IBS - Irritable Bowel SyndromeNCT04760353
The Effect of a Probiotic Mixture in Obese Patients With Irritable Bowel Syndrome
A study testing Probiotic mixture (OMNi-BiOTiC STRESS) in people with IBS - Irritable Bowel Syndrome and Obesity, run by University Hospital Rijeka at 2 sites in Croatia.
Trial summary
The objective of the current study is to evaluate the effect of a probiotic mixture on the adequate relief and faecal microbiota in obese patients with irritable bowel syndrome Read more about this study
- Who is it for?
- Ages 18 to 65 years
- Conditions the study is for
- IBS - Irritable Bowel Syndrome, Obesity
- What is being tested?
- Probiotic mixture (OMNi-BiOTiC STRESS)
- Type of treatment
- Pill or oral medicine
- Could I receive a placebo?
- Yes, some participants may receive a placebo
- How many people
- 80 participants
- Where
- 2 sitesCroatia
- Study dates
- 10 Nov 2021to 17 Oct 2025
- 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 65 years
- All sexes
- No healthy volunteers
- Adult, Older adult
Who may be able to join
- Obese [Body mass index (BMI) ≥30] men or women with confirmed IBS (all subtypes based on Rome IV Diagnostic Criteria for IBS) aged between 18 and 65 years.
- Written informed consent.
Who cannot join
- Pregnancy or lactation
- Severe systemic illness [cancer, gastrointestinal illness (e.g., colitis, Crohn's disease, celiac disease, recurrent diverticulitis), chronic renal failure, an endocrine disorder, metabolic disorder, angina, congestive heart failure, uncontrolled hypertension] or severely impaired general health
- Organic abnormality which is excluded by full blood count, C-reactive protein or erythrocyte sedimentation rate, and thyroid-stimulating hormone for constipated IBS participants. To exclude other organic lower gastrointestinal disease faecal calprotectin will be checked, and celiac test and colonoscopy will be performed if needed.
- Previous abdominal surgery except for appendectomy, cholecystectomy and abdominal wall hernia repair
- History of psychiatric disorder
- History of participation in another clinical trial within 3 months before the onset of this trial
- Medications that could affect the outcomes: oral steroid, sulfasalazine, cholestyramine, misoprostol and probiotics usage 3 months prior to and during the study; and antacids with magnesium or aluminium usage during the study
Trial locations and contacts
2 sites in 1 country.
Croatia2 sites
Clinical Hospital Centre
Rijeka, Croatia, 51000
University Hospital Rijeka
Rijeka, Rijeka, 51000
About this study
Official title: The Effect of a Probiotic Mixture on the Symptoms and Fecal Microbiota in Obese Patients With Irritable Bowel Syndrome, Randomised, Double-blind, Controlled Study
The objective of the current study is to evaluate the effect of a probiotic mixture on the adequate relief and faecal microbiota in obese patients with irritable bowel syndrome
Read the detailed description
- The treatment period will last 8 weeks and after the treatment period, patients will be followed-up for another 2 weeks. Thus the overall trial period is the 10-week study period and end of 10th week is the end of the trial.
- Planned visits to gastroenterologists are at the screening period (-1 week), randomization period (0 weeks), and at the end of the treatment period (8th week).
- Patients will be instructed that unplanned visits to gastroenterologist are allowed only in case of a need or an urgency [e.g., adverse reactions, clinical deterioration and/or need for additional irritable bowel syndrome (IBS) management]. Unplanned visits will be recorded and does not exclude patients from the trial.
- For assessing other needed parameters (e.g., adequate relief, adverse reactions, irritable bowel syndrome (IBS) management) patients will be assessed by a physician, using an interactive voice response by telephone.
- Laboratory tests will be performed by certified clinical laboratories. Blood samples will be obtained by experienced trial nurses at the time of randomization (0 weeks).
- Anthropometric measurements will be assessed at the baseline and at the end of the treatment period (8th week).
