Long-term safety and efficacy of sodium zirconium cyclosilicate for hyperkalaemia in patients with mild/moderate versus severe/end-stage chronic kidney disease: comparative results from an open-label, Phase 3 study

Plant-based diet in hyperkalemic chronic kidney disease patients receiving sodium zirconium cyclosilicate: a feasibility clinical trial

BACKGROUND

Plant-based diets (PBD) may induce hyperkalemia in chronic kidney disease (CKD) patients.

OBJECTIVES

We explored the safety and feasibility of PBD in hyperkalemic CKD patients receiving the potassium binder sodium zirconium cyclosilicate (SZC).

METHODS

In the current 6-wk trial, 26 hyperkalemic patients with CKD stage 4-5 not on dialysis received a low-protein low-potassium diet plus SZC for 3 wk and then a PBD with high potassium content delivered as a weekly food basket while continuing SZC for subsequent 3 wk. Plasma potassium was monitored weekly and SZC was titrated to achieve normokalemia. The 24-h urine excretion of potassium and sodium, 24-h food records, dietary quality, nutritional status, Bristol stool scale, Quality of life (QoL), and renal treatment satisfaction were assessed at baseline (week 0), week 3, and week 6.

RESULTS

Mean plasma potassium decreased from 5.5 to 4.4 mEq/L within 48-72 h after baseline, then rose to 4.7-5.0 mEq/L throughout the remaining study period following dose adjustments of SZC that matched the increased potassium intake of PBD from week 3 to week 6. Over the study period, 24-h urinary potassium excretion decreased from week 0 to week 3 and increased from week 3 to week 6. During the study, 58% of patients had fasting plasma potassium between 3.5 and 5.0 mEq/L and there was no episode of plasma potassium >6.5 mEq/L or <3.0 mEq/L during the study. P-carbon dioxide increased from baseline until week 6 (21 ± 2 to 23 ± 2 mEq/L; P = 0.002; mean ± SD), whereas remaining laboratory values remained unchanged. Fiber intake, dietary quality, the domain physical functioning from QoL, and 1 question of renal treatment satisfaction improved, whereas stool type and frequency did not change after starting PBD.

CONCLUSIONS

PBD in hyperkalemia-prone CKD patients receiving SZC improved dietary quality and increased the intake of healthy foods, whereas plasma potassium concentration remained stable within normal values for most patients.

TRIAL REGISTRATION NUMBER

This trial was registered at the https://clinicaltrials.gov/study/NCT04207203 as NCT04207203.

Sodium Zirconium Cyclosilicate in CKD, Hyperkalemia, and Metabolic Acidosis: NEUTRALIZE Randomized Study

Key Points

Sodium zirconium cyclosilicate effectively lowers serum potassium and maintains normokalemia in patients with CKD with concomitant hyperkalemia and metabolic acidosis. Despite high screen failure and small sample size, a nominally significant increase in sHCO3– was seen for sodium zirconium cyclosilicate versus placebo. Further studies on the basis of an appropriate cohort size may help validate the trend observed in sHCO3– levels, supporting these clinically relevant findings.

Background

Metabolic acidosis and hyperkalemia are common in CKD. A potential dual effect of sodium zirconium cyclosilicate (SZC), a selective binder of potassium in the gastrointestinal tract, on serum potassium (sK+) and serum bicarbonate (sHCO3−) was evaluated in patients with hyperkalemia and metabolic acidosis associated with CKD.

Methods

In the NEUTRALIZE study (NCT04727528 ), non-dialysis patients with stage 3–5 CKD, hyperkalemia (sK+>5.0 to ≤5.9 mmol/L), and metabolic acidosis (sHCO3− 16–20 mmol/L) received open-label SZC 10 g three times daily for ≤48 hours. Patients achieving normokalemia (sK+ 3.5–5.0 mmol/L) were randomized 1:1 to SZC 10 g or placebo daily for 4 weeks. The primary end point was patients (%) maintaining normokalemia at the end of treatment (EOT) without rescue. Secondary end points included mean change in sHCO3− at EOT (day 29) and patients (%) with normokalemia with a ≥3-mmol/L increase in sHCO3− without rescue.

Results

Of 229 patients screened, 37 were randomized (SZC, n =17; placebo, n =20). High screen failure led to early study termination. At EOT, 88.2% (SZC) versus 20.0% (placebo) of patients maintained normokalemia (odds ratio, 56.2; P = 0.001). Low enrollment rendered secondary end point P values nominal. SZC treatment provided nominally significant increases in sHCO3– versus placebo from day 15 onward. Patients with normokalemia with a ≥3-mmol/L increase in sHCO3− without rescue were 35.3% (SZC) and 5.0% (placebo; P < 0.05). No new safety concerns were reported.

Conclusions

SZC effectively lowered sK+ and maintained normokalemia, with nominally significant increases in sHCO3– observed for SZC versus placebo.

Advancing crush syndrome management: the potent role of Sodium zirconium cyclosilicate in early hyperkalemia intervention and survival enhancement in a rat model

Background: Crush Syndrome (CS), a severe trauma resulting from prolonged muscle compression, is commonly seen in large-scale disasters such as earthquakes. It not only causes localized tissue damage but also triggers electrolyte imbalances, particularly hyperkalemia, increasing the risk of early mortality. This study aims to assess the early intervention effects of Sodium Zirconium Cyclosilicate (SZC) on hyperkalemia in rat CS model. Methods: A rat CS model was established using a self-developed multi-channel intelligent small-animal crush injury platform. Rats in the experimental groups were treated with varying doses of SZC before compression and immediately post-decompression. The efficacy of SZC was evaluated by continuous monitoring of blood potassium levels and survival rates. Serum creatinine (Cre) and blood urea nitrogen (BUN) levels were analyzed, and renal damage was assessed through histopathological examination. Results: SZC treatment significantly reduced blood potassium levels and improved survival rates in rats. Compared to the placebo group, the SZC-treated rats showed a significant decrease in blood potassium levels at 6 and 12 h post-decompression, maintaining lower levels at 24 h. Biochemical analysis indicated no significant impact of SZC on renal function, with no notable differences in Cre and BUN levels between groups. Histopathological findings revealed similar levels of renal damage in both groups. Conclusion: SZC demonstrates significant early intervention effects on hyperkalemia in a rat model of crush injury, effectively improving survival rates without adverse effects on renal function. These results provide a new strategic direction for the clinical treatment of Crush Syndrome and lay the foundation for future clinical applications.

