Healthy VolunteersPhase 2/3NCT05587036
Effects of Rifaximin on Gut Microbiota and Emotion
A Phase 2/3 study testing Rifaximin in people with Healthy Volunteers and Stress, run by Universitaire Ziekenhuizen KU Leuven at 1 site in Belgium.
Trial summary
A randomized, triple-blind, placebo-controlled study on the effect of rifaximin on psychobiological functions in healthy men. Read more about this study
- Who is it for?
- Ages 18 to 50 years, men onlyHealthy volunteers can take part
- Conditions the study is for
- Healthy Volunteers, Stress, Fear
- What is being tested?
- Rifaximin
- Type of treatment
- Pill or oral medicine
- Could I receive a placebo?
- Yes, some participants may receive a placebo
- How many people
- 60 participants
- Where
- 1 siteBelgium
- Study dates
- 2 Feb 2023to Jul 2025
- Phase
- Phase 2/3
- Are there results?
- Not yet: the study is under way
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 50 years
- Men only
- Healthy volunteers accepted
- Adult
Who may be able to join
- Voluntary written informed consent of the participant or their legally authorized representative has been obtained prior to any screening procedures
- Proficiency in English and/or Dutch
- Healthy with no intestinal and/or psychological complaints
- Access to a -18°C freezer (i.e. ordinary household freezer)
- Male participants
- Age 18-50 years
- BMI 18.5-25 kg/m2
Who cannot join
- Participant has a history of previous or current neurological, psychiatric, gastrointestinal or endocrine disorder
- Any disorder, which in the Investigator's opinion might jeopardize the participant's safety or compliance with the protocol
- Any prior or concomitant treatment(s) that might jeopardize the participant's safety or that would compromise the integrity of the Trial
- Participation in an interventional Trial with an investigational medicinal product (IMP) or device
- Hypersensitivity to the active substance rifaximin, to any rifamycin (e.g. rifampicin or rifabutin) or any of the excipients
- Current or recent medication use
Show all 18Show fewer
- Use of antibiotics within three months preceding the study
- Current or recent (1-month) infection (e.g. common cold, influenza, COVID-19, etc.)
- Previous or current substance/alcohol dependence or abuse (>2 units per day or 14 units per week)
- One or more diagnoses based on the mini international neuropsychiatric interview (MINI-S)
- One or more diagnoses based on ROME IV for gastrointestinal disorders
- Smoking
- Night-shift work
- Adherence to special diets (e.g. vegan, vegetarian, weight-loss, lactose-free, gluten-free, etc.)
- Use of pre- or probiotics within one month preceding the study
- Previous experience with any of the tasks used in the study (not including questionnaires)
- Color vision deficiency (colorblindness)
- Magnetic Resonance Imaging (MRI) contraindications, including claustrophobia, severe back problems, conditions that would interfere with MRI scanning (e.g. cochlear implant, metal fragments in eyes, metallic body inclusion, or other metal implanted in the body), and if the participant does not want to be informed of incidental findings that might be found during imaging.
Trial locations and contacts
1 site in 1 country. Contact the study team or a site near you to ask about taking part.
Belgium1 site, 1 recruiting
- Recruiting
UZ/KU Leuven
Leuven, 3000
Lukas Van Oudenhove, MD, PhD, +32 16 33 01 47, lukas.vanoudenhove@kuleuven.be
About this study
Official title: A Randomized, Triple-blind, Placebo-controlled Study on the Effect of Rifaximin on Psychobiological Functions in Healthy Men
A randomized, triple-blind, placebo-controlled study on the effect of rifaximin on psychobiological functions in healthy men.
Read the detailed description
This study is a randomized, triple-blind, placebo-controlled, interventional trial aiming to elucidate the impact of rifaximin-induced gut microbiota alteration to the psychobiological functioning of healthy men. The intervention will be performed in a parallel group design where one group will receive rifaximin (Targaxan 550 mg) twice daily for two weeks (treatment arm), while the other group will receive placebo (placebo arm).