- Irritable bowel syndrome (IBS) management (non-medication and medication therapy) will be assessed at the baseline, during the trial at the planned and unplanned visits to gastroenterologists, and at the end of the trial (by a physician using an interactive voice response by telephone). In a case of clinical deterioration IBS management is allowed during the trial and each will be recorded by gastroenterologists.
- Participants will receive 112 powder portion bags at the beginning of the trial and will be instructed to return the container after the 8-week treatment period. Leftover powder portion bags will be counted at the end of the treatment period (8th week) to estimate compliance. Compliant is considered a participant where no leftover powder portion bags will be recorded. Otherwise, the participant is considered non-compliant.
- Safety will be ensured by following adverse reactions during the trial. Scheduled assessment of adverse reactions is at the time of randomization, after 4 weeks, 8 weeks, and at the end of the trial. Responses will be recorded by a physician, at the planned visit of gastroenterologists and/or using an interactive voice response by telephone. Unscheduled recording of adverse reactions is during the entire trial by patients which will be instructed at the randomization period to report any adverse reactions to gastroenterologists using an interactive voice response by telephone. In a case of severe adverse reactions patients will be withdrawn from the trial and if needed. In case of a need or urgency (e.g., adverse reactions, clinical deterioration) clinical management will be provided in line with the best medical practice, by gastroenterologists and/or medical specialists depending on a medical condition.
- Patients can withdrawal from the trial any time. During the trial period withdrawal and its reason will be assessed by gastroenterologists at the visits or using an interactive voice response by telephone. Patients will be instructed in a case of a withdrawal to inform gastroenterologists and report the reason. In a lack of response the reason will be considered as other.
- Conditions
- IBS - Irritable Bowel Syndrome, Obesity
- Being tested
- Probiotic mixture (OMNi-BiOTiC STRESS), Placebo
- Keywords
- IBS, Obesity, microbiota
- Medical subject headings
- Irritable Bowel Syndrome, Obesity
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
Probiotic mixture (OMNi-BiOTiC STRESS)Dietary supplement
OMNi-BiOTiC STRESS containing 9 human bacterial strains [Lactobacillus casei W56, Lactobacillus acidophilus W22, Lactobacillus paracasei W20, Bifidobacterium lactis W51, Bifidobacterium lactis W52, Lactobacillus salivarius W24, Lactococcus lactis W19, Lactobacillus plantarum W62, Bifidobacterium bifidum W23, with at least 7,5 billion CFU per one dose (3 g) and 15 billion CFU per two doses (6 g)] and vitamin B (B2, B6, B12),
PlaceboOther
one powder portion bag self-administered orally twice a day for 8 weeks, identical in all aspects (organoleptic) as investigational product (IP) but containing excipient only.
- Powder portion bags are suitable for participants with intolerance to yeasts or lactose
- Each patient will receive a container with 112 powder portion bags (IP or placebo depending on the randomization) at the randomization period (0 weeks).
| Study group | Role | What they receive |
|---|---|---|
| Probiotic | Experimental | one powder portion bag of the probiotic mixture (OMNi-BiOTiC STRESS) containing 9 human bacterial strains [Lactobacillus casei W56, Lactobacillus acidophilus W22, Lactobacillus paracasei W20, Bifidobacterium lactis W51 Bifidobacterium lactis W52, Lactobacillus salivarius W24, Lactococcus lactis W19, Lactobacillus plantarum W62, Bifidobacterium bifidum W23, with at least 7,5 billion CFU per one dose (3 g) and 15 billion CFU per two doses (6 g)] and vitamin B (B2, B6, B12), self-administered orally twice a day for 8 weeks Receives: Dietary Supplement: Probiotic mixture (OMNi-BiOTiC STRESS) |
| Placebo | Placebo comparator | one powder portion bag self-administered orally twice a day for 8 weeks, identical in all aspects (organoleptic) as investigational product (IP) but containing excipient only.
