There is disconnect between dietary guidelines to limit potassium intake in dialysis and clinical practice. The number of unknowns and differences make the results unlikely to be translatable into clinical practice and will not benefit patients.

Prescribing Sodium zirconium cyclosilicate (SZC) with enhanced nutritional advice to participants with hyperkalaemia on haemodialysis will reduce serum K+ (S-K+ ) and enable the consumption of more fruit and vegetables and more satisfying diet. The study aims to show that participants using SZC achieve S-K+ reduction as well as participants on SoC (other than K+ binders), without the need for restricting K+ in the diet.

This is a Phase IV, randomised, controlled, open-label, parallel-group, multicentre, prospective study to evaluate the effect of the combination of SZC and enhanced nutritional advice to consume fruit and vegetables as compared to SoC in reducing S-K+ levels in participants with hyperkalaemia on haemodialysis. Following 7-day screening, all participants who are enrolled will begin an up to 1-month HK Treatment Phase with SZC as per local label. Participants will receive dietary advice consistent with SoC at that site, including K+ restriction. A 4-month Diet Comparison Phase will begin next with participants being randomised to either continue taking SZC, which can be titrated as needed to maintain target S-K+ , and receive enhanced nutritional advice to consume fruit and vegetables (SZC arm), or SZC will be withdrawn and participants will receive SoC, including dietary K+ restriction (SoC arm).

Inclusion Criteria:

1. Participant must be ≥18 years of age at the time of signing the informed consent.

2. Participants with prevalent HK (S-K+ >5.5 mmol/L at the end of LIDI) not requiring acute treatment.

3. Receiving haemodialysis 3 times a week with stable vascular access for at least 3 months before screening visit.

4. Participants who have and are able and willing to use smart phone (android or iOS) nutrition app.

5. Contraceptive use by men or women should be consistent with local regulations regarding the methods of contraception for those participating in clinical studies.

   • Female participants of childbearing potential must have a negative pregnancy test.
   • Female participants must be 1 year post-menopausal, surgically sterile, or using 1 highly effective form of birth control (defined as one that can achieve a failure rate of less than 1% per year when used consistently and correctly). They should have been stable on their chosen method of birth control for a minimum of 3 months before entering the study and willing to remain on the birth control until 12 weeks after the last dose.

6. Capable of giving signed informed consent, which includes compliance with the requirements and restrictions listed in the Informed Consent Form (ICF) and in the protocol.

Exclusion Criteria:

1. As judged by the investigator or sponsor, any medical condition (including active, clinically significant infection) that may pose a safety risk to the participant in this study, may confound safety or efficacy assessments and jeopardise the quality of data, or may interfere with study participation.
2. Myocardial infarction, acute coronary syndrome (ST-elevation myocardial infarction, non-ST-elevation myocardial infarction, or unstable angina), stroke, seizure, thrombotic/thromboembolic event (eg, deep vein thrombosis or pulmonary embolism, but excluding vascular access thrombosis), percutaneous transluminal coronary angioplasty, or coronary artery bypass graft within 12 weeks prior to screening visit.
3. Severe leucocytosis (>20 × 109 /L) or thrombocytosis (≥450 × 109 /L) during screening.
4. Polycythaemia (haemoglobin >14 g/dL) during screening.
5. Severe constipation, bowel obstruction, post-operative motility disorders.
6. Scheduled date for living donor kidney transplant.
7. Participants with a life expectancy of less than 6 months.
8. Females of childbearing potential, unless using contraception as detailed in the protocol or sexually abstinent.
9. Currently pregnant (confirmed with positive pregnancy test) or breast-feeding.
10. Presence of cardiac arrhythmias or conduction defects that require immediate treatment at HCP discretion.
11. History of alcohol or drug abuse within 2 years prior to screening visit.
12. History of QT prolongation associated with other medications that required discontinuation of that medication.
13. Congenital long QT syndrome or QT interval corrected for heart rate (QTc) using Fridericia's method (QTcF) >550 ms.
14. Symptomatic or uncontrolled atrial fibrillation despite treatment, or asymptomatic sustained ventricular tachycardia. Subjects with atrial fibrillation controlled by medication are permitted.
15. If the participant has evidence of Coronavirus disease 2019 (COVID-19) within 2 weeks prior to screening (see Appendix D), the participant cannot be enrolled in the study.
16. Participants treated with SZC, sodium polystyrene sulfonate (SPS: Kayexalate™; Resonium™ A), calcium polystyrene sulfonate (CPS: Calcium Resonium™), or patiromer (Veltassa™) 1 within 4 weeks before screening.
17. Participants with a known hypersensitivity or previous anaphylaxis to SZC or any of the excipients of the product.
18. Participants unable to take oral SZC. Prior/Concurrent Clinical Study Experience
19. Participation in another clinical study with an investigational product administered during the month before screening2 .
20. Involvement in the planning and/or conduct of the study (applies to both AstraZeneca staff and/or staff at the study site).
21. Judgment by the investigator that the participant should not participate in the study if the participant is unlikely to comply with study procedures, restrictions, and requirements.
22. Previous enrolment in the present study.

Qualified researchers can request access to anonymized individual patient-level data from AstraZeneca group of companies sponsored clinical trials via the request portal. All request will be evaluated as per the AZ disclosure commitment:

https://astrazenecagrouptrials.pharmacm.com/ST/Submission/Disclosure Yes, indicates that AZ are accepting requests for IPD, but this does not mean all requests will be shared.

AstraZeneca will meet or exceed data availability as per the commitments made to the EFPIA Pharma Data Sharing Principles. For details of our timelines, please rerefer to our disclosure commitment at:

https://astrazenecagrouptrials.pharmacm.com/ST/Submission/Disclosure

When a request has been approved AstraZeneca will provide access to the de-identified individual patient-level data in an approved sponsored tool . Signed Data Sharing Agreement (non-negotiable contract for data accessors) must be in place before accessing requested information. Additionally, all users will need to accept the terms and conditions of the SAS MSE to gain access. For additional details, please review the Disclosure Statements at:

https://astrazenecagrouptrials.pharmacm.com/ST/Submission/Disclosure

The baseline population includes the one participant randomized in this study.

Assessed for a total of up to 179 days from screening/enrollment visit (Visit 1).

The study was terminated by the sponsor with only 1 participant randomized. There was disconnect between dietary guidelines to limit potassium intake in dialysis and clinical practice.