Safety and efficacy of sodium zirconium cyclosilicate for the management of acute and chronic hyperkalemia in children with chronic kidney disease 4-5 and on dialysis

BACKGROUND

Sodium zirconium cyclosilicate (SZC), an ion-exchange resin, is effective in the control of hyperkalemia in adults with chronic kidney disease (CKD); reports of use in children are limited. Prolonged therapy with SZC to relax dietary potassium restriction in CKD has not been examined.

METHODS

We conducted a retrospective chart review of patients 6 months to 18 years of age with CKD stage 4-5 or on dialysis (5D) administered SZC for sustained hyperkalemia (potassium ≥ 5.5 mEq/L, three consecutive values). Patients received SZC (0.5-10 g per dose; age-based) either short-term (< 30 days) or long-term (> 30 days).

RESULTS

Twenty patients with median age 10.8 (inter-quartile range 3.9, 13.4) years were treated with SZC. Short-term SZC, for 5 (3, 19) days, was associated with safe management of dialysis catheter insertions (n = 5) and access dysfunction (n = 4), and was useful during palliative care (n = 1). Serum potassium levels decreased from 6.7 (6.1, 6.9) to 4.4 (3.7, 5.2) mEq/L (P < 0.001). Long-term SZC for 5.3 (4.2, 10.1) months achieved decline in serum potassium from 6.1 (5.8, 6.4) to 4.8 (4.2, 5.4) mEq/L (P < 0.001). SZC use was associated with liberalization of diet (n = 6) and was useful in patients with poor adherence to dietary restriction (n = 3). Adverse events or edema were not observed; serum sodium and blood pressure remained stable.

CONCLUSIONS

SZC was safe and effective for the management of acute and chronic hyperkalemia in children with CKD4-5/5D. Its use was associated with relaxation of dietary potassium restriction. Studies to examine its routine use to improve diet and nutritional status in children with CKD are required.

Comparative Efficacy of Sodium Zirconium Cyclosilicate and Sodium Polystyrene Sulfonate for Acute Hyperkalemia: A Retrospective Chart Review

Background: Sodium polystyrene sulfonate (SPS) is a nonselective sodium-potassium exchange resin commonly used along with intravenous (IV) insulin, albuterol, furosemide, and/or calcium for the treatment of acute hyperkalemia. Sodium zirconium cyclosilicate (SZC) is a newer non-absorbed exchange resin that preferentially increases fecal potassium excretion from the gastrointestinal tract. Limited data exists on the efficacy of SZC for the treatment of acute hyperkalemia. Objectives: To assess the achievement of normokalemia (serum potassium level [K+] 3.5-5.2 mmol/L) within 24 hours after administration of SZC or SPS in combination with insulin regular IV push. Methods: A multicenter, retrospective chart review (2020-2021) using electronic medical records at an academic health system. The study population included adult patients receiving one or more doses of SZC or SPS in combination with IV insulin for acute hyperkalemia (K+ >5.2 mmol/L). Patients receiving dialysis were excluded. Serum chemistries were assessed at baseline and an additional 2 values within 24 hours to determine normokalemia and hypokalemia at each follow-up. Results: Of 141 patients included, 51 received SZC and 90 received SPS. Normokalemia at the first follow-up was achieved in 51.0% of patients receiving SZC and 46.7% of patients receiving SPS (P = .622) and was sustained in 35.3%versus 44.4% (P = .289) of patients within 24 hours. Mean serum potassium differences from baseline to first follow-up were similar between SZC and SPS groups (0.9 mmol/L vs 1.0 mmol/L). Hypokalemia within 24 hours of administration occurred in 4 patients-1 in SZC, 3 in SPS. Conclusion: Both SZC and SPS yielded similar rates of normokalemia achievement with IV insulin for the treatment of acute hyperkalemia. Further prospective studies are needed to confirm these findings.

Recommendations for the management of hyperkalemia in patients receiving renin-angiotensin-aldosterone system inhibitors

Hyperkalemia is common in clinical practice and can be caused by medications used to treat cardiovascular diseases, particularly renin-angiotensin-aldosterone system inhibitors (RAASis). This narrative review discusses the epidemiology, etiology, and consequences of hyperkalemia, and recommends strategies for the prevention and management of hyperkalemia, mainly focusing on guideline recommendations, while recognizing the gaps or differences between the guidelines. Available evidence emphasizes the importance of healthcare professionals (HCPs) taking a proactive approach to hyperkalemia management by prioritizing patient identification and acknowledging that hyperkalemia is often a long-term condition requiring ongoing treatment. Given the risk of hyperkalemia during RAASi treatment, it is advisable to monitor serum potassium levels prior to initiating these treatments, and then regularly throughout treatment. If RAASi therapy is indicated in patients with cardiorenal disease, HCPs should first treat chronic hyperkalemia before reducing the dose or discontinuing RAASis, as reduction or interruption of RAASi treatment can increase the risk of adverse cardiovascular and renal outcomes or death. Moreover, management of hyperkalemia should involve the use of newer potassium binders, such as sodium zirconium cyclosilicate or patiromer, as these agents can effectively enable optimal RAASi treatment. Finally, patients should receive education regarding hyperkalemia, the risks of discontinuing their current treatments, and need to avoid excessive dietary potassium intake.

Cost analysis of patiromer vs sodium zirconium cyclosilicate for the treatment of hyperkalemia in Spain and the UK

BACKGROUND

Hyperkalemia is an electrolyte abnormality with potentially life-threatening consequences. Published data have shown that potassium-binding polymer patiromer (Veltassa) is associated with reduced rates of severe edema and hospitalization for heart failure compared with sodium zirconium cyclosilicate (SZC, Lokelma) when treating hyperkalemia. The aim of this study was to evaluate the possible costs associated with these interventions in the Spanish and UK settings.

METHODS

A cost-analysis model was developed in Microsoft Excel to compare the costs associated with patiromer and SZC for the management of hyperkalemia. Clinical event rates were taken from a published real-world comparative study, with the base case capturing the statistically significant reduction in severe edema with patiromer vs SZC and a sensitivity analysis also including the non-statistically significant reduction in hospitalization for heart failure. Country-specific costs, expressed in 2022 Euros (EUR) and British pounds sterling (GBP), were evaluated from a healthcare payer perspective and included pharmacy costs and costs of clinical events.

