Ardelyx Presents Real-World Data at ASN Kidney Week 2026 Showing Serum Phosphate Reductions Following XPHOZAH® (tenapanor) Initiation With or Without Phosphate Binders

Phosphate reductions were observed both without a phosphate binder and when tenapanor was added to a single binder.

Rhea-AI Summary

Ardelyx (ARDX) presented real-world results showing serum phosphate reductions after XPHOZAH initiation in adults on dialysis at ASN Kidney Week 2026.

The analysis included more than 1,400 adults with elevated blood phosphate who started tenapanor without a phosphate binder or alongside a single binder. Across all treatment groups, adjusted mean phosphate reductions at month six ranged from 0.80 to 1.55 mg/dL. The adjusted probability of reaching phosphate below 5.5 mg/dL ranged from 16% to 41% across groups. At 180 days, 60% to 70% of patients remained on tenapanor, with comparable probabilities of remaining on treatment across phosphate-binder groups.

Positive

• Minor pointAdjusted mean serum phosphate reductions at month six ranged from 0.80 to 1.55 mg/dL across treatment groups.
• Minor pointAdjusted probability of reaching serum phosphate below 5.5 mg/dL ranged from 16% to 41% across groups.
• Minor pointTenapanor treatment continuation was 60% to 70% at 180 days, with comparable probabilities across phosphate-binder groups.

Negative

• None.

Key Figures

Analysis population: More than 1,400 adults Adjusted mean serum phosphate reduction: 0.80–1.55 mg/dL Reached serum phosphate below 5.5 mg/dL: 16%–41% +1 more

Analysis population

More than 1,400 adults

Adults on dialysis with hyperphosphatemia who initiated tenapanor

Adjusted mean serum phosphate reduction

0.80–1.55 mg/dL

At month six across treatment groups

Reached serum phosphate below 5.5 mg/dL

16%–41%

Adjusted probability across groups

Remained on tenapanor

60%–70%

At 180 days across groups

Key Terms

hyperphosphatemia, phosphate absorption inhibitor, paracellular pathway, chronic kidney disease

4 terms

hyperphosphatemia medical

"challenges patients experience in managing hyperphosphatemia"

An elevated level of phosphate in the blood, often caused by reduced kidney function or certain medications, that can harm bones, blood vessels and organs if untreated. Investors should care because prevalence, safety concerns and regulatory scrutiny around treatments or diagnostics for this condition can drive demand, affect clinical trial outcomes, influence healthcare spending and change a company’s revenue and risk profile—similar to how a common road hazard can change demand for safety products.

phosphate absorption inhibitor medical

"the first and only phosphate absorption inhibitor (PAI) approved"

A phosphate absorption inhibitor is a type of medicine that reduces the amount of dietary phosphorus the body takes in from the gut, acting like a sieve that prevents excess mineral from entering the bloodstream. Investors watch these drugs because they target a chronic condition common in kidney disease, so clinical trial results, regulatory approval, safety and ease of use can drive sales, market share and long‑term revenue potential.

paracellular pathway medical

"blocks phosphate absorption through the paracellular pathway"

The paracellular pathway is the route that substances take when moving between adjacent cells across a tissue layer, rather than passing through the interior of cells. In epithelia and endothelia this pathway is controlled by intercellular junctions—especially tight junctions—that restrict passage by size and charge, so it governs how small ions, water, and some solutes cross barrier tissues and contributes to overall tissue permeability and barrier function.

chronic kidney disease medical

"adults with chronic kidney disease (CKD) on dialysis"

Chronic kidney disease is a long-term, progressive loss of kidney function that reduces the organs’ ability to filter waste, control fluid levels and balance body salts. For investors, CKD matters because it creates sustained demand for tests, drugs, dialysis machines and transplants; advances in treatment or regulatory decisions can meaningfully change revenue prospects for companies—like a car that needs ongoing repairs, it creates predictable, long-term market needs.

AI-generated analysis. How Rhea-AI works. Not financial advice.

