Effects of Extracorporeal Blood Flow Rates on Patient Tolerance for LIXELLE<sup>®</sup> Treatment during Outpatient Hemodialysis

<b><i>Introduction:</i></b> Accumulation of β2-microglobulin (B2M) in dialysis patients contributes to several comorbidities of end-stage kidney disease (ESKD). The LIXELLE^® device adsorbs B2M from blood using sorbent bead technology. Studies in Japan showed that LIXELLE treatment during hemodialysis (HD) at blood flow rates up to 250 mL/min removes B2M above HD alone and is well tolerated. We investigated tolerance for LIXELLE treatment during HD at higher HD blood flow rates standard in the USA. <b><i>Methods:</i></b> A prospective, open-label, non-randomized, single-arm, early-feasibility study (EFS) assessed tolerance and safety of LIXELLE treatment during HD at blood flow rates up to 450 mL/min. ESKD patients (40–75 years old) on thrice weekly outpatient HD were eligible. After a 1-week HD run-in, patients received LIXELLE plus HD at a blood flow rate of 250 mL/min (1 week), followed by LIXELLE plus HD at a blood flow rate up to 450 mL/min (1 week). These blood flow rates were tested with three LIXELLE column sizes in sequence (treatment = 6 weeks). B2M removal was assessed for each combination. <b><i>Results:</i></b> Ten patients with a historic intradialytic hypotension (IDH) rate of 0.42 events/HD session/patient were enrolled. Nine patients completed all combinations without IDH events (treatment IDH rate: 0.56 events/HD session/patient). No treatment-emergent serious adverse events or significant changes in red blood cell, platelet, or complement indices except haptoglobin were reported. B2M reduction ratios and removal of select proteins (&lt;40 kDa) increased with escalating column size and blood flow rate. <b><i>Conclusion:</i></b> LIXELLE plus HD across all column sizes was safe and well tolerated at blood flow rates up to 450 mL/min. Extent of B2M removal corresponded to column size-blood flow rate combinations. This EFS provides a risk profile to guide further studies of LIXELLE in ESKD patients at US-standard blood flow rates.