Primary objective: to test the effect of rifaximin on stress sensitivity and fear-related processes
Secondary objective: to determine the mediating and/or moderating factors that underlie rifaximin-induced psychobiological changes
- Conditions
- Healthy Volunteers, Stress, Fear
- Being tested
- Rifaximin, Placebo
- Keywords
- Rifaximin, Anti-Bacterial Agents, Stress, Fear, Inflammation, Short-Chain Fatty Acid, Microbiota-Gut-Brain Axis
- Medical subject headings
- Inflammation
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
RifaximinDrug
Also called Targaxan
Rifaximin oral tablet, 550 mg, twice daily, two-weeks
PlaceboDietary supplement
Placebo oral tablet, twice daily, two-weeks
| Study group | Role | What they receive |
|---|---|---|
| Rifaximin | Experimental | Rifaximin oral tablets, 550 mg, twice daily, two-weeks Receives: Drug: Rifaximin |
| Placebo | Placebo comparator | Placebo oral tablets, twice daily, two-weeks Receives: Dietary Supplement: Placebo |
What is being measured
The primary outcome is the main question the study is designed to answer.
Stress sensitivity (biological)
Biological stress sensitivity is measured by quantifying cortisol levels (ng/ml) from multiple saliva samples taken before, during, and after a stress task performed during the pre-intervention and post-intervention visit.
Measured: Throughout study completion, on average 1 year
Stress sensitivity (psychological)
Psychological stress sensitivity is measured through subjective stress reports of the participants using the visual analogue scale (VAS). VAS scorings are taken before, during, and after a stress task performed during the pre-intervention and post-intervention visit.
Measured: Throughout study completion, on average 1 year
Fear (biological)
Fear-related processes will be explored using a computerized task. Biological fear response is measured using skin conductance, and a skin conductance response (μS) is calculated .
Measured: Throughout study completion, on average 1 year
Fear (psychological)
Fear-related processes will be explored using a computerized task. Psychological fear response is measured subjectively by asking participants to indicate their expectancy score of an aversive stimulus.
Measured: Throughout study completion, on average 1 year
Secondary outcomes (6)
Positive and Negative Affect Schedule (PANAS)
Assessing ratings on the subscales of PANAS, positive and negative affect, before and after intervention. PA subscale scores range between 10-50, with higher scores indicating better outcome. NA subscale scores range between 10-50, with higher scores indicating worse outcome.
Measured: Throughout study completion, on average 1 year
Perceived Stress Scale (PSS)
Assessing ratings on PSS before and after intervention. PSS scores range between 0-40 with higher scores indicating worse outcome.
Measured: Throughout study completion, on average 1 year
Gastrointestinal Symptom Rating Scale (GSRS)
Assessing ratings on the subscales of GSRS and its total score before and after intervention. It has 5 subscales (Reflux, Diarrhea, Constipation, Abdominal Pain, and Indigestion Syndrome). Subscale scores range from 1 to 7 and higher scores indicates a worse outcome.
Measured: Throughout study completion, on average 1 year
Leiden Index of Depression Sensitivity (LEIDS-R)
Assessing ratings on the subscales of LEIDS-R and its total score before and after intervention. This is a self-report on cognitive reactivity comprised of 34 items with six subscales. Hopelessness/suicidality; Acceptance/Coping; Aggression; Control/Perfectionism; Risk Aversion; Rumination.
Measured: Throughout study completion, on average 1 year
State-Trait Anxiety Inventory, State Anxiety Subscale (STAI-S)
Assessing ratings on the momentary (state) anxiety subscale of STAI before and after intervention. This is a self-report comprised of 20 questions specifically for state anxiety, rated on a 4-point scale. State anxiety is rated with anxiety absent and anxiety present questions. Anxiety absent questions constitute the absence of anxiety in a statement like, "I feel secure." Anxiety present questions represent the presence of anxiety in a statement like "I feel worried." The 4-point scale are as follows: 1 'not at all', 2 'somewhat', 3 'moderately so', and 4 'very much so'.
Measured: Throughout study completion, on average 1 year
Brain response to stress
Brain response (brain oxygenation level-dependent signals) to a fMRI-adapted stress task will be measured before and after intervention
Measured: Throughout study completion, on average 1 year
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted19 Oct 2022
- Study start2 Feb 2023
- Primary completionJul 2025 (estimated)
- Study completionJul 2025 (estimated)
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for Healthy VolunteersStudies of the same condition, open and under way.
