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

Status

Recruiting

Phase

Early phase 1

Enrollment

26 participants (estimated)

Sponsor

University of Nottingham · Other

Design

Randomized · Triple masking

Countries

1 country

United Kingdom

Start

9 Mar 2026

Primary completion

Aug 2026 (estimated)

Completion

Oct 2026 (estimated)

First posted

6 May 2026

Last update posted

6 May 2026

Conditions

Cystic Fibrosis (CF)

Linaclotide is a medicine used to treat constipation and irritable bowel syndrome with constipation (IBS-C). It works by acting on the surface of the gut lining, where it increases the movement of salt and water into the bowel. This softens stools, makes them easier to pass, and can also reduce gut pain One advantage of linaclotide is that, unlike some natural substances in the gut, it is stable and can act throughout the intestine. Studies in animals show that it has the strongest effect in the upper small intestine, but it may act in other parts of the bowel as well. In people, however, it is not yet clear whether linaclotide mainly works in the small intestine or in the large intestine (colon). Knowing this is important, because it could help the investigators understand whether linaclotide might also be useful in other conditions, such as cystic fibrosis, where the gut does not handle fluid properly. Linaclotide is taken as a capsule, but less than 1% is absorbed into the bloodstream. Instead, it stays in the gut, where it is broken down into smaller active parts. This means both the small intestine and colon may be exposed to its effects. Until now, it has been hard to study this because traditional methods only measure one part of the gut at a time. A team at the University of Nottingham has developed MRI scanning methods that can safely and non-invasively measure water content in the small intestine and colon. The aim of this pilot study is to use MRI in healthy volunteers to see exactly where linaclotide acts. This knowledge will help optimise future studies in conditions such as cystic fibrosis.

• Experimental

  Linaclotide

  290 mcg linaclotide across 2 days

• Placebo comparator

  Placebo

  Lactose placebo

1. Small bowel water content

   Time frame · Baseline, and 0, 60, 120, 180, 240, 300, 360 minutes post-dose

   Registry description

   Area under curve (AUC) 0-360 minutes Water content in small bowel as assessed by MRI (mL)