FDA to Review Resubmitted Tenapanor NDA for Hyperphosphatemia in CKD

The Food and Drug Administration (FDA) has accepted for review the resubmitted New Drug Application (NDA) for tenapanor (Xphozah^®) for the control of serum phosphate in adult patients with chronic kidney disease (CKD) on dialysis who have had an inadequate response or intolerance to a phosphate binder therapy.

Tenapanor is a first-in-class oral medication designed to block sodium/hydrogen exchanger 3 in the gastrointestinal (GI) tract, reducing the absorption of dietary sodium resulting in increased protons within the cells. The increase in protons causes a selective reduction in phosphate uptake by tightening junctions that regulate phosphate absorption in the GI tract. Tenapanor is minimally absorbed and is designed to work only within the GI tract, reducing the potential for side effects.

The NDA is supported by data from three phase 3 trials: PHREEDOM, BLOCK, and AMPLIFY (ClinicalTrials.gov Identifier: NCT03427125, NCT02675998, NCT03824587, respectively), which included more than 1200 adults with CKD on dialysis. The PHREEDOM and BLOCK trials evaluated tenapanor as monotherapy, while the AMPLIFY trial evaluated tenapanor as adjunctive therapy to phosphate binders. The application also included findings from two phase 4, open-label studies: OPTIMIZE (ClinicalTrials.gov Identifier: NCT04549597) and NORMALIZE (ClinicalTrials.gov Identifier: NCT03988920).

In November 2022, the FDA’s Cardiovascular and Renal Drugs Advisory Committee voted that the benefits of tenapanor outweigh its risks for the control of serum phosphorus in adult patients with CKD on dialysis. Recent data presented at the National Kidney Foundation 2023 Spring Clinical Meetings further supported the efficacy and safety of the treatment. Tenapanor was found to consistently lower serum phosphate in CKD patients on maintenance dialysis, regardless of race. Additionally, comparable serum phosphate reductions were observed among tenapanor- and sevelamer-treated patients.

A regulatory decision is expected on October 17, 2023. If approved, tenapanor, marketed under the brand name Xphozah, is expected to be commercially available in the fourth quarter of 2023.