- More trials run by Universitaire Ziekenhuizen KU LeuvenThe sponsor's other registered studies.
- 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 2/3
- Primary purpose
- Basic science
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Masking
- Triple blind
- Who is masked
- Participant, Investigator, Outcomes assessor
- Enrolment
- 60 participants (estimated)
Sponsor and investigators
- Lead sponsor
- Universitaire Ziekenhuizen KU Leuven
- Sponsor type
- University, hospital or other
- Responsible party
- Principal investigator, Lukas Van Oudenhove, Universitaire Ziekenhuizen KU Leuven
- Investigators
- Lukas Van Oudenhove, MD, PhD, Principal investigator, KU LeuvenKristin Verbeke, Pharm, PhD, Principal investigator, KU LeuvenBoushra Dalile, PhD, Principal investigator, KU LeuvenJeroen Raes, PhD, Principal investigator, VIB-KU Leuven
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT05587036
- Sponsor's protocol ID
- S66407
- Other IDs
- 2021-006814-35
- Status last verified
- Dec 2024
- First submitted
- 29 Sep 2022
- Last updated
- 20 Dec 2024
- Results posted
- No
- Data monitoring committee
- No
- FDA-regulated drug
- No
- FDA-regulated device
- No
- Individual data sharing
- Yes: IPD that underlie results in a publication will be made available to other researchers with all identifying information removed.
Study at a glance
From the registry record, last updated by the sponsor on 20 Dec 2024. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- A Randomized, Triple-blind, Placebo-controlled Study on the Effect of Rifaximin on Psychobiological Functions in Healthy Men
- ClinicalTrials.gov ID
- NCT05587036
- Acronym / sponsor ID
- S66407
- Conditions
- Healthy Volunteers, Stress, Fear
- Keywords
- Rifaximin, Anti-Bacterial Agents, Stress, Fear, Inflammation, Short-Chain Fatty Acid, Microbiota-Gut-Brain Axis
- Phase
- Phase 2/3
- Study type
- Interventional
- Recruitment status
- Recruiting
- Enrolment
- 60 participants (estimated)
- Lead sponsor
- Universitaire Ziekenhuizen KU LeuvenUniversity, hospital or other
- Study start
- 2 Feb 2023 (actual)
- Primary completion
- Jul 2025 (estimated)
- Study completion
- Jul 2025 (estimated)
- First posted
- 19 Oct 2022 (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.
A randomized, triple-blind, placebo-controlled study on the effect of rifaximin on psychobiological functions in healthy men.
Detailed description
This study is a randomized, triple-blind, placebo-controlled, interventional trial aiming to elucidate the impact of rifaximin-induced gut microbiota alteration to the psychobiological functioning of healthy men. The intervention will be performed in a parallel group design where one group will receive rifaximin (Targaxan 550 mg) twice daily for two weeks (treatment arm), while the other group will receive placebo (placebo arm).