RESULTS

Patiromer may be associated with cost savings of EUR 107 and GBP 630 per patient-year of treatment vs SZC in Spain and the UK, respectively. The majority of cost savings were due to the possible lower daily cost of patiromer compared with SZC. Including the difference in heart failure hospitalization rates in a sensitivity analysis led to greater cost savings with patiromer over SZC, increasing to EUR 460 and GBP 902 in Spain and the UK, respectively. Extrapolation of patient-level economic outcomes to a population level found that patiromer was associated with annual cost savings of EUR 30.6 million in Spain, and GBP 801.7 million in the UK vs SZC.

CONCLUSIONS

Patiromer has the potential to be cost saving vs SZC for the treatment of hyperkalemia in Spain and the UK based on the results of a real-world evidence analysis.

Sodium zirconium cyclosilicate reconciles management of hyperkalemia and continuity of renin-angiotensin-aldosterone system inhibitors: a retrospective observational study

BACKGROUND

Sodium zirconium cyclosilicate, a non-absorbed non-polymer zirconium silicate, is a new potassium binder for hyperkalemia. A previous report showed that administering sodium zirconium cyclosilicate to patients with hyperkalemia allows a higher continuation rate of renin-angiotensin-aldosterone system inhibitors. However, no studies have compared sodium zirconium cyclosilicate with existing potassium binders for renin-angiotensin-aldosterone system inhibitor continuity. The purpose of this study was to evaluate the effect of sodium zirconium cyclosilicate on angiotensin-converting enzyme inhibitor /angiotensin receptor blocker continuation in patients with hyperkalemia compared to that of calcium polystyrene sulfonate.

METHODS

Patients on angiotensin-converting enzyme inhibitors/angiotensin receptor blockers who were newly prescribed sodium zirconium cyclosilicate or calcium polystyrene sulfonate to treat hyperkalemia at a tertiary referral hospital between August 2020 and April 2022 were enrolled in this single-center, retrospective observational study. The primary outcome measure was angiotensin-converting enzyme inhibitor/angiotensin receptor blocker prescription three months after initiating potassium binders.

RESULTS

In total, 174 patients on angiotensin-converting enzyme inhibitors/angiotensin receptor blockers who were newly administered sodium zirconium cyclosilicate (n = 62) or calcium polystyrene sulfonate (n = 112) were analyzed. The prescription rate of angiotensin-converting enzyme inhibitors /angiotensin receptor blockers at 3 months was significantly higher in the sodium zirconium cyclosilicate group than in the calcium polystyrene sulfonate group (89 vs. 72%). Multivariate logistic regression models showed that sodium zirconium cyclosilicate was independently associated with the primary outcome (odds ratio 2.66, 95% confidence interval 1.05-7.43). The propensity score-matched comparison also showed a significant association between sodium zirconium cyclosilicate and the primary outcome.

CONCLUSIONS

Our study suggests that administering sodium zirconium cyclosilicate to patients with hyperkalemia allows for a higher continuation rate of angiotensin-converting enzyme inhibitors/angiotensin receptor blockers than calcium polystyrene sulfonate. These findings suggest that sodium zirconium cyclosilicate has potential benefits for patients with chronic kidney disease receiving renin-angiotensin-aldosterone system inhibitors.

Therapeutic update on oral potassium exchange resin use in chronic kidney disease patients: a systematic review of randomized controlled clinical trials

Hyperkalemia is a common electrolyte disorder in patients with chronic kidney disease (CKD) that increases in prevalence with the decline of glomerular fltration rate (GFR). Another risk of hyperkalemia is the use of renin-angiotensin-aldosterone system inhibitors (RAASi) and/or mineralocorticoid receptor antagonists (MRAs) in managing CKD and proteinuria. The treatment of chronic hyperkalemia is challenging especially for outpatients. Treatment options for hyperkalemia include the potassium exchange resins of which two new potassium binders, Patiromer Sorbitex Calcium, and Sodium Zirconium Cyclosilicate (SZC) have demonstrated their clinical efficacy in reducing serum potassium with a positive safety profile. The old potassium exchange resin sodium polystyrene sulfonate (Kayexalate™) has some negative side effects including colonic necrosis, hypomagnesemia, and hypernatremia. In this review and literature search, we compare the available oral potassium exchange resins, highlight their advantages and disadvantages and comment on efficacy and safety parameters specifically in CKD patients.

Practical patient care appraisals with use of new potassium binders in heart failure and chronic kidney diseases

Hyperkalaemia is a life-threatening condition leading to significant morbidity and mortality. It is common in heart failure and in chronic kidney disease (CKD) patients due to the diseases themselves, which often coexist, the high co-presence of diabetes, the fluctuations in renal function, and the use of some drugs [i.e. renin-angiotensin-aldosterone system (RAAS) inhibitors]. Hyperkalaemia limits their administration or uptitration, thus impacting on mortality. New K + binders, namely patiromer and sodium zirconium cyclosilicate (ZS-9), are an intriguing option to manage hyperkalaemia in heart failure and/or CKD patients, both to reduce its fatal effects and to let clinicians uptitrate RAAS inhibition. Even if their real impact on strong outcomes is still to be determined, we hereby provide a practical approach to favour their use in routine clinical practice in order to gain the correct confidence and provide an additive tool to heart failure and CKD patients' wellbeing. New trials are welcome to fill the gap in knowledge.

Hyperkalemia in chronic kidney disease: a focus on potassium lowering pharmacotherapy

INTRODUCTION

Hyperkalemia is one of the most common electrolyte disorders in chronic kidney disease (CKD) and is associated with serious adverse outcomes. Hyperkalemia risk is even greater when CKD patients also have additional predisposing conditions such as diabetes or heart failure. Renin-angiotensin-aldosterone-system blockers are first-line treatments for cardio- and nephroprotection, but their use is often limited due to K+ elevation, resulting in high rates of discontinuation.

AREAS COVERED

This article provides an overview of factors interfering with K+ homeostasis and discusses recent data on newer therapeutic agents used for the treatment of hyperkalemia. A detailed literature search was performed in two major databases (PubMed/MEDLINE and Scopus) up to April 2023.