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Real-world analysis showed serum phosphate reductions following XPHOZAH initiation across all phosphate binder groups evaluated

Additional data highlighted the challenges of managing hyperphosphatemia and the morbidity and mortality risks associated with long-term elevated phosphorus

WALTHAM, Mass., Oct. 23, 2026 (GLOBE NEWSWIRE) -- Ardelyx, Inc. (Nasdaq: ARDX), a commercial-stage biopharmaceutical company focused on the development and commercialization of innovative medicines that meet significant unmet medical needs, today announced results from a real-world analysis presented at the American Society of Nephrology (ASN) Kidney Week 2026 evaluating real-world serum phosphate outcomes among adults on dialysis who initiated XPHOZAH either without a phosphate binder or as add-on therapy to a single phosphate binder. Ardelyx also presented data on the challenges patients experience in managing hyperphosphatemia, as well as the association between long-term hyperphosphatemia and serious health outcomes in patients on dialysis, including morbidity and mortality.

"These findings add meaningful real-world evidence describing serum phosphate reductions following XPHOZAH initiation in patients both with and without a phosphate binder at baseline," said Rajani Dinavahi, MD, Chief Medical Officer of Ardelyx. "The broader research we presented at ASN Kidney Week also highlights how persistently difficult it is for patients to manage hyperphosphatemia, and the serious mortality and morbidity risks associated with cumulative phosphate burden. Taken together, these data reinforce the ongoing challenges of phosphate management and why we need more treatment options to help patients on dialysis gain control of their phosphate levels "

The real-world analysis looked at serum phosphate outcomes in more than 1,400 adults on dialysis with hyperphosphatemia who started tenapanor either without a phosphate binder or alongside a single phosphate binder. Across all treatment groups, serum phosphate levels declined over six months of follow-up, with adjusted mean reductions at month six ranging from 0.80 to 1.55 mg/dL. The adjusted probability of reaching a serum phosphate level below 5.5 mg/dL ranged from 16% to 41% across groups, and 60% to 70% of patients remained on tenapanor at 180 days. The probability of remaining on tenapanor at 180 days was comparable across phosphate-binder groups. Overall, similar serum phosphate reductions were observed across the phosphate-binder groups evaluated, including among patients who initiated tenapanor without a phosphate binder.

Presentations at ASN 2026 include:

Presentation Title	Authors	Poster Number	Presentation Details
Real-World Effectiveness of Tenapanor: Serum Phosphate Outcomes by Existing Phosphate Binder Use	Alan Fossa, Dhajanae Sylvertooth, Angelo Karaboyas, Roberto Pecoits-Filho, Luisa L. Scott	FR-PO0317	Poster, Oct 23, 10:00 AM to 12:00 PM MDT
Patient Perspectives on Hyperphosphatemia Management in a Contemporary End-Stage Kidney Disease Cohort: Results of an Online Survey	Nissreen Elfadawy, Jaime Uribarri, Janet Diaz-Martinez, Asa Renfroe, Emily Belcher, Luisa L. Scott	FR-PO0324	Poster, Oct 23, 10:00 AM to 12:00 PM MDT
Morbidity and Mortality Risks Associated with Cumulative Hyperphosphatemia in a Contemporary Cohort of US Dialysis Patients	Julia Scialla, Bernard Jaar, Nan Ji, Roberto Pecoits-Filho, Keith McCullough, Luisa L. Scott	FR-PO0316	Poster, Oct 23, 10:00 AM to 12:00 PM MDT

The posters are available on the ASN Kidney Week 2026 website here.

About XPHOZAH® (tenapanor)
XPHOZAH® (tenapanor) is the first and only phosphate absorption inhibitor (PAI) approved by the U.S. Food and Drug Administration 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. With a differentiated mechanism of action, XPHOZAH blocks phosphate absorption through the paracellular pathway, the primary pathway of phosphate absorption, and is administered as one tablet taken twice daily. Diarrhea was the most common side effect experienced by patients taking XPHOZAH in clinical trials. Please see Important Safety Information below and click for full Prescribing Information.

