Ardelyx Posts Strong XPHOZAH Real-World Data at Kidney Week
New studies demonstrate significant phosphate reduction and high patient satisfaction, bolstering the case for its novel kidney disease drug.
Ardelyx, Inc. (NASDAQ: ARDX) presented compelling new real-world evidence for its kidney disease drug, XPHOZAH (tenapanor), at the American Society of Nephrology's (ASN) Kidney Week 2025, reinforcing the drug's efficacy in a setting outside of controlled clinical trials. The data, which showed significant reductions in serum phosphate levels for patients on dialysis, underscores the drug's potential in a challenging treatment landscape.
In midday trading Friday, shares of Ardelyx were trading around $5.59. The company, with a market capitalization of approximately $1.37 billion, has an average analyst price target of $11.73, suggesting significant upside potential in the eyes of some Wall Street analysts.
The new data, detailed in a company announcement, comes from a prospective, observational study of patients with hyperphosphatemia who were not adequately controlled on their existing binder therapies. The results demonstrated an average serum phosphate reduction of approximately 1.0 mg/dL over a 120-day follow-up period. Notably, nearly half of the participants (45.3%) experienced a reduction of at least 1.0 mg/dL.
“Phosphate management is critical for patients with chronic kidney disease on dialysis, as the failure to do so leads to a higher risk of comorbidities, death, and a potential delay in transplant waitlisting,” said Edward Conner, M.D., Chief Medical Officer of Ardelyx. “Our results show the impact XPHOZAH can have in reducing serum phosphorus levels for these patients, and that its effectiveness extends outside the clinical trial setting and into the real-world.”
The study also highlighted strong patient-reported outcomes. Among patients who could assess the change, 63% felt their phosphate levels were better controlled after starting XPHOZAH. Furthermore, 69% of those patients reported an improved outlook on managing their condition, attributing it to better phosphate control and a lower pill burden.
This positive clinical data provides a crucial tailwind for Ardelyx as it navigates the commercial rollout of XPHOZAH. The drug has shown steady prescription growth, with U.S. net product sales reaching $27.4 million in the third quarter of 2025, a 9% sequential increase from the second quarter. However, the company has faced commercial headwinds. According to regulatory filings, changes to Medicare Part D coverage that took effect at the beginning of 2025 impacted the reimbursement landscape for oral-only therapies like XPHOZAH.
Despite these challenges, the consistent growth and strong real-world efficacy data may bolster the company's case with both physicians and payers. XPHOZAH works with a first-in-class mechanism, blocking phosphate absorption at the primary pathway, which distinguishes it from traditional phosphate binders. This novel approach allows it to be used as a standalone therapy or in conjunction with binders for patients who are not meeting their treatment goals.
Analysts have maintained a generally positive outlook on the stock, with the consensus rating leaning towards 'Buy'. The latest data from ASN Kidney Week is likely to reinforce this view, providing tangible evidence of the drug's value proposition. The company has previously stated it believes XPHOZAH could achieve peak annual U.S. net product sales of $750 million.
Investors will be closely watching to see if the strong clinical and real-world performance of XPHOZAH can translate into accelerated sales momentum and help the company overcome the existing reimbursement hurdles to reach its ambitious commercial targets.