Ardelyx, Inc. announced that the U.S. Food and Drug Administration (FDA) has approved XPHOZAH (tenapanor), the first and only phosphate absorption inhibitor, indicated to reduce serum phosphorus in adults with chronic kidney disease (CKD) on dialysis 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. XPHOZAH is a single tablet taken twice daily that offers a first-in-class mechanism of action that blocks phosphate absorption through its primary pathway. FDA approval of XPHOZAH is based on a comprehensive development program, including a diverse population of more than 1,000 patients in three Phase 3 clinical trials evaluating the efficacy and safety of XPHOZAH, as monotherapy and in combination with phosphate binder therapy, all of which met their primary and key secondary endpoints (PHREEDOM [1], BLOCK [2] and AMPLIFY [3]).

Data from the three clinical trials demonstrated that XPHOZAH significantly reduced elevated serum phosphorus in patients receiving maintenance hemodialysis. Diarrhea, which occurred in 43% to 53% of patients, was the only adverse reaction reported in at least 5% of XPHOZAH-treated patients with CKD on dialysis across trials. The majority of diarrhea events in the XPHOZAH-treated patients were reported to be mild-to-moderate in severity and resolved over time, or with dose reduction.

Diarrhea was typically reported soon after initiation but could occur at any time during treatment with XPHOZAH. Severe diarrhea was reported in five percent of XPHOZAH-treated patients in these trials. Ardelyx also completed two open-label clinical trials (OPTIMIZE and NORMALIZE) to evaluate different options for integrating XPHOZAH into clinical practice.