EXPERT OPINION

Major clinical trials have tested new and promising kidney protective therapies such as sodium/glucose-cotransporter-2 inhibitors and mineralocorticoid-receptor-antagonists, with promising results. Until recently, the only treatment option for hyperkalemia was the cation-exchanging resin sodium-polystyrene-sulfonate. However, despite its common use, the efficacy and safety data of this drug in the long-term management of hyperkalemia are scarce. During the last decade, two novel orally administered K+-exchanging compounds (patiromer and sodium-zirconium-cyclosilicate) have been approved for the treatment of adults with hyperkalemia, as they both effectively reduce elevated serum K+ and maintain chronically K+ balance within the normal range with an excellent tolerability and no serious adverse events.

Potassium homeostasis - Physiology and pharmacology in a clinical context

Membrane voltage controls the function of excitable cells and is mainly a consequence of the ratio between the extra- and intracellular potassium concentration. Potassium homeostasis is safeguarded by balancing the extra-/intracellular distribution and systemic elimination of potassium to the dietary potassium intake. These processes adjust the plasma potassium concentration between 3.5 and 4.5 mmol/L. Several genetic and acquired diseases but also pharmacological interventions cause dyskalemias that are associated with increased morbidity and mortality. The thresholds at which serum K+ not only associates but also causes increased mortality are hotly debated. We discuss physiologic, pathophysiologic, and pharmacologic aspects of potassium regulation and provide informative case vignettes. Our aim is to help clinicians, epidemiologists, and pharmacologists to understand the complexity of the potassium homeostasis in health and disease and to initiate appropriate treatment strategies in dyskalemic patients.

Rationale and design of CONTINUITY: a Phase 4 randomized controlled trial of continued post-discharge sodium zirconium cyclosilicate treatment versus standard of care for hyperkalemia in chronic kidney disease

Background

Individuals with chronic kidney disease (CKD) hospitalized with hyperkalemia are at risk of hyperkalemia recurrence and re-hospitalization. We present the rationale and design of CONTINUITY, a study to examine the efficacy of continuing sodium zirconium cyclosilicate (SZC)-an oral, highly selective potassium (K⁺) binder-compared with standard of care (SoC) on maintaining normokalemia and reducing re-hospitalization and resource utilization among participants with CKD hospitalized with hyperkalemia.

Methods

This Phase 4, randomized, open-label, multicenter study will enroll adults with Stage 3b-5 CKD and/or estimated glomerular filtration rate <45 mL/min/1.73 m², within 3 months of eligibility screening, hospitalized with a serum potassium (sK⁺) level of >5.0-≤6.5 mmol/L, without ongoing K⁺ binder treatment. The study will include an in-hospital phase, where participants receive SZC for 2-21 days, and an outpatient (post-discharge) phase. At discharge, participants with sK⁺ 3.5-5.0 mmol/L will be randomized (1:1) to SZC or SoC and monitored for 180 days. The primary endpoint is the occurrence of normokalemia at 180 days. Secondary outcomes include incidence and number of hospital admissions or emergency department visits both with hyperkalemia as a contributing factor, and renin-angiotensin-aldosterone system inhibitor down-titration. The safety and tolerability of SZC will be evaluated.Ethics approval has been received from all relevant ethics committees. Enrollment started March 2022 and the estimated study end date is December 2023.

Conclusions

This study will assess the potential of SZC versus SoC in managing people with CKD and hyperkalemia post-discharge.

Trial registration

ClinicalTrials.gov identifier: NCT05347693; EudraCT: 2021-003527-14, registered on 19 October 2021.

Understanding and Treatment Strategies of Hypertension and Hyperkalemia in Chronic Kidney Disease

Hypertension and potassium imbalance are commonly observed in chronic kidney disease (CKD) patients. The development of hypertension would be related to several mechanisms. Hypertension is related to body mass index, dietary salt intake, and volume overload and is treated with antihypertensives. In CKD patients, managing hypertension can provide important effects that can slow the progression of CKD or reduce complications associated with reduced glomerular filtration rate. The prevalence of hyperkalemia and hypokalemia in CKD patients was similar at 15-20% and 15-18%, respectively, but more attention needs to be paid to treating and preventing hyperkalemia, which is related to a higher mortality rate, than hypokalemia. Hyperkalemia is prevalent in CKD due to impaired potassium excretion. Serum potassium level is affected by renin-angiotensin-aldosterone system inhibitors and diuretics and dietary potassium intake and can be managed by potassium restriction dietary, optimized renin-angiotensin-aldosterone system inhibitor, sodium polystyrene sulfonate, patiromer, and hemodialysis. This review discussed strategies to mitigate and care for the risk of hypertension and hyperkalemia in CKD patients.

In pursuit of balance: renin-angiotensin-aldosterone system inhibitors and hyperkalaemia treatment

Hyperkalaemia is a life-threatening condition leading to significant morbidity and mortality. It is common in heart failure (HF) patients due to the disease itself, which often co-exists with chronic kidney disease and diabetes mellitus, the fluctuations in renal function, and the use of some drugs [i.e. renin-angiotensin-aldosterone system (RAAS) inhibitors]. In particular, hyperkalaemia opposes to their administration or up-titration, thus impacting on mortality. New K+ binders, namely, patiromer and sodium zirconium cyclosilicate, are an intriguing option to manage hyperkalaemia in HF patients, both to reduce its fatal effects and to let clinicians up-titrate RAAS inhibitors. Even if their real impact on strong outcomes is still to be determined, we hereby provide an overview of hyperkalaemia in HF and its current management. New trials are welcome to fill the gap in knowledge.

Evaluation of safety, effectiveness and treatment patterns of sodium zirconium cyclosilicate in management of hyperkalaemia in China: a real-world study protocol

INTRODUCTION

Hyperkalaemia (HK) is a potentially life-threatening electrolyte imbalance associated with several adverse clinical outcomes. The efficacy and negative effects of currently existing treatment options have made HK management questionable. Sodium zirconium cyclosilicate (SZC), a novel highly selective potassium binder, is approved for the treatment of HK. The present study will be aimed to assess the safety, effectiveness and treatment patterns of SZC in Chinese patients with HK in a real-world clinical setting as it is required by China's drug review and approval process.

