Kidney Week

Abstract: PO0378

The Effect of Phosphate Lowering Using Sucroferric Oxyhydroxide on Endogenous Calciprotein Particle Formation in Dialysis Patients: Post Hoc Analysis of a Randomized Controlled Trial

Session Information

• Biochemical Aspects of Mineral and Bone Disease
  October 22, 2020 | Location: On-Demand
  Abstract Time: 10:00 AM - 12:00 PM

Category: Bone and Mineral Metabolism

• 402 Bone and Mineral Metabolism: Clinical

Authors

• Thiem, Ursula, Department of Medicine III - Nephrology, Hypertension, Transplantation, Rheumatology, Geriatrics, Ordensklinikum Linz - Elisabethinen Hospital, Linz, Oberösterreich, Austria

Ursula Thiem,

• Hewitson, Timothy D., Department of Nephrology, The Royal Melbourne Hospital, Parkville, Victoria, Australia

Timothy D. Hewitson,

• Toussaint, Nigel David, Department of Nephrology, The Royal Melbourne Hospital, Parkville, Victoria, Australia

Nigel David Toussaint,

• Haller, Maria C., Department of Medicine III - Nephrology, Hypertension, Transplantation, Rheumatology, Geriatrics, Ordensklinikum Linz - Elisabethinen Hospital, Linz, Austria

Maria C. Haller,

• Pasch, Andreas, Calciscon AG, Nidau, Switzerland

Andreas Pasch,

• Cejka, Daniel, Department of Medicine III - Nephrology, Hypertension, Transplantation, Rheumatology, Geriatrics, Ordensklinikum Linz - Elisabethinen Hospital, Linz, Oberösterreich, Austria

Daniel Cejka,

• Smith, Edward R., Department of Nephrology, The Royal Melbourne Hospital, Parkville, Victoria, Australia

Edward R. Smith,

Background

We have recently demonstrated in a randomized, controlled, cross-over study in 39 chronic hemodialysis patients with hyperphosphatemia that high-dose phosphate binder therapy with 2000 mg/d of sucroferric oxyhydroxide (SO) over two weeks significantly reduces calcification propensity as determined by the T₅₀-test compared with a two-week wash-out phase (Cejka, Kidney Week 2019, FR-PO149). Based on these results, we hypothesized that SO would influence endogenous calciprotein particle (CPP) formation and crystallization, i.e. conversion from primary to secondary CPP.

Methods

To test this hypothesis, we conducted post-hoc analyses of our RCT (74% men, mean age 63±27 years, median dialysis vintage 24, IQR 16-36 months). We compared native serum CPP levels (measured by a fluorescent probe-based flow cytometric assay) by Wilcoxson matched-pairs test and hydrodynamic radii (R_h) of secondary CPP formed after enrichment with exogenous calcium and phosphate (measured by three-dimensional cross-correlation dynamic light scattering) by paired t-test between the phosphate binder wash-out and high-dose treatment phase.

Results

Upon SO therapy serum phosphate levels decreased from 2.28±0.5 mmol/l to 1.63±0.43 mmol/l (p<0.0001), coincident with a reduction (median, IQR) in primary (-62%, 44-78%, p<0.0001) and secondary CPP (-40%, 0.5-62%, p<0.0006, figure). Mean R_h of secondary CPP was significantly lower during SO therapy compared to wash-out (214±55 nm vs. 231±52 nm, p<0.01).

Conclusion

In dialysis patients, lowering serum phosphate with SO is associated with a reduction in the load of primary and secondary CPP and a smaller size of secondary CPP.

Funding

• Commercial Support – Vifor Fresenius Medical Care Renal Pharma AG, St. Gallen, Switzerland