The clinical investigation will be performed to generate clinical data on clearances and removal rates for ß2-microglobulin and other uremic toxins and on clinical adverse events of the modified polysulfone membrane to fulfil obligations to follow the FX P600 dialyzer in the market.

The primary objective of this study is to test whether the FX P600 is non-inferior to the Xevonta Hi 15 dialyzer and the Elisio 150H dialyzer in removing β2-microglobulin related to the albumin removal into the dialysate during high volume online hemodiafiltration.

The secondary objective of this study is to compare the FX P600 dialyzer with the comparator dialyzers with regard to their efficacies in removing other performance variables (see below). Furthermore, the safety of the FX P600 will be investigated by collecting and analyzing clinical adverse events.

Inclusion Criteria:

General:

• Informed consent signed and dated by study patient and investigator/authorized physician
• Minimum age of 18 years
• Legally competent and able to understand the nature, risk, meaning, and consequences of the clinical trial (cf. MPG § 20 Sec. 2 Sentence 1 No. 1)
• Chronic kidney disease stage 5D (end stage renal disease) on hemodiafiltration as extracorporeal renal replacement therapy

Study-specific:

• On high volume online (>21 L/session substitution volume postdilution per session) hemodiafiltration (HDF), at least 4 h treatment time thrice weekly ≥3 month
• Vascular access (fistula or graft) and high flow double lumen catheter which enables suitable effective blood flow rate (≥ 300 ml/min)

Exclusion Criteria:

General:

• Any condition which could interfere with the patient's ability to comply with the study. This decision is at the discretion of the treating physician and relates to the general stable condition of the patient (e.g. any acute condition, e.g. infection or mental problem which might give reason for concern etc.)
• Ongoing participation in an interventional clinical study during the preceding 30 days
• Previous participation in this study
• Pregnancy or lactation period
• Patient is not able to give informed consent according to MPG § 20 Sec. 2 Sentence 1 No. 1

Study-specific:

• Recurrent episodes of vascular access failure characterized by e.g. repeated cannulation problems or unstable blood flows within the last 2 months prior to study start (>3 times, respectively)
• Single needle treatments
• Catheter as vascular access (except high flow double lumen catheter)
• Unstable patients (due to e.g. acute intercurrent disease like myocardial infarction, cerebrovascular accident, peripheral arterial occlusion, active malignant disease, use of antibiotics within the last 4 weeks)
• Patients with heart failure (NYHA ≥ 3), COPD (GOLD 2-4), frequent intradialytic symptomatic hypotension requiring intervention within the last 2 months prior to study start (>3 times, respectively)
• Patients with known or suspected allergy to trial product and related products
• Patients with chronic antiallergic medication due to immune-mediated disease
• Planned absence from dialysis unit within the 4 weeks of study duration e.g. due to scheduled hospitalization, holidays or any other reason
• Active HBV, HCV, HIV infection