Efficacy and safety of patiromer for non-dialysis and dialysis patients with hyperkalemia: the randomized, placebo-controlled and long-term study.

Background: The objectives of this phase two study are to investigate the efficacy of two starting doses of 8.4 g and 16.8 g and evaluate the long-term safety of patiromer in Japanese patients with hyperkalemia.

Methods: This study comprised three cohorts; non-dialysis patients with baseline serum potassium (sK) level of 5.1 to < 6.0 mmol/L (NDC1); 6.0 to < 6.5 mmol/L (NDC2); dialysis patients with baseline sK level of 5.5 to < 6.5 mmol/L (DC). The study design was one-week, randomized, double-blind, placebo-controlled, and open label extension for one year in NDC1, open label during the study in NDC2 and DC. Patients were randomly assigned to patiromer 8.4 g, 16.8 g or placebo in NDC1, 8.4 g or 16.8 g in NDC2 and DC. Dose was adjusted up to 25.2 g according to the titration algorism in open label period.

Results: A total of 185 patients were randomized (NDC1:153, NDC2:10, and DC:22). The primary endpoint of the change in least squares mean sK levels at Week 1 in NDC1 was  - 0.55,  - 0.77 and  - 0.10 mmol/L for the 8.4 g, 16.8 g and placebo group (P < 0.001 for the patiromer group vs the placebo group). In all cohorts for each patiromer group, more than 80% of patients achieved normal sK at Week 5. There was no severe treatment-related adverse event.

Conclusion: Treatment with patiromer was effective in lowering and maintaining target sK levels, also well tolerated for one year in Japanese patients with hyperkalemia.