EndometriosisProMetrioSNCT06929364
The Role of Probiotics in the Treatment of Endometriosis (ProMetrioS): a Randomised Double-blinded Placebo-controlled Cross-over Trial
A study testing Omni Biotic Stress in people with Endometriosis and Probiotics, run by The Gut Microbiome Center (Centar za crijevni mikrobiom) at 1 site in Croatia.
Trial summary
ProMetrioS is a randomised blinded placebo-controlled cross-over trial investigating the effect of specific multistrain probiotics in patients with endometriosis. The aim of this clinical trial is to determine whether probiotic treatment can significantly modulate gut microbiome composition and functionality in… Read more about this study
- Who is it for?
- Ages Up to 35 years, women only
- Conditions the study is for
- Endometriosis, Probiotics
- What is being tested?
- Omni Biotic Stress
- Could I receive a placebo?
- Yes, some participants may receive a placebo
- How many people
- 40 participants
- Where
- 1 siteCroatia
- Study dates
- 1 Nov 2024to 30 Nov 2025
- Phase
- Interventional
- 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 Up to 35 years
- Women only
- No healthy volunteers
- Child, Adult
Who may be able to join
- adult subjects with stage III or IV endometriosis diagnosis confirmed by biopsy
Who cannot join
- Age > 35 years
- Immunocompromised patients
- Patients with chronic inflammatory diseases (e.g., autoimmune disorders)
- Pregnancy
- Use of supplements and foods with probiotics
- Use of immunosuppressant, antibiotic, proton pump inhibitors and corticosteroid drugs
- Use of probiotics product less than one month before start of study or during study
Trial locations and contacts
1 site in 1 country. Contact the study team or a site near you to ask about taking part.
Croatia1 site, 1 recruiting
- Recruiting
University Hospital Center Zagreb
Zagreb, 10000
Ira Renko, MS, info@ccm.hr
Andrija Karacic, dr.med, andrija@ccm.hr
About this study
ProMetrioS is a randomised blinded placebo-controlled cross-over trial investigating the effect of specific multistrain probiotics in patients with endometriosis. The aim of this clinical trial is to determine whether probiotic treatment can significantly modulate gut microbiome composition and functionality in endometriosis patients, specifically parameters associated with the estrobolome.
Read the detailed description
Patients will be recruited among the outpatient population of the National Center for Endometriosis, Department of Gynecological Surgery and Urology, Gynecology Department, University Hospital Center Zagreb following the inclusion and exclusion criteria.
To participate in the study all patients will be required to sign the Informed Consent form.
All patients will undergo a complete anamnesis via a digital form to investigate their lifestyle (occupation, stress, diet, physical activity level).
The study period will be 6 months: eight weeks on either option (verum/placebo), with an eight week washout period in between. The purpose of the washout period is to allow the gut microbiome to return to baseline. The washout period was determined based on previous gut microbiota studies with a similar design (reference), based on the fact that the gut microbiota can change rapidly (\< 7 days) r.
The outcome measures (gut microbiome, quality of life) will be assessed in four distinct time points in context of the planned intervention.
T1 - before the intervention (start-of-study)
T2 - after the first intervention cycle/phase 1 (verum/placebo) of two months
T3 - after the wash-out phase of two months
T4 - after the second intervention cycle/phase 2 (verum/placebo) of two months (end-of-study)
Stool sampling will be performed with the aid of specific kits indepently by the patients. Lifestyle and quality of life will be evaluated by an online form designed specifically for the purpose of this study in Microsoft Office Forms (Microsoft, San Francisco, USA), short Online Form.
Through the process of randomization, patients will be allocated to either first receive the verum (probiotic) or the placebo (maltodextrin), and second the placebo or verum inversely.
Both patients and researchers involved will be blinded (double-blind study), the patients will be informed that they are going to take a probiotic twice for two months with a two-month time division. The intervention will consist of treatment with a multistrain probiotic formulation (Omni Biotic Stress) and the placebo which is identical in all its characteristics and packaging. Patients will be instructed to consume one sachet a day of each (probiotic) for 8 weeks and to report any symptoms or side effects related to its use. Adherence control will be carried out through the patient's notes on a separate online form provided, and also by checking the number of sachets used.
