AstraZeneca Axes Two Phase III Hyperkalemia Trials for Lokelma

AstraZeneca CA_iStock, Sundry Photography

Pictured: AstraZeneca building/iStock, Sundry Photography

AstraZeneca is dropping two Phase III “evidence” trials of Lokelma (sodium zirconium cyclosilicate), its already-approved potassium binder drug for hyperkalaemia. The company announced Friday the late-stage trials are being discontinued due to slow enrollment and low clinical event rates. 

The STABILIZE-CKD and DIALIZE-Outcomes trials were part of AstraZeneca’s CRYSTALIZE evidence program researching the potential benefit of Lokelma “in the management of hyperkalemia (HK) across the cardiorenal spectrum.” The former trial was studying the drug as an adjunct to renin-angiotensin-aldosterone system inhibitor (RAASi) therapy on chronic kidney disease (CKD) patients with hyperkalemia or at high-risk of developing. The latter studied the effects of the treatment on arrythmia-related heart outcomes for patients on chronic hemodialysis. 

However, long enrollment times and low event rates made it “prohibitive to deliver study results within a timeframe to meaningfully advance clinical practice” according to Friday’s announcement. In addition, AstraZeneca emphasized that its decision is not due to safety concerns and does not change the approved indication. 

Lokelma has been approved for hyperkalemia—elevated potassium levels in the blood—since 2018. According to the National Kidney Foundation, about 26 million people globally have experienced heart failure and are living with high potassium blood levels.  

Since its approval, AstraZeneca has continued studies on the drug to add more evidence of value in different cardiorenal conditions.  

In November 2023, the company touted evidence that the drug more than doubled the odds of patients with CKDor heart failure to maintain their ability to stay on lifesaving RAASi therapy than those not on a potassium binder treatment. 

The drug was originally expected to be a blockbuster at its launch but has so far fallen short of that goal. Annual sales in 2022 for Lokelma came in at $289 million. Third-quarter 2023 results showed an increase in demand for the drug with $300 million in revenue recorded for the first nine months of the year. GlobalData predicts worldwide sales to increase to $799 million by 2029. 

Kate Goodwin is a freelance life science writer based in Des Moines, Iowa. She can be reached at and on LinkedIn

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