Mesenchymal Stem Cells for the Treatment of Rectovaginal Fistulas in Participants With Crohn's Disease

Approximately 10% of all female Crohn's patients have a rectovaginal fistula. Rectovaginal fistulas cause air, stool, and/or drainage per vagina and may be associated with pain, recurrent urinary tract infections and diminished quality of life. Conventional therapy includes immunosuppressive medications used to treat Crohn's disease and various surgical interventions. However, all have limited ability to heal these fistulas. The purpose of this study is to determine the safety and efficacy of using allogeneic bone marrow derived mesenchymal stem cells (MSCs) to treat people with rectovaginal fistulas in the setting of Crohn's disease.

This study is designed to determine the safety and efficacy of direct injection of adult allogeneic bone marrow derived mesenchymal stem cells for the treatment of rectovaginal fistulas in the setting of Crohn's disease. The study will randomize 20 participants. Enrolled participants will be randomized to treatment group with MSCs versus placebo in a 3:1 fashion. Participants in the treatment group will have a direct injection of MSCs at a dose of 75 million cells. This will be given as a direct injection in and around the fistula tract. Participants will be evaluated for complete healing at three months. If complete healing has been achieved patients will continue to be followed for one year. If complete healing has not been achieved at three months, participants will be eligible for a second injection of MSCs at the same dose of 75 million cells. Control participants without complete healing from placebo will cross over at the six month visit to receive an injection of MSCs, and will be followed for one year after treatment for a total duration of 18 months.

Eligibility Criteria:
Inclusion Criteria:

1. Females 18-75 years of age with a diagnosis of Crohn's disease for at least six months duration.
2. Single-tract, rectovaginal fistula in the setting of Crohn's disease.
3. Have no contraindications to MR evaluations: e.g. pacemaker or magnetically active metal fragments, claustrophobia
4. Ability to comply with protocol
5. Competent and able to provide written informed consent, and ability to comply with protocol
6. Concurrent Crohn's related therapies with stable doses (\>2 months) corticosteroids, 5-ASA drugs, immunomodulators, anti-TNF therapy, anti-integrin and anti-interleukin are permitted

Exclusion Criteria:

1. Inability to give informed consent.
2. Clinically significant medical conditions within the six months before administration of MSCs: e.g. myocardial infarction, active angina, congestive heart failure or other conditions that would, in the opinion of the investigators, compromise the safety of the subject.
3. Specific exclusions:

   1. Hepatitis B or C
   2. HIV
   3. Abnormal AST or ALT at screening(defined as \>/= 2x ULN)
4. History of cancer including melanoma (with the exception of localized skin cancers) within one year of screening.
5. History of colorectal cancer within 5 years.
6. Investigational drug within 30 days of treatment
7. Pregnant or breast feeding or trying to become pregnant.
8. Presence of a rectovaginal or perineal body fistula
9. Change in Crohn's immunosuppressive regimen within the 2 months prior to enrollment
10. Uncontrolled intestinal Crohn's disease which will require escalation for medical therapy or surgery within 2 months of enrollment
11. Severe anal canal disease that is stenotic and requires dilation
12. Inability to wean corticosteroids
13. Unwilling to agree to use acceptable contraception methods during participation in study