Study of REC-4881 in Adults with Familial Adenomatous Polyposis to Assess Safety and Efficacy

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What is this study about?

Familial Adenomatous Polyposis is a hereditary condition in which many small growths called polyps develop in the colon and rectum and can turn into cancer if not treated. The study uses an oral capsule of REC-4881, a new medication taken by mouth, and a matching placebo that looks the same but contains no active drug.

The aim of the trial is to find out how well REC-4881 works and how safe it is for people with this condition. Participants will take the study medication or placebo for several months, with regular visits to have blood tests that look at the drug’s pharmacokinetics—how the body absorbs and clears the medicine—and to check for any side effects. Doctors will also perform examinations of the colon to see how the number and size of polyps, known as polyp burden, change over time.

1 enrollment visit

after you join the study, you will meet with study staff to confirm consent and to collect information about your medical history, including the diagnosis of familial adenomatous polyposis (fap).

baseline laboratory tests and imaging will be performed to record the number and size of polyps before any study medication is taken.

2 randomization

based on the study design, you will be assigned to receive either the active drug rec-4881 or an inactive placebo. both are provided as identical oral capsules, so you will not know which one you receive.

3 start of study medication

if you are assigned to the active arm, you will take one capsule containing 999 mg of rec-4881 by mouth each day; if you are assigned to the placebo arm, you will take a matching capsule containing only inactive ingredients.

the medication will be taken for the entire study period, with dosing instructions given by the study staff.

4 first efficacy and safety assessment (week 12)

after approximately 12 weeks of taking the study medication, you will return for a visit that includes blood samples to measure drug levels (pharmacokinetics) and safety laboratory tests.

the number and size of polyps will be re‑evaluated to determine the percent change from the baseline measurement.

5 second efficacy and safety assessment (week 25)

around week 25, another visit will be scheduled to repeat blood sampling, safety assessments, and polyp evaluation.

the data will be used to track ongoing safety and to see how the polyp burden has changed compared with the start of the study.

6 third efficacy and safety assessment (week 37)

at about week 37, a further assessment will be performed, again collecting blood for drug level analysis and checking for any adverse events.

polyp measurements will be taken to calculate the percent change from baseline, completing the interval‑dosing evaluation.

7 end‑of‑treatment visit

when the study medication period ends, you will have a final visit that includes a comprehensive safety review, final blood tests, and a complete assessment of polyp burden.

any treatment‑emergent adverse events, serious adverse events, or dose modifications that occurred during the study will be documented.

8 follow‑up

after the end‑of‑treatment visit, a short follow‑up may be scheduled to ensure that any lingering side effects are resolved and to collect final safety information.

Who Can Join the Study?

Be at least 18 years old.
Have been diagnosed with Familial Adenomatous Polyposis (FAP), a condition that continues to cause growths in the remaining parts of the intestines (the bowels) even after surgery to remove all or part of the colon (the large intestine).
For the second part of the study, have a confirmed mutation (a change) in the APC gene, a specific piece of DNA that is linked to FAP.

Who Cannot Join the Study?

Abnormal test results or any health problem that could make it unsafe for you to take part in the study. (Test results are the numbers doctors get from blood work or other checks.)
Having had radiation treatment aimed at the lower belly (also called the pelvic area) at any time before the study.
Having a diagnosis of cancer in the stomach, duodenum (the first part of the small intestine), colon, rectum, or a surgical pouch at the screening visit for Part 2 of the study.
Having a large polyp that cannot be completely removed. (A polyp is a small growth that can appear in the intestine.)
Currently receiving treatment for cancer of the lower belly, or having taken certain medicines that could interfere with the study drug REC‑4881 before joining the study.

Where you can join this trial?

Verified and Recommended Sites

No sites found in this category

Verified Sites

No sites found in this category

Other Sites

Site Name	City	Country
Rheinische Friedrich-Wilhelms-Universitaet Bonn	Bonn	Germany
Hospital Clinic De Barcelona	Barcelona	Spain
Axjuuqphl Uhd	Amsterdam	The Netherlands

Trial status

Country	Status	Recruitment Start
Germany	Not yet recruiting	24.07.2026
Spain	Not yet recruiting	24.07.2026
The Netherlands	Not yet recruiting	24.07.2026

Trial locations

REC-4881 is an experimental oral capsule being tested in people with familial adenomatous polyposis (FAP). In this trial, the drug is given by mouth to see how it is absorbed, distributed, and cleared from the body (its pharmacokinetics). Researchers also want to find the best dose for future studies, check that it is safe and well‑tolerated, and look at whether it can reduce the number and size of polyps in the colon. The medication is taken as a capsule, and it is being studied as a potential new treatment for this inherited condition.

Familial Adenomatous Polyposis – Familial Adenomatous Polyposis is an inherited disorder that causes hundreds to thousands of small growths called adenomatous polyps to form in the lining of the colon and rectum. These polyps usually appear in late childhood or early teenage years and gradually increase in number and size over time. As the polyps grow, they can also develop in the upper part of the small intestine and other parts of the digestive tract. The growing polyps may cause abdominal pain, bleeding, or changes in bowel habits as they become larger.

Trial ID:

2026-525282-50-00

Protocol code:

REC-4881-201

NCT ID:

NCT05552755

Trial Phase:

Therapeutic exploratory (Phase II)

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Study of REC-4881 in Adults with Familial Adenomatous Polyposis to Assess Safety and Efficacy

What is this study about?

Who Can Join the Study?

Who Cannot Join the Study?