Primary objective: to test the effect of rifaximin on stress sensitivity and fear-related processes
Secondary objective: to determine the mediating and/or moderating factors that underlie rifaximin-induced psychobiological changes
Study design
- Primary purpose
- Basic science
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Masking
- Triple blind (participant, investigator, outcomes assessor)
- Number of arms
- 2
| Arm | Type | Receives |
|---|---|---|
| Rifaximin | Experimental | Drug: RifaximinRifaximin oral tablets, 550 mg, twice daily, two-weeks |
| Placebo | Placebo comparator | Dietary Supplement: PlaceboPlacebo oral tablets, twice daily, two-weeks |
Who may qualify
- Ages
- 18 to 50 years
- Sex
- Male only
- Healthy volunteers
- Accepted
- Age groups
- Adult
Key inclusion criteria (7 listed)
- Voluntary written informed consent of the participant or their legally authorized representative has been obtained prior to any screening procedures
- Proficiency in English and/or Dutch
- Healthy with no intestinal and/or psychological complaints
- Access to a -18°C freezer (i.e. ordinary household freezer)
- Male participants
Key exclusion criteria (18 listed)
- Participant has a history of previous or current neurological, psychiatric, gastrointestinal or endocrine disorder
- Any disorder, which in the Investigator's opinion might jeopardize the participant's safety or compliance with the protocol
- Any prior or concomitant treatment(s) that might jeopardize the participant's safety or that would compromise the integrity of the Trial
- Participation in an interventional Trial with an investigational medicinal product (IMP) or device
- Hypersensitivity to the active substance rifaximin, to any rifamycin (e.g. rifampicin or rifabutin) or any of the excipients
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 |
|---|---|---|
| RifaximinAlso: TargaxanRifaximin oral tablet, 550 mg, twice daily, two-weeks | Drug | Rifaximin |
| PlaceboPlacebo oral tablet, twice daily, two-weeks | Dietary supplement | Placebo |
Primary outcome
Stress sensitivity (biological)
Time frame: Throughout study completion, on average 1 year
Biological stress sensitivity is measured by quantifying cortisol levels (ng/ml) from multiple saliva samples taken before, during, and after a stress task performed during the pre-intervention and post-intervention visit.
Stress sensitivity (psychological)
Time frame: Throughout study completion, on average 1 year
Psychological stress sensitivity is measured through subjective stress reports of the participants using the visual analogue scale (VAS). VAS scorings are taken before, during, and after a stress task performed during the pre-intervention and post-intervention visit.
Fear (biological)
Time frame: Throughout study completion, on average 1 year
Fear-related processes will be explored using a computerized task. Biological fear response is measured using skin conductance, and a skin conductance response (μS) is calculated .
Fear (psychological)
Time frame: Throughout study completion, on average 1 year
Fear-related processes will be explored using a computerized task. Psychological fear response is measured subjectively by asking participants to indicate their expectancy score of an aversive stimulus.
6 secondary outcomes
Positive and Negative Affect Schedule (PANAS)
Time frame: Throughout study completion, on average 1 year
Perceived Stress Scale (PSS)
Time frame: Throughout study completion, on average 1 year
Gastrointestinal Symptom Rating Scale (GSRS)
Time frame: Throughout study completion, on average 1 year
Leiden Index of Depression Sensitivity (LEIDS-R)
Time frame: Throughout study completion, on average 1 year
State-Trait Anxiety Inventory, State Anxiety Subscale (STAI-S)
Time frame: Throughout study completion, on average 1 year
Brain response to stress
Time frame: Throughout study completion, on average 1 year
Results and safety
This study is still under way. Results are not available in the source record yet.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 20 Dec 2024.
- Individual participant dataSharing planned: Yes. IPD that underlie results in a publication will be made available to other researchers with all identifying information removed.
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Screening Protocol
Pain
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.
Lukas Van Oudenhove, MD, PhD principal investigator
KU Leuven
Kristin Verbeke, Pharm, PhD principal investigator
KU Leuven
Boushra Dalile, PhD principal investigator
KU Leuven
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A Phase 2/3 study testing Rifaximin in people with Healthy Volunteers and Stress, run by Universitaire Ziekenhuizen KU Leuven at 1 site in Belgium.
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 7 inclusion and 18 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: looking for participants now, as of the sponsor's last update on 20 Dec 2024. 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 Belgium. 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.
What does this combined phase mean?
Phase 2 studies give the treatment to a larger group to see whether it has the intended effect and to keep checking safety.
Phase 3 studies compare the treatment with the current standard treatment or a placebo in a large group, to confirm how well it works and watch for side effects.
Not every study follows the same path, and some studies (observational studies, device studies) have no phase.
Are results available for this study?
This study is still under way. Results are not available in the source record yet.
How can a doctor refer a patient or contact the research team?
Contact Lukas Van Oudenhove, MD, PhD (+32 16 33 01 47, lukas.vanoudenhove@kuleuven.be), or a site near the patient. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Stress sensitivity (biological) (time frame: Throughout study completion, on average 1 year). The study lists 4 primary outcomes in all. 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 20 Dec 2024.