Ardelyx Announces Abstract Exploring IBS-C Treatment Patterns Accepted for Poster Presentation at Digestive Disease Week 2026

WALTHAM, Mass., April 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 an abstract, exploring the patient characteristics associated with irritable bowel syndrome with constipation (IBS-C) treatment patterns and their impact on gastrointestinal (GI) related healthcare resource utilization (HCRU), has been accepted as a poster presentation at the upcoming Digestive Disease Week Conference (DDW), to be held May 2-5, 2026, in Chicago.

Information regarding DDW can be found here.

Patient Factors Associated with Irritable Bowel Syndrome with Constipation (IBS-C) Treatment Changes
Authors: Alan Fossa, Kyle Staller, Lavanya Viswanathan, Asma Khapra, Luisa Scott
Poster: Sa1729
Display Time: May 2, 2026, 12:30 – 1:30 PM CT

In addition to the poster presentation during DDW, Ardelyx is sponsoring a Product Theater titled “IBS-C: Identifying and Managing the Symptoms,” on May 5 at 3:00 PM CT, where Darren Brenner, MD will lead an engaging clinical discussion on managing adult patients with IBS-C. The session will explore the pathophysiology of IBS-C, examine patient case studies, and discuss practical strategies for identifying when and how to optimize care for patients who may not be achieving adequate symptom relief.

About IBSRELA® (tenapanor)
IBSRELA (tenapanor) is a locally acting inhibitor of the sodium/hydrogen exchanger 3 (NHE3), an antiporter expressed on the apical surface of the small intestine and colon primarily responsible for the absorption of dietary sodium. By inhibiting NHE3 on the apical surface of the enterocytes, tenapanor reduces absorption of sodium from the small intestine and colon, thus retaining luminal water content, which accelerates intestinal transit time and results in a softer stool consistency. IBSRELA has also been shown to reduce abdominal pain by decreasing visceral hypersensitivity and by decreasing intestinal permeability in animal models. In a rat model of colonic hypersensitivity, tenapanor reduced visceral hyperalgesia and normalized colonic sensory neuronal excitability.

About Irritable Bowel Syndrome with Constipation (IBS-C)
Irritable bowel syndrome with constipation (IBS-C) is a gastrointestinal disorder characterized by both abdominal pain and altered bowel movements, estimated to affect 12 million people in the U.S. IBS-C is associated with significantly impaired quality of life, reduced productivity, and substantial economic burden.

IMPORTANT SAFETY INFORMATION (IBSRELA)

CONTRAINDICATIONS

• IBSRELA is contraindicated in patients less than 6 years of age due to the risk of serious dehydration.
• IBSRELA is contraindicated in patients with known or suspected mechanical gastrointestinal obstruction.

WARNINGS AND PRECAUTIONS
Risk of Serious Dehydration in Pediatric Patients

• IBSRELA is contraindicated in patients below 6 years of age. The safety and effectiveness of IBSRELA in patients less than 18 years of age have not been established. In young juvenile rats (less than 1 week old; approximate human age equivalent of less than 2 years of age), decreased body weight and deaths occurred, presumed to be due to dehydration, following oral administration of tenapanor. There are no data available in older juvenile rats (human age equivalent 2 years to less than 12 years).
• Avoid the use of IBSRELA in patients 6 years to less than 12 years of age. Although there are no data in older juvenile rats, given the deaths in younger rats and the lack of clinical safety and efficacy data in pediatric patients, avoid the use of IBSRELA in patients 6 years to less than 12 years of age.

Diarrhea
Diarrhea was the most common adverse reaction in two randomized, double-blind, placebo-controlled trials of IBS-C. Severe diarrhea was reported in 2.5% of IBSRELA-treated patients. If severe diarrhea occurs, suspend dosing and rehydrate patient.

MOST COMMON ADVERSE REACTIONS
The most common adverse reactions in IBSRELA-treated patients (incidence ≥2% and greater than placebo) were: diarrhea (16% vs 4% placebo), abdominal distension (3% vs <1%), flatulence (3% vs 1%) and dizziness (2% vs <1%).

INDICATION
IBSRELA (tenapanor) is indicated for the treatment of Irritable Bowel Syndrome with Constipation (IBS-C) in adults.

Please see full Prescribing Information, including Boxed Warning, for additional risk 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.

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

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