Ardelyx Inc.

ARDX

Held by 4 specialist biotech funds

High Convergence

4 funds opened new positions. Next phase3 readout (Tenapanor 50 MG): Jun 2026. Short interest: 11.2% of float.

BiotechnologyCEO: Michael G. RaabIPO: 2014Website ↗

Ardelyx, Inc., a biopharmaceutical company, discovers, develops, and commercializes medicines to treat gastrointestinal and cardiorenal therapeutic areas in the United States and internationally. The company's lead product candidate is tenapanor, which has completed Phase III clinical trial for the treatment of patients with irritable bowel syndrome with constipation, as well as in Phase III clinical trial to control serum phosphorus in adult patients with chronic kidney disease (CKD)on dialysis, or hyperphosphatemia. It is also developing RDX013, a potassium secretagogue, for the treatment of elevated serum potassium, or hyperkalemia, a problem among certain patients with kidney and/or heart disease; and RDX020, an early-stage program in metabolic acidosis, a serious electrolyte disorder in patients with CKD. The company has agreements with Kyowa Kirin in Japan, Fosun Pharmaceutical Industrial Development Co. Ltd. in China, and Knight Therapeutics, Inc. in Canada for the development and commercialization of tenapanor in their respective territories. The company was formerly known as Nteryx, Inc. and changed its name to Ardelyx, Inc. in June 2008. Ardelyx, Inc. was incorporated in 2007 and is headquartered in Waltham, Massachusetts.

Catalysts

Phase 2Q4 2011RDX5791Constipation Predominant Irritable Bowel SyndromeNCT01340053

Primary: Complete Spontaneous Bowel Movement (CSBM) Frequency Change From Baseline (Baseline and Week 4)Enrollment:186/186Sites: 16RANDOMIZED, DOUBLE, TREATMENT

Phase 3PositiveQ4 2014AZD1722Constipation Predominant Irritable Bowel SyndromeNCT01923428

Primary: Percent Complete Spontaneous Bowel Movement Responders vs Placebo (12 weeks)Enrollment:356/356Sites: 4RANDOMIZED, QUADRUPLE, TREATMENT

Phase 3PositiveQ4 2016TenapanorHyperphosphatemiaNCT02675998

Phase 3PositiveQ1 2017TenapanorConstipation Predominant Irritable Bowel SyndromeNCT02621892

Phase 2NegativeQ2 2017RDX227675HyperkalemiaNCT03018067

Primary: Exponential Rate of Change in Serum Potassium from Baseline (48 hours)Enrollment:Target 60Sites: 1RANDOMIZED, SINGLE, TREATMENT

Phase 3PositiveQ3 2019TenapanorHyperphosphatemiaNCT03824587

Primary: Change in Serum Phosphorus (s-P) Level From Baseline to Week 4. (4 Weeks (28 days randomization period; from baseline to week 4))Enrollment:236/236Sites: 48RANDOMIZED, TRIPLE, TREATMENT

Phase 3PositiveQ4 2019TenapanorHyperphosphatemiaNCT03427125

Primary: Change in Serum Phosphorus Levels During Placebo Controlled Randomized Withdrawal Period in the Responder Population (12 weeks (randomized withdrawal period))Enrollment:1,559/1,559Sites: 2RANDOMIZED, TRIPLE, TREATMENT

Phase 3Q2 2026Tenapanor 50 MGIrritable Bowel Syndrome With Constipation (IBS-C)NCT05643534

Primary: 6/12-week APS (abdominal pain and SBM) +2 response (12 weeks)Enrollment:Target 180Sites: 41RANDOMIZED, DOUBLE, TREATMENT

Phase 2Q3 2026TenapanorIrritable Bowel Syndrome With Constipation (IBS-C)NCT06553547

Primary: Average weekly SBM (week 4) (4 weeks)Enrollment:Target 72Sites: 17RANDOMIZED, DOUBLE, TREATMENT

Phase 3Q1 2027Tenapanor 5 mg BIDChronic Idiopathic Constipation (CIC)NCT07382167

Primary: Durable complete spontaneous bowel movements (CSBM) response (12 Weeks)Enrollment:Target 692Sites: 79RANDOMIZED, QUADRUPLE, TREATMENT

Phase 3Q3 2031TenapanorIrritable Bowel Syndrome With Constipation (IBS-C)NCT05905926

Primary: Safety Measure Assessment (Adverse Event) (40 weeks)Enrollment:Target 150Sites: 22NA, HEALTH_SERVICES_RESEARCH

Recent News & Research

PubMed

Tenapanor reduces phosphate binder pill burden among hemodialysis patients in a post hoc phase 3 analysis.