Since this is a cross-over study, data will be compared between time-points T1 and T2, and time-points T3 and T4, with the goal of minimizing the potential effect if we find that the effect of the probiotics lasted longer than eight weeks in those randomized into the intervention arm first.
- Conditions
- Endometriosis, Probiotics
- Being tested
- Omni Biotic Stress, Placebo
- Keywords
- endometriosis, probiotics, microbiome
- Medical subject headings
- Endometriosis
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
Omni Biotic StressDietary supplement
Multistrain probiotic formulation (Omni Biotic Stress), 1 sachet daily for 8 weeks
PlaceboOther
Inert powder identical in appearance and taste to probiotic, 1 sachet daily for 8 weeks
| Study group | Role | What they receive |
|---|---|---|
| patient group 1 | Experimental | Arm 1: Probiotic-Placebo Sequence Description: Participants will consume Omni Biotic Stress (multistrain probiotic formulation) once daily for 8 weeks during the first phase, followed by an 8-week washout period, and then placebo once daily for 8 weeks during the second phase.
Interventions:
Dietary Supplement: Omni Biotic Stress; Other: Placebo Receives: Dietary Supplement: Omni Biotic Stress; Other: Placebo |
| patient group 2 | Experimental | Arm 2: Placebo-Probiotic Sequence Description: Participants will consume placebo once daily for 8 weeks during the first phase, followed by an 8-week washout period, and then Omni Biotic Stress once daily for 8 weeks during the second phase.
Interventions:
Other: Placebo; Dietary Supplement: Omni Biotic Stress
Participants will record adherence and any potential side effects in an online form. Researchers will check the number of used sachets to ensure accuracy of adherence data. Receives: Dietary Supplement: Omni Biotic Stress; Other: Placebo |
What is being measured
The primary outcome is the main question the study is designed to answer.
Change in relative abundance of gut microbial taxa and functional pathways related to the estrobolome in fecal samples
The primary outcome is the modulation of the gut microbiome. The fecal microbiome, as a genuine proxy of the gut microbiome, will be analyzed. Specific attention will be brought to taxa and metabolic pathways involved in the estrobolome.
Measured: At baseline, after 8 weeks (end of phase 1), and after 24 weeks (end of phase 2)
Secondary outcomes (2)
Change in quality of life measured by EHP-5 questionnaire
Quality of life will be assessed using the Endometriosis Health Profile-5 (EHP-5) questionnaire at baseline, after each intervention phase, and at the end of the study.
Measured: Week 1, Week 8, Week 16, Week 24 (6 months)
Change in quality of life measured by SEQOL questionnaire
Quality of life will be assessed using the Stellenbosch Endometriosis Quality of Life (SEQOL) questionnaire at baseline, after each intervention phase, and at the end of the study.
Measured: Week 1, Week 8, Week 16, Week 24 (6 months)
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted16 Apr 2025
- Study start1 Nov 2024
- Primary completion1 May 2025 (estimated)
- Study completion30 Nov 2025 (estimated)
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Publications (1)Papers the sponsor has linked to this study.
- Other trials for EndometriosisStudies 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
- Crossover
- Masking
- Double blind
- Who is masked
- Participant, Investigator
- Enrolment
- 40 participants (estimated)
Sponsor and investigators
- Lead sponsor
- The Gut Microbiome Center (Centar za crijevni mikrobiom)
- Sponsor type
- University, hospital or other
- Collaborators
- Clinical Hospital Centre Zagreb
- Responsible party
- Sponsor
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT06929364
- Sponsor's protocol ID
- ProMetrioS2024
- Acronym
- ProMetrioS
- Status last verified
- Apr 2025
- First submitted
- 17 Sep 2024
- Last updated
- 16 Apr 2025
- Results posted
- No
- Data monitoring committee
- No
- FDA-regulated drug
- No
- FDA-regulated device
- No
- Individual data sharing
- Undecided: That has to be decided more with the whole team
Publications
Kralj S, Zeman K, Mikus M, Karacic A, Prso AL, Coric M, Renko I. The role of probiotics in the treatment of endometriosis (ProMetrioS): a randomized double-blinded placebo-controlled cross-over trial. Trials. 2026 Feb 20;27(1):242. doi: 10.1186/s13063-025-09405-5.
