670. VRE Clearance in Patients with Recurrent Clostridium difficile Infection Following Treatment with Microbiota-Based Drug RBX2660

BACKGROUND: Vancomycin-resistant Enterococcus (VRE) infection is frequently associated with immunocompromised and critically ill patients. VRE carriers are at increased risk for infection due to VRE colonization and they pose a risk as a transmission source. VRE infection and Clostridium difficile infection (CDI) share common risk factors, including disruption of the intestinal microbiome. Thus, therapeutic approaches that decolonize VRE would be valuable. Herein, we report on stool VRE clearance in a cohort analysis from a Phase 2 open-label study of RBX2660, standardized microbiota-based drug, for recurrent CDI. METHODS: This prospective, multicenter, open-label Phase 2 study enrolled subjects with recurrent CDI. Participants received up to 2 doses of RBX2660 delivered via enema with doses 7 days apart. Patients were requested to voluntarily submit stool samples at baseline and at 7, 30 and 60 days, 6, 12, and 24 months after the last administration of RBX2660. Stool samples were tested for VRE using bile esculin azide agar with 6 µg/mL vancomycin and gram staining. Vancomycin resistance was confirmed via blood agar and etest. RESULTS: Stool samples were available for 143 patients. Twenty-one patients were VRE-positive at the first test (baseline or 7 day). Of the 19 VRE-positive patients that provided additional samples at later timepoints, 18 (94.7%) converted to negative as of the last available follow-up (30 or 60 days and 6, 12, or 24 months). The remaining patient remained positive at all follow-ups. CONCLUSION: This cohort analysis of VRE-positive patients within an rCDI population provides additional support that microbiota-based formulations, such as RBX2660, may have additional benefit beyond reducing the recurrence of CDI. Additional study is needed to confirm the role of microbiome restoration on VRE clearance. DISCLOSURES: All authors: No reported disclosures