IBSPhase 4NCT05995899
Effect of Tenapanor on the Metagenomics and Metabolomics of Patients With Irritable Bowel Syndrome With Constipation
A Phase 4 study testing Tenapanor in people with IBS and IBS - Irritable Bowel Syndrome, run by Kyle Staller, MD, MPH at 1 site in United States.
Trial summary
The aim of this study is to better understand how tenapanor affects the metagenomics and metabolomics of patients with irritable bowel syndrome with constipation (IBS-C). Tenapanor is the newest FDA-approved agent for IBS-C. Read more about this study
- Who is it for?
- Ages 18 to 75 years
- Conditions the study is for
- IBS, IBS - Irritable Bowel Syndrome
- What is being tested?
- Tenapanor
- Type of treatment
- Pill or oral medicine
- Could I receive a placebo?
- No, everyone receives an active treatment
- How many people
- 36 participants
- Where
- 1 siteUnited States
- Study dates
- 6 Feb 2024to 17 Dec 2025
- Phase
- Phase 4
- Are there results?
- None posted in the registry
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 18 to 75 years
- All sexes
- No healthy volunteers
- Adult, Older adult
Who may be able to join
- Ages 18-75 years old
- BMI >18.5 and <35 kg/m2
- Rome IV criteria for IBS-C for at least 6 months
- Compliant with baseline stool submission prior to initiation of medication
- Ability to follow verbal and written instructions
- Ability to record daily bowel habits, including frequency, stool consistency (BSFS), and symptom severity
- Willingness to avoid major dietary changes and use of probiotics during the study period
- Informed consent form signed by the subjects
Who cannot join
- History of loose stools
- History of irritable bowel syndrome with diarrhea (IBS-D) or mixed irritable bowel syndrome (IBS-M)
- Non-compliance with baseline stool submission
- Previous use of tenapanor
- GI motility obstruction or GI tract structural abnormality
- Current use of prescribed or illicit opioids
Show all 47Show fewer
- History of pelvic floor dysfunction
- Need for manual maneuvers in order to achieve a BM
- History of GI lumen surgery at any time or other GI or abdominal operations within 60 days prior to entry into the study
- History of high-dose stimulative or cathartic laxative abuse as judged by investigator team
- Severe IBS-C as judged by the investigator
- Neurological disorders, metabolic disorders, or other significant disease that would impair their ability to participate in the study
- Cardiovascular disease, diabetes, cancer, Crohn's disease, ulcerative colitis
- BMI of <18.5 or >35 kg/m2
- Pregnancy (or positive serum or urine pregnancy test(s) in females of childbearing potential) or lactation
- Absence of contraception in females of childbearing potential
- History of allergic reaction to tenapanor
- Administration of other FDA-approved agents for the treatment of IBS-C within 1 month prior to Screening Visit:
- Linaclotide
- Lubiprostone
- Plecanatide
- If treated with any of the following medications, dosing (or approximate frequency of 'as needed' use) must be stable for at least 30 days prior to Screening Visit and the subject must agree to maintain the same dose (or approximate frequency of 'as needed' use) or a decreased dose of medication throughout the study:
- Probiotics
- Bulk laxatives, fiber, and stool softeners
- Exclusion of colonic inertia with symptoms of < 1 BM per 2 weeks
- Subjects anticipating surgical intervention during the study
- Known history of diabetes (type 1 or 2)
- Subjects with recent antibiotic use (last 3 months) or anticipated antibiotic use during the study period
- History of inflammatory bowel disease
- Supine SBP > 160 mm Hg and/or supine DBP > 95 mm Hg (mean of two consecutive readings)
- Angina, coronary bypass, or myocardial infarction within 6 months prior to Screening Visit
- History of swallowing disorders
- History of gastric bypass or any other gastric surgery
- History of small bowel resection (except if related to appendectomy)
- History of gastric or duodenal ulcer
- History of gastroparesis
- History of abdominal radiation treatment
- History of pancreatitis
- History of intestinal stricture (e.g., Crohn's disease)
- History of intestinal obstruction or subjects at high risk of intestinal obstruction including suspected small bowel adhesions
- History of malabsorption
- History of hepatitis B or C
- History of human immunodeficiency virus
- History of cancer within the past 5 years (except adequately-treated localized basal cell skin cancer or in situ uterine cervical cancer)
- Any other clinically significant disease interfering with the assessments of tenapanor, according to the Investigator (e.g., disease requiring corrective treatment, potentially leading to study discontinuation)
- HbA1c > 8.5% (> 69 mmol/mol)
- 43. Any relevant biochemical abnormality interfering with the assessments of tenapanor, according to the Investigator 44. Antidiabetic medications within 1 month prior to Screening Visit (except stable dose of metformin, ≤ 1500 mg/day, for at least 1 month in subjects with type 2 diabetes) 45. Medications requiring mandatory administration twice per day with meals
Trial locations and contacts
1 site in 1 country.
