Researchers presented two preliminary studies at ASN Kidney Week 2014 that demonstrate the potential of tenapanor—a minimally-systemic inhibitor of the intestinal sodium/proton exchanger subtype 3 (NHE3)—to help reduce phosphorus absorption in patients with kidney disease.

Previous studies have shown that tenapanor can reduce the absorption of sodium. In the first study, researchers used two animal models to determine if the drug could also reduce phosphorus absorption.

Investigators found that tenapanor reduced phosphorous absorption in the rodent model demonstrated by an increase in fecal phosphorus excretion in animals receiving the drug compared to controls. A second model examining cardiovascular effects found reductions in vascular calcification markers for animals receiving tenapanor.

Investigational drug reduces hyperkalemia levels in chronic kidney disease patients

“These results suggest that tenapanor may provide a new approach to [phosphorus] management in renal disease and associated mineral disorders,” the authors reported.

The second study investigated the effects of the drug on phosphorus absorption in healthy volunteers. Two double-blinded, placebo-controlled studies examined two dosing regimens over a seven day period—multiple ascending dosing and different dosing.

Both regimens demonstrated increased phosphorus excretion for participants receiving the drug compared to placebo.

“Tenapanor may provide a new mechanism for the treatment of hyperphosphatemia, with the potential added benefits of reducing pill burden and improving Na overload in patients with end stage renal disease,” the authors concluded.

Study authors acknowledged receiving funding from Ardelyx Inc., and AstraZeneca.

“Tenapanor Inhibits Phosphorous Absorption, and Protects against Vascular Calcification in Nephrectomized Rats” (Abstract FR-OR111)

“Tenapanor, a Minimally Absorbed NHE3 Inhibitor, Reduces Dietary Phosphorus Absorption in Healthy Volunteers” (Abstract FR-OR112)