Tenapanor may reduce the number of phosphate binder pills patients on hemodialysis (HD) take daily to control their serum phosphorus levels.

In a study, 67 Japanese patients on HD were given tenapanor twice daily in addition to their usual phosphate binders. Tenapanor dose ranged from 5 to 30 mg with half of patients eventually receiving 30 mg daily.

Over 26 weeks, mean daily phosphate binder use fell from 14.7 to 3.0 pills, Tadao Akizawa, MD, of Showa University School of Medicine in Tokyo, Japan, and colleagues reported in Kidney International Reports. Use of high-dose bixalomer, sevelamer hydrochloride, and ferric citrate hydrate decreased first. Mean serum phosphorus levels also declined from 5.19 to 4.71 mg/dL.

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The primary endpoint of a 30% or more reduction in the mean number of daily phosphate binder and tenapanor tablets was achieved by 71.6% of patients. A total of 28.4% of patients completely switched from phosphate binders to tenapanor. 

Dialysis patients are prescribed 10 to 12 different medications and take an average of 20 pills per day, half of which are phosphate binders, the investigators noted. Tenapanor is a first-in-class nonbinder that is taken twice daily as small pills. It reduces paracellular absorption of phosphate by local inhibition of the intestinal sodium/hydrogen exchanger.

Diarrhea occurred in 74.6% of study participants taking tenapanor, and 6.0% of patients discontinued the study due to it. Patients with conditions associated with diarrhea, such as irritable bowel syndrome or inflammatory bowel disease, were previously excluded from the study. Patients with intact parathyroid hormone levels exceeding 600 pg/mL also were not permitted to enroll.

“Patients who completely switched from the phosphate binder regimen were able to reduce not only the number of tablets taken but also the number of medication administration times per day for hyperphosphatemia,” Dr Akizawa’s team wrote.

The investigators will assess the safety of tenapanor treatment for 1 year and test whether reducing the starting dose of tenapanor improves diarrhea.

Disclosure: This research was supported by Kyowa Kirin Co., Ltd. Please see the original reference for a full list of disclosures.


Akizawa T, Sato Y, Ikejiri K, Kanda H, Fukagawa M. Effect of tenapanor on phosphate binder pill burden in hemodialysis patients. Kidney Int Rep. Published online July 7, 2021. doi:10.1016/j.ekir.2021.06.030