An interventional study of MBiotix® HBI Caps and Placebo in Autism Spectrum Disorder and Gastrointestinal Symptoms, sponsored by Institute of Mother and Child, Warsaw, Poland. Not yet recruiting at 1 site in Poland. Open to participants aged 6 Years to 12 Years. Per ClinicalTrials.gov, last updated 2026-01-27.
Sponsored by Institute of Mother and Child, Warsaw, Poland · Not applicable, Interventional, and Treatment
The aim of the study is to evaluate the effectiveness and safety of fecal microbiota transplantation (FMT) in reducing gastrointestinal (GI) and behavioral symptoms in children with autism spectrum disorder (ASD).
Children with ASD often experience GI problems such as constipation, diarrhea, and abdominal pain. These symptoms can negatively affect their daily life and behavior. Recent research suggests that the gut microbiota-the community of bacteria and other microorganisms living in the intestines-plays an important role in digestion, immunity, and communication with the brain through the gut-brain axis. Modifying the gut microbiota may help improve GI symptoms and possibly behavioral functioning.
FMT involves giving a preparation containing gut microbiota from a healthy donor after bowel cleansing. The product used in this study is MBiotix HBI Caps, produced by Human Biome Institute. A placebo (inactive substance) will also be used for comparison. Both will be given as frozen oral capsules that look identical.
20 children aged 6-12 years will take part. Participants will be randomly assigned to receive either the microbiota preparation or placebo. The study includes several visits over about 6 months. Before the first dose, every child will undergo bowel cleansing with a special preparation (Polyethylene Glycol, PEG). During the study, participants will be asked to keep a symptom diary, complete questionnaires, and record child's diet. Biological samples (stool, urine, saliva) will be collected at specific time points for analysis. Every child will also be assessed by a psychologist before the study begins and again during the study using standardized tools (Autism Diagnostic Observation Schedule, Second Edition, ADOS-2) to evaluate behavioral functioning and quality of life.
1,030 studies on the registry are indexed under Autistic Disorder; 266 are open to participants now.
This study's planned enrollment of 20 is below the median of 49 across 811 interventional studies indexed under Autistic Disorder.
Browse Autistic Disorder studies →Institute of Mother and Child, Warsaw, Poland is the lead sponsor of 8 studies on the registry; 3 are open to participants now.
Compared within Autistic Disorder, this study's primary condition as ClinicalTrials.gg classifies it; the registry's first condition term is Autism Spectrum Disorder. The counts are of registry records indexed under each term, refreshed daily. How we classify →
Go through the criteria one by one — yes, no or not sure — and take the list to your doctor or the study team. Kept in this browser only.
Patients with an average stool consistency greater than 5 on the Bristol Stool Form Scale (BSFS) during the baseline period will be classified as having diarrhea.
Patients with an average stool consistency less than 3 on the Bristol Stool Form Scale during the baseline period will be classified as having constipation.
Exclusion Criteria:
Underlined terms in the criteria open these too. Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Before you join, the study team explains what taking part involves — its purpose, what happens, the risks and possible benefits — and answers your questions, so you can decide freely. Consent is usually recorded on a form (the informed consent form, ICF) signed by you or, where the law allows, by someone legally authorised to decide for you.
You can keep asking questions during the study, you are told of new information that matters, and you can choose to leave at any time.
The American Psychiatric Association’s manual of mental health diagnoses. DSM-5 (2013, revised as DSM-5-TR in 2022) replaced DSM-IV, and some studies still name the older edition. “Meets DSM criteria for …” means diagnosed by that edition’s diagnostic criteria, usually by a clinician in an interview.
A drug or device being studied in a clinical trial.
It may be new, or already approved and being studied for another use, dose or form. Criteria often leave out people who took part in another study of one within a recent period, commonly 30 days or five half-lives.
The number of neutrophils, white blood cells that help fight infection, in a given amount of blood. Too few raises the risk of infection.
It is a count, not a percentage of the white cells. Limits are written in units that mean the same: ≥ 1.5 × 10⁹/L is ≥ 1,500 per mm³ (µL). Each lab has its own reference range.
Weight in kilograms divided by height in metres squared. Example: 70 kg and 1.75 m gives 70 ÷ (1.75 × 1.75) ≈ 22.9.
What counts as overweight or obesity differs between countries (some use lower cut-offs), so go by the range the study states.
Informed consent
Before you join, the study team explains what taking part involves — its purpose, what happens, the risks and possible benefits — and answers your questions, so you can decide freely. Consent is usually recorded on a form (the informed consent form, ICF) signed by you or, where the law allows, by someone legally authorised to decide for you.
You can keep asking questions during the study, you are told of new information that matters, and you can choose to leave at any time.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
DSM diagnostic criteria
The American Psychiatric Association’s manual of mental health diagnoses. DSM-5 (2013, revised as DSM-5-TR in 2022) replaced DSM-IV, and some studies still name the older edition. “Meets DSM criteria for …” means diagnosed by that edition’s diagnostic criteria, usually by a clinician in an interview.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Investigational drug or device
A drug or device being studied in a clinical trial.