United States1 site
Massachusetts General Hospital
Boston, Massachusetts, 02114
About this study
Official title: An Open-label, Single Center Investigator Sponsored Study Assessing the Effect of Tenapanor on Metagenomic and Metabolomic Markers in Patients With Irritable Bowel Syndrome With Constipation
The aim of this study is to better understand how tenapanor affects the metagenomics and metabolomics of patients with irritable bowel syndrome with constipation (IBS-C). Tenapanor is the newest FDA-approved agent for IBS-C. It is a small molecule that inhibits the NHE3 receptor, leading to impaired sodium and water absorption in the intestine. Previous clinical trials comparing tenapanor to placebo showed that a 50 mg dose of tenapanor led to increased bowel movements and decreased abdominal pain. This study consists of an 8-week treatment period in which subjects will ingest one capsule of tenapanor (50 mg per dose), twice daily, and send in stool samples following 4 weeks and 8 weeks of treatment.
- Conditions
- IBS, IBS - Irritable Bowel Syndrome
- Being tested
- Tenapanor
- Medical subject headings
- Irritable Bowel Syndrome
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
TenapanorDrug
IBS-C patients will ingest one capsule of tenapanor (50 mg per dose), twice daily, before breakfast and dinner for a total of 8 weeks
| Study group | Role | What they receive |
|---|---|---|
| Patients with IBS-C | Experimental | Not described Receives: Drug: Tenapanor |
What is being measured
The primary outcome is the main question the study is designed to answer.
Measuring metagenomics of stool samples using whole genome shotgun sequencing (WGS)
Sequence-based microbial community surveys will be carried out by whole genome shotgun sequencing (WGS) at the Broad Institute using their established sequencing and analysis pipeline for the Illumina HiSeq2000 platform used in Human Microbiome Project (HMP) to characterize rare taxa and understand relationships between community membership and function. Composition analysis of metagenome will be performed using the read-based bioinformatics analysis suite. Functional genomic profiles, detailed species-specific reconstruction of microbial metabolic pathways, their complement of gene orthologs, taxonomic distributions, and abundances will be generated with HUMAnN2. This will provide taxon-specific profiles of UniRef orthologous gene families, MetCyc, UniPathway, and KEGG pathways to survey microbial community metabolite production potential in each metagenome according to tenapanor use.
Measured: Subjects will submit stool samples at 0 weeks, 4 weeks, and 8 weeks following treatment.
Measuring metabolomics of stool samples using the DiscoveryHD4TM Platform
Stool samples will also undergo metabolomics profiling at Metabolon Inc using the DiscoveryHD4TM Platform, a comprehensive and well-validated high-throughput metabolomics platform available for clinical and research use. Metabolites are identified by automated comparison of the ion features in the experimental samples to a reference library of ~8,000 chemical standard entries that include retention time, molecular weight (m/z), preferred adducts, in-source fragments and MS spectra, and they are visually curated for quality control using Metabolon software.
Measured: Subjects will submit stool samples at 0 weeks, 4 weeks, and 8 weeks following treatment.
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted16 Aug 2023
- Study start6 Feb 2024
- Primary completion17 Dec 2025
- Study completion17 Dec 2025
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for IBSStudies of the same condition, open and under way.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Interventional
- Phase
- Phase 4
- Primary purpose
- Treatment
- Allocation
- Not applicable
- Intervention model
- Single group
- Masking
- None (open label)
- Enrolment
- 36 participants (actual)
Sponsor and investigators
- Lead sponsor
- Kyle Staller, MD, MPH
- Sponsor type
- University, hospital or other
- Collaborators
- Ardelyx
- Responsible party
- Sponsor-investigator, Kyle Staller, MD, MPH, Massachusetts General Hospital
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT05995899
- Sponsor's protocol ID
- 2023P001911
- Status last verified
- Mar 2026
- First submitted
- 3 Aug 2023
- Last updated
- 12 Mar 2026
- Results posted
- No
- FDA-regulated drug
- Yes
- FDA-regulated device
- No
Study at a glance
From the registry record, last updated by the sponsor on 12 Mar 2026. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- An Open-label, Single Center Investigator Sponsored Study Assessing the Effect of Tenapanor on Metagenomic and Metabolomic Markers in Patients With Irritable Bowel Syndrome With Constipation
- ClinicalTrials.gov ID
- NCT05995899
- Acronym / sponsor ID
- 2023P001911
- Conditions
- IBS, IBS - Irritable Bowel Syndrome
- Phase
- Phase 4
- Study type
- Interventional
- Recruitment status
- Completed
- Enrolment
- 36 participants (actual)
- Lead sponsor
- Kyle Staller, MD, MPHUniversity, hospital or other
- Collaborators
- Ardelyx
- Study start
- 6 Feb 2024 (actual)
- Primary completion
- 17 Dec 2025 (actual)
- Study completion
- 17 Dec 2025 (actual)
- First posted
- 16 Aug 2023 (actual)
- Results
- Not posted in the source record
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
The aim of this study is to better understand how tenapanor affects the metagenomics and metabolomics of patients with irritable bowel syndrome with constipation (IBS-C). Tenapanor is the newest FDA-approved agent for IBS-C. It is a small molecule that inhibits the NHE3 receptor, leading to impaired sodium and water absorption in the intestine. Previous clinical trials comparing tenapanor to placebo showed that a 50 mg dose of tenapanor led to increased bowel movements and decreased abdominal pain. This study consists of an 8-week treatment period in which subjects will ingest one capsule of tenapanor (50 mg per dose), twice daily, and send in stool samples following 4 weeks and 8 weeks of treatment.
