Lokelma may be prescribed at general hospitals in Korea

Approved by drug committees at major hospitals nationwide, including Seoul National University Hospital

Expected to address the dilemma that follows RAAS inhibitor discontinuation

Lokelma, a new treatment for hyperkalemia, is gaining access to general hospital formularies in Korea.

According to industry sources, AstraZeneca Korea’s Lokelma (sodium zirconium cyclosilicate, SZC) has passed the drug committees at major medical institutions, including Seoul National University Hospital, Gangnam Severance Hospital, and Seoul National University Bundang Hospital.

Lokelma is gaining attention as a treatment option that may help address the clinical dilemma of patients having to discontinue renin-angiotensin-aldosterone system (RAAS) inhibitors when managing hyperkalemia.

Approved in Korea last November, Lokelma is the first new treatment option for hyperkalemia to emerge in approximately 40 years.

Unlike conventional organic polymer-based adsorbents, Lokelma is an inorganic crystalline potassium binder. It selectively captures potassium throughout the gastrointestinal tract and removes it from the body. In vitro studies show its selectivity for potassium is more than 125 times higher than that of conventional agents. The fact that it is not absorbed systemically is also considered a key differentiating feature.

Hyperkalemia is defined as a serum potassium level greater than 5.0 mmol/L and commonly occurs in patients with chronic kidney disease, heart failure, and diabetes. It develops in 40% to 50% of patients with chronic kidney disease, and one in three patients (32.8%) who take RAAS inhibitors reportedly experience hyperkalemia at least once. Progression to severe disease can lead to potentially fatal outcomes, including arrhythmia and cardiac arrest.

The problem lies in the conflict between treatment strategies. RAAS inhibitors are essential therapies for protecting the heart and kidneys, but they can raise potassium levels. Consequently, the onset of hyperkalemia often leads to dose reduction or treatment discontinuation.

Guidelines from organizations including Kidney Disease | Improving Global Outcomes (KDIGO), as well as clinical practice guidelines from the Korean Society of Nephrology, mention the use of potassium binders as an adjunctive strategy for maintaining RAAS inhibitor therapy.

Lokelma has demonstrated its efficacy in two clinical studies. In the ZS-003 study involving 753 patients with hyperkalemia, treatment with Lokelma 10 g produced a significant reduction in serum potassium within 1 hour. Within 48 hours, 86.4% of Lokelma patients achieved potassium levels within the normal range, compared with 47.8% in the placebo group.

In the HARMONIZE (ZS-004) study, mean serum potassium decreased from 5.6 mmol/L to 4.5 mmol/L within 48 hours and remained stably controlled at a low level during the maintenance phase.

The effect was also sustained in the long-term data. In the ZS-005 study, 88% of patients maintained normal potassium levels during treatment for up to 12 months. Among patients using RAAS inhibitors, 87% were able to continue treatment or increase their dose.