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A study to evaluate the effect of allogeneic faecal microbiota on the core symptoms of autism spectrum disorder in children

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What is this trial about?

A plain-language summary of the goals, design and what participants do

This study focuses on Autism Spectrum Disorder, a developmental condition that can affect how a person communicates and interacts with others. The research aims to describe the effect of faecal microbiota transplantation on the core symptoms of this condition. This procedure involves using a suspension for faecal microbiota transplantation, which contains allogeneic faecal microbiota. This substance consists of healthy bacteria collected from a donor to be placed into the digestive system of the participant.

Participants in this study will receive the treatment through a method intended for use in the digestive tract. During the course of the trial, the progress of the symptoms and the physical response to the bacteria will be observed over time.

The research process

The trial runs in 2 steps – from screening to follow-up. Each step says what happens and what the team monitors.

  1. Step 1

    Administration of the test product

    The faecal microbiota transplantation, which is a process of transferring healthy bacteria into the digestive system, is administered using a gastroenteral suspension.

    The dose consists of 150 ml of the allogeneic faecal microbiota, which is a mixture of healthy bacteria from a donor, provided via the digestive tract.

  2. Step 2

    Monitoring of symptoms and health

    The intensity of autism spectrum disorder core symptoms is measured using the ADOS-2, Module 1 examination to determine if there is an improvement or worsening in the condition.

    Various health indicators are tracked, including stool consistency through the bristol stool scale, gastrointestinal symptoms via the atn-gissi-17 questionnaire, and quality of life through the peds-ql questionnaire.

    Additional assessments are conducted using the cars2, seq, and sdq questionnaires to monitor developmental and behavioral aspects, while any adverse events, which are unintended or harmful side effects, are recorded.

Who can join the trial?

6 criteria

  • The person must be between 3 and 12 years old.
  • The person must have a confirmed diagnosis of autism spectrum disorder, which is a developmental condition that can affect how a person communicates and interacts with others, as verified by a clinical psychologist (a mental health specialist) or a psychiatrist (a doctor specializing in mental health).
  • The person must have previously completed an ADOS-2 examination, which is a standardized tool used by professionals to help identify signs of autism, and the results must have fallen within the autism range.
  • The person must have minimum verbal ability, meaning they use very little spoken language, specifically matching the requirements of the ADOS-2 Module 1 assessment.
  • A parent or legal representative must provide informed consent, which means they have been given all necessary information and agree to let the child participate.
  • The family must be willing to attend all scheduled study visits and follow all instructions, particularly those regarding bowel preparation, which involves specific steps to clean out the digestive system before the procedure.

Who cannot join the trial?

10 criteria

  • Having a birth defect in the gastrointestinal tract (the digestive system, including the stomach and intestines) or a primary disease of the digestive system, such as coeliac disease (an immune reaction to eating gluten that damages the small intestine).
  • Starting a new or recently changing behavioral therapy (treatments aimed at changing how a person thinks, feels, or behaves) or cognitive-behavioral therapy (a type of talk therapy to manage patterns of thinking) within the last 30 days.
  • A history of early reactions to food (such as allergies or immediate sensitivities to certain foods).
  • Being unable to complete bowel preparation (the process of cleaning out the intestines, which often involves drinking special liquids).
  • Having a medical reason why sedative medication (medicines used to make a person feel calm or sleepy) cannot be used, or having a history of serious problems while being sedated.
  • Currently using or having used systemic immunosuppressants (medicines that lower the body's ability to fight infections) in the last 3 months, or having an immunocompromised status (a weakened immune system).
  • Currently using or having used antiplatelet drugs (medicines that prevent blood cells from sticking together), anticoagulants (blood thinners), or systemic antibiotics (medicines used to treat bacterial infections throughout the body) in the last 3 months.
  • Currently using or having used probiotics, prebiotics, or postbiotics (supplements used to support healthy bacteria in the gut) in the last 3 months.
  • Having severe co-morbid conditions (other serious health problems occurring at the same time), such as psychosis (a mental state where a person loses touch with reality), epilepsy that is not controlled by medicine, or severe loss of sight or hearing.
  • Starting a new or recently changing pharmacotherapy (treatment using medicinal drugs) within the last 30 days.
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Investigated drugs

Faecal microbiota transplantation is a therapy that involves transferring healthy bacteria from a donor into the digestive system of a person. In this study, it is being tested to see if changing the types of bacteria living in the gut can help improve the main symptoms of autism spectrum disorder.

What is already known about the treatment

Allogeneic faecal microbiota - This treatment is administered as a liquid suspension taken through the digestive tract to introduce healthy bacteria into the body. While currently being studied for its potential to help manage symptoms of autism spectrum disorder, it is not yet an established standard medical treatment for this condition. The therapy works by restoring a healthy balance of microorganisms in the gut, which may influence how the brain and digestive system communicate. It is classified as a biological therapy used to modify the internal microbial environment.

Investigated diseases

Autism spectrum disorder - This is a developmental condition that affects how people communicate and interact with others. It often involves challenges with social skills and repetitive patterns of behavior. Symptoms typically appear in early childhood and can vary significantly in intensity from person to person. As the condition progresses, these social and behavioral patterns continue to influence how an individual experiences the world.
Trial detailsLast updated 2 Oct 2026
Age0-17PhasePhase IITrial ID2025-524673-16-00Protocol codeFMT-PAS-2025Estimated enrolment20 patientsSponsorMasarykova Univerzita

sourced from the EU Clinical Trials Register and site verification

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