* Powder portion bags are suitable for participants with intolerance to yeasts or lactose
* Each patient will receive a container with 112 powder portion bags (IP or placebo depending on the randomization) at the randomization period (0 weeks). Receives: Other: Placebo |
What is being measured
The primary outcome is the main question the study is designed to answer.
Adequate relief
Adequate relief (AR) related question of overall IBS symptoms "In the past 7 days have you had adequate relief of your IBS pain and discomfort?" which will be assessed weekly for 10 weeks (starting with 0 week till 10th week). A responder is defined as a patient who experiences AR (answers YES to AR related question) for at least 50% of the 10-week study period (5 of the 10 weekly assessments). 10-point analog scale will be used for the measurement of response rate among patients in each group.
Measured: eight weeks
Secondary outcomes (1)
The fecal flora compositions
The fecal flora compositions will be analyzed by Real Time polymerase chain reaction (PCR) for specific strain detection. The concordance rate of each patient's denaturing gradient gel electrophoresis (DGGE) profile before and after the treatment will be measured by the visual scale where each band of the DGGE profile represents a different organism and the similarity of band locations represents the same composition of the population of organisms.
Measured: eight weeks
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted18 Feb 2021
- Study start10 Nov 2021
- Primary completion17 Oct 2025
- Study completion17 Oct 2025
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for IBS - Irritable Bowel SyndromeStudies 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
- Triple blind
- Who is masked
- Participant, Investigator, Outcomes assessor
- Enrolment
- 80 participants (actual)
Sponsor and investigators
- Lead sponsor
- University Hospital Rijeka
- Sponsor type
- University, hospital or other
- Collaborators
- Institut AllergoSan Pharma GmbH
- Responsible party
- Principal investigator, Goran Hauser, University Hospital Rijeka
- Investigators
- GORAN HAUSER, MD, PhD, Principal investigator, KBC Rijeka; Medicinski fakultet Sveučilišta u Rijeci
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT04760353
- Sponsor's protocol ID
- Omni Stress 1.1
- Status last verified
- Nov 2025
- First submitted
- 26 Jan 2021
- Last updated
- 19 Nov 2025
- Results posted
- No
- Data monitoring committee
- No
- FDA-regulated drug
- No
- FDA-regulated device
- No
- Individual data sharing
- Yes: We will share all necessary documents which are not under GDPR protection
Study at a glance
From the registry record, last updated by the sponsor on 19 Nov 2025. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- The Effect of a Probiotic Mixture on the Symptoms and Fecal Microbiota in Obese Patients With Irritable Bowel Syndrome, Randomised, Double-blind, Controlled Study
- ClinicalTrials.gov ID
- NCT04760353
- Acronym / sponsor ID
- Omni Stress 1.1
- Conditions
- IBS - Irritable Bowel Syndrome, Obesity
- Keywords
- IBS, Obesity, microbiota
- Study type
- Interventional
- Recruitment status
- Completed
- Enrolment
- 80 participants (actual)
- Lead sponsor
- University Hospital RijekaUniversity, hospital or other
- Collaborators
- Institut AllergoSan Pharma GmbH
- Study start
- 10 Nov 2021 (actual)
- Primary completion
- 17 Oct 2025 (actual)
- Study completion
- 17 Oct 2025 (actual)
- First posted
- 18 Feb 2021 (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.
The objective of the current study is to evaluate the effect of a probiotic mixture on the adequate relief and faecal microbiota in obese patients with irritable bowel syndrome
Detailed description
- The treatment period will last 8 weeks and after the treatment period, patients will be followed-up for another 2 weeks. Thus the overall trial period is the 10-week study period and end of 10th week is the end of the trial.
- Planned visits to gastroenterologists are at the screening period (-1 week), randomization period (0 weeks), and at the end of the treatment period (8th week).
- Patients will be instructed that unplanned visits to gastroenterologist are allowed only in case of a need or an urgency [e.g., adverse reactions, clinical deterioration and/or need for additional irritable bowel syndrome (IBS) management]. Unplanned visits will be recorded and does not exclude patients from the trial.
