Patiromer Lowers Serum Potassium When Taken without Food: Comparison to Dosing with Food from an Open-Label, Randomized, Parallel Group Hyperkalemia Study

Abstract

Background: Patiromer is a sodium-free, nonabsorbed, potassium binder approved for treatment of hyperkalemia. This open-label study compares the efficacy and safety of patiromer administered without food versus with food.

Methods: Adults with hyperkalemia (potassium ≥5.0 mEq/L) were randomized (1:1) to receive patiromer once daily without food or with food for 4 weeks. The dosage was adjusted (maximum: 25.2 g/day) using a prespecified titration schedule to achieve and maintain potassium within a target range (3.8-5.0 mEq/L). The primary efficacy endpoint was the proportion of patients with serum potassium in the target range at either week 3 or week 4. Safety was assessed by adverse events (AEs) and laboratory testing.

Results: Efficacy was evaluated in 112 patients; 65.2% were ≥65 years of age, 75.9% had chronic kidney disease, and 82.1% had diabetes. Baseline mean serum potassium was similar in the without-food (5.44 mEq/L) and with-food (5.34 mEq/L) groups. The primary endpoint was achieved by 87.3% (95% CI 75.5-94.7) and 82.5% (95% CI 70.1-91.3) of patients in the with-food and without-food groups, respectively; least squares mean changes in serum potassium from baseline to week 4 were -0.65 and -0.62 mEq/L, respectively (p < 0.0001). The most common AEs were diarrhea and constipation. Serum K+ remained ≥3.5 mEq/L in all patients; 5 patients developed serum magnesium <1.4 mg/dL, including 4 whose baseline magnesium was below the lower limit of normal.

Conclusion: Patiromer is equally effective and well tolerated when taken without food or with food, thereby offering the potential for dosing flexibility.

Keywords: Hyperkalemia; Patiromer; Potassium.

Fig. 1

Study schema for without-food and with-food dosing. ↑, scheduled blood draw; B, baseline; F1, follow-up; F2, follow-up visit 2; HK, hyperkalemia; QD, once daily; R, randomized; * At the baseline visit (day 1), patients remained fasted from the evening before and blood samples were obtained immediately prior to the initial 8.4 g dose of patiromer (baseline/hour 0); patients were provided with a light meal after the 1-h blood draw. Starting day 2, patients began the starting dose of 8.4 g patiromer QD with food or without food based on their assigned treatment group.

Fig. 2

CONSORT diagram. ^a Screen failure: patients who met all study entry criteria except for local potassium at the screening visit could be re-screened once. More than one reason for screening failure may have been reported for a patient. Re-screened patients that had the same screen failure reason were only counted once for that reason.

Fig. 3

Mean (SE) serum potassium over time. The shaded box represents the target range for serum K⁺ (3.8–5.0 mEq/L). BL, baseline; K⁺, potassium; PwoF, patiromer without food; PwF, patiromer with food.

Fig. 4

Forest plot of responders at either week 3 or 4 by subgroup. DM, diabetes mellitus; eGFR, estimated glomerular filtration rate; K⁺, potassium. p = ns for all interactions between treatment groups, by chi-square test.