It may be new, or already approved and being studied for another use, dose or form. Criteria often leave out people who took part in another study of one within a recent period, commonly 30 days or five half-lives.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Absolute neutrophil count (ANC)
The number of neutrophils, white blood cells that help fight infection, in a given amount of blood. Too few raises the risk of infection.
It is a count, not a percentage of the white cells. Limits are written in units that mean the same: ≥ 1.5 × 10⁹/L is ≥ 1,500 per mm³ (µL). Each lab has its own reference range.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
BMI (body mass index)
Weight in kilograms divided by height in metres squared. Example: 70 kg and 1.75 m gives 70 ÷ (1.75 × 1.75) ≈ 22.9.
What counts as overweight or obesity differs between countries (some use lower cut-offs), so go by the range the study states.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Other: MBiotix® HBI Caps
Other: Placebo
MBiotix HBI Caps (Human Biome Institute, Poland) are enteric-coated capsules containing a concentrated suspension of gut microbiota obtained by centrifugation of a solution prepared from 60 g of donor stool suspended in 200 ml of 0.9% NaCl and glycerol. Each capsule set contains approximately 10¹³ viable bacterial cells. Dosing depends on body weight: Children weighing \*\*\>35 kg\*\* will receive 60 g at visit 1 and 30 g at visits 2 (after 4 weeks) and 3 (after 8 weeks). Children weighing \*\*\<35 kg\*\* will receive 30 g at visit 1 and 15 g at visits 2 (after 4 weeks) and 3 (after 8 weeks).
Placebo
Number of patients who showed an improvement in stool consistency by at least 1 point on the Bristol Stool Scale compared to the baseline period.
The average stool consistency will be calculated from the one-week baseline period and from weekly observation periods during the study.
Time frame: 4,8,9,12,26,20 weeks
Bowel movements
Change in the number of bowel movements compared to the baseline period.
Time frame: 4,8,9,12,16,20 weeks
Abdominal pain episodes
Change in the number of abdominal pain episodes compared to the baseline period.
Time frame: 4,8,9,12,16,20 weeks
Days with abdominal pain
Change in the number of days with abdominal pain compared to the baseline period. Endpoints assessing abdominal pain will be evaluated only in children who are able to communicate their symptoms.
Time frame: 4,8,9,12,16,20 weeks
Excessive gas
Change in the number of days with excessive gas according to parent's assessment.
Time frame: 4,8,9,12,16,20 weeks
Regurgitation
Change in the number of days with regurgitation compared to the baseline period.
Time frame: 4,8,9,12,16,20 weeks
Vomiting
Change in the number of days with vomiting compared to the baseline period.
Time frame: 4,8,9,12,16,20 weeks
Child absence
Change in the number of days absent from kindergarten or school due to symptoms.
Time frame: 4,8,9,12,16,20 weeks
Parent's work absence
Change in the number of days of parental or caregiver work absence due to symptoms
Time frame: 4,8,9,12,16,20 weeks
Adverse events
Adverse events reported by children and parents, recorded in the symptom diary and reported to the physician.
Time frame: 0,4,8,9,12,16,20 weeks
SRS-2
Change in the score of the psychological test Social Responsiveness Scale-2 (SRS-2) compared to baseline.
Time frame: 9,20 weeks
ASRS
Change in the score of the psychological test Autism Spectrum Rating Scales (ASRS) compared to baseline
Time frame: 9,20 weeks
ADOS-2
Change in the score of the psychological test Autism Diagnostic Observation Schedule-2 (ADOS-2) compared to baseline.
Time frame: 9,20 weeks
CBCL
Change in the score of the psychological test Child Behavior Checklist (CBCL) compared to baseline.
Time frame: 9,20 weeks
ABAS-3
Change in the score of the psychological test Adaptive Behavior Assessment System-3 (ABAS-3) compared to baseline.
Time frame: 9,20 weeks
QoLA
Change in parental quality of life assessed using the Quality of Life in Autism Questionnaire (QoLA) compared to baseline.
Time frame: 9,20 weeks
Plan to share: Yes — IPD used in the results publication
No publications or documents are linked to this record.
Start is estimated for Jan 2026; primary completion for Dec 2026, 11 months later.
Of 354 non-industry interventional studies with no phase under Autistic Disorder, half reached primary completion within 26 months of starting (the median), counting those still running; a quarter within 14 and three quarters within 52. This study's planned 11 months is below that.
Counting every sponsor, half of 366 studies reached it within 26 months; a quarter within 13 and three quarters within 52.
How these figures are worked out, and which studies are left out of them.
This study is not yet recruiting, as verified in Dec 2025. You cannot join it, but the record below documents what was studied.
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Institute of Mother and Child, Warsaw, Poland