# Ardelyx Investment Summary Tenapanor demonstrated a clinically meaningful reduction in phosphate binder pill burden among hemodialysis patients in post hoc phase 3 analysis, potentially addressing a significant adherence barrier in this population. This finding strengthens the value proposition for tenapanor's commercial positioning by quantifying a tangible patient benefit beyond phosphate control alone, which could improve market adoption among nephrologists and patients seeking to reduce medication load. For investors, reduced pill burden translates to improved treatment compliance, better clinical outcomes, and potentially broader formulary coverage—all factors that could drive patient uptake and revenue expansion in the large dialysis market.

Jul 1, 2026

PubMed

Tenapanor-Associated Bowel Effects in Hemodialysis: Persistence Barriers and Practical Continuation Strategies.

# Investment Summary: Tenapanor Bowel Effects Study **Clinical Finding:** This 2026 study examines persistent gastrointestinal side effects from tenapanor (Ardelyx's phosphate binder) in hemodialysis patients, identifying adherence barriers and potential mitigation strategies for treatment continuation. **Commercial Implication:** Bowel-related adverse effects represent a significant real-world barrier to patient persistence and market penetration for tenapanor, directly impacting revenue trajectory and competitive positioning against alternative phosphate binders; the study's focus on "continuation strategies" suggests ongoing tolerability challenges require active management rather than being resolved. **Investor Relevance:** The findings indicate tenapanor's commercial success depends on successfully implementing GI side effect management protocols—failure to do so could constrain adoption rates and market share in the hemodialysis population, affecting revenue forecasts and long-term commercial

Jun 14, 2026

PubMed

Tenapanor Beyond Phosphate: Gut Sodium Transport, Stool Transit, and Volume Balance in Dialysis.

# Ardelyx (ARDX) Research Summary **Study Focus:** This research explores tenapanor's mechanisms beyond its primary phosphate-lowering indication, specifically examining effects on gut sodium transport, bowel transit, and fluid balance in dialysis patients. **Investor Implications:** The findings could support label expansion or combination therapy opportunities if tenapanor demonstrates clinically meaningful benefits in managing fluid overload or electrolyte balance—common comorbidities in dialysis populations that currently lack effective oral treatments. However, the clinical and commercial significance depends on whether these secondary mechanisms translate to measurable patient outcomes that justify reimbursement and physician adoption beyond the existing hyperphosphatemia indication. **Key Question:** Success hinges on whether improved stool transit or sodium handling demonstrates efficacy in a Phase 2/3 trial and whether payers view this as additive value versus existing standard-of-care fluid management strategies.

May 31, 2026

PubMed

Correction to: Safety and Efficacy of Tenapanor for Long-term Serum Phosphate Control in Maintenance Dialysis: A 52-Week Randomized Phase 3 Trial (PHREEDOM).

# Ardelyx Inc. (ARDX) - Tenapanor Research Summary This correction to the PHREEDOM Phase 3 trial data for tenapanor reinforces the drug's safety and efficacy profile for managing hyperphosphatemia in dialysis patients over 52 weeks, supporting its commercial viability in a market currently dominated by older phosphate binders. The long-term safety demonstration is clinically meaningful as chronic kidney disease patients require ongoing phosphate control, potentially establishing tenapanor as a competitive alternative with differentiated tolerability. For investors, validation of sustained efficacy and safety over one year strengthens the drug's market positioning and reimbursement prospects, though the correction nature suggests prior data clarifications that warrant review of the original trial details.

May 7, 2026

PubMed

Correction to: Abdominal Symptom Improvement During Clinical Trials of Tenapanor in Patients With Irritable Bowel Syndrome With Constipation: A Post Hoc Analysis.

# Investment Summary: Ardelyx Tenapanor IBS-C Data Correction This correction to a post hoc analysis of tenapanor's abdominal symptom benefits in IBS-C patients suggests the company is refining efficacy claims around its lead product. The correction itself—without seeing the specific changes—indicates potential issues with the original data interpretation or statistical methodology that could affect how regulators and clinicians view tenapanor's clinical profile relative to competitors. **Investor implications:** Corrections to published efficacy data create uncertainty around tenapanor's commercial positioning for IBS-C, particularly given the crowded market landscape and prior regulatory scrutiny of symptom improvement claims in this indication. The timing and nature of the correction should be tracked against upcoming label discussions and reimbursement discussions with payers.

May 4, 2026

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