- For assessing other needed parameters (e.g., adequate relief, adverse reactions, irritable bowel syndrome (IBS) management) patients will be assessed by a physician, using an interactive voice response by telephone.
- Laboratory tests will be performed by certified clinical laboratories. Blood samples will be obtained by experienced trial nurses at the time of randomization (0 weeks).
- Anthropometric measurements will be assessed at the baseline and at the end of the treatment period (8th week).
- Irritable bowel syndrome (IBS) management (non-medication and medication therapy) will be assessed at the baseline, during the trial at the planned and unplanned visits to gastroenterologists, and at the end of the trial (by a physician using an interactive voice response by telephone). In a case of clinical deterioration IBS management is allowed during the trial and each will be recorded by gastroenterologists.
- Participants will receive 112 powder portion bags at the beginning of the trial and will be instructed to return the container after the 8-week treatment period. Leftover powder portion bags will be counted at the end of the treatment period (8th week) to estimate compliance. Compliant is considered a participant where no leftover powder portion bags will be recorded. Otherwise, the participant is considered non-compliant.
- Safety will be ensured by following adverse reactions during the trial. Scheduled assessment of adverse reactions is at the time of randomization, after 4 weeks, 8 weeks, and at the end of the trial. Responses will be recorded by a physician, at the planned visit of gastroenterologists and/or using an interactive voice response by telephone. Unscheduled recording of adverse reactions is during the entire trial by patients which will be instructed at the randomization period to report any adverse reactions to gastroenterologists using an interactive voice response by telephone. In a case of severe adverse reactions patients will be withdrawn from the trial and if needed. In case of a need or urgency (e.g., adverse reactions, clinical deterioration) clinical management will be provided in line with the best medical practice, by gastroenterologists and/or medical specialists depending on a medical condition.
- Patients can withdrawal from the trial any time. During the trial period withdrawal and its reason will be assessed by gastroenterologists at the visits or using an interactive voice response by telephone. Patients will be instructed in a case of a withdrawal to inform gastroenterologists and report the reason. In a lack of response the reason will be considered as other.
Study design
- Primary purpose
- Treatment
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Masking
- Triple blind (participant, investigator, outcomes assessor)
- Number of arms
- 2
| Arm | Type | Receives |
|---|---|---|
| Probiotic | Experimental | Dietary Supplement: Probiotic mixture (OMNi-BiOTiC STRESS)one powder portion bag of the probiotic mixture (OMNi-BiOTiC STRESS) containing 9 human bacterial strains [Lactobacillus casei W56, Lactobacillus acidophilus W22, Lactobacillus paracasei W20, Bifidobacterium lactis W51 Bifidobacterium lactis W52, Lactobacillus salivarius W24, Lactococcus lactis W19, Lactobacillus plantarum W62, Bifidobacterium bifidum W23, with at least 7,5 billion CFU per one dose (3 g) and 15 billion CFU per two doses (6 g)] and vitamin B (B2, B6, B12), self-administered orally twice a day for 8 weeks |
| Placebo | Placebo comparator | Other: Placeboone powder portion bag self-administered orally twice a day for 8 weeks, identical in all aspects (organoleptic) as investigational product (IP) but containing excipient only. * Powder portion bags are suitable for participants with intolerance to yeasts or lactose * Each patient will receive a container with 112 powder portion bags (IP or placebo depending on the randomization) at the randomization period (0 weeks). |
Who may qualify
- Ages
- 18 to 65 years
- Sex
- All
- Healthy volunteers
- Not accepted
- Age groups
- Adult, Older adult
Key inclusion criteria (2 listed)
- Obese [Body mass index (BMI) ≥30] men or women with confirmed IBS (all subtypes based on Rome IV Diagnostic Criteria for IBS) aged between 18 and 65 years.
- Written informed consent.
