Study of gaxilose to assess intestinal barrier integrity and permeability in patients with celiac disease

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What is this study about?

celiac disease is a condition in which the lining of the small intestine is damaged by eating gluten, a protein found in wheat, barley, and rye. This damage can lead to poor absorption of nutrients and a range of digestive and other symptoms. The study will use a powder called LacTEST 0.45 g, which contains a small amount of the sugar gaxilose that is broken down by the enzyme lactase in the intestine. Measuring how much lactase works helps to assess the health of the intestinal lining and its ability to act as a barrier.

The purpose of the study is to determine whether the results from this test can serve as a simple marker of intestinal health and help monitor recovery while participants follow a gluten‑free diet. Participants will take the test powder, provide a urine sample a few hours later, and have blood, stool, and small tissue samples collected at the start of the study and again after six and twelve months. Throughout the study, they will continue their usual gluten‑free diet and complete questionnaires about symptoms and quality of life.

Changes in the test results will be compared with other indicators such as antibody levels that signal ongoing celiac activity, measures of intestinal permeability that reflect how well the gut barrier works, and symptom scores. By looking at these data over time, researchers hope to learn whether the test can reliably show how the intestinal lining heals or worsens, providing a useful tool for managing the condition.

1 baseline visit

arrive at the study site after enrollment and complete the initial paperwork.

provide a blood sample for antitransglutaminase antibody measurement and for future cytokine analysis.

provide a stool sample for zonulin measurement.

undergo an endoscopic biopsy to measure intestinal lactase activity and to assign a marsh‑oberhuber classification.

receive lacTEST 0.45 g powder, dissolve it in water according to the instructions, and ingest the 0.45 g oral solution.

collect urine for five hours after taking lacTEST to measure xylose excreted in milligrams.

perform a lactulose/mannitol (l/m) test to assess intestinal permeability.

complete the required questionnaires (gsrs, canadian celiac health survey, cd‑qol, cdat).

provide a cheek swab or blood for genotyping of the mcm6 polymorphisms.

2 start gluten‑free diet

begin a strict gluten‑free diet (gfd) as the standard treatment for celiac disease.

continue routine daily activities while adhering to the diet.

3 six‑month follow‑up

return to the study site for the six‑month visit.

provide a blood sample for antitransglutaminase antibodies and cytokine analysis.

provide a stool sample for zonulin measurement.

receive another dose of lacTEST 0.45 g, dissolve and ingest it, then collect urine for five hours to measure xylose excretion.

repeat the lactulose/mannitol test.

complete the same set of questionnaires to assess symptoms and quality of life.

4 twelve‑month follow‑up

return for the final twelve‑month visit.

provide a blood sample for antitransglutaminase antibodies, cytokine analysis, and other laboratory parameters.

provide a stool sample for zonulin measurement.

undergo a second endoscopic biopsy to re‑measure intestinal lactase activity and to assign a new marsh‑oberhuber classification.

receive the last dose of lacTEST 0.45 g, ingest it, and collect urine for five hours to assess xylose excretion.

repeat the lactulose/mannitol test.

complete the questionnaires again to evaluate symptom changes.

receive a summary of the results as required by the study protocol.

Who Can Join the Study?

Be an adult between 18 and 70 years old who is thought to have celiac disease because they have symptoms that fit and a blood test called anti‑TG antibodies that is positive, and they have one of the genetic markers known as HLA DQ2 or HLA DQ8. Anti‑TG antibodies are proteins in the blood that show the immune system is reacting to gluten, and HLA DQ2/DQ8 are common genetic variations that increase the risk of celiac disease.
Be able to understand what the study involves and sign a written informed consent form. Informed consent is a document that explains the study so you can decide whether you want to take part.

Who Cannot Join the Study?

Pregnancy or breastfeeding – you cannot take part if you are currently pregnant or feeding a baby.
Myxedema – a severe form of thyroid hormone deficiency that causes swelling; people with this condition are excluded.
Pentosuria or galactosemia – rare disorders where certain sugars build up in the body; anyone with a history of these conditions cannot join.
Hypersensitivity to Gaxilose – an allergic reaction to the study’s active ingredient; if you are allergic, you are excluded.
Use of blood‑thinning medicines (anticoagulants or antiplatelet drugs) that cannot be stopped before the endoscopy – you must be able to pause these medicines for a few days.
Contraindication for endoscopy with multiple biopsies – if your doctor says an endoscopy (a procedure that looks inside the gut) with several tissue samples is unsafe, you cannot participate. This also includes people who cannot stop blood‑thinners 3‑5 days before the intestinal biopsy.
History of neoplasia (cancer) or active intestinal diseases that are inflammatory, bleeding (hemorrhagic), autoimmune, or infectious, as well as any other untreated chronic illness that can cause diarrhea or poor nutrient absorption.
Severe and long‑lasting mental illnesses, such as psychosis (loss of touch with reality).
Diagnosed with Parkinson’s disease, dementia, or other neurodegenerative disorders (conditions where the brain gradually loses function).
Liver cirrhosis or other serious, long‑term liver or digestive diseases, including previous major digestive surgery (except simple procedures like appendix removal or gallbladder removal).
Moderate or severe renal failure – significant loss of kidney function that would affect the study.

Where you can join this trial?

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Other Sites

Site Name	City	Country	Status
Hxlgyely Vdnt djhmmbkn	Barcelona	Spain

Trial status

Country	Status	Recruitment Start
Spain	Not yet recruiting	04.05.2026

Trial locations

Investigated drugs:

GAXILOSE

LacTEST is a powder that is mixed with water to make a liquid you drink. It contains a sugar called gaxilose, which is broken down by the enzyme lactase in the small intestine. By measuring how much of this sugar is processed, doctors can see how well the intestinal lining is working. In this study, the test is used to check the health of the gut lining and how leaky the intestine might be in people with celiac disease. It helps researchers find out if the test can show damage to the intestinal tissue and track how the gut recovers over time.

Investigated diseases:

Coeliac disease

Celiac disease – Celiac disease is an immune‑mediated condition triggered by eating gluten, a protein found in wheat, barley, and rye. When gluten is consumed, the body’s immune system attacks the lining of the small intestine, causing inflammation and flattening of the tiny finger‑like projections called villi. This damage reduces the intestine’s ability to absorb nutrients, leading to digestive discomfort and other symptoms. If gluten exposure continues, the intestinal lining can become increasingly flattened, worsening absorption problems over time.

Trial ID:

2026-525518-70-00

Protocol code:

VPH-GXL-2025-04

Trial Phase:

Therapeutic confirmatory (Phase III)

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Study of gaxilose to assess intestinal barrier integrity and permeability in patients with celiac disease

What is this study about?

Who Can Join the Study?

Who Cannot Join the Study?