The investigational drug patiromer decreased high potassium levels and maintained normal potassium levels in patients with chronic kidney disease, according to the results of a multicenter trial appearing in the New England Journal of Medicine. The study was funded by Relypsa Inc., which makes patiromer.

Hyperkalemia increases the risk of death in high-risk patients and limits the use of several types of drugs, called RAAS (renin-angiotensin-aldosterone system) inhibitors, commonly used to control hypertension and cardiovascular disease and prevent kidney disorders.

"Patients with advanced kidney disease are at highest risk for hyperkalemia thanks to a double whammy," says the study's principal investigator, Matthew R. Weir, MD, professor of medicine and director of the Division of Nephrology at the University of Maryland School of Medicine. "Their kidneys are unable to remove potassium from the body effectively, and the patient may also be taking certain blood pressure control drugs that have been linked to high potassium levels. Current medications for hyperkalemia have gastrointestinal side effects that limit their extended use. We hoped the drug in this study would do the job with minimal side effects."

In this Phase 3 study of 237 patients with chronic kidney disease who were receiving RAAS inhibitors, 76% of the patients reached the target potassium level after four weeks on patiromer. Subsequently, 107 patients were randomly assigned to the drug or a placebo. The potassium level increase was greater in the placebo group than with patiromer, and elevated potassium recurred in 60% of the placebo group compared to 15% of the patiromer group through week eight. Mild-to-moderate constipation was the most common adverse event.