FDA panel okays tenapanor as monotherapy for control of serum phosphorus in CKD patients on dialysis

Use of tenapanor (Xphozah®) as monotherapy for the control of serum phosphorus in adult patients with chronic kidney disease (CKD) on dialysis has been favourably voted by FDA panel. Also the panel voted in favor of use of tenapanor in combination with phosphate binders (10 to 2, with 1 abstention).

"Today's vote by the CRDAC is a promising development for the chronic kidney disease community, as patients continue to struggle to control serum phosphorus levels despite use of currently available therapies, which are all limited to the phosphate binder class," said Mike Raab, president and chief executive officer of Ardelyx. "We are confident that the data from three Phase 3 clinical trials involving more than 1,200 patients support the approval of XPHOZAH in the U.S. for the control of serum phosphorus in adult patients with CKD on dialysis.

We want to thank the patients, physicians and the advocacy community who shared their valuable insights today and throughout the development program. We are hopeful following today's discussion that the data, the opinion of the advisory committee, the needs of patients, and the compelling voice of the broader nephrology community will be reflected in the FDA's decision on our appeal."

Sharon Moe, M.D., chief of the division of nephrology and hypertension, Indiana University School of Medicine, added, "XPHOZAH is a novel treatment that provides a clinically meaningful effect on serum phosphate. I am encouraged by the committee's vote. The nephrology community is enthusiastic to have access to this therapy with its novel mechanism of action to help our patients."

The CRDAC review of XPHOZAH for the control of serum phosphorus in adult patients with CKD on dialysis was based on findings from a comprehensive development program including more than 1,200 patients in three Phase 3 clinical trials evaluating the safety and efficacy of XPHOZAH, all of which met their primary and key secondary endpoints (PHREEDOM, BLOCK and AMPLIFY).

The CRDAC's recommendations, while not binding, will be considered by the Office of New Drugs (OND), Center for Drug Evaluation and Research of the FDA, when making its decision on Ardelyx's second level appeal of the Complete Response Letter received on July 28, 2021, for XPHOZAH. The OND is expected to provide a response to Ardelyx's appeal within thirty (30) days.

About XPHOZAH (tenapanor) for Hyperphosphatemia

XPHOZAH (tenapanor), discovered and developed by Ardelyx, is an investigational first-in-class phosphate absorption inhibitor (PAI). XPHOZAH, with its unique blocking mechanism of action, acts locally in the gut to inhibit the sodium hydrogen exchanger 3 (NHE3), reducing phosphate absorption through the paracellular pathway, the primary pathway of phosphate absorption. This novel blocking mechanism enables a one 30 mg tablet BID (twice) daily dosing regimen. The most common side effect with tenapanor in clinical trials was diarrhea.

About Hyperphosphatemia

Elevated levels of serum phosphorus in the blood, or hyperphosphatemia (HP), is a serious condition resulting in an abnormally elevated level of phosphorus in the blood that is estimated to affect more than 745,000 dialysis patients in major developed countries. The kidney is the organ responsible for regulating phosphorus levels, but when kidney function is significantly impaired, phosphorus is not adequately eliminated from the body. As a result, hyperphosphatemia is a nearly universal condition among people with CKD on dialysis with internationally recognized KDIGO treatment guidelines that recommend lowering elevated phosphate levels toward the normal range (2.5-4.5mg/dL).

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Press release