This study will assess the safety of a new biologic drug, RBX2660 (microbiota suspension) as a treatment for recurrent Clostridium difficile-associated diarrhea (CDAD), which is the primary symptom of recurrent Clostridium difficile infection. All eligible subjects will receive RBX2660.

This is the first study of a microbiota suspension derived from intestinal microbes. The primary assessments for this open label, multi-center study are (i) occurrence of product-related adverse events and (ii) resolution of CDAD at 56 days after administration of RBX2660. Subjects will also be assessed for time to CDAD recurrence, quality of life changes, and number of hospitalizations and length of stay for recurrent CDAD. Study visits will be at 7, 30, and 60 days after RBX2660 administration with additional follow-up at 3 and 6 months post treatment. Patients who have had at least two recurrences of CDAD after a primary episode and have completed at least two rounds of standard-of-care oral antibiotic therapy or have had at least two episodes of severe CDAD resulting in hospitalization may be eligible for the study.

Inclusion Criteria:

• ≥ 18 years
• Medical record documentation of CDAD either: a) at least two recurrences after a primary episode and have completed at least two rounds of standard-of-care oral antibiotic therapy or b) have had at least two episodes of severe CDAD resulting in hospitalization.
• Willing and able to have an enema(s).
• Already taking or will start a course of oral antibiotics for CDAD symptoms for 10-14 days, including at least seven days of oral vancomycin.
• Willing and able to complete the required subject diary.

Exclusion Criteria:

• Continued (uncontrolled) CDAD after completing a 10-14 day course of oral antibiotics.
• Requires antibiotic therapy for a condition other than CDAD.
• Previous fecal transplant prior to study enrollment.
• History of inflammatory bowel disease (IBD), e.g., ulcerative colitis, Crohn's disease, or microscopic colitis.
• History of irritable bowel syndrome (IBS).
• History of chronic diarrhea.
• History of celiac disease.
• History of cirrhosis of the liver or ascites.
• Disease symptoms caused by a confirmed intestinal pathogen other than Clostridium difficile.
• Has a colostomy.
• Intraabdominal surgery within the last 60 days.
• Evidence of active, severe colitis.
• History of short gut syndrome or motility disorders.
• Requires the regular use of medications that affect bowel motility (e.g., metoclopramide, narcotics, loperamide).
• Planned therapy in the next 3 months that may cause diarrhea (e.g., chemotherapy).
• Planned surgery requiring perioperative antibiotics within 6 months of study enrollment.
• Life expectancy of < 12 months.
• Compromised immune system, e.g., HIV infection (any CD4 count); AIDS-defining diagnosis or CD4 <200/mm3; inherited/primary immune disorders; immunodeficient or immunosuppressed due to a medical condition or medication; current or recent (< 90 days) treatment with chemotherapy; or current or recent (< 90 days) treatment with immunosuppressant medications.
• Taking steroids (≥ 20 mg a day) or is expected to be on steroids for more than 30 days after enrollment.
• Neutropenia (white blood cell count <1000 cells/µL).