P0242SUBGROUP EFFICACY ANALYSIS OF SODIUM ZIRCONIUM CYCLOSILICATE (SZC) IN HYPERKALAEMIC HAEMODIALYSIS PATIENTS IN THE DIALIZE STUDY

Abstract

Abstract Background and Aims Patients with end-stage renal disease have severely reduced renal potassium excretion and many require haemodialysis (3 days/week) to maintain normal serum potassium (sK+). The phase 3b DIALIZE study (NCT03303521) showed that sodium zirconium cyclosilicate (SZC) reduces predialysis sK+ after the long interdialytic interval and is well tolerated in haemodialysis patients with hyperkalaemia. This post-hoc analysis of the DIALIZE data assessed the efficacy of SZC in patient subgroups. Method The DIALIZE study randomised 196 patients 1:1 to placebo (n=99) or SZC (n=97). The study consisted of an 8-week treatment period, comprising a 4-week SZC dose titration phase followed by a 4-week evaluation phase. The starting dose of SZC was 5 g orally once daily on non-dialysis days (4 days/week) for the 4-week dose titration phase (titrated in 5 g increments to a maximum of 15 g) to achieve predialysis sK+ 4.0–5.0 mmol/L. Patients maintained a stable SZC dose for the 4-week evaluation phase (SZC 5, 10 or 15 g). Here, we assessed the proportion of treatment responders, i.e. those who during the 4-week evaluation phase achieved predialysis sK+ of 4.0–5.5 mmol/L during ≥3 of 4 haemodialysis treatments after the long interdialytic interval and who did not require potassium-lowering rescue therapy. Treatment responders were stratified by patient subgroups: sex, country, race, age (years), baseline weight (kg) and baseline sK+ (mmol/L). Results For patients receiving SZC, at baseline 59% were male, mean age was 55.7 years, 52% were white, 11% were Black or African American and 34% were Asian, and mean predialysis sK+ was 5.8 mmol/L. Using a predialysis sK+ range of 4.0–5.5 mmol/L, 69.1% (n=67/97) of SZC patients and 19.2% (n=19/99) of placebo patients were deemed treatment responders. Response to SZC was generally consistent across patient subgroups vs placebo for sex, country, race, age, baseline weight and baseline sK+, with some variation between subgroup subcategories (Table). Conclusion Our results suggest that SZC is generally effective across all groups of haemodialysis patients with hyperkalaemia. SZC responder rates for some patient subgroup subcategories were limited by low patient numbers.