Morbid ObesityDACHNCT06268990
FMT in Obesity: RYGB vs. LEAN vs. Autologous FMT
A study testing Fecal microbiota transplantation in people with Morbid Obesity and Metabolic Syndrome, run by Wiebke Kristin Fenske at 1 site in Austria.
Trial summary
This double-blinded proof-of-concept study is proposed to explore the effects of fecal microbiota transfer (FMT) in human subjects. Here we perform FMTs into obese recipients using stool from lean unoperated donors and from previously obese patients after successfull treatment with bariatric Roux-en-Y Gastric Bypass… Read more about this study
- Who is it for?
- Ages 18 to 60 yearsHealthy volunteers can take part
- Conditions the study is for
- Morbid Obesity, Metabolic Syndrome, Diabetes
- What is being tested?
- Fecal microbiota transplantation
- Type of treatment
- Surgery or procedure
- Could I receive a placebo?
- Yes, some participants may receive a placebo
- How many people
- 29 participants
- Where
- 1 siteAustria
- Study dates
- 1 Jan 2023to 30 Apr 2026
- Phase
- Interventional
- Are there results?
- None posted in the registry
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 18 to 60 years
- All sexes
- Healthy volunteers accepted
- Adult
Who may be able to join
- Inclusion criteria for patients
- Age >18 years
- Morbid obesity defined by a BMI ≥ 40 kg/m2
- Prediabetes or diabetes with HbA1C between ≥ 5.7 % OR
- Fasting plasma glucose > 5.6 mmol/l (> 100 mg/dl) (no caloric intake for at least 8 hours) OR
- Random plasma glucose > 11.1 mmol/l (> 200 mg/dl)
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- Informed consent
- Sustained total weight loss of ≥30% ≥12 months after RYGB surgery
- HbA1c < 6.5% without insulin treatment or oral antidiabetic medication
- Age >18 years
- Informed consent
- Normal weight (BMI ≥ 20 to < 25 >18 years
- Informed consent
Who cannot join
- Non-Compliance
- Insulin dependent diabetes mellitus, treated with GLP-1 agonists or poorly controlled on oral antidiabetic medications (HbA1C > 8%)
- Use of any weight loss medication or participation in a weight loss program
- History of recent body weight change (defined as body weight loss or body weight gain of ≥ 5 kg within the two months preceding study enrolment).
- Use of immunosuppressive medication or immune modulators (glucocorticoids, methotrexate, tacrolimus, cyclosporine, thalidomide, interleukin-10 or -11) within the last three months preceding study enrolment.
- Congenital or acquired immunodeficiencies.
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- Anatomical reconstruction of the nutrient passage (i.e. hemicolectomy, resection of small bowel, gastrectomy, sleeve gastrectomy, gastric bypass surgery, biliopancreatic diversion, fundoplication etc) or cholecystectomy.
- Chronic diarrhoea
- History of serious chronic disease including malignancy, rheumatic heart disease, endocarditis, or valvular disease (due to risk of bacteremia)
- Any condition, based on clinical judgment that may make study participation unsafe
- Pregnancy or Breast Feeding
- Intake of pre-, pro- or antibiotics within < 3 months before study entry
- Use of immunosuppressive medication or immune modulators (glucocorticoids, methotrexate, tacrolimus, cyclosporine, thalidomide, interleukin-10 or -11) within the last three months preceding study enrolment.
- Congenital or acquired immunodeficiencies.
- Chronic or acute infectious diseases (specified under 6.2.1)
- Drug abuse
- Anatomical reconstruction of the nutrient passage other than surgical RYGB configuration (i.e. hemicolectomy, resection of small bowel, fundoplication, LSG-to-RYGB transformation etc) or cholecystectomy.
- History of recent body weight change (defined as body weight loss or body weight gain of ≥ 5 kg within the two months preceding study enrolment).
- Chronic diarrhoea or steatorrhea or acute gastrointestinal infection within ≤ 3 months before study entry.
- History of serious chronic disease including malignancy, chronic kidney disease (eGFR < 60 ml/min), heart failure (NYHA ≥ III).
- Any further condition, based on clinical judgment that may disqualify the candidate as an appropriate donor.
