FDA Announces Advisory Committee Meeting for Xphozah

The FDA’s Cardiovascular and Renal Drugs Advisory Committee meeting is tentatively scheduled for Nov. 16, 2022, to discuss the new drug application for Ardelyx’s Xphozah (tenapanor) for the control of serum phosphorus in adult patients with chronic kidney disease (CKD) who are on dialysis.

As part of its response to Ardelyx’s appeal of the complete response letter received on July 28, 2021, the FDA’s Office of New Drugs stated that additional input from an advisory committee, including the addition of input from expert clinicians who care for patients on dialysis, would be valuable in further considering the clinical meaningfulness of the phosphate lowering effect observed in Ardelyx’s phase 3 clinical program in order to reach a decision on the company's formal dispute resolution request. A response from the OND to Ardelyx’s appeal is expected within thirty calendar days after the conclusion of the Advisory Committee meeting.

Related: FDA to Hold Advisory Committee for Xphozah in Kidney Disease

Hyperphosphatemia is a serious condition resulting in an abnormally elevated level of phosphorus in the blood that is estimated to affect the vast majority of the 550,000 patients in the United States with chronic kidney disease on dialysis. When kidney function is impaired, phosphorus is not adequately eliminated from the body.

Hyperphosphatemia is a major cause of morbidity and mortality in patients with chronic kidney disease.

Xphozoh is a first-in-class phosphate absorption inhibitor that acts locally in the gut to inhibit the sodium hydrogen exchanger 3, reducing phosphate absorption through the paracellular pathway, the primary pathway of phosphate absorption.

Data on Xphozah was released in April. Ardelyx has completed three phase 3 pivotal trials, and two phase 4 clinical trials (OPTIMIZE and NORMALIZE) for Xphozah. In the OPTIMIZE phase 4 trial, Xphoza as monotherapy helped 63% of patients with uncontrolled hyperphosphatemia who were naïve to phosphate binder therapy to achieve target serum phosphate levels. For those with uncontrolled hyperphosphatemia despite being on treatment with phosphate binders, switching to Xphozah or adding Xphozah to a reduced binder dose enabled 34% to 38% of these patients to achieve target levels.

In the NORMALIZE phase 4 trial, up to 49.4% of patients treated with Xphozah monotherapy or in combination with sevelamer achieved a serum phosphate level within the normal range during the 18-month treatment period.