METHODS AND ANALYSIS

This is a multicentre, prospective cohort study which plans to enrol 1000 patients taking SZC or willing to take SZC from approximately 40 sites in China. Patients ≥18 years of age at the time of signing the written informed consent and with documented serum potassium levels ≥5.0 mmol/L within 1 year before study enrolment day will be included. Eligible patients will receive SZC treatment and will be followed up for 6 months from enrolment day. The primary objective will be to evaluate the safety of SZC for the management of HK in Chinese patients in terms of adverse events (AEs), serious AEs as well as discontinuation of SZC. The secondary objectives will include understanding the SZC dosage information in terms of its effectiveness and treatment patterns under real-world clinical practice and assessing effectiveness of SZC during the observational period.

ETHICS AND DISSEMINATION

This study protocol was approved by the Ethics Committee of the First Affiliated Hospital of Dalian Medical University (approval number: YJ-JG-YW-2020). All the participating sites have received the ethics approval. Results will be disseminated through national and international presentations and peer-reviewed publications.

TRIAL REGISTRATION NUMBER

NCT05271266.

An evaluation of sodium zirconium cyclosilicate: a new treatment option for hyperkalaemia in China

INTRODUCTION

Hyperkalemia is a common complication of chronic kidney disease (CKD), diabetes mellitus (DM), and heart failure (HF) that can lead to severe arrhythmias and sudden death and is associated with a higher risk of mortality. Therefore, the prevention and treatment of hyperkalemia is important. Sodium zirconium cyclosilicate (SZC), a new oral potassium-lowering drug, has offered an additional treatment option for Chinese patients with hyperkalemia since its launch in China in late 2019, and some experience has been accumulated regarding its efficacy and safety.

AREAS COVERED

In this review, the authors summarize the epidemiological features of hyperkalemia in China and review the clinical data regarding the use of sodium zirconium cyclosilicate in Chinese patients.

EXPERT OPINION

The prevalence of hyperkalemia is particularly high in Chinese patients with chronic kidney disease and heart failure. In China, recent clinical studies have shown that SZC rapidly reduces serum potassium, maintains normal potassium concentration, and is well tolerated and safe. Two Chinese expert consensus statements have recommended the use of SZC for the acute correction and chronic maintenance of potassium concentration.

Sodium zirconium cyclosilicate and metabolic acidosis: Potential mechanisms and clinical consequences

Metabolic acidosis is frequent in chronic kidney disease (CKD) and is associated with accelerated progression of CKD, hypercatabolism, bone disease, hyperkalemia, and mortality. Clinical guidelines recommend a target serum bicarbonate ≥ 22 mmol/L, but metabolic acidosis frequently remains undiagnosed and untreated. Sodium zirconium cyclosilicate (SZC) binds potassium in the gut and is approved to treat hyperkalemia. In clinical trials with a primary endpoint of serum potassium, SZC increased serum bicarbonate, thus treating CKD-associated metabolic acidosis. The increase in serum bicarbonate was larger in patients with more severe pre-existent metabolic acidosis, was associated to decreased serum urea and was maintained for over a year of SZC therapy. SZC also decreased serum urea and increased serum bicarbonate after switching from a potassium-binding resin in normokalemic individuals. Mechanistically, these findings are consistent with SZC binding the ammonium ion (NH₄⁺) generated from urea by gut microbial urease, preventing its absorption and, thus, preventing the liver regeneration of urea and promoting the fecal excretion of H⁺. This mechanism of action may potentially result in benefits dependent on corrected metabolic acidosis (e.g., improved well-being, decreased catabolism, improved CKD mineral bone disorder, better control of serum phosphate, slower progression of CKD) and dependent on lower urea levels, such as decreased protein carbamylation. A roadmap is provided to guide research into the mechanisms and clinical consequences of the impact of SZC on serum bicarbonate and urate.

Safety and Efficacy of Patiromer in Hyperkalemic Patients with CKD: A Pooled Analysis of Three Randomized Trials

BACKGROUND

Hyperkalemia is a common electrolyte abnormality in patients with CKD, which is associated with worse outcomes and limits use of renin-angiotensin-aldosterone system inhibitors (RAASi). This post hoc subgroup analysis of three clinical trials evaluated the efficacy and safety of the sodium-free, potassium-binding polymer, patiromer, for the treatment of hyperkalemia in adults with nondialysis CKD.

METHODS

Data from the 4-week treatment periods of AMETHYST-DN, OPAL-HK, and TOURMALINE studies were combined. Patients had baseline diagnosis of CKD, hyperkalemia (serum potassium >5.0 mEq/L), and received patiromer 8.4-33.6 g/day. Patients were stratified by baseline eGFR into two subgroups: severe/end-stage CKD (stage 3b-5; eGFR <45 ml/min per 1.73 m²) and mild/moderate CKD (stage 1-3a; eGFR ≥45 ml/min per 1.73 m²). Efficacy was assessed by the change in serum potassium (mean±SE) from baseline to week 4. Safety assessments included incidence and severity of adverse events (AEs).

RESULTS

Efficacy analyses (n=626; 62% male, mean age 66 years) included 417 (67%) patients with severe/end-stage CKD and 209 (33%) with mild/moderate CKD. Most patients were receiving RAASi therapy at baseline (severe/end-stage CKD 92%; mild/moderate CKD 98%). The mean±SE change in serum potassium (baseline to week 4) was -0.84±0.03 in the severe/end-stage CKD subgroup, and -0.60±0.04 mEq/L in the mild/moderate CKD subgroup. AEs were reported for 40% and 27% patients in the severe/end-stage and mild/moderate CKD subgroups, respectively, with 16% and 12% reporting AEs considered related to patiromer. The most frequent AEs were mild-to-moderate constipation (8% and 3%) and diarrhea (4% and 2%). AEs leading to patiromer discontinuation occurred in 6% and 2% of patients with severe/end-stage CKD, and mild/moderate CKD, respectively.

CONCLUSIONS

Patiromer was effective for treatment of hyperkalemia and well tolerated in patients across stages of CKD, most of whom were receiving guideline-recommended RAASi therapy.

