Overview
Sponsor-declared trial summary
Phase
Therapeutic exploratory (Phase II)
Status
Not authorised
Participants planned
50
Countries
1
Sites
2
substance use disorder
The primary objective is to determine whether 4 weeks of treatment with rifaximin, compared with placebo, results in measurable improvement in intestinal barrier integrity and gut-derived inflammatory signalling compared with placebo.
Key facts
- Sponsor
- Fondazione Santa Lucia
- Participant type
- Patients
- Age range
- 18-64 years
- Gender
- Male and Female
- Therapeutic area
- Psychiatry and Psychology [F] - Mental Disorders [F03]
- Decision date (initial)
- 2026-04-29
- Transition trial
- No
- Low-intervention
- No
- Rare-disease indication
- No
- Vulnerable population
- No
- Funding sources
- IRCSS - Santa Lucia Foundation
External identifiers
- EU CT number
- 2025-524778-41-00
- WHO UTN
- U1234-5678-9123
- ClinicalTrials.gov
- NCT12345678
- ISRCTN
- ISRCTN12345678
Trial design
CTIS Part I — objectives, methods, condition coding
Main objective
Scope: Therapy
The primary objective is to determine whether 4 weeks of treatment with rifaximin, compared with placebo, results in measurable improvement in intestinal barrier integrity and gut-derived inflammatory signalling compared with placebo.
Secondary objectives 1
- 1) To evaluate the effect of rifaximin on systemic inflammatory biomarkers associated with intestinal barrier disruption. 2) To evaluate whether biological modulation of intestinal permeability and inflammatory signalling is associated with changes in cue-induced opioid craving.
Conditions and MedDRA coding
substance use disorder
Study design 1 period
| # | Title | Allocation | Blinding | Roles blinded | Arms |
|---|---|---|---|---|---|
| 1 | na na
|
Randomised Controlled | Double | [{"id":179559,"code":2,"name":"Investigator"},{"id":179558,"code":1,"name":"Subject"}] |
Eligibility criteria
Principal inclusion / exclusion criteria as submitted by sponsor
Inclusion criteria 1
- Diagnosis of OUD according to DSM‑5 criteria; patients in the early phase of withdrawal or in treatment with the intention to discontinue opioid use; age between 18 and 60 years; for female participants, not pregnant and not breastfeeding; ability to understand and sign informed consent. Patients with recent abstinence (e.g., within 1–4 weeks from last opioid use) will be preferentially included to capture the early adaptation phase, but not those in uncontrolled acute withdrawal. Patients receiving methadone maintenance treatment are eligible, provided they are on a stable dose and willing not to modify it for at least the first month of the study.
Exclusion criteria 1
- Presence of known organic gastrointestinal diseases (e.g., Crohn’s disease, ulcerative colitis, untreated celiac disease, advanced-stage liver cirrhosis, GI malignancies) that may significantly alter intestinal permeability or contraindicate biopsy; diagnosis of active chronic infection; severe uncontrolled medical conditions; active psychiatric disorders that impair cooperation; current use of antibiotics or probiotics that significantly alter the microbiota (requiring at least a 4‑week washout before the study); HIV/AIDS or immunocompromised status; known allergy or severe adverse reaction to rifaximin or to antibiotics of the rifamycin class; for women, confirmed or planned pregnancy during the study period. Concurrent participation in other interventional clinical trials; inability to comply with study procedures.
Endpoints
Primary and secondary outcome measures (English text)
Primary endpoints 1
- The primary efficacy endpoints concern the improvement of craving and social disconnection/isolation in OUD paties treated with rifaximin compared with placebo. Specifically: Intensity of opioid craving, Indicators of social isolation/disconnection, Tapering of methadone therapy
Secondary endpoints 1
- Improvement in: Intestinal permeability measures, Fecal microbiota characteristics, Adverse events and infections
Investigational products
Investigational medicinal products (IMPs), comparators, placebo, auxiliary
Test 1
Normix 200 mg compresse rivestite con film
PRD11412027 · Product
- Active substance
- Rifaximin
- Pharmaceutical form
- FILM-COATED TABLET
- Route of administration
- ORAL
- Max daily dose
- 800 mg milligram(s)
- Max total dose
- 22400 mg milligram(s)
- Max treatment duration
- 4 Week(s)
- Authorisation status
- Authorised
- ATC code
- A07AA11 — RIFAXIMIN
- Marketing authorisation
- 025300070
- MA holder
- ALFASIGMA S.P.A.
- MA country
- Italy
- Paediatric formulation
- No
- Orphan designation
- No
- Modified vs. Marketing Authorisation
- No
Placebo 1
N/A · Product
- Other product name
- N/A
- Pharmaceutical form
- N/A
- ATC code
- N/A — N/A
- Marketing authorisation
- N/A
- MA holder
- N/A
- MA country
- Iceland
- Paediatric formulation
- No
Sponsors and contacts
Sponsor organisations, regulatory contacts, third parties
Fondazione Santa Lucia
- Sponsor organisation
- Fondazione Santa Lucia
- Address
- Via Ardeatina 306
- City
- Rome
- Postcode
- 00179
- Country
- Italy
Scientific contact point
- Organisation
- Fondazione Santa Lucia
- Contact name
- Daniele Caprioli
Public contact point
- Organisation
- Fondazione Santa Lucia
- Contact name
- Daniele Caprioli
Locations
1 EU/EEA country · 2 investigational sites
By country
| Country | MS status | Planned subjects | Sites |
|---|---|---|---|
| Italy | Not authorised | 50 | 2 |
| Rest of world | — | 0 | — |
Investigational sites
Results and documents
Annex IV summary of results, Annex V layperson summary, and all documents registered in CTIS for this trial
Documents 10 files
Public protocol annexes, IB summaries, regulatory submissions and post-authorisation documents registered in CTIS.
| Type | Title | Version |
|---|---|---|
| Protocol (for publication) | 3_Blinding_and_Packaging_Comparison_Statement | 1 |
| Protocol (for publication) | Protocol_v3_1_English_CTR_clear | 3.1 |
| Protocol (for publication) | Protocol_v3_1_English_CTR_with edits | 3.1 |
| Recruitment arrangements (for publication) | 17_Disposizioni reclutamento | 1 |
| Subject information and informed consent form (for publication) | 2_Consenso_informato_ITA_2_0 | 2.0 |
| Subject information and informed consent form (for publication) | 2_Consenso_informato_ITA_SITE NEUTRAL 2_0 | 2.0 |
| Subject information and informed consent form (for publication) | 2_Consenso_informato_ITA_track changes 2_0 | 2.0 |
| Summary of Product Characteristics (SmPC) (for publication) | 8_IMP | 1 |
| Synopsis of the protocol (for publication) | 5_CE_SPERIM_MOD_1_Sinossi_ENG | 2.0 |
| Synopsis of the protocol (for publication) | 5_CE_SPERIM_MOD_1_Sinossi_ITA | 2.0 |
Application history
1 submissions — initial application plus substantial / non-substantial modifications
| # | Type | Code | Submitted | Reference MS | Conclusion | Decision date |
|---|---|---|---|---|---|---|
| 1 | INITIAL | IN | 2025-12-18 | Italy | Not acceptable 2026-04-27
|
2026-04-29 |