A Study to Evaluate the Safety and Tolerability of Rebiotix RBX2660 (microbiota suspension) in Subjects with Recurrent Clostridium difficile Infection


About this study

To assess the safety and tolerability of RBX2660 in subjects with recurrent CDI who have had prior recurrent CDI that was resolved with antibiotic treatment.

Participation eligibility

Participant eligibility includes age, gender, type and stage of disease, and previous treatments or health concerns. Guidelines differ from study to study, and identify who can or cannot participate. There is no guarantee that every individual who qualifies and wants to participate in a trial will be enrolled. Contact the study team to discuss study eligibility and potential participation.

Inclusion Criteria:

  • ≥ 18 years old.
  • Medical record documentation of either:
    • recurrent CDI per the study definition, that includes at least one recurrence after a primary episode and has completed at least one round of standard-of-care oral antibiotic therapy; or
    • has had at least two episodes of severe CDI resulting in hospitalization.
  • A positive stool test for the presence of toxigenic C. difficile or C. difficile toxin within 30 days prior to or on date of enrollment.
  • Is currently taking or was just prescribed antibiotics to control CDI related diarrhea at the time of enrollment.
    • Note: Subject’s CDI diarrhea must be controlled (<3 unformed/loose, i.e., Bristol Stool Scale type 6-7, stools/day for the two consecutive days prior to the washout period) while taking antibiotics during screening.
  • Willing and able to have an enema(s).
  • Willing and able to complete the stool and blood testing required for the study.
  • Agrees to not take non-dietary probiotics through 8 weeks after receiving the last study enema (including OTC and prescription).
  • Agrees to not take any oral vancomycin, metronidazole, fidaxomicin, rifaximin, nitazoxanide, bezlotoxumab, or IVIG through the 8-week follow-up assessment unless newly prescribed by a treating investigator during the course of the study as a result of recurrent CDI diagnosis.
    • Note: Use of IVIG for treatment of a non-CDI indication is allowed.
  • Agrees to practice a form of effective contraception during study participation; does not apply to persons with documented non-child bearing potential.
  • Has a negative urine pregnancy test at the time of enrollment and on the day of each enema prior to administration (persons of child-bearing potential only).
  • Willing and able to provide informed consent, and local privacy authorization as applicable.
  • Willing and able to complete the required Subject Diary.
  • Willing and able to meet all study requirements, including attending all assessment visits and telephone calls.

Exclusion Criteria:

  • A known history of refractory CDI.
  • Currently has continued CDI diarrhea despite being on a course of antibiotics prescribed for CDI treatment.
  • Requires systemic antibiotic therapy for a condition other than CDI.
  • Fecal microbiota transplant (FMT) within the past 6 months.
  • FMT with an associated serious adverse event related to the FMT product or procedure.
  • Bezlotoxumab (CDI monoclonal antibodies) if received within the last year.
  • Disease symptoms (diarrhea) caused by a confirmed intestinal pathogen other than C. difficile.
  • Currently has a colostomy.
  • Intraabdominal surgery within the last 60 days.
    • Note: laparoscopic procedures that do not involve the GI tract are permitted.
  • Planned surgery requiring perioperative antibiotics through the 8-week follow-up assessment.
  • Life expectancy of < 6 months.
  • CD4 count <200/mm3 during Screening.
  • An absolute neutrophil count of <1000 cells/μL during Screening.
  • Known or suspected current (< 90 days) illicit drug use.
    • Note: marijuana use is allowed.
  • Pregnant, breastfeeding, or intends to become pregnant during study participation.
  • Participating in a clinical study of another investigational product (drug, device or other) and has not completed the required follow-up period.
  • Subject is eligible for another RBX2660 study.
  • Subject, in the opinion of the investigator, for whatever reason, should be excluded from the study.

Participating Mayo Clinic locations

Study statuses change often. Please contact the study team for the most up-to-date information regarding possible participation.

Mayo Clinic Location Status Contact

Rochester, Minn.

Mayo Clinic principal investigator

Sahil Khanna, M.B.B.S., M.S.

Closed for enrollment

Contact information:

Rebecca Hofschulte CRCST

(507) 284-9709


More information


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