Study design
- Primary purpose
- Treatment
- Allocation
- Not applicable
- Intervention model
- Single group
- Masking
- None (open label)
- Number of arms
- 1
| Arm | Type | Receives |
|---|---|---|
| Patients with IBS-C | Experimental | Drug: Tenapanor |
Who may qualify
- Ages
- 18 to 75 years
- Sex
- All
- Healthy volunteers
- Not accepted
- Age groups
- Adult, Older adult
Key inclusion criteria (8 listed)
- Ages 18-75 years old
- BMI >18.5 and <35 kg/m2
- Rome IV criteria for IBS-C for at least 6 months
- Compliant with baseline stool submission prior to initiation of medication
- Ability to follow verbal and written instructions
Key exclusion criteria (47 listed)
- History of loose stools
- History of irritable bowel syndrome with diarrhea (IBS-D) or mixed irritable bowel syndrome (IBS-M)
- Non-compliance with baseline stool submission
- Previous use of tenapanor
- GI motility obstruction or GI tract structural abnormality
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Interventions
| Intervention | Type | Arms |
|---|---|---|
| TenapanorIBS-C patients will ingest one capsule of tenapanor (50 mg per dose), twice daily, before breakfast and dinner for a total of 8 weeks | Drug | Patients with IBS-C |
Primary outcome
Measuring metagenomics of stool samples using whole genome shotgun sequencing (WGS)
Time frame: Subjects will submit stool samples at 0 weeks, 4 weeks, and 8 weeks following treatment.
Sequence-based microbial community surveys will be carried out by whole genome shotgun sequencing (WGS) at the Broad Institute using their established sequencing and analysis pipeline for the Illumina HiSeq2000 platform used in Human Microbiome Project (HMP) to characterize rare taxa and understand relationships between community membership and function. Composition analysis of metagenome will be performed using the read-based bioinformatics analysis suite. Functional genomic profiles, detailed species-specific reconstruction of microbial metabolic pathways, their complement of gene orthologs, taxonomic distributions, and abundances will be generated with HUMAnN2. This will provide taxon-specific profiles of UniRef orthologous gene families, MetCyc, UniPathway, and KEGG pathways to survey microbial community metabolite production potential in each metagenome according to tenapanor use.
Measuring metabolomics of stool samples using the DiscoveryHD4TM Platform
Time frame: Subjects will submit stool samples at 0 weeks, 4 weeks, and 8 weeks following treatment.
Stool samples will also undergo metabolomics profiling at Metabolon Inc using the DiscoveryHD4TM Platform, a comprehensive and well-validated high-throughput metabolomics platform available for clinical and research use. Metabolites are identified by automated comparison of the ion features in the experimental samples to a reference library of ~8,000 chemical standard entries that include retention time, molecular weight (m/z), preferred adducts, in-source fragments and MS spectra, and they are visually curated for quality control using Metabolon software.
Results and safety
The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 12 Mar 2026.
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Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part. This study is not recruiting at the moment.
The record lists no contact. Use the official record to reach the sponsor.
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A Phase 4 study testing Tenapanor in people with IBS and IBS - Irritable Bowel Syndrome, run by Kyle Staller, MD, MPH at 1 site in United States.
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
The sponsor lists 8 inclusion and 47 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: finished, as of the sponsor's last update on 12 Mar 2026. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 1 site in United States. Whether a site is taking part right now should be confirmed with that site. See every site.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
What does this phase mean?
Phase 4 studies take place after a treatment is approved, to learn more about its long-term benefits and risks in everyday use.
Not every study follows the same path, and some studies (observational studies, device studies) have no phase.
Are results available for this study?
The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.
How can a doctor refer a patient or contact the research team?
The record lists no contact. The official record names the sponsor, who can be asked directly. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Measuring metagenomics of stool samples using whole genome shotgun sequencing (WGS) (time frame: Subjects will submit stool samples at 0 weeks, 4 weeks, and 8 weeks following treatment.). The study lists 2 primary outcomes in all. It is what the study was designed to measure, not a finding.
Where can I read the original study information?
Does a listing mean the treatment is approved or proven to work?
No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.
How often is this information updated?
AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 12 Mar 2026.