Table 1 Participant selection criteria

Inclusion criteria

Individuals must satisfy the following criteria to be enrolled in the study:

1. Male or female aged ≥ 18 years at the time of signing the ICF.

2. Individual must understand and voluntarily sign an ICF before conducting the study-related assessments/procedure.

3. Willing and able to adhere to the scheduled study visits and other protocol requirements.

4. Individuals must have been operated with IPAA with a duration of at least 6 month before the screening visit.

5. Individuals must have a diagnosis of recurrent pouchitis defined as at least two episodes in the last year or relapsing immediately after a reasonable response to antibiotherapy (the antifungal medication is allowed until the day before transplantation).

6. Individuals must be in remission with a PDAI < 7 at screening

7. Individuals must have affiliation with a social security system or be a beneficiary of such a system

8. Women of childbearing age must have a negative pregnancy test at screening and must agree to practice effective methods of contraception

Exclusion criteria

Individuals who meet any of the following exclusion criteria cannot be enrolled in this study:

1. Crohn’s disease or indeterminate colitis

2. Anastomotic stenosis

3. Individuals with prior treatment by probiotic within 3 months before the transplantation visit

4. Individuals with prior treatment by corticosteroids within 6 weeks before the transplantation visit

5. Individuals with prior treatment by immunosuppressors within 3 month before the transplantation visit

6. Prior treatment with a biologic within 3 month before the transplantation visit

7. Documented active infection of any kind in the last 6 months

8. ANC < 1.5 × 10⁹ /L (1500 mm³)

9. Infection with chronic HIV

10. Pregnant or breastfeeding women

11. Chronic medical or psychiatric disease that may interfere with the individual’s ability to comply with study procedures

12. Administration of investigational drugs within 3 months before planned FMT

13. Adults under guardianship, safeguard justice, or trusteeship

14. Individuals with difficulty in follow-up (vacation, job transfer, geographical distance, lack of motivation)

15. Patients with contraindication to colonoscopy or anesthesia (if necessary)