About Hyperphosphatemia
Hyperphosphatemia is a serious condition characterized by elevated levels of phosphate in the blood that affects many of the approximately 550,000 people in the United States with chronic kidney disease (CKD) on maintenance dialysis. As kidney function declines, the kidneys are unable to adequately eliminate excess phosphate, leading to its accumulation in the blood. Elevated phosphate levels are associated with adverse clinical outcomes in patients with CKD on dialysis. International KDIGO treatment guidelines recommend lowering progressively or persistently elevated serum phosphate toward the laboratory-specific normal range. In adults, a commonly used reference range is approximately 2.5–4.5 mg/dL.

IMPORTANT SAFETY INFORMATION
CONTRAINDICATIONS
XPHOZAH is contraindicated in:

• Pediatric patients under 6 years of age
• Patients with known or suspected mechanical gastrointestinal obstruction
  
  

WARNINGS AND PRECAUTIONS
Diarrhea
Patients may experience severe diarrhea. Treatment with XPHOZAH should be discontinued in patients who develop severe diarrhea.

MOST COMMON ADVERSE REACTIONS
Diarrhea, which occurred in 43-53% 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 5% of XPHOZAH-treated patients in these trials.

INDICATION
XPHOZAH (tenapanor), 30 mg BID, is 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.

For additional safety information, please see full Prescribing Information.

About Ardelyx
Ardelyx is a commercial-stage biopharmaceutical company focused on the development and commercialization of innovative medicines that meet significant unmet medical needs. Ardelyx has two commercial products approved in the United States, IBSRELA® (tenapanor) and XPHOZAH® (tenapanor). The company’s pipeline includes the Phase 3 development of IBSRELA for chronic idiopathic constipation (CIC) and RDX10531, a next-generation NHE3 inhibitor with potential application across multiple therapeutic areas. Ardelyx works with its partners to develop and commercialize its products outside of the United States. For more information, please visit https://ardelyx.com/ and connect with us on X (formerly known as Twitter), LinkedIn and Facebook.

Forward Looking Statements
To the extent that statements contained in this press release are not descriptions of historical facts regarding Ardelyx, they are forward-looking statements reflecting the current beliefs and expectations of management made pursuant to the safe harbor of the Private Securities Litigation Reform Act of 1995, including Ardelyx’s current expectations regarding: the presentation sessions at ASN Kidney Week 2026, including their timing and content; any clinical implications of the real-world or other analyses described in this press release; and our ongoing development programs. Such forward-looking statements involve known and unknown risks, uncertainties and other factors that are in some cases beyond our control, that could cause actual outcomes or results to differ materially from those expressed or implied by the forward-looking statements. Such risks and uncertainties include, among others, uncertainties associated with the development of, regulatory process for, and commercialization of drugs in the U.S. and internationally, and the risk that real-world, post hoc, observational, survey or other analyses may not be indicative of future results or outcomes in broader patient populations, or may be interpreted differently by others. Ardelyx undertakes no obligation to update or revise any forward-looking statements. For a further description of the risks and uncertainties that could cause actual results to differ from those expressed in these forward-looking statements, as well as risks relating to Ardelyx’s business in general, please refer to Ardelyx's Quarterly Report on Form 10-Q filed with the Securities and Exchange Commission on August 6, 2026, and its future current and periodic reports to be filed with the Securities and Exchange Commission.

Investor Contact:
Lisa Caperelli
SVP, Investor Relations & Corporate Communications
lcaperelli@ardelyx.com

Media Contact:
Lindsey Manuel
Associate Director, Corporate Communications
lmanuel@ardelyx.com

FAQ

AI-generated questions and answers. How Rhea-AI works. Not financial advice.

What did Ardelyx's real-world XPHOZAH analysis show at ASN Kidney Week 2026?

Adjusted mean serum phosphate reductions at month six ranged from 0.80 to 1.55 mg/dL across treatment groups. The analysis covered more than 1,400 adults on dialysis who started tenapanor without a phosphate binder or alongside a single binder.