Ardelyx Opts Out of TDAPA to Maintain XPHOZAH® Access

Ardelyx, Inc. (Nasdaq: ARDX), a biopharmaceutical company dedicated to creating innovative medications for unmet medical needs, has decided not to apply for the inclusion of its phosphate absorption inhibitor, XPHOZAH® (tenapanor), in the Centers for Medicare & Medicaid Services (CMS) End-Stage Renal Disease (ESRD) Prospective Payment System (PPS) Transitional Drug Add-on Payment Adjustment (TDAPA). The company made this decision to ensure continued patient access to XPHOZAH.

Ardelyx's analysis of CMS's policy to include oral-only medications in the PPS and the Calendar Year 2025 ESRD PPS Proposed Rule, released on June 27, 2024, indicated that the policy would likely impose significant restrictions on XPHOZAH usage. This could limit the drug's availability to all patients, regardless of their insurance coverage, thereby interfering with the crucial decision-making process between healthcare professionals and their patients.

Mike Raab, President and CEO of Ardelyx, stated that the company is committed to ensuring that innovative medicines like XPHOZAH are accessible to patients. XPHOZAH is the only approved therapy for patients who do not respond adequately to phosphate binder therapy. Over the eight months it has been in clinical use, it has shown significant benefits for patients needing to lower elevated serum phosphorus levels. Raab emphasized that including XPHOZAH in the Medicare PPS, even during the TDAPA period, would result in restrictions that effectively eliminate patient access to the therapy. He urged Congress to pass proposed bipartisan legislation to extend the exclusion of oral-only medications from the Medicare ESRD PPS, arguing that this would be the best option to maintain patient access to XPHOZAH.

XPHOZAH received U.S. Food and Drug Administration (FDA) approval in October 2023 to reduce serum phosphorus in adults with chronic kidney disease (CKD) on dialysis, particularly for those who have an inadequate response to phosphate binders. Approximately 80% of CKD patients on dialysis require medication to lower elevated serum phosphorus levels, and phosphate binders alone are insufficient for most patients. XPHOZAH, taken as a single tablet twice daily, offers a novel mechanism of action by blocking phosphate absorption through its primary pathway.

A conference call to discuss this announcement is scheduled for July 2, 2024, at 8:00 AM Eastern Time. Participants can join by dialing the provided domestic or international numbers. A webcast will also be accessible on Ardelyx's website and will be available for 30 days following the call.

XPHOZAH, developed by Ardelyx, acts locally in the gut to inhibit the sodium hydrogen exchanger 3 (NHE3), reducing phosphate absorption through the primary pathway. The most common side effect observed in clinical trials was diarrhea. XPHOZAH is contraindicated in pediatric patients under six years of age and those with known or suspected mechanical gastrointestinal obstruction.

Hyperphosphatemia, characterized by elevated phosphate levels in the blood, affects nearly all of the 550,000 CKD patients in the United States on maintenance dialysis. As kidney function declines, the body cannot adequately eliminate excess phosphate, leading to this condition. Internationally recognized guidelines recommend lowering elevated phosphate levels to within the normal range.

Ardelyx was founded to develop and commercialize innovative, first-in-class medicines for significant unmet medical needs. The company has two commercial products approved in the United States: IBSRELA® (tenapanor) and XPHOZAH®. Ardelyx has agreements for the development and commercialization of tenapanor outside the U.S., with Kyowa Kirin commercializing PHOZEVEL® in Japan, and a New Drug Application for tenapanor for hyperphosphatemia has been submitted in China with Fosun Pharma. Knight Therapeutics commercializes IBSRELA in Canada.