Wearable and implantable artificial kidney devices for end-stage kidney disease treatment-Current status and review

BACKGROUND

Chronic kidney disease (CKD) is a major cause of early death worldwide. By 2030, 14.5 million people will have end-stage kidney disease (ESKD, or CKD stage 5), yet only 5.4 million will receive kidney replacement therapy (KRT) due to economic, social, and political factors. Even for those who are offered KRT by various means of dialysis, the life expectancy remains far too low.

OBSERVATION

Researchers from different fields of artificial organs collaborate to overcome the challenges of creating products such as Wearable and/or Implantable Artificial Kidneys capable of providing long-term effective physiologic kidney functions such as removal of uremic toxins, electrolyte homeostasis, and fluid regulation. A focus should be to develop easily accessible, safe, and inexpensive KRT options that enable a good quality of life and will also be available for patients in less-developed regions of the world.

CONCLUSIONS

Hence, it is required to discuss some of the limits and burdens of transplantation and different techniques of dialysis, including those performed at home. Furthermore, hurdles must be considered and overcome to develop wearable and implantable artificial kidney devices that can help to improve the quality of life and life expectancy of patients with CKD.

Optimizing Therapies in Heart Failure: The Role of Potassium Binders

Heart failure (HF) is a worrisome cardiac pandemic with a negative prognostic impact on the overall survival of individuals. International guidelines recommend up-titration of standardized therapies in order to reduce symptoms, hospitalization rates, and cardiac death. Hyperkalemia (HK) has been identified in 3–18% of HF patients from randomized controlled trials and over 25% of HF patients in the “real world” setting. Pharmacological treatments and/or cardio-renal syndrome, as well as chronic kidney disease may be responsible for HK in HF patients. These conditions can prevent the upgrade of pharmacological treatments, thus, negatively impacting on the overall prognosis of patients. Potassium binders may be the best option in patients with HK in order to reduce serum concentrations of K⁺ and to promote correct upgrades of therapies. In addition to the well-established use of sodium polystyrene sulfonate (SPS), two novel drugs have been recently introduced: sodium zirconium cyclosilicate (SZC) and patiromer. SZC and patiromer are gaining a central role for the treatment of chronic HK. SZC has been shown to reduce K⁺ levels within 48 h, with guaranteed maintenance of normokalemia for up to12 months. Patiromer has resulted in a statistically significant decrease in serum potassium for up to 52 weeks. Therefore, long-term results seemed to positively promote the implementation of these compounds in clinical practice due to their low rate side effects. The aim of this narrative review is to delineate the impact of new potassium binders in the treatment of patients with HF by providing a critical reappraisal for daily application of novel therapies for hyperkalemia in the HF setting.

Risk of hospitalization for heart failure in patients with hyperkalemia treated with sodium zirconium cyclosilicate versus patiromer

BACKGROUND

Sodium zirconium cyclosilicate (SZC) and patiromer were recently approved to treat hyperkalemia. Whether the initiation of SZC is associated with an increased risk of hospitalization for heart failure (HHF) compared to patiromer in routine practice remains unknown.

METHODS AND RESULTS

We conducted a new-user cohort study of non-dialysis adults who initiated SZC or patiromer using Optum's de-identified Clinformatics® Data Mart Database from May 2018 to September 2020. We performed propensity score (PS) matching in a variable ratio to match each SZC initiator with up to three patiromer initiators. The primary outcome was HHF. Cox proportional hazards regression models generated hazard ratios (HRs) with 95% confidence intervals (CIs) in the PS-matched groups. The cohort included 1,126 SZC initiators and 2,839 PS-matched patiromer initiators. The mean age was 72 years old, about 30% had a history of heart failure, and 85% had chronic kidney disease stages 3-5. The SZC group had 88 cases of HHF (incidence rate [IR] 35.8 per 100 person-years [PY]), and the patiromer group had 245 cases of HHF (IR 25.1 per 100 PY). The rate of HHF was numerically higher in the SZC initiators than patiromer initiators (HR 1.22, 95%CI 0.95, 1.56), but did not reach statistical significance. Results were consistent across sensitivity and subgroup analyses.

CONCLUSIONS

Initiation of SZC might be associated with an increased risk of hospitalization for heart failure compared to patiromer in routine practice. Larger comparative studies are needed to evaluate the safety of SZC in routine practice more precisely.

Can Novel Potassium Binders Liberate People with Chronic Kidney Disease from the Low-Potassium Diet? A Cautionary Tale

The advent of new potassium binders provides an important breakthrough in the chronic management of hyperkalemia for people with CKD. In addition to the direct benefits of managing hyperkalemia, many researchers and clinicians view these new medications as a possible means to safely transition patients away from the low-potassium diet to a more healthful eating pattern. In this review, we examine the mechanisms of potassium binders in the context of hyperkalemia risk related to dietary potassium intake in people with CKD. We note that whereas these medications target hyperkalemia caused by potassium bioaccumulation, the primary evidence for restricting dietary potassium is risk of postprandial hyperkalemia. The majority of ingested potassium is absorbed alongside endogenously secreted potassium in the small intestines, but the action of these novel medications is predominantly constrained to the large intestine. As a result and despite their effectiveness in lowering basal potassium levels, it remains unclear whether potassium binders would provide protection against hyperkalemia caused by excessive dietary potassium intake in people with CKD. Until this knowledge gap is bridged, clinicians should consider postprandial hyperkalemia risk when removing restrictions on dietary potassium intake in people with CKD on potassium binders.

The Role of Patiromer in Delaying the Onset of Renal Replacement Therapy in Patients with Advanced Renal Failure

Patients with chronic kidney disease (CKD) are at an increased risk of developing hyperkalemia, which can be potentially life threatening. Hyperkalemia is frequently encountered with renin-angiotensin-aldosterone system inhibitor (RAASi) therapy use in patients with CKD and often results in the underdosing or discontinuation of these drugs. RAASi therapy has been proven to delay the progression of CKD, ameliorate proteinuria, and reduce the overall risk of cardiovascular morbidity and mortality. Patiromer is a sodium-free, potassium-binding polymer used for the treatment of hyperkalemia. We present a case series of four patients with Stage 4 or 5 CKD in whom the initiation of dialysis was delayed with the use of patiromer. For one patient, dialysis was delayed by 18 months, whereas the remaining three patients, in whom hyperkalemia was one of the main complications, remain dialysis independent to date.

