Study to Assess Efficacy and Safety of SZC for the Management of High Potassium in Patients With Symptomatic HFrEF Receiving Spironolactone

NCT ID: NCT04676646

Last Updated: 2025-07-09

Study Results

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Basic Information

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Recruitment Status

COMPLETED

Clinical Phase

PHASE4

Total Enrollment

366 participants

Study Classification

INTERVENTIONAL

Study Start Date

2021-03-08

Study Completion Date

2024-07-15

Brief Summary

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The main objective of this study is to evaluate the efficacy of SZC as compared with placebo in keeping potassium levels within the normal range (3.5-5.0 mEq/L) while on spironolactone ≥25 mg daily without assistance of rescue therapy for hyperkalaemia (HK).

Detailed Description

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REALIZE-K is a Phase 4, multinational, multicenter, double-blind, placebo-controlled, randomized-withdrawal, parallel-group study that includes the following 3 phases: screening, 4-6 week open-label run-in phase where sodium zirconium cyclosilicate (SZC) and spironolactone will be optimized, followed by a 6-month double-blind, placebo-controlled, randomized withdrawal treatment phase.

Patients meeting the following criteria will enter the 4-6 week open-label run-in phase: symptomatic heart failure with reduced ejection fraction (HFrEF); receiving an angiotensin-converting enzyme inhibitor (ACEi), angiotensin II receptor blocker (ARB), or angiotensin receptor-Neprilysin inhibitor (ARNi); receiving no spironolactone or eplerenone, or receiving low-dose spironolactone (\<25 mg daily); receiving a beta-blocker unless contraindicated; AND with hyperkalemia (sK+ 5.1-5.9 mEq/L) and an eGFR \>/= 30 mL/min/1.73m2, OR normokalemic (sK+ 3.5-5.0 mEq/L) and 'at risk' of developing hyperkalemia (ie, history of hyperkalemia within the past 36 months and eGFR \>/= 30 mL/min/1.73m2, or sK+ 4.5-5.0 mEq/L and eGFR 30-60 mL/min/1.73m2 and/or age \>75 years).

Patients who are normokalemic on SZC and receiving spironolactone \>/= 25 mg daily at the end of the open-label run-in phase will enter the 6-month double-blind, placebo-controlled, randomized withdrawal treatment phase. Eligible patients will be randomized 1:1, stratified by run-in phase sK+ cohort.

Conditions

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Hyperkalaemia Heart Failure With Reduced Ejection Fraction

Study Design

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Allocation Method

RANDOMIZED

Intervention Model

PARALLEL

REALIZE-K is a Phase 4, multinational, multicenter, double-blind, placebo-controlled, randomized-withdrawal, parallel-group study.
Primary Study Purpose

TREATMENT

Blinding Strategy

DOUBLE

Participants Investigators
All participants entering the double-blind, randomised treatment period will be centrally assigned to randomised study intervention using an Interactive Response Technology/Randomisation and Trial Supply Management (IRT/RTSM). Randomisation will be stratified by the sK+ cohort determined by central laboratory at the start of the open-label phase (Day 1). Before the study is initiated, the telephone number and call-in directions for the IRT and/or the log in information and directions for the RTSM will be provided to each site.

The IRT/RTSM will provide to the investigator(s) or pharmacists the kit identification number to be allocated to the participant at the dispensing visit. Routines for this will be described in the IRT/RTSM user manual that will be provided to each centre.

The randomisation code should not be broken except in medical emergencies when the appropriate management of the participant requires knowledge of the treatment randomisation.

Study Groups

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Open-label run-in phase

Cohort 1 (4 weeks duration): Patients who are hyperkalemic at study entry will begin SZC 10 g TID for up to 48 hours followed by SZC 10 g once daily to achieve and maintain normokalemia. The SZC dose will be adjusted as needed to maintain normokalemia (dose range = 5 g every other day, to 5-15 g once daily).

Cohort 2 (up to 6 weeks duration): Patients who develop hyperkalemia during the uptitration of spironolactone will receive SZC 10 g TID for up to 48 hours followed by SZC 10 g once daily to achieve and maintain normokalemia. The SZC dose will be adjusted as needed to maintain normokalemia (dose range = 5 g every other day, to 5-15 g once daily).

Group Type EXPERIMENTAL

Sodium zirconium cyclosilicate

Intervention Type DRUG

Investigational medicinal product

Placebo

Intervention Type DRUG

Placebo comparator

Spironolactone

Intervention Type OTHER

Background intervention.

