Inclusion Criteria:

• Body Weight > or = 40kg
• Documented diagnosis of Crohn's disease, including patients with documented diagnosis of ileitis, colitis, or ileocolitis
• Presence of at least one draining fistula. Patients with enterocutaneous fistulas can be included if they have > or = 1 draining perianal fistula. Women with rectovaginal fistulas can be included if they have > or = 1 draining perianal fistula.
• Crohn's Disease Activity Index (CDAI) score < 400
• Platelet count (thrombocytes) > or = 100,000/uL
• Able and willing to comply with all protocol procedures for the duration of the study
• Able and willing to understand, sign and date an informed consent document, and authorize access to protected health information
• Females must be postmenopausal, surgically incapable of bearing children, or practicing a reliable method of birth control (hormonal contraceptives, intrauterine devices, spermicide and barrier). Partner/spouse sterility may also qualify at the Investigator's discretion. Females of child-bearing potential must have a negative urine pregnancy test at baseline.

Exclusion Criteria:

• Non-response to infliximab or other biological immunosuppressants/ immunomodulators for fistulas associated with Crohn's disease (response is defined as a > or = 50% reduction from baseline in the number of fistulas over at least four weeks); patients who respond once to infliximab and eventually fail can be included
• Infliximab (and/or other biological immunosuppressant/immunomodulatory) therapy within 3 months prior to enrollment in the study
• Presence of symptomatic strictures or suggestion of significant clinical obstruction
• Patients with setons are excluded, unless the setons are removed within 48 hours prior to study entry
• Presence of entero-entero, recto-vesicular, entero-vesicular fistulas
• Platelet count (thrombocytes) < 100,000/uL
• CDAI score of > or = 400
• Patient is unable to stay on a stable dose of concomitant Crohn's disease medication(s) for at least 10 weeks in the opinion of the investigator
• Currently symptomatic untreated diarrhea due to conditions other than mild to moderately active Crohn's disease (e.g., bacterial or parasitic gastroenteritis, bile salt diarrhea, etc.)
• Severe diarrhea defined by > 10 liquid bowel movements per day
• Other local manifestations of mild to moderately active Crohn's disease such as abscesses, or other disease manifestations for which surgery might be indicated or which might preclude utilization of a CDAI to assess response to therapy (e.g., short bowel syndrome)
• Presence of an ileostomy
• Receiving Total Parenteral Nutrition (TPN) as the sole source of nutrition within 3 weeks of Screen
• Poor tolerability of venipuncture or lack of adequate venous access for required blood sampling.
• Hemoglobin < 8.5 g/dL (females) or hemoglobin < 10 g/dL (males) at Screen
• Women who are pregnant, breast feeding, or planning to become pregnant during the study
• Other major physical or major psychiatric illness within the last 6 months that in the opinion of the investigator would affect the patient's ability to complete the trial
• Uncontrolled systemic disease
• Patients undergoing chemotherapy for the treatment of cancer
• Known hypersensitivity or contraindication to any component of the test product (study drugs) or diagnostics used
• Participation in another study within eight (8) weeks prior to the study
• Unable to attend all visits required by the protocol