PubMed 41715206
Study at a glance
From the registry record, last updated by the sponsor on 16 Apr 2025. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- The Role of Probiotics in the Treatment of Endometriosis (ProMetrioS): a Randomised Double-blinded Placebo-controlled Cross-over Trial
- ClinicalTrials.gov ID
- NCT06929364
- Acronym / sponsor ID
- ProMetrioS / ProMetrioS2024
- Conditions
- Endometriosis, Probiotics
- Keywords
- endometriosis, probiotics, microbiome
- Study type
- Interventional
- Recruitment status
- Recruiting
- Enrolment
- 40 participants (estimated)
- Lead sponsor
- The Gut Microbiome Center (Centar za crijevni mikrobiom)University, hospital or other
- Collaborators
- Clinical Hospital Centre Zagreb
- Study start
- 1 Nov 2024 (actual)
- Primary completion
- 1 May 2025 (estimated)
- Study completion
- 30 Nov 2025 (estimated)
- First posted
- 16 Apr 2025 (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.
ProMetrioS is a randomised blinded placebo-controlled cross-over trial investigating the effect of specific multistrain probiotics in patients with endometriosis. The aim of this clinical trial is to determine whether probiotic treatment can significantly modulate gut microbiome composition and functionality in endometriosis patients, specifically parameters associated with the estrobolome.
Detailed description
Patients will be recruited among the outpatient population of the National Center for Endometriosis, Department of Gynecological Surgery and Urology, Gynecology Department, University Hospital Center Zagreb following the inclusion and exclusion criteria.
To participate in the study all patients will be required to sign the Informed Consent form.
All patients will undergo a complete anamnesis via a digital form to investigate their lifestyle (occupation, stress, diet, physical activity level).
The study period will be 6 months: eight weeks on either option (verum/placebo), with an eight week washout period in between. The purpose of the washout period is to allow the gut microbiome to return to baseline. The washout period was determined based on previous gut microbiota studies with a similar design (reference), based on the fact that the gut microbiota can change rapidly (\< 7 days) r.
The outcome measures (gut microbiome, quality of life) will be assessed in four distinct time points in context of the planned intervention.
T1 - before the intervention (start-of-study)
T2 - after the first intervention cycle/phase 1 (verum/placebo) of two months
T3 - after the wash-out phase of two months
T4 - after the second intervention cycle/phase 2 (verum/placebo) of two months (end-of-study)
Stool sampling will be performed with the aid of specific kits indepently by the patients. Lifestyle and quality of life will be evaluated by an online form designed specifically for the purpose of this study in Microsoft Office Forms (Microsoft, San Francisco, USA), short Online Form.
Through the process of randomization, patients will be allocated to either first receive the verum (probiotic) or the placebo (maltodextrin), and second the placebo or verum inversely.
Both patients and researchers involved will be blinded (double-blind study), the patients will be informed that they are going to take a probiotic twice for two months with a two-month time division. The intervention will consist of treatment with a multistrain probiotic formulation (Omni Biotic Stress) and the placebo which is identical in all its characteristics and packaging. Patients will be instructed to consume one sachet a day of each (probiotic) for 8 weeks and to report any symptoms or side effects related to its use. Adherence control will be carried out through the patient's notes on a separate online form provided, and also by checking the number of sachets used.
Since this is a cross-over study, data will be compared between time-points T1 and T2, and time-points T3 and T4, with the goal of minimizing the potential effect if we find that the effect of the probiotics lasted longer than eight weeks in those randomized into the intervention arm first.
