Ardelyx gets hard-fought dialysis drug approval

Oct. 18, 2023

Almost two years after formally disputing an FDA rejection, Ardelyx has won approval for tenapanor to reduce serum phosphorus in adults with chronic kidney disease (CKD) on dialysis.

The drug, branded Xphozah, was approved as add-on therapy in patients who have an inadequate response to phosphate binders or who are intolerant of any dose of phosphate binder therapy. According to the Massachusetts-based biopharma, Xphozah, a single tablet taken twice daily, is the first phosphate absorption inhibitor approved for this indication. 

The drug was approved by the FDA in April 2022 for irritable bowel syndrome — branded as Ibsrela — but it's road to approval for CKD has been rocky.

Back in July 2021, Ardelyx was handed a complete response letter pertaining to its NDA for tenapanor for the control of s-P in adults with CKD on dialysis. The agency characterized the magnitude of the treatment effect as "small and of unclear clinical significance" and asked the drugmaker to conduct an additional clinical trial. 

In November 2021 Ardelyx formally disputed the decision — a mechanism by which applicants can obtain formal review of any FDA decision by raising the matter with the supervisor of the employee who made the decision. Ultimately, this lead to an AdComm reassessment and positive vote in November 2022.

Now, the drugmaker says Xphozah will be available as soon as this November.