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

Phase 4

Completed

Conditions: Hyperkalaemia
Heart Failure With Reduced Ejection Fraction

Interventions: Drug: Sodium zirconium cyclosilicate
Drug: Placebo
Other: Spironolactone

Registration Number: NCT04676646

Lead Sponsor: AstraZeneca

Brief Summary: 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: 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.

Recruitment & Eligibility

Status: COMPLETED

Sex: All

Target Recruitment: 366

Inclusion Criteria

Not provided

Exclusion Criteria

Not provided

Study & Design

Study Type: INTERVENTIONAL

Study Design: PARALLEL

Arm && Interventions

Group	Intervention	Description
Open-label run-in phase	Placebo	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).
Randomized withdrawal phase (6 months)	Placebo	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).
Randomized withdrawal phase (6 months)	Spironolactone	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).
Open-label run-in phase	Spironolactone	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).
Open-label run-in phase	Sodium zirconium cyclosilicate	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).
Randomized withdrawal phase (6 months)	Sodium zirconium cyclosilicate	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).

Primary Outcome Measures

Name	Time	Method
Participants Who Achieved Response, Defined as Serum Potassium (sK+) Within 3.5 to 5.0 mEq/L, Spironolactone Greater Than or Equal to 25 mg Daily, no Rescue Therapy for Hyperkalaemia	From Month 1 (Visit 9) to Month 6 (Visit 14), up to 6 months	The median percentages of participants having a response are presented. Response means all three requirements were met. Non-response was indicated for participants lost to follow-up, including death. The treatment effect was analysed using a generalised estimating equation (GEE) model with a binomial family and a log link, a dependent variable of response per visit, fixed independent variables of randomised treatment, subject recruitment country, a per visit indicator variable and open-label period cohort. The common odds ratio was derived together with two-sided 95% confidence intervals.

Secondary Outcome Measures

Name	Time	Method
Participants Who Achieved Response, Defined as sK+ Within 3.5-5.0 mEq/L, on the Same Dose of Spironolactone as Randomisation, no Rescue Therapy for Hyperkalaemia	From Month 1 (Visit 9) to Month 6 (Visit 14), up to 6 months	The median percentages of participants who achieved a response are presented. Response means all three requirements were met. Non-response was indicated for participants lost to follow-up, including death. The analysis was performed using a GEE model with a binomial family and a log link, a dependent variable of response per visit, fixed independent variables of randomised treatment, subject recruitment country, a per visit indicator variable and open-label period cohort. The common odds ratio was derived together with two-sided 95% confidence intervals.
Participants Who Achieved Response, Defined as Spironolactone Greater Than or Equal to 25 mg Daily	From Month 1 (Visit 9) to Month 6 (Visit 14), up to 6 months	The median percentages of participants who achieved a response are presented. Response means that the requirement was met. Non-response was indicated for subjects lost to follow-up, including death. The analysis was performed using a GEE model with a binomial family and a log link, a dependent variable of response per visit, fixed independent variables of randomised treatment, subject recruitment country, a per visit indicator variable and open-label period cohort. The common odds ratio was derived together with two-sided 95% confidence intervals.
Time to First Hyperkalaemia (sK+ Greater Than 5.0mEq/L) Episode	From randomisation to the end of treatment (EOT) visit, up to 6 months	The time to first hyperkalaemia episode for participants on SZC compared to placebo during the randomised-withdrawal period, with hyperkalaemia defined as sK+ greater than 5.0 mEq/L as assessed by central laboratory, is presented in median time (days). The analysis was performed using a Cox regression model including randomised treatment group and subject recruitment country, adjusted for the stratification factor (hyperkalaemia vs normokalaemia at study entry). Placebo group used as reference level in Cox model.
Time to First Instance of Decrease or Discontinuation of Spironolactone Dose Due to Hyperkalaemia	From randomisation to the EOT visit, up to 6 months	The time to first instance of decrease or discontinuation of spironolactone dose due to hyperkalaemia is presented in median time (days). The analysis was performed using a Cox regression model, adjusted for the stratification factor (hyperkalaemia vs normokalaemia at study entry).
Kansas City Cardiomyopathy Questionnaire Clinical Summary Score (KCCQ-CSS) at EOT	At EOT visit (approximately 6 months post-randomisation)	The KCCQ is a 23-item instrument measuring, from the patients' perspectives, their heart failure-related symptoms, physical and social limitations, self-efficacy, and health-related quality of life (QoL) over the prior 2 weeks. It was scored as follows: Physical Limitation (items 1a-f), Symptom Stability (item 2), Symptom Frequency (items 3, 5, 7, and 9), Symptom Burden (items 4, 6, and 8), Self Efficacy (items 10 and 11), QoL (items 12, 13, and 14), and Social Limitation (items 15a-d). Scores were calculated by summing the responses within each domain and by taking the average. Scale scores were transformed to a 0 to 100 range, with 0 implying the lowest level of functioning and 100 for the highest level of functioning. The CSS was calculated as the average of Physical Limitation Score and Total Symptom Score (TSS) and the TSS was calculated as the average of Symptom Frequency and Symptom Burden Scores. The change from randomisation in KCCQ-CSS is reported.