Study design
- Primary purpose
- Treatment
- Allocation
- Randomised
- Intervention model
- Crossover
- Masking
- Double blind (participant, investigator)
- Number of arms
- 2
| Arm | Type | Receives |
|---|---|---|
| patient group 1 | Experimental | Dietary Supplement: Omni Biotic Stress, Other: PlaceboArm 1: Probiotic-Placebo Sequence Description: Participants will consume Omni Biotic Stress (multistrain probiotic formulation) once daily for 8 weeks during the first phase, followed by an 8-week washout period, and then placebo once daily for 8 weeks during the second phase. Interventions: Dietary Supplement: Omni Biotic Stress; Other: Placebo |
| patient group 2 | Experimental | Dietary Supplement: Omni Biotic Stress, Other: PlaceboArm 2: Placebo-Probiotic Sequence Description: Participants will consume placebo once daily for 8 weeks during the first phase, followed by an 8-week washout period, and then Omni Biotic Stress once daily for 8 weeks during the second phase. Interventions: Other: Placebo; Dietary Supplement: Omni Biotic Stress Participants will record adherence and any potential side effects in an online form. Researchers will check the number of used sachets to ensure accuracy of adherence data. |
Who may qualify
- Ages
- Up to 35 years
- Sex
- Female only
- Healthy volunteers
- Not accepted
- Age groups
- Child, Adult
Key inclusion criteria (1 listed)
- adult subjects with stage III or IV endometriosis diagnosis confirmed by biopsy
Key exclusion criteria (7 listed)
- Age > 35 years
- Immunocompromised patients
- Patients with chronic inflammatory diseases (e.g., autoimmune disorders)
- Pregnancy
- Use of supplements and foods with probiotics
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 |
|---|---|---|
| Omni Biotic StressMultistrain probiotic formulation (Omni Biotic Stress), 1 sachet daily for 8 weeks | Dietary supplement | patient group 1, patient group 2 |
| PlaceboInert powder identical in appearance and taste to probiotic, 1 sachet daily for 8 weeks | Other | patient group 1, patient group 2 |
Primary outcome
Change in relative abundance of gut microbial taxa and functional pathways related to the estrobolome in fecal samples
Time frame: At baseline, after 8 weeks (end of phase 1), and after 24 weeks (end of phase 2)
The primary outcome is the modulation of the gut microbiome. The fecal microbiome, as a genuine proxy of the gut microbiome, will be analyzed. Specific attention will be brought to taxa and metabolic pathways involved in the estrobolome.
2 secondary outcomes
Change in quality of life measured by EHP-5 questionnaire
Time frame: Week 1, Week 8, Week 16, Week 24 (6 months)
Change in quality of life measured by SEQOL questionnaire
Time frame: Week 1, Week 8, Week 16, Week 24 (6 months)
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 16 Apr 2025.
- Derived from this study: PubMed 41715206Kralj S, Zeman K, Mikus M, Karacic A, Prso AL, Coric M, Renko I. The role of probiotics in the treatment of endometriosis (ProMetrioS): a randomized double-blinded placebo-controlled cross-over trial. Trials. 2026 Feb 20;27(1):242. doi: 10.1186/s13063-025-09405-5.
- Individual participant dataSharing planned: Undecided. That has to be decided more with the whole team
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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.
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A study testing Omni Biotic Stress in people with Endometriosis and Probiotics, run by The Gut Microbiome Center (Centar za crijevni mikrobiom) at 1 site 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 1 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: looking for participants now, as of the sponsor's last update on 16 Apr 2025. 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 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. 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?
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 Ira Renko, MS (955096473, ira.renko@gmail.com), or a site near the patient. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Change in relative abundance of gut microbial taxa and functional pathways related to the estrobolome in fecal samples (time frame: At baseline, after 8 weeks (end of phase 1), and after 24 weeks (end of phase 2)). It is what the study was designed to measure, not a finding.
Where can I read the original study information?
On the ClinicalTrials.gov record for NCT06929364, which also lists 1 linked publication.
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 16 Apr 2025.