During the run-in phase, spironolactone will be initiated/uptitrated up to a maximum of 50 mg per day. During the randomized withdrawal phase the spironolactone dose at the end of the run-in phase will be maintained.

Randomized withdrawal phase (6 months)

SZC arm and Placebo arm: Patients will continue on the SZC dose they were receiving at the end of the run-in phase.

The SZC / Placebo dose will be adjusted as needed to maintain normokalemia (dose range = 5 g every other day, to 5-15 g once daily).

Group Type EXPERIMENTAL

Sodium zirconium cyclosilicate

Intervention Type DRUG

Investigational medicinal product

Placebo

Intervention Type DRUG

Placebo comparator

Spironolactone

Intervention Type OTHER

Background intervention.

During the run-in phase, spironolactone will be initiated/uptitrated up to a maximum of 50 mg per day. During the randomized withdrawal phase the spironolactone dose at the end of the run-in phase will be maintained.

Interventions

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Sodium zirconium cyclosilicate

Investigational medicinal product

Intervention Type DRUG

Placebo

Placebo comparator

Intervention Type DRUG

Spironolactone

Background intervention.

During the run-in phase, spironolactone will be initiated/uptitrated up to a maximum of 50 mg per day. During the randomized withdrawal phase the spironolactone dose at the end of the run-in phase will be maintained.

Intervention Type OTHER

Other Intervention Names

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SZC

Eligibility Criteria

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Inclusion Criteria

* Adults aged ≥18 years
* Potassium and estimated glomerular filtration rate (eGFR):
* Cohort 1: sK+ 5.1-5.9 mEq/L at screening/study enrolment and eGFR ≥30 mL/min/1.73 m2; OR
* Cohort 2: Normokalaemic (sK+ 3.5-5.0 mEq/L) at screening and 'at risk' of developing HK defined as any of the following:
* Have a history of HK (sK+ \>5.0 mEq/L) within the prior 36 months and eGFR ≥30 mL/min/1.73 m2; or
* sK+ 4.5-5.0 mEq/L and eGFR 30 to 60 mL/min/1.73 m2; or
* sK+ 4.5-5.0 mEq/L, and age \>75 years
* Symptomatic HFrEF (New York Heart Association \[NYHA\] class II-IV), which has been present for at least 3 months
* Left ventricular ejection fraction (LVEF) ≤40%
* Receiving angiotensin-converting enzyme inhibitor (ACEi), angiotensin II receptor blocker (ARB), or angiotensin receptor-Neprilysin inhibitor (ARNi)
* Not on or on low-dose spironolactone or eplerenone (\<25 mg daily)
* Receiving beta-blocker unless contraindicated

Exclusion Criteria

* Heart failure due to restrictive cardiomyopathy, active myocarditis, constrictive pericarditis, hypertrophic (obstructive) cardiomyopathy, or severe stenotic valve disease as a primary cause of HF
* Current inpatient hospitalisation with unstable HF, defined as any of the following:
* Systolic blood pressure \<95 mmHg during the 6 hours prior to screening.
* Intravenous diuretic therapy during the 12 hours prior to screening.
* Use of intravenous inotropic drugs during the 24 hours prior to screening.
* Received mechanical circulatory support during the 48 hours prior to screening
* Previous cardiac transplantation or implantation of a ventricular assistance device (VAD) or similar device, or transplantation or implantation expected after randomisation
Minimum Eligible Age

18 Years

Maximum Eligible Age

130 Years

Eligible Sex

ALL

Accepts Healthy Volunteers

No

Sponsors

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AstraZeneca

INDUSTRY

Sponsor Role lead

Responsible Party

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Responsibility Role SPONSOR

Locations

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Research Site

Fairhope, Alabama, United States

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Los Angeles, California, United States

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Torrance, California, United States

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Evanston, Illinois, United States

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Hazel Crest, Illinois, United States

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Oak Lawn, Illinois, United States

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Kansas City, Missouri, United States

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New York, New York, United States

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Winston-Salem, North Carolina, United States

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Greenville, South Carolina, United States

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Houston, Texas, United States

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Falls Church, Virginia, United States

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Belo Horizonte, , Brazil

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Bragança Paulista, , Brazil

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Brasília, , Brazil

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Brasília, , Brazil

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Campina Grande do Sul, , Brazil

