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Abstract: PO0537

Effects of Patiromer on Serum Phosphate over 4 Weeks of Treatment in Hyperkalemic Patients with Hyperphosphatemia: Pooled Analysis of the AMETHYST-DN, OPAL-HK and TOURMALINE Trials

Session Information

Category: Bone and Mineral Metabolism

  • 402 Bone and Mineral Metabolism: Clinical

Authors

  • Bushinsky, David A., University of Rochester School of Medicine and Dentistry, Rochester, New York, United States
  • Epstein, Murray, University of Miami School of Medicine, Miami, Florida, United States
  • Budden, Jeffrey J., Vifor Pharma Group, Redwood City, California, United States
  • Yuan, Jinwei, Vifor Pharma Group, Redwood City, California, United States
  • Kalra, Philip A., Salford Royal NHS Foundation Trust, Salford, United Kingdom
Background

Elevated serum phosphate (sP) is associated with increased mortality in non-dialysis CKD. KDIGO guidelines suggest elevated sP should be lowered into the normal range: 2.5–4.5 mg/dL. Patiromer is a non-absorbed, sodium-free, potassium (K+) binder that uses calcium as the exchange ion which, when released, likely binds to intestinal phosphate. We conducted a post-hoc analysis of pooled data from AMETHYST-DN, OPAL-HK and TOURMALINE to evaluate patiromer’s effect on sP over 4 weeks in patients with sP>4.5mg/dL.

Methods

Eligible patients had CKD and hyperkalemia (HK; serum K+ [sK+]>5.0 mEq/L). Prescription of phosphate binders was not allowed. Hyperphosphatemia subgroup was defined as baseline sP>4.5mg/dL. Patients in the analysis received ≥1 dose of patiromer (8.4–33.6 g/day to start) and had ≥1 post-baseline sP assessment. Mean (± SD) changes from baseline in sP, sK+, serum magnesium and serum calcium at weeks 2 and 4 were evaluated.

Results

86/578 (15%) patients had baseline sP>4.5mg/dL: 56% were male, mean (SD) age was 63.9 (10.5) years, 84% had diabetes, mean (SD) eGFR was 25.9 (17.2) mL/min/1.73m2 and 76% had stage 4/5 CKD. Mean (SD) baseline sP and K+ were 5.0 (0.5) mg/dL and 5.5 (0.4) mEq/L, respectively. At 2 or 4 weeks of patiromer treatment, both mean sP and sK+ levels decreased into the normal range (Table). Most frequent adverse events (AEs) were constipation (8/86; 9%) and diarrhea (6/86; 7%); most cases were mild or moderate in severity. AEs leading to study discontinuation occurred in 3/86 (4%) patients.

Conclusion

Patiromer decreased both sP and sK+ into the normal range in patients with elevated sP and sK+. Patiromer was well tolerated with mild/moderate gastrointestinal events. The ability of patiromer to normalize sP may be therapeutically useful in hyperkalemic patients with CKD and hyperphosphatemia.

Funding

  • Commercial Support