Courtney Jones

Successful Response to Microbiota-Based Drug RBX2660 in Patients with Recurrent Clostridium Difficile Infection is Associated with More Pronounced Alterations in Microbiome Profile

Abstract Background Recurrent Clostridium difficile infections (rCDI) are associated with decreased diversity and altered intestinal microbiome compared with healthy patients. RBX2660, a standardized microbiota-based drug, is designed to restore microbiome diversity and composition in patients’. The effect of RBX2660 on rCDI patient microbiomes was evaluated by comparing pre- and post-treatment samples from PUNCH CD 2—a randomized, double-blind, placebo-controlled study. Methods rCDIsubjects were randomized to receive blinded treatments of 2 doses of RBX2660 (Group A), 2 doses of placebo (Group B), or 1 dose each of RBX2660 and placebo (Group C), by enema 7 days apart. Subjects submitted stool samples at baseline, day 7, 30, and 60 after treatment. Stool samples from responders to RBX2660 treatment per protocol defined as the absence of CDI for 8 weeks after treatment were compared with non-responders. Relative taxonomic abundances at the class level were determined using 16s rRNA sequencing analysis for 94 stool samples from 45 patients in Groups A and C. Relative abundance data were grouped longitudinally using Bray-Curtis dissimilarity index. Analyses were performed based on the Dirichlet-Multinomial distribution to compare group mean relative taxonomic abundances; Simpson and Shannon diversity indices were compared among groups longitudinally. Results Baseline patient microbiomes were similar across response groups. RBX2660 treatment shifted the relative microbiome densities with taxa-specific increase in Bacteroidia, Clostridia, and decrease in Gamma-proteobacteria abundance. A larger shift from baseline microbiome was seen in responders to RBX2600 compared with non-responders (Figure 1). Microbiome changes in responders were durable to 60 days. RBX2660 treatment increased Shannon and Simpson diversity at 7 days post-treatment in responders but not in non-responders (P < 0.05). Conclusion RBX2660 treatment shifts patient intestinal microbiomes with greater alterations seen in those with a successful clinical outcome. Funded by Rebiotix Inc., Roseville, MN.Figure 1 Responders to RBX2660 have a greater change in taxa abundance from baseline relative to non-responders at 30 days. Dirichlet-Multinomial parameter pi presented as mean (95% CI). Disclosures S. Khanna, Rebiotix, Inc.: Scientific Advisor, Consulting fee; K. Blount, Rebiotix, Inc.: Employee, Salary; C. Jones, Rebiotix, Inc.: Employee, Salary; B. Shannon, Rebiotix, Inc.: Research Contractor, Consulting fee; S. Carter, Rebiotix, Inc.: Research Contractor, Consulting fee

Impact of RBX2660 on the Intestinal Microbiota of Patients with Recurrent Clostridium difficile Infection Enrolled in the Randomized Placebo-Controlled PUNCH CD 2 Trial

The maximum likelihood estimate of π is shown with the 95% confidence interval for each group. The “Pooled” group consists of the least abundant taxa which jointly represent <5