Patiromer Treatment in Patients With CKD, Hyperkalemia, and Hyperphosphatemia: A Post Hoc Analysis of 3 Clinical Trials

Abstract

Patients with chronic kidney disease (CKD), hyperkalemia (serum potassium [sK+]>5.0 mEq/L), and hyperphosphatemia experience poor clinical outcomes. Patiromer, a potassium binder that uses calcium as the exchange ion, may also reduce serum phosphorus (sP). We characterized the effect ofpatiromer on sP in patients with CKD, hyperkalemia, and hyperphosphatemia. A post hoc pooled analysis of individual-level data from the AMETHYST-DN, OPAL-HK, and TOURMALINE trials of patiromer. Patients with CKD and hyperkalemia. Patients treated with patiromer (8.4-33.6 g/day). Mean changes from baseline in sP, sK+, serum calcium (sCa2+), and serum magnesium (sMg2+) after 2 and 4 weeks of treatment. Descriptive statistics to summarize pooled data on the study outcomes from the 3 studies. We included 578 patients in the analysis. Of these participants, 86 patients (14.9%) had baseline hyperphosphatemia of whom 75.6% (65 of 86) had CKD stage 4/5 and 31.1% (153 of 492) with sP≤4.5mg/dL had CKD stage4/5. Among the patients with elevated sPand sK+at baseline, the mean±SD reduction insP and sK+after 4 weeks of patiromer treatment was-0.62±1.09mg/dL and-0.71± 0.51mEq/L,respectively. Additionally, the mean±SDreduction in sMg2+in these patients was -0.25±0.23mg/dL while sCa2+remained unchanged. Both sMg2+and sCa2+remained within the normal range. Patiromer was generally well tolerated, and no serious adverse events were considered related to patiromer. These were post hoc analyses, no placebo comparison was performed due to the design of the original studies, and the follow-up period was limited to 4 weeks. Reductions in sP and sK+to the normal range were observed after 2 weeks of patiromer treatment, and the reduction was sustained during 4 weeks of treatment among patients with non-dialysis-dependent CKD, hyperkalemia, and hyperphosphatemia. Future controlled trials are needed to establish if patiromer is useful to reduce both sK+and sP in hyperkalemic patients with CKD and hyperphosphatemia.