Consensus-Based Recommendations for the Management of Hyperkalemia in the Hemodialysis Setting

Hyperkalemia (serum K⁺ >5.0 mmol/L) is commonly observed among patients receiving maintenance hemodialysis and associated with increased risk of cardiac arrhythmias. Current international guidelines may not reflect the latest evidence on managing hyperkalemia in patients undergoing hemodialysis, and there is a lack of high-quality published studies in this area. This consensus guideline aims to provide recommendations in relation to clinical practice. Available published evidence was evaluated through a systematic literature review, and the nominal group technique was used to develop consensus recommendations from a panel of experienced nephrologists, covering monitoring, dietary restrictions, prescription of K⁺ binders, and concomitant prescription of renin-angiotensin-aldosterone system inhibitors. Recent studies have shown that K⁺ binders reduce the incidence of hyperkalemia, but further evidence is needed in areas including whether reduced-K⁺ diets or treatment with K⁺ binders improve patient-centered outcomes. Treatment of hyperkalemia in the hemodialysis setting is complex, and decisions need to be tailored for individual patients.

Hyperkalemia in Chronic Kidney Disease in the New Era of Kidney Protection Therapies

Despite recent therapeutic advances, chronic kidney disease (CKD) is one of the fastest growing global causes of death. This illustrates limitations of current therapeutic approaches and, potentially, unidentified knowledge gaps. For decades, renin-angiotensin-aldosterone system (RAAS) blockers have been the mainstay of therapy for CKD. However, they favor the development of hyperkalemia, which is already common in CKD patients due to the CKD-associated decrease in urinary potassium (K⁺) excretion and metabolic acidosis. Hyperkalemia may itself be life-threatening as it may trigger potentially lethal arrhythmia, and additionally may limit the prescription of RAAS blockers and lead to low-K⁺ diets associated to low dietary fiber intake. Indeed, hyperkalemia is associated with adverse kidney, cardiovascular, and survival outcomes. Recently, novel kidney protective therapies, ranging from sodium/glucose cotransporter 2 (SGLT2) inhibitors to new mineralocorticoid receptor antagonists have shown efficacy in clinical trials. Herein, we review K⁺ pathophysiology and the clinical impact and management of hyperkalemia considering these developments and the availability of the novel K⁺ binders patiromer and sodium zirconium cyclosilicate, recent results from clinical trials targeting metabolic acidosis (sodium bicarbonate, veverimer), and an increasing understanding of the role of the gut microbiota in health and disease.

Management of Chronic Hyperkalemia in Patients With Chronic Kidney Disease: An Old Problem With News Options

Hyperkalemia is one of the main electrolyte disorders in patients with chronic kidney disease (CKD). The prevalence of hyperkalemia increases as the Glomerular Filtration Rate (GFR) declines. Although chronic hyperkalemia is not a medical emergency, it can have negative consequences for the adequate cardio-renal management in the medium and long term. Hyperkalemia is common in patients on renin-angiotensin-aldosterone system inhibitors (RAASi) or Mineralocorticoid Receptor Antagonists (MRAs) and can affect treatment optimization for hypertension, diabetes mellitus, heart failure (HF), and CKD. Mortality rates are higher with suboptimal dosing among patients with CKD, diabetes or HF compared with full RAASi dosing, and are the highest among patients who discontinue RAASis. The treatment of chronic hyperkalemia is still challenging. Therefore, in the real world, discontinuation or reduction of RAASi therapy may lead to adverse cardiorenal outcomes, and current guidelines differ with regard to recommendations on RAASi therapy to enhance cardio and reno-protective effects. Treatment options for hyperkalemia have not changed much since the introduction of the cation exchange resin over 50 years ago. Nowadays, two new potassium binders, Patiromer Sorbitex Calcium, and Sodium Zirconium Cyclosilicate (SZC) already approved by FDA and by the European Medicines Agency, have demonstrated their clinical efficacy in reducing serum potassium with a good safety profile. The use of the newer potassium binders may allow continuing and optimizing RAASi therapy in patients with hyperkalemia keeping the cardio-renal protective effect in patients with CKD and cardiovascular disease. However, further research is needed to address some questions related to potassium disorders (definition of chronic hyperkalemia, monitoring strategies, prediction score for hyperkalemia or length for treatment).

Sodium zirconium cyclosilicate increases serum bicarbonate concentrations among patients with hyperkalaemia: exploratory analyses from three randomized, multi-dose, placebo-controlled trials

BACKGROUND

Sodium zirconium cyclosilicate (SZC) binds potassium and ammonium in the gastrointestinal tract. In addition to serum potassium reduction, Phase 2 trial data have shown increased serum bicarbonate with SZC, which may be clinically beneficial because maintaining serum bicarbonate ≥22 mmol/L preserves kidney function. This exploratory analysis examined serum bicarbonate and urea, and urine pH data from three SZC randomized, placebo-controlled Phase 3 studies among patients with hyperkalaemia [ZS-003 (n = 753), HARMONIZE (n = 258) and HARMONIZE-Global (n = 267)].

METHODS

In all studies, patients received ≤10 g SZC 3 times daily (TID) for 48 h to correct hyperkalaemia, followed by randomization to maintenance therapy with SZC once daily (QD) versus placebo for ≤29 days among those achieving normokalaemia.

RESULTS

Significant dose-dependent mean serum bicarbonate increases from baseline of 0.3 to 1.5 mmol/L occurred within 48 h of SZC TID in ZS-003 (all P < 0.05), which occurred regardless of chronic kidney disease (CKD) stage. Similar acute increases in HARMONIZE and HARMONIZE-Global were maintained over 29 days. With highest SZC maintenance doses, patient proportions with serum bicarbonate <22 mmol/L fell from 39.4% at baseline to 4.9% at 29 days (P = 0.005) in HARMONIZE and from 87.9% to 70.1%, (P = 0.006) in HARMONIZE-Global. Path analyses demonstrated that serum urea decreases (but not serum potassium or urine pH changes) were associated with SZC effects on serum bicarbonate.

CONCLUSIONS

SZC increased serum bicarbonate concentrations and reduced patient proportions with serum bicarbonate <22 mmol/L, likely due to SZC-binding of gastrointestinal ammonium. These SZC-induced serum bicarbonate increases occurred regardless of CKD stage and were sustained during ongoing maintenance therapy.

