FDA Advisory Committee Recommends Tenapanor Approval as Both Monotherapy, Combination Therapy

A US Food and Drug Administration (FDA) Advisory Committee has recommended the approval of tenapanor (XPHOZAH) as both a monotherapy and combination therapy for the control of serum phosphorus in adult patients with chronic kidney disease on dialysis.

On Nov. 16, the FDA’s Cardiovascular and Renal Drugs Advisory Committee voted 9-4 that the benefits outweigh the risk for the treatment, developed by Ardelyx, as a monotherapy and voted 10-2 for tenapanor as a combination treatment with phosphate binder treatment.

The drug works by blocking the mechanism of action in the gut to inhibit the sodium hydrogen exchanger 3 (NHE3), reducing phosphate absorption through the paracellular pathway, the primary pathway of phosphate absorption. The novel mechanism enables a single 30 mg tabled twice daily dosing regimen.

The application is based on the findings from a development program that included more than 1200 patients in 3 phase 3 clinical trials evaluating the safety and efficacy of the treatment in adult patients. Each trial met the primary endpoint, as well as key secondary endpoints.

For safety, the most common side effect was diarrhea.

"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, in a statement. "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.”

In July, the FDA issued a Complete Response Letter to Ardelyx for the treatment, saying for the application to be approved, the company will need to conduct an additional trial to demonstrate clinically relevant treatment effects on serum phosphorus or on the clinical outcome assumed to be caused by hyperphosphatemia in the patient population.

There were no safety, clinical pharmacology, or non-clinical issues were identified within the CRL.