Efficacy and Safety of Brenipatide (LY3537031) in Adults with Irritable Bowel Syndrome‑Constipation (IBS‑C) – A Phase 2 Randomized, Double‑Blind, Placebo‑Controlled Study

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What is this study about?

The study focuses on adults with Irritable Bowel Syndrome – Constipation, a condition that causes abdominal pain, bloating and hard, infrequent stools. The investigational medicine being tested is Brenipatide, identified by the code LY3537031. It is given as a subcutaneous injection, meaning the medicine is placed just under the skin.

The main aim is to determine whether Brenipatide improves symptoms compared with placebo. Participants are assigned by chance to receive either the study drug or the placebo, and the trial is conducted in a double‑blind manner so that neither the participants nor the study staff know which treatment is administered. After a short screening period, injections are given regularly for several weeks, and participants attend clinic visits to report how they feel and to have safety checks.

Throughout the 16‑week period, the study records how many weeks each participant experiences a meaningful reduction in pain and stool difficulty, and it monitors any side effects. The collected information will help decide if the medicine is both effective and safe for people with this type of irritable bowel syndrome.

1 initial enrollment and baseline assessments

after agreeing to take part, you will sign the required forms and provide basic health information.

the study team will record your current symptoms of irritable bowel syndrome with constipation and perform any standard measurements needed before treatment begins.

2 random assignment to study medication

you will be randomly placed into one of two groups without knowing which group you are in.

one group receives brenipatide, the active drug, and the other group receives a matching placebo, which looks identical but contains no active substance.

3 receiving the injection device

the medication is supplied as a solution for injection in a pre‑filled syringe.

the route of administration is subcutaneous, meaning the injection is given just under the skin.

4 weekly subcutaneous injections

you will inject the assigned product once each week for the duration of the study.

the product description lists the dose as 0 units; the exact amount to be injected is determined by the study protocol and will be explained by the study staff.

injections continue for up to 16 weeks.

5 recording weekly symptoms

each week you will complete a diary that captures bowel habits, abdominal discomfort, and any other relevant symptoms.

the diary information is used to calculate the weekly composite clinical response.

6 scheduled clinic visits

you will attend clinic visits at predetermined times (for example, at weeks 4, 8, 12, and 16) where the study team checks your safety, reviews your diary, and may perform routine laboratory tests.

these visits help ensure that the medication is tolerated and that any adverse effects are identified promptly.

7 primary efficacy assessment (weeks 9‑16)

the main outcome of the study is measured during weeks 9 through 16.

the percentage of weeks in which you achieve a satisfactory combined symptom response is calculated and compared between the two groups.

8 final evaluation and study completion

at the end of the 16‑week treatment period, a final assessment is performed to summarize safety and efficacy data.

after this visit the study medication is stopped and you will receive any further instructions from the study team.

Who Can Join the Study?

You must have irritable bowel syndrome with constipation that meets the official Rome IV guidelines, which means most of your bowel movements are hard (type 1 or 2 on the Bristol Stool Form Scale) and less than 25% are loose (type 6 or 7).
During the 14 days before you join the study, you must record your worst stomach pain each day in an electronic diary (eDiary) and the average of those scores must be 3 or higher on a 0‑to‑10 scale (0 = no pain, 10 = worst possible pain).
You must be an adult (usually 18 years of age or older). Both men and women can take part.

Who Cannot Join the Study?

Having a type of irritable bowel syndrome (IBS) that causes diarrhea, mixed symptoms, or is not clearly classified, according to the Rome IV guidelines (a set of rules doctors use to diagnose IBS).
Having a past or current inflammatory or immune‑mediated gastrointestinal disorder, such as Crohn’s disease, ulcerative colitis, or celiac disease (conditions where the immune system attacks the digestive tract).
Having a known problem with how quickly the stomach empties its contents, called a gastric emptying abnormality, that is considered important for health.

Where you can join this trial?

Verified and Recommended Sites

No sites found in this category

Verified Sites

Site Name	City	Country
Hospital Universitario De Salamanca	Salamanca	Spain
Hospital Clinico San Carlos	Madrid	Spain
Katholieke Universiteit te Leuven	Leuven	Belgium

Other Sites

Site Name	City	Country
Clinica Gaias Santiago	Santiago De Compostela	Spain
Sint-Lucas General Hospital	Brugge	Belgium
CHC MontLegia	Liege	Belgium
Hospital Universitario Puerta De Hierro De Majadahonda	Majadahonda	Spain
Algemeen Ziekenhuis Delta	Roeselare	Belgium
Az Maria Middelares Gent	Gent	Belgium
AZ Sint-Lucas & Volkskliniek	Gent	Belgium
Eap Osona Sud Alt Congost S.L.P.	Centelles	Spain
Hospital Universitario Virgen De Las Nieves	Granada	Spain
Hospital Costa del Sol	Marbella	Spain
UZ Brussel	Brussels	Belgium
UZ Gent	Gent	Belgium
Hjsdwlsf Vemf dkfqitdo	Barcelona	Spain
Hzq Zjexojvcxfabhzfzt Ahdhilpnn	Antwerp	Belgium
Umtnuudxqk Oe Ajrccyn	Edegem	Belgium

Trial status

Country	Status	Recruitment Start
Belgium	Not yet recruiting	20.07.2026
Spain	Not yet recruiting	20.07.2026

Trial locations

Investigated Drugs:

LY3537031

Brenipatide is an experimental drug being tested in this study. It is a liquid that is placed in a pre‑filled syringe and given as an injection under the skin (subcutaneous use). The trial is looking at whether this medication can help adults who have constipation‑predominant irritable bowel syndrome (IBS‑C) feel better over several weeks.

Irritable Bowel Syndrome with Constipation – A chronic condition that causes recurring abdominal discomfort or pain together with hard or infrequent stools. The symptoms often appear after meals and may improve after a bowel movement. Over time, episodes can become more frequent or persist for longer periods, leading to a pattern of alternating flare‑ups and quieter phases. The condition can affect daily activities because of urgency, bloating, and the need for regular bathroom visits. It is considered a functional disorder, meaning no structural damage is seen in the intestines. The course varies between individuals, with some experiencing mild symptoms and others having more noticeable changes in bowel habits.

Trial ID:

2025-524974-41-00

Protocol code:

J2S-MC-GZMT

Trial Phase:

Therapeutic exploratory (Phase II)

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Efficacy and Safety of Brenipatide (LY3537031) in Adults with Irritable Bowel Syndrome‑Constipation (IBS‑C) – A Phase 2 Randomized, Double‑Blind, Placebo‑Controlled Study

What is this study about?

Who Can Join the Study?

Who Cannot Join the Study?