Renal Tubular Acidosis and Management Strategies: A Narrative Review

Renal tubular acidosis (RTA) occurs when the kidneys are unable to maintain normal acid−base homeostasis because of tubular defects in acid excretion or bicarbonate ion reabsorption. Using illustrative clinical cases, this review describes the main types of RTA observed in clinical practice and provides an overview of their diagnosis and treatment. The three major forms of RTA are distal RTA (type 1; characterized by impaired acid excretion), proximal RTA (type 2; caused by defects in reabsorption of filtered bicarbonate), and hyperkalemic RTA (type 4; caused by abnormal excretion of acid and potassium in the collecting duct). Type 3 RTA is a rare form of the disease with features of both distal and proximal RTA. Accurate diagnosis of RTA plays an important role in optimal patient management. The diagnosis of distal versus proximal RTA involves assessment of urinary acid and bicarbonate secretion, while in hyperkalemic RTA, selective aldosterone deficiency or resistance to its effects is confirmed after exclusion of other causes of hyperkalemia. Treatment options include alkali therapy in patients with distal or proximal RTA and lowering of serum potassium concentrations through dietary modification and potential new pharmacotherapies in patients with hyperkalemic RTA including newer potassium binders.

Effects and Safety of a Novel Oral Potassium-Lowering Drug-Sodium Zirconium Cyclosilicate for the Treatment of Hyperkalemia: a Systematic Review and Meta-Analysis

Background

Oral sodium zirconium cyclosilicate (SZC) is a novel potassium binder capable of achieving a rapid reduction of serum potassium (sK⁺) and maintaining a long-term normokalemia. We undertook a meta-analysis to summarize and evaluate the effects surrounding SZC in patients with hyperkalemia.

Method

We searched data sources from MEDLINE (from 1950 to Sep 2020), EMBASE (from 1970 to Sep 2020), and the Cochrane Library database (from 1950 to Sep 2020) for eligible studies. All randomized controlled trials (RCTs) regarding comparison of therapeutic effects of SZC in hyperkalemia participants were included.

Results

Seven studies, including 1697 patients with hyperkalemia, were analyzed. SZC significantly reduced mean sK⁺ (−0.42 mmol/L; 95% CI: −0.63 to −0.20 mmol/L, p = 0.0001) compared with placebo, with a significantly greater proportion of patients with normokalemia (RR 3.48, 95% CI 1.49 to 8.11, p = 0.004). Subgroup analyses showed that the longer durations of SZC treatment, the greater magnitudes of potassium reduction when compared with those of placebo (p between subgroups = 0.01) at correction phase. Besides, it also demonstrated sK⁺ tended to decrease more in patients who got longer treatment or larger dosage of SZC at maintenance phase; however, the difference did not reach statistical significance. Additionally, the drug was equally effective in studies with larger than 50% of patients with chronic kidney disease (CKD) or diabetes or patients using renin-angiotensin aldosterone system inhibitor (RAAS) inhibitors (all p < 0.05). The risk of edema (4.30, 1.17 to 15.84; p = 0.03) in SZC group was higher than those of placebo group. No statistically significant differences in the risks of other adverse events were observed between the two groups.

Conclusions

SZC effectively decreased the sK⁺ level in patients with hyperkalemia within 48 h and had benefits in the long-term control of serum potassium in patients who continued to receive SZC with a favorable safety profile from available data.

Supplementary Information

The online version contains supplementary material available at 10.1007/s10557-020-07134-2.

New Treatment Options for Hyperkalemia in Patients with Chronic Kidney Disease

Hyperkalemia may cause life-threatening cardiac and neuromuscular alterations, and it is associated with high mortality rates. Its treatment includes a multifaceted approach, guided by potassium levels and clinical presentation. In general, treatment of hyperkalemia may be directed towards stabilizing cell membrane potential, promoting transcellular potassium shift and lowering total K+ body content. The latter can be obtained by dialysis, or by increasing potassium elimination by urine or the gastrointestinal tract. Until recently, the only therapeutic option for increasing fecal K+ excretion was represented by the cation-exchanging resin sodium polystyrene sulfonate. However, despite its common use, the efficacy of this drug has been poorly studied in controlled studies, and concerns about its safety have been reported. Interestingly, new drugs, namely patiromer and sodium zirconium cyclosilicate, have been developed to treat hyperkalemia by increasing gastrointestinal potassium elimination. These medications have proved their efficacy and safety in large clinical trials, involving subjects at high risk of hyperkalemia, such as patients with heart failure and chronic kidney disease. In this review, we discuss the mechanisms of action and the updated data of patiromer and sodium zirconium cyclosilicate, considering that the availability of these new treatment options offers the possibility of improving the management of both acute and chronic hyperkalemia.

Hyperkalemia in heart failure: Foe or friend?

Hyperkalemia is a frequent and sometimes life‐threatening condition that may be associated with arrhythmia and cardiac dysfunction in patients with heart failure (HF). High potassium levels in HF represent both a direct risk for cardiovascular complication and an indirect biomarker of the severity of the underlying disease, reflecting neurohormonal activation and renal dysfunction. Evaluating the prevalence and significance of hyperkalemia in HF patients is essential for optimizing the use of potassium sparing agents, such the renin–angiotensin–aldosterone system inhibitors (RAASi) or angiotensin receptor‐neprilysin inhibitors and mineralocorticoid receptor antagonists, which represent a well‐established cornerstone and life‐saving therapy. In this review we discuss recent findings and current concepts related to the epidemiology, pathological mechanisms and implications of hyperkalemia, as well as novel therapeutic approaches to counteract it in patients with HF. The balance between optimizing life‐saving potassium sparing medication and minimizing hyperkalemia‐associated risk is much needed in patients with HF. Although older potassium‐binding agents are associated with serious adverse events, novel potassium‐binding drugs are effective in lowering potassium levels and are generally well tolerated. Novel potassium‐binding drugs, such as patiromer and sodium zirconium cyclosilicate, may help to optimize therapy in HF and achieve guideline‐recommended doses. Hyperkalemia is common in HF patients and is associated with a poorer prognosis and an increased risk of cardiovascular complications: Contrariwise, “moderate” potassium levels go with a better prognosis, while the emergence of new drugs, potassium binders, could allow target doses of RAASi to be achieved.