Key exclusion criteria (7 listed)
- Pregnancy or lactation
- Severe systemic illness [cancer, gastrointestinal illness (e.g., colitis, Crohn's disease, celiac disease, recurrent diverticulitis), chronic renal failure, an endocrine disorder, metabolic disorder, angina, congestive heart failure, uncontrolled hypertension] or severely impaired general health
- Organic abnormality which is excluded by full blood count, C-reactive protein or erythrocyte sedimentation rate, and thyroid-stimulating hormone for constipated IBS participants. To exclude other organic lower gastrointestinal disease faecal calprotectin will be checked, and celiac test and colonoscopy will be performed if needed.
- Previous abdominal surgery except for appendectomy, cholecystectomy and abdominal wall hernia repair
- History of psychiatric disorder
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 |
|---|---|---|
| Probiotic mixture (OMNi-BiOTiC STRESS)OMNi-BiOTiC STRESS containing 9 human bacterial strains [Lactobacillus casei W56, Lactobacillus acidophilus W22, Lactobacillus paracasei W20, Bifidobacterium lactis W51, Bifidobacterium lactis W52, Lactobacillus salivarius W24, Lactococcus lactis W19, Lactobacillus plantarum W62, Bifidobacterium bifidum W23, with at least 7,5 billion CFU per one dose (3 g) and 15 billion CFU per two doses (6 g)] and vitamin B (B2, B6, B12), | Dietary supplement | Probiotic |
| Placeboone powder portion bag self-administered orally twice a day for 8 weeks, identical in all aspects (organoleptic) as investigational product (IP) but containing excipient only. * Powder portion bags are suitable for participants with intolerance to yeasts or lactose * Each patient will receive a container with 112 powder portion bags (IP or placebo depending on the randomization) at the randomization period (0 weeks). | Other | Placebo |
Primary outcome
Adequate relief
Time frame: eight weeks
Adequate relief (AR) related question of overall IBS symptoms "In the past 7 days have you had adequate relief of your IBS pain and discomfort?" which will be assessed weekly for 10 weeks (starting with 0 week till 10th week). A responder is defined as a patient who experiences AR (answers YES to AR related question) for at least 50% of the 10-week study period (5 of the 10 weekly assessments). 10-point analog scale will be used for the measurement of response rate among patients in each group.
1 secondary outcome
The fecal flora compositions
Time frame: eight weeks
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 19 Nov 2025.
- Individual participant dataSharing planned: Yes. We will share all necessary documents which are not under GDPR protection
Related trials for IBS - Irritable Bowel Syndrome
RecruitingObservational study
Abdominal Symptoms and Rosacea: An Observational Study on the Association Between Irritable Bowel Syndrome (IBS) and the Gut-Skin Axis
IBS (Irritable Bowel Syndrome), Rosacea
Recruiting
Stress Reduction and Lifestyle Modification in Irritable Bowel Syndrome Patients
Irritable Bowel Syndrome
Recruiting
Exercise Interventions and Dietary Advice in Fibromyalgia and IBS
Fibromyalgia, Irritable Bowel Syndrome
RecruitingPhase 2
A Study of Brenipatide (LY3537031) in Participants With Irritable Bowel Syndrome-Constipation (IBS-C)
Irritable Bowel Syndrome, Constipation
RecruitingPhase 2
A Study of Brenipatide (LY3537031) in Participants With Irritable Bowel Syndrome-Diarrhea (IBS-D)
Irritable Bowel Syndrome, Diarrhea
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.
GORAN HAUSER, MD, PhD principal investigator
KBC Rijeka; Medicinski fakultet Sveučilišta u Rijeci
2 sites in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A study testing Probiotic mixture (OMNi-BiOTiC STRESS) in people with IBS - Irritable Bowel Syndrome and Obesity, run by University Hospital Rijeka at 2 sites in Croatia.
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 2 inclusion and 7 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 19 Nov 2025. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 2 sites in Croatia. 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?
Adequate relief (time frame: eight weeks). 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 19 Nov 2025.