Study to Assess Efficacy and Safety of Cx601, Adult Allogeneic Expanded Adipose-derived Stem Cells (eASC) for the Treatment of Complex Perianal Fistula(s) in Participants With Crohn's Disease (CD)

Inclusion Criteria:

1. Signed informed consent.

2. Participants of either gender greater than or equal to (>=) 18 years and less thanor equal to (<=) 75 years of age.

3. Participants with CD diagnosed at least 6 months prior to Screening visit inaccordance with accepted clinical, endoscopic, histological and/or radiologicalcriteria.

4. Presence of complex perianal fistula(s) with a maximum of 2 internal openings and amaximum of 3 external openings based on clinical assessment; a central reading of alocally performed contrast enhanced (gadolinium) pelvic MRI will be performed toconfirm location of the fistula and potential associated perianal abscess(es).Fistula(s) must have been draining for at least 6 weeks prior to Screening visit.Actively draining simple subcutaneous fistula(s), at the time of Screening visit,are not allowed in this study. A complex perianal fistula is defined as a fistulathat meets one or more of the following criteria :

• High inter-sphincteric, high trans-sphincteric, extra-sphincteric orsuprasphincteric.

• Presence of >=2 external openings.

• Associated perianal abscess(es). Note: Abscesses that are larger than 2 cm atleast 2 dimensions on MRI must be confirmed to have been drained adequately bythe surgeon during the preparation curettage in order to be eligible.

5. Clinically controlled, nonactive or mildly active CD, during the last six monthsprior to Screening visit with:

• A patient reported outcomes (PRO-2) score <14 at Screening, AND

• A colonoscopy documenting the absence of ulcers larger than 0.5 cm in thecolonic mucosa:

• If colonoscopy data are not available within 6 months prior to Screening:

• A simple endoscopic score for Crohn's Disease (SES-CD) <=6 with absence ofrectal ulcers larger than 0.5 cm must be documented in a colonoscopy performedat Screening before randomization.

• If colonoscopy data are available within 6 months prior to Screening, thefollowing must be documented, otherwise a new colonoscopy (as above) willbe mandatory:

• The absence of ulcers larger than 0.5 cm in the colonic mucosa AND

• the improvement or no worsening in abdominal pain and/or in the diarrhea,sustained for one week or more, since the last colonoscopy was performed in theclinical records until Screening visit. AND o No hemoglobin decrease >=2.0 gram per deciliter (g/dL) or an unexplained risingC-reactive protein (CRP), > 5.0 milligram per liter (mg/L) to a concentration abovethe referenced upper limit of normal (ULN) (unless the rise is due to a knownprocess other than luminal Crohn's Disease), since the last colonoscopy wasperformed as compared to results during the Screening visit. AND o no initiation or intensification of treatment with corticosteroids,immunosuppressants or monoclonal antibodies (mAbs) dose regimen since the lastendoscopy up to Screening visit.

6. Participants whose perianal fistulas were previously treated and have shown aninadequate response or a loss of response while they were receiving either animmunosuppressive agent or tumour necrosis factor (TNF)-alpha antagonist orvedolizumab or ustekinumab, or having documented intolerance to any of thesetreatments administered at least at approved or recommended doses during the minimumperiod mentioned:

• Immunosuppressive agents: at least 3 months treatment with azathioprine (2-3milligram per kilogram per day [mg/kg/day]), 6-mercaptopurine (1-1.5mg/kg/day), or subcutaneous/intramuscular methotrexate (25 mg/week) prior toScreening for the study.

• TNFalpha antagonists:

• Infliximab: at least 14 weeks treatment at the approved doses for inductionand/or maintenance in Crohn´s disease prior to screening for the study. Forinduction: 1 intravenous dose of 5 milligram per kilogram (mg/kg) followed bythe same dose 2 and 6 weeks after. For maintenance: 5-10 mg/kg intravenouslyevery 8 weeks, or more frequently.

• Adalimumab: at least 14 weeks treatment at the approved doses for inductionand/or maintenance in Crohn's disease prior to screening for the study. Forinduction: 1 subcutaneous dose of 160 milligram (mg), followed by 80 mg 2 weeksafter. For maintenance: 40 mg subcutaneously every other week, or weekly.

• Certolizumab l: at least 14 weeks treatment at the approved doses for inductionand/or maintenance in Crohn´s disease prior to screening for the study. Forinduction: 1 subcutaneous dose of 400 mg, followed by the same dose 2 and 4weeks after. For maintenance: 400 mg subcutaneously every 2 to 4 weeks.