- Exclusion Criteria for Lean-FMT Intervention Donors • History of overweight or obesity in the past (BMI > 25 kg/m2)
- History of recent body weight change (defined as body weight loss or body weight gain of ≥ 5 kg within the two months preceding study enrolment).
- HbA1C > 6.5% or treatment with insulin or oral anti-diabetic medication.
- Use of any weight loss medication or participation in a weight loss program
- Use of immunosuppressive medication or immune modulators (glucocorticoids, methotrexate, tacrolimus, cyclosporine, thalidomide, interleukin-10 or -11) within the last three months preceding study enrolment.
- Congenital or acquired immunodeficiencies.
- Chronic or acute infectious diseases (specified under 6.2.1)
- Drug abuse
- Anatomical reconstruction of the nutrient passage (i.e. hemicolectomy, resection of small bowel, fundoplication etc) or cholecystectomy.
- Chronic diarrhoea or acute gastrointestinal infection within ≤ 3 months before study entry.
- History of serious chronic disease including malignancy, chronic kidney disease (eGFR < 60 ml/min), heart failure (NYHA ≥ III).
- Any further condition, based on clinical judgment that may disqualify the candidate as an appropriate donor.
Trial locations and contacts
1 site in 1 country.
Austria1 site
Department of Internal Medicine, Medical University Graz
Graz, 8010
About this study
Official title: Metabolic Outcome of Obese Subjects Receiving Fecal Microbiota Transplantation of Lean Versus Gastric Bypass Treated Subjects. A Pilot Study
This double-blinded proof-of-concept study is proposed to explore the effects of fecal microbiota transfer (FMT) in human subjects. Here we perform FMTs into obese recipients using stool from lean unoperated donors and from previously obese patients after successfull treatment with bariatric Roux-en-Y Gastric Bypass (RYGB) surgery. Obese patients treated with their own material (autologous FMT) serve as controls. After FMT treatment the functional impact of post-surgery microbiome changes on host energy consumption and regulation of blood glucose levels will be analysed. Additionally the variations on the microbiota and metabolite composition will be profiled using extensive sequencing analyses. The major aim of the study is to explore the scientific rationale for targeted gut microbiota modulation in management of obesity and related metabolic diseases.We estimate the transfer of microbiota from RYGB donors is superior to the transfer of lean microbiota at inducing reduced adiposity and improving high blood glucose levels in obese recipients. Each is better than a sham procedure (autologous FMT), which itself can also induce considerable short-term effects.
Read the detailed description
Patients and stool donors (for RYGB-/Lean-FMT-intervention groups) will be recruited at the Endocrinology outpatient clinic at the University Hospital of Graz. Patients will be randomized in a 1:1:1 manner. In all three study groups, patients will be treated with FMT totaling three times every 7 days after an antibiotic pretreatment.
Patients randomized to the RYGB- FMT-intervention group will be treated with donor stool from previously obese patients successfully treated with RYGB surgery in terms of maintained weight reduction and improved glucose homeostasis. Patients randomized to Lean-FMT-intervention group will be treated with donor stool from un-operated, metabolically healthy and lean individuals, while patients randomized to the FMT-placebo group will be treated with autologous FMT.
For both allogenic FMT interventions, the donor stool from five different patients successfully treated with RYGB surgery (for RYGB-FMT intervention) and from five un-operated, lean and healthy individuals (for Lean-FMT intervention), respectively, will be anaerobically processed before active study period and stored at - 20° C for analysis and subsequent FMT.
In addition, stool from all 30 obese FMT recipients (FMT-intervention groups and FMT-placebo group) will be collected before the active study period, processed anaerobically and frozen at -80° C. Only stool samples from patients randomized to the FMT-placebo group (n=10) will be used as allogenic transplants.