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Campinas, , Brazil

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Canoas, , Brazil

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Joinville, , Brazil

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Porto Alegre, , Brazil

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Porto Alegre, , Brazil

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Porto Alegre, , Brazil

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Ribeirão Preto, , Brazil

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Salvador, , Brazil

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Santa Cruz do Sul, , Brazil

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São Paulo, , Brazil

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São Paulo, , Brazil

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São Paulo, , Brazil

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São Paulo, , Brazil

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Votuporanga, , Brazil

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Cambridge, Ontario, Canada

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Kitchener, Ontario, Canada

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Scarborough Village, Ontario, Canada

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Scarborough Village, Ontario, Canada

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Toronto, Ontario, Canada

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Whitby, Ontario, Canada

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Montreal, Quebec, Canada

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Montreal, Quebec, Canada

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Québec, Quebec, Canada

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Terrebonne, Quebec, Canada

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Brandýs nad Labem, , Czechia

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Broumov, , Czechia

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Hradec Králové, , Czechia

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Jaroměř, , Czechia

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Louny, , Czechia

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Ostrava, , Czechia

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Uherské Hradiště, , Czechia

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Budapest, , Hungary

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Budapest, , Hungary

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Zalaegerszeg, , Hungary

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Gdynia, , Poland

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Lodz, , Poland

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Lodz, , Poland

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Lódz, , Poland

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Skórzewo, , Poland

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Żarów, , Poland

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A Coruña, , Spain

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Almería, , Spain

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Barcelona, , Spain

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Barcelona, , Spain

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Bilbao (Vizcaya), , Spain

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Granada, , Spain

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Huelva, , Spain

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Jaén, , Spain

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Lleida, , Spain

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Madrid, , Spain

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Majadahonda, , Spain

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Murcia, , Spain

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Palma de Mallorca, , Spain

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Palma de Mallorca, , Spain

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Pamplona, , Spain

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Sabadell, , Spain

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Salamanca, , Spain

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Santiago de Compostela, , Spain

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Seville, , Spain

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Seville, , Spain

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Valencia, , Spain

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Valencia, , Spain

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Zaragoza, , Spain

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Ashington, , United Kingdom

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Bridgend, , United Kingdom

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Bristol, , United Kingdom

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Glasgow, , United Kingdom

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Leicester, , United Kingdom

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Liverpool, , United Kingdom

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Manchester, , United Kingdom

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Newport, , United Kingdom

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Sheffield, , United Kingdom

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Countries

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United States Brazil Canada Czechia Hungary Poland Spain United Kingdom

References

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Kosiborod MN, Cherney DZI, Desai AS, Testani JM, Verma S, Chinnakondepalli K, Dolling D, Patel S, Dahl M, Eudicone JM, Friberg L, Ouwens M, Antunes MO, Connelly KA, Madrini V Jr, Kuthi L, Lala A, Lorenzo M, Guimaraes PO, Marcos MC, Merkely B, Nunez J, Squire I, Vaclavik J, Wranicz J, Petrie MC. Sodium Zirconium Cyclosilicate for Management of Hyperkalemia During Spironolactone Optimization in Patients With Heart Failure. J Am Coll Cardiol. 2025 Mar 18;85(10):971-984. doi: 10.1016/j.jacc.2024.11.014. Epub 2024 Nov 18.

Reference Type DERIVED
PMID: 39566872 (View on PubMed)

Kosiborod MN, Cherney D, Connelly K, Desai AS, Guimaraes PO, Kuthi L, Lala A, Madrini V Jr, Merkely B, Villota JN, Squire I, Testani JM, Vaclavik J, Verma S, Wranicz J, Dahl M, Eudicone JM, Friberg L, Petrie MC. Sodium Zirconium Cyclosilicate in HFrEF and Hyperkalemia: REALIZE-K Design and Baseline Characteristics. JACC Heart Fail. 2024 Oct;12(10):1707-1716. doi: 10.1016/j.jchf.2024.05.003. Epub 2024 May 13.

Reference Type DERIVED
PMID: 38878009 (View on PubMed)

Provided Documents

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Document Type: Study Protocol

View Document

Document Type: Statistical Analysis Plan

View Document

Other Identifiers

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2020-003312-27

Identifier Type: EUDRACT_NUMBER

Identifier Source: secondary_id

D9480C00018

Identifier Type: -

Identifier Source: org_study_id

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