• Anti-integrin: at least 14 weeks treatment of the approved dose for inductionand/or maintenance in Crohn´s disease prior to screening for the study. Forinduction: Vedolizumab 300 mg. For maintenance: Vedolizumab 300 mg every 4 to 8weeks.

• Anti-interleukin (IL)-12/23: at least 16 weeks treatment of the approved dosein Crohn´s disease prior to screening for the study. For induction:Ustekinumab, approximately 6mg/kg intravenously initially then followed by 90mg subcutaneously every 8 weeks.

7. Women of childbearing potential (WCBP) must have negative serum pregnancy test atscreening (sensitive to 25 international units [IU] human chorionic gonadotropin [hCG]). Both WCBP or male participants participating in this study, with a WCBP aspartner, must agree to use an adequate method of contraception during the entireduration of the study. An adequate method of contraception is defined as complete,non-periodic sexual abstinence (refraining from heterosexual intercourse),single-barrier method, vasectomy, adequate hormonal contraception (to have startedat least 7 days prior to Screening visit), or an intra-uterine device (to have beenin place for at least 2 months prior to Screening visit).

Exclusion Criteria:

1. Concomitant rectovaginal or rectovesical fistula(s).

2. Participant naïve to prior specific medical treatment for complex perianalfistula(s) including immunosuppressant (IS) or anti-TNFs.

3. Presence of a perianal collection >2 cm in at least two dimensions on the centralreading MRI at Screening visit that was not adequately drained as confirmed by thesurgeon during the preparation procedure (week -3 to day 0).

4. Severe rectal and/or anal stenosis and/or severe proctitis (defined as the presenceof large >0.5 cm ulcers in the rectum) that make impossible to follow the surgeryprocedure manual.

5. Participant with diverting stomas.

6. Active, uncontrolled infection requiring parenteral antibiotics.

7. Participant with ongoing systemic or rectal steroids for CD in the last 2 weeksprior to the Preparation visit.

8. Participants with major alteration on any of the following laboratory tests orincreased risk for the surgical procedure:

• Serum creatinine levels >1.5 times the ULN

• Total bilirubin >1.5 ULN

• Aspartate Transaminase (AST)/ Alanine Transaminase (ALT) >3 times ULN

• Hemoglobin <10.0 g/dL

• Platelets <75.0*10^9/L

• Albuminemia <3.0 g/dL

9. Suspected or documented infectious enterocolitis within two weeks prior to Screeningvisit.

10. Any prior invasive malignancy diagnosed within the last 5 years prior to Screeningvisit. Participants with basal-cell carcinoma of the skin completely resectedoutside the perineal region can be included.

11. Current or recent (within 6 months prior to the Screening visit) history of severe,progressive, and/or uncontrolled hepatic, haematological, gastrointestinal (GI) (other than CD), renal, endocrine, pulmonary, cardiac, neurological or psychiatricdisease that may result in participants increased risk from study participationand/or lack of compliance with study procedures.

12. Participants with primary sclerosing cholangitis.

13. Participants with known chronically active hepatopathy of any origin, includingcirrhosis and participants with persistent positive Hepatitis B Virus (HBV) surfaceantigen (HBsAg) and quantitative HBV polymerase chain reaction (PCR), or positiveserology for Hepatitis C Virus (HCV) and quantitative HCV PCR within 6 months priorto Screening.

14. Congenital or acquired immunodeficiencies, including participants known to be HIVcarriers

15. Known allergies or hypersensitivity to penicillin or aminoglycosides; DulbeccoModified Eagle's Medium (DMEM); bovine serum; local anaesthetics or gadolinium (MRIcontrast).

16. Contraindication to MRI scan (example, due to the presence of pacemakers, hipreplacements or severe claustrophobia).

17. Severe trauma within 6 months prior to Screening visit.

18. Pregnant or breastfeeding women.

19. Participants who do not wish to or cannot comply with study procedures.

20. Participants currently receiving, or having received any investigational drug within 3 months prior to Screening visit.

21. Participants previously treated with Cx601 or other allogeneic stem-cell therapycannot be enrolled into this clinical study.

22. Any major surgery of the GI tract (including one or more segments of the colon orterminal ileum) within 6 months prior the screening or any minor surgery of the GItract within 3 months prior to screening.

23. Participants who had local perianal surgery other than drainage for the fistulawithin 6 months prior to the Screening visit, or those who may need surgery in theperianal region for reasons other than fistulas at the time of inclusion in thestudy.

24. Contraindication to the anaesthetic procedure.