESRD) subjects.

Inclusion Criteria:

1. Must be an adult, older than 22 years of age.
2. Has been prescribed in-center thrice-weekly HD continuously for at least 180 days prior to the date of signed informed consent
3. Has been prescribed the Optiflux F160NR dialyzer continuously for at least 30 days prior to the date of signed informed consent
4. Has a prescribed HD treatment time ≥180 minutes (3 hours) and ≤270 minutes (4.5 hours)
5. Has been on heparin anticoagulation for dialysis and has had no change in heparin prescription within 14 days prior to the date of signed informed consent
6. Has a most recent single pool Kt/V (spKt/V) ≥1.2 within 45 days prior to the date of a signed informed consent
7. Has a most recent hemoglobin ≥9 g/dL within 45 days prior to the date of a signed informed consent
8. Has a most recent platelet count ≥100,000/mm3 within 45 days prior to the date of a signed informed consent
9. A female of childbearing potential must have a negative serum pregnancy test at the time of screening and agree to use an acceptable method of contraception during the study

Exclusion Criteria:

1. Use of citric acid concentrate (such as Citrasate®) at the time of signed informed consent
2. Known allergic reactions to Endexo
3. Hospitalization within 30 days prior to the date of signed informed consent
4. Presence of active malignancy, congestive heart failure New York Heart Association (NYHA) Class III or IV, or liver cirrhosis
5. Are receiving or have received chemotherapy / radiation therapy / plasmapheresis therapy within 90 days prior to the date of signed informed consent
6. Are receiving antibiotics or have used antibiotics within 14 days prior to the date of signed informed consent
7. Are currently enrolled in or have completed any other investigational product study within 30 days prior to the date of signed informed consent
8. Has a life expectancy of less than 1 year

Subjects who sign the ICF, are eligible, are enrolled in the study, and have at least one HD treatment with the dialyzer with Endexo.

a max of 22 weeks for a subject to complete the study