- Conditions
- Morbid Obesity, Metabolic Syndrome, Diabetes, PreDiabetes, Insulin Resistance
- Being tested
- Fecal microbiota transplantation
- Keywords
- Fecal microbiota transfer, obesity, glucose homeostasis, bariatric surgery, gut microbiome
- Medical subject headings
- Obesity, Morbid, Metabolic Syndrome, Diabetes Mellitus, Prediabetic State, Insulin Resistance, Obesity
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
Fecal microbiota transplantationProcedure or surgery
Also called FMT
FMT is the transfer of fecal material containing gut microorganisms from a donor into the intestinal tract of a recipient
| Study group | Role | What they receive |
|---|---|---|
| RYGB-FMT intervention group | Active comparator | morbidly obese patients randomized for FMT from patients successfully treated with RYGB surgery Receives: Procedure: Fecal microbiota transplantation |
| LEAN-FMT intervention group | Active comparator | morbidly obese patients randomized for FMT from normal weight (lean) volonteers Receives: Procedure: Fecal microbiota transplantation |
| M-FMT intervention group | Sham comparator | morbidly obese patients randomized for autologous FMT Receives: Procedure: Fecal microbiota transplantation |
What is being measured
The primary outcome is the main question the study is designed to answer.
Insulin sensitivity
Change in insulin sensitivity after FMT compared to baseline as assessed by hyperinsulinemic-euglycemic clamp technique
Measured: after 6 weeks treatment
Secondary outcomes (13)
Insulin sensitivity
Change in insulin sensitivity after 16-/24-week treatment compared to baseline as assessed by hyperinsulinemic-euglycemic clamp.
Measured: after 16/24 weeks treatment
Glucose homeostasis
Change in glucose homeostasis compared to baseline as assessed by HOMA-IR model, fasting glucose level, and HbA1C value
Measured: after 6-/16-/24-week treatment
Body weight
Change in total body weight, body mass index (BMI) and body composition after 6-/16-/24-week treatment compared to baseline as assessed by Dual-energy X-ray absorptiometry, DXA)
Measured: after 6-/16-/24-week treatment
Blood pressure
Change in blood pressure and antihypertensive medication compared to baseline.
Measured: after 6-/16-/24-week treatment
Fasting lipid profile
Change in fasting lipid profile compared to baseline.
Measured: after 6-/16-/24-week treatment
Fasting blood liver enzyme levels
Change in fasting blood liver enzyme levels and liver fat content (assessed by CAP values with the XL probe) compared to baseline
Measured: after 6-/16-/24-week treatment
Dietary intake levels
Change in dietary intake assessed using MyFitnessPal compared to baseline.
Measured: after 6-/16-/24-week treatment
Metabolic inflammation
Change in metabolic inflammation and endotoxemia as assessed by circulating pro-inflammatory cytokines (TNF-a, IL-6, IL-1ß) and bacterial endotoxins (lipopolysachharide (LPS), LPS-binding protein) compared to baseline
Measured: after 6-/16-/24-week treatment
Gut hormones
Change in postprandial release of gut hormones (PYY, GLP-1, GIP, ghrelin, CCK), insulin and bacterial metabolites (SCFA, Bile acids) before (fasting condition) and during a standardized mixed meal test (MMT) (Fresubin 200ml, 400kcal) compared to baseline
Measured: after 6-/16-/24-week treatment
Hunger and Satiety Scores
Change in Hunger and Satiety Scores assessed via visual analog scales during the MMT
Measured: daily
Fecal microbiota composition
Change in diversity and composition of the fecal microbiota as assessed by 16S rRNA gene profiling compared to baseline
Measured: after 6-/16-/24-week treatment
Health-related quality of life
Change in health-related quality of life and behavior as assessed by established self-report questionnaires compared to baseline measuring: (a) eating behavior including trait food craving (FCQ-T-r), hedonic eating (PFS), restrained eating, overeating, and binge eating (EDE-Q), and emotional eating as well as disinhibition (EI); (b) personality factors such as impulsivity (BIS-15) and reward sensitivity (BIS/BAS); (c) mental and physical health, including depression, anxiety, and substance use (PHQ-D), attention-deficit/hyperactivity disorder (ASRS), and quality of life (EQ-5D). All these questionnaires have established reliability and validity.
Measured: after 6-/16-/24-week treatment
Tolerability of repeated FMT
Safety and tolerability of repeated FMT assessed by review of adverse event diary card
Measured: daily
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted21 Feb 2024
- Study start1 Jan 2023
- Primary completion6 Nov 2025
- Study completion30 Apr 2026
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for Morbid ObesityStudies of the same condition, open and under way.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Interventional
- Phase
- Phase N/A
- Primary purpose
- Treatment
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Masking
- Quadruple blind
- Who is masked
- Participant, Care provider, Investigator, Outcomes assessor
- Enrolment
- 29 participants (actual)
Sponsor and investigators
- Lead sponsor
- Wiebke Kristin Fenske
- Sponsor type
- University, hospital or other
- Collaborators
- Medical University of Graz
- Responsible party
- Sponsor-investigator, Wiebke Kristin Fenske, University Hospital Bergmannsheil Bochum
- Investigators
- Wiebke K. Fenske, Prof. Dr., Principal investigator, University Hospital Bergmannsheil Bochum
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT06268990
- Sponsor's protocol ID
- FE 1159/6-1
- Acronym
- DACH
- Status last verified
- Jun 2026
- First submitted
- 29 Jan 2024
- Last updated
- 26 Jun 2026
- Results posted
- No
- Data monitoring committee
- No
- FDA-regulated drug
- No
- FDA-regulated device
- No
Study at a glance
From the registry record, last updated by the sponsor on 26 Jun 2026. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Metabolic Outcome of Obese Subjects Receiving Fecal Microbiota Transplantation of Lean Versus Gastric Bypass Treated Subjects. A Pilot Study
- ClinicalTrials.gov ID
- NCT06268990
- Acronym / sponsor ID
- DACH / FE 1159/6-1
- Conditions
- Morbid Obesity, Metabolic Syndrome, Diabetes, PreDiabetes, Insulin Resistance
- Keywords
- Fecal microbiota transfer, obesity, glucose homeostasis, bariatric surgery, gut microbiome
- Study type
- Interventional
- Recruitment status
- Completed
- Enrolment
- 29 participants (actual)
- Lead sponsor
- Wiebke Kristin FenskeUniversity, hospital or other
- Collaborators
- Medical University of Graz
- Study start
- 1 Jan 2023 (actual)
- Primary completion
- 6 Nov 2025 (actual)
- Study completion
- 30 Apr 2026 (actual)
- First posted
- 21 Feb 2024 (actual)
- Results
- Not posted in the source record
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
This double-blinded proof-of-concept study is proposed to explore the effects of fecal microbiota transfer (FMT) in human subjects. Here we perform FMTs into obese recipients using stool from lean unoperated donors and from previously obese patients after successfull treatment with bariatric Roux-en-Y Gastric Bypass (RYGB) surgery. Obese patients treated with their own material (autologous FMT) serve as controls. After FMT treatment the functional impact of post-surgery microbiome changes on host energy consumption and regulation of blood glucose levels will be analysed. Additionally the variations on the microbiota and metabolite composition will be profiled using extensive sequencing analyses. The major aim of the study is to explore the scientific rationale for targeted gut microbiota modulation in management of obesity and related metabolic diseases.We estimate the transfer of microbiota from RYGB donors is superior to the transfer of lean microbiota at inducing reduced adiposity and improving high blood glucose levels in obese recipients. Each is better than a sham procedure (autologous FMT), which itself can also induce considerable short-term effects.
Detailed description
Patients and stool donors (for RYGB-/Lean-FMT-intervention groups) will be recruited at the Endocrinology outpatient clinic at the University Hospital of Graz. Patients will be randomized in a 1:1:1 manner. In all three study groups, patients will be treated with FMT totaling three times every 7 days after an antibiotic pretreatment.
Patients randomized to the RYGB- FMT-intervention group will be treated with donor stool from previously obese patients successfully treated with RYGB surgery in terms of maintained weight reduction and improved glucose homeostasis. Patients randomized to Lean-FMT-intervention group will be treated with donor stool from un-operated, metabolically healthy and lean individuals, while patients randomized to the FMT-placebo group will be treated with autologous FMT.
For both allogenic FMT interventions, the donor stool from five different patients successfully treated with RYGB surgery (for RYGB-FMT intervention) and from five un-operated, lean and healthy individuals (for Lean-FMT intervention), respectively, will be anaerobically processed before active study period and stored at - 20° C for analysis and subsequent FMT.
In addition, stool from all 30 obese FMT recipients (FMT-intervention groups and FMT-placebo group) will be collected before the active study period, processed anaerobically and frozen at -80° C. Only stool samples from patients randomized to the FMT-placebo group (n=10) will be used as allogenic transplants.
Study design
- Primary purpose
- Treatment
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Masking
- Quadruple blind (participant, care provider, investigator, outcomes assessor)
- Number of arms
- 3
| Arm | Type | Receives |
|---|---|---|
| RYGB-FMT intervention group | Active comparator | Procedure: Fecal microbiota transplantationmorbidly obese patients randomized for FMT from patients successfully treated with RYGB surgery |
| LEAN-FMT intervention group | Active comparator | Procedure: Fecal microbiota transplantationmorbidly obese patients randomized for FMT from normal weight (lean) volonteers |
| M-FMT intervention group | Sham comparator | Procedure: Fecal microbiota transplantationmorbidly obese patients randomized for autologous FMT |
Who may qualify
- Ages
- 18 to 60 years
- Sex
- All
- Healthy volunteers
- Accepted
- Age groups
- Adult
Key inclusion criteria (13 listed)
- Inclusion criteria for patients
- Age >18 years
- Morbid obesity defined by a BMI ≥ 40 kg/m2
- Prediabetes or diabetes with HbA1C between ≥ 5.7 % OR
- Fasting plasma glucose > 5.6 mmol/l (> 100 mg/dl) (no caloric intake for at least 8 hours) OR
Key exclusion criteria (33 listed)
- Non-Compliance
- Insulin dependent diabetes mellitus, treated with GLP-1 agonists or poorly controlled on oral antidiabetic medications (HbA1C > 8%)
- Use of any weight loss medication or participation in a weight loss program
- History of recent body weight change (defined as body weight loss or body weight gain of ≥ 5 kg within the two months preceding study enrolment).
- Use of immunosuppressive medication or immune modulators (glucocorticoids, methotrexate, tacrolimus, cyclosporine, thalidomide, interleukin-10 or -11) within the last three months preceding study enrolment.
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Interventions
| Intervention | Type | Arms |
|---|---|---|
| Fecal microbiota transplantationAlso: FMTFMT is the transfer of fecal material containing gut microorganisms from a donor into the intestinal tract of a recipient | Procedure or surgery | LEAN-FMT intervention group, M-FMT intervention group, RYGB-FMT intervention group |
Primary outcome
Insulin sensitivity
Time frame: after 6 weeks treatment
Change in insulin sensitivity after FMT compared to baseline as assessed by hyperinsulinemic-euglycemic clamp technique
13 secondary outcomes
Insulin sensitivity
Time frame: after 16/24 weeks treatment
Glucose homeostasis
Time frame: after 6-/16-/24-week treatment
Body weight
Time frame: after 6-/16-/24-week treatment
Blood pressure
Time frame: after 6-/16-/24-week treatment
Fasting lipid profile
Time frame: after 6-/16-/24-week treatment
Fasting blood liver enzyme levels
Time frame: after 6-/16-/24-week treatment
Dietary intake levels
Time frame: after 6-/16-/24-week treatment
Metabolic inflammation
Time frame: after 6-/16-/24-week treatment
Gut hormones
Time frame: after 6-/16-/24-week treatment
Hunger and Satiety Scores
Time frame: daily
Fecal microbiota composition
Time frame: after 6-/16-/24-week treatment
Health-related quality of life
Time frame: after 6-/16-/24-week treatment
Tolerability of repeated FMT
Time frame: daily
Results and safety
The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 26 Jun 2026.
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Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part. This study is not recruiting at the moment.
Wiebke K. Fenske, Prof. Dr. principal investigator
University Hospital Bergmannsheil Bochum
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A study testing Fecal microbiota transplantation in people with Morbid Obesity and Metabolic Syndrome, run by Wiebke Kristin Fenske at 1 site in Austria.
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
The sponsor lists 13 inclusion and 33 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: finished, as of the sponsor's last update on 26 Jun 2026. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 1 site in Austria. Whether a site is taking part right now should be confirmed with that site. See every site.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. Some participants in this study may receive a placebo. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
Are results available for this study?
The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.
How can a doctor refer a patient or contact the research team?
The record lists no contact. The official record names the sponsor, who can be asked directly. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Insulin sensitivity (time frame: after 6 weeks treatment). It is what the study was designed to measure, not a finding.
Where can I read the original study information?
Does a listing mean the treatment is approved or proven to work?
No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.
How often is this information updated?
AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 26 Jun 2026.