RecruitingEARLY_PHASE1INTERVENTIONAL

Proof of Principle Study for an Efficacy Trial of Linaclotide for Cystic Fibrosis

This early-stage study, led by the University of Nottingham, is investigating a medicine called linaclotide, which is currently used for constipation. Researchers are interested in whether it could also help people with Cystic Fibrosis (CF), a condition that often causes digestive problems. The medicine works by increasing fluid in the gut, making stools softer. The study aims to use special MRI scans in healthy volunteers to pinpoint exactly where in the gut linaclotide has its effect. Understanding this will help them plan future research into whether this medicine can effectively treat the gut symptoms experienced by people with CF.

At a glance

Status

Recruiting

Phase

EARLY_PHASE1

Sponsor

University of Nottingham

Enrolment target

Start

09 Mar 2026

Estimated completion

01 Oct 2026

Cystic Fibrosis (CF)

What is this study about?

Cystic Fibrosis (CF) is a condition that affects many parts of the body, including the digestive system. Many people with CF experience gut issues like bloating, pain, and especially constipation, because their gut doesn't handle fluids normally. Current treatments for these problems can sometimes be uncomfortable or even involve surgery, so doctors are looking for better options.

Linaclotide is a medicine already approved in the UK for treating long-term constipation and a type of Irritable Bowel Syndrome (IBS-C). It works by helping the gut lining release more salt and water into the bowel, which softens stools and makes them easier to pass, and can also help reduce gut pain. Although the medicine is taken as a capsule, very little of it gets absorbed into the bloodstream; instead, it stays and works within the gut itself. It gets broken down into smaller active parts as it travels, meaning both the small and large bowel could potentially be affected.

Researchers previously found it difficult to study where exactly this medicine works in the gut. However, a team at the University of Nottingham has developed new, safe MRI scanning techniques that can measure water content in different parts of the bowel without needing invasive procedures. This study will use these MRI scans in healthy volunteers to clearly track linaclotide's effects. The information they gather will be crucial for designing future studies to explore if linaclotide could be a helpful new treatment for the gut problems associated with Cystic Fibrosis.

Key takeaways

Study aims to understand how linaclotide works in the gut.
Potentially could help gut problems in Cystic Fibrosis patients.
Uses special MRI scans in healthy volunteers to track its effects.
Linaclotide is already approved for constipation and IBS-C.
Very little of the medicine enters the bloodstream; it primarily works in the gut.
Results will guide future research into new CF treatments.

Who may be eligible?

This study is looking for healthy volunteers between the ages of 18 and 60 years old. You should be willing to follow all study instructions, which include things like fasting, dietary changes, taking the study medication or placebo, and having MRI scans.

There are several reasons why you might not be able to take part. These include if you have any metal implants or other items that make MRI scans unsafe, or if you are pregnant, breastfeeding, or planning to become pregnant. You also can't participate if you have any existing gut conditions, have had surgery on your food pipe, stomach, or intestines (except for appendix removal), or have an intestinal stoma.

Other reasons for not being able to join include if you have specific food intolerances (like to rice pudding, which is part of the study), or if you have a Body Mass Index (BMI) that is either too low (below 18.5) or very high (above 35). You also shouldn't be taking certain medications that affect gut movement, or have taken antibiotics or probiotics in the last three months. Finally, if you've worked night shifts in the week before the study day, you won't be able to participate.

Could this study suit you?

Answer these quick questions to see if you may be eligible. This is a guide only — the research team makes the final call.

Are you between 18 and 60 years old?
Can you have an MRI scan safely (no metal implants, etc.)?
Are you not pregnant, breastfeeding, or planning to be?
Do you have any existing serious gut conditions or past gut surgeries?
Have you taken antibiotics or probiotics in the last 3 months?
Are you able to follow specific diet/lifestyle instructions and attend study visits?

Answer every question to see your result.

What does participation involve?

If you take part in this study, you will need to give your informed consent, meaning you understand and agree to participate. You will be asked to follow specific instructions, including fasting overnight before study visits, and making some temporary changes to your diet and lifestyle. You will be given either linaclotide or a placebo pill (a dummy pill that looks the same) to take. The main part of the study involves having MRI scans, which will measure water content in your gut. You will also eat a special meal (rice pudding with a blue dye) during the study. Throughout the study, you will be asked to rate how often you pass stools and what they look like. The total duration of your involvement will be explained in full by the study team.

Potential risks and benefits

Participating in this study might not offer a direct benefit to you, but the information gained will be very important in understanding how linaclotide works and could lead to new treatments for people with Cystic Fibrosis. Potential risks might include discomfort from fasting, dietary changes, or lying still during MRI scans. As with any medication, even a placebo, there's always a small chance of unexpected effects, although linaclotide is generally well-tolerated. It's important to remember that you are free to withdraw from the study at any time, for any reason, without it affecting your medical care.

Locations (1)

Some site locations are approximate. We're improving this — please verify with the trial team before travelling.

Sir Peter Mansfield Imaging Centre
Verified postcode
Nottingham, United Kingdom· Recruiting

Common questions

What is linaclotide used for?

Linaclotide is a medicine currently approved for treating chronic constipation and a type of irritable bowel syndrome (IBS-C).

Why are you studying linaclotide for Cystic Fibrosis?

Many people with Cystic Fibrosis experience gut problems and constipation. Linaclotide helps increase fluid in the gut, which might help these symptoms by making stools softer and easier to pass.

What is a 'placebo pill'?

A placebo pill is a dummy pill that looks exactly like the study medication but contains no active drug. It helps researchers compare the effects of the real medicine.

Are the MRI scans safe?

Yes, the MRI scans developed for this study are safe and do not involve radiation. They are used to non-invasively measure water in your gut.

Will I know if I'm taking the real medicine or the placebo?

No, this is a 'blinded' study, meaning neither you nor the study team will know if you are receiving linaclotide or the placebo. This helps ensure fair and unbiased results.

How to find out more

Josh Thorley, PhD

josh.thorley@nottingham.ac.uk 07342646598 Official trial record

Always speak to your GP or specialist before deciding to take part in a study.