Sodium zirconium cyclosilicate maintains pre-dialysis serum potassium

Sodium zirconium cyclosilicate was shown to be significantly more effective than placebo in maintaining pre-dialysis serum potassium with normokalaemic levels during a 4-week evaluation period in Chinese patients with kidney failure who received maintenance haemodialysis. The treatment was well tolerated and no new safety concerns were raised [1].

China and Chinese patients are generally underrepresented in pivotal clinical studies. Furthermore, end-stage renal disease (ESRD) aetiology differs from Western populations. To address these issues, the DIALIZE China study (NCT04217590) evaluated the safety and efficacy of sodium zirconium cyclosilicate – an antihyperkalaemia therapy (oral potassium binder) – in Chinese patients with ESRD receiving haemodialysis. This was a randomised, double-blind, placebo controlled, multicentre, phase 3b study. After a screening period of 1 week, 134 adults with ESRD receiving haemodialysis 3 times weekly for kidney failure with hyperkalaemia (serum potassium >5.4 mmol/L after the long interdialytic interval [LIDI] and >5.0 mmol/L after 1 short interdialytic interval) were randomised 1:1 to sodium zirconium cyclosilicate (5 g/day on non-dialysis days), or placebo (QD on non-dialysis days for 8 weeks). Sodium zirconium cyclosilicate was titrated over 4 weeks up to 15 g/day as required to achieve normokalaemia (pre-dialysis serum potassium 3.5–5.5 mmol/L), prior to a 4-week evaluation and 2-week follow-up. The primary outcome was the proportion of patients categorised as responders. One of the key secondary outcomes was the probability of maintaining normokalaemia at the LIDI visit during the evaluation period. Safety outcomes included adverse events, serious adverse events, vital signs, ECGs, and clinical laboratory values. There was a significantly higher proportion of responders in the sodium zirconium cyclosilicate arm (37.3%) compared with the placebo arm (10.4%; odds ratio 5.10; 95% CI 1.90–15.12; P<0.001). Regarding the pre-dialysis serum potassium concentration, patients were more likely to maintain normokalaemia at the LIDI visit with sodium zirconium cyclosilicate than with placebo (0.58 vs 0.17; odds ratio 6.41). Sodium zirconium cyclosilicate raised no new safety concerns, and the safety profile was consistent with that observed in the study population from the DIALIZE global study [1].

1. Zhao J, et al. DIALIZE China: A Phase 3b Study to Reduce Pre-Dialysis Hyperkalemia With Sodium Zirconium Cyclosilicate in Chinese Subjects. TH-OR16, ASN Kidney Week 2022, 3–6 Nov.

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