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Brenipatide (LY3537031) treatment for adults with IBS‑D

A Phase 2, Randomized, Double-Blind, Placebo-Controlled Study to Evaluate the Efficacy and Safety of Brenipatide in the Treatment of Adult Participants With IBS-D

Phase 2 Interventional Eli Lilly and Company · NCT07545759

This will test whether brenipatide (LY3537031) given under the skin helps adults with IBS‑D reduce belly pain and improve stool consistency compared with placebo.

Quick facts

PhasePhase 2
Study typeInterventional
Enrollment531 (estimated)
Ages18 Years to 75 Years
SexAll
SponsorEli Lilly and Company Industry-sponsored
Locations88 sites (Mesa, Arizona and 87 other locations)
Trial IDNCT07545759 on ClinicalTrials.gov

What this trial studies

This Phase 2 study gives adults with IBS‑D subcutaneous injections of brenipatide (LY3537031) or placebo over an approximately 35‑week period to characterize safety, tolerability, side effects, and preliminary symptom effects. Participants complete a daily eDiary during screening and treatment to confirm Rome IV IBS‑D criteria and to track abdominal pain and stool form. The trial compares patient-reported outcomes between the brenipatide and placebo groups and excludes people with other IBS subtypes or inflammatory/immune‑mediated GI disorders. Dosing and follow-up visits occur at clinical sites in the United States.

Who should consider this trial

Good fit: Adults who meet Rome IV criteria for IBS‑D with frequent loose stools (BSFS types 6–7 on a substantial portion of bowel movements), an average worst abdominal pain score ≥3 on a 0–10 scale during screening, and no major recent diet changes are the intended participants.

Not a fit: People with constipation‑predominant, mixed, or unclassified IBS, those with inflammatory or immune-mediated gastrointestinal disorders, or those with known clinically significant gastric emptying abnormalities are unlikely to benefit from this study.

Why it matters

Potential benefit: If successful, brenipatide could reduce abdominal pain and diarrhea and improve daily functioning for people with IBS‑D.

How similar studies have performed: Some other peptide- or receptor-targeting drugs for IBS‑D have shown symptom benefit in prior trials, but brenipatide (LY3537031) is a novel agent and its efficacy has not yet been established.

Eligibility criteria

Show full inclusion / exclusion criteria 
Inclusion Criteria:

* Meet Rome IV criteria for IBS-D, which includes having greater than 25% of bowel movements with Bristol Stool Form Scale (BSFS) Types 6 or 7 and \<25% of bowel movements with BSFS Types 1 or 2
* Based on the daily eDiary collection during the screening period:

  * Have average of worst abdominal pain score of ≥3.0 on a 0-to-10-point scale during the 14 consecutive days prior to randomization
  * Have at least 4 days per week with a maximum BSFS ≥5 AND with at least 2 days of the 4 days per week with a maximum BSFS ≥6 during the 14 consecutive days prior to randomization
* Have had no major changes in diet in the 4 weeks prior to screening

Exclusion Criteria:

* Have a diagnosis of IBS with a subtype of constipation, mixed IBS, or unclassified IBS by the Rome IV criteria
* Have a history of inflammatory or immune-mediated gastrointestinal disorders
* Have a known clinically significant gastric emptying abnormality

Where this trial is running

Mesa, Arizona and 87 other locations

+38 more sites — see ClinicalTrials.gov for the full list.

Study contacts

How to participate

  1. Review the eligibility criteria above with your treating physician.
  2. Visit the official trial page on ClinicalTrials.gov for the most current contact information and recruitment status.
  3. Contact the listed study coordinator or principal investigator to request pre-screening. Pre-screening is free and never obligates you to enroll.
View on ClinicalTrials.gov → Find more trials like this →
Conditions Irritable Bowel SyndromeDiarrhea
Last reviewed 2026-06-13 by the Find a Trial editorial team. Information on this page is for educational purposes and is not medical advice. Always consult qualified healthcare professionals about clinical trial participation.