Multiple microbiota therapeutics are currently in clinical development for preventing recurrent Clostridium difficile infection (rCDI) in multi-recurrent patients.
As these therapies move closer to potential approval, it will be important to assess their broad utility among demographic groups.
In a recent double-blind, placebo-controlled Phase 2B trial of RBX2660, a standardized microbiota-based drug, there were no differences in efficacy among key demographic designations.
Herein, we evaluated data from a Phase 2 controlled open-label trial of RBX2660 to determine whether rCDI prevention differed in relationship to age, sex, or geographic region.
Data analyzed were from a prospective, multicenter, open-label Phase 2 study (NCT02589847) consisting of an RBX2660 treatment arm and a historical control group.
Key inclusion criteria: >18 years old with documentation of either 2 recurrences after a primary episode and has completed at least two rounds of standard-of-care oral antibiotic therapy, or at least 2 episodes of severe CDI resulting in hospitalization; a positive stool test for the presence of toxigenic C. difficile within 60 days prior to enrollment.
Key exclusion criteria: History of inflammatory bowel disease (ulcerative colitis, Crohn’s disease or microscopic colitis), irritable bowel syndrome, chronic diarrhea, celiac disease, colostomy; evidence of active colitis; planned surgery that will require perioperative antibiotics within 6 months of treatment; compromised immune system (white blood cell count <1000 cells/μL).
Antibiotics were discontinued 24-48 hours prior to administration of the first enema.
Patients received up to 2 RBX2660 ddoses elivered via enema with doses 7 +/- 2 days apart.
Safety was assessed via a patient diary: in clinic at 1, 4, and 8 weeks and via telephone at 2, 3, between 5-7 weeks, and at 3, 6, 12 and 24 months.
Success was defined as the absence of CDI at 8 weeks following completion of the last treatment. Patients were classified as a treatment failure if all four (4) of the following criteria were met: recurrence of diarrhea less than 8 weeks after administration of the last assigned study enema, a positive laboratory diagnosis of C. difficile as conducted and reported by the study investigator, a need for retreatment for CDI, and no other cause for diarrhea.
Pearson’s chi-square test or a Fisher’s exact test was used to compared the proportion of subjects in the treatment arm who were recurrence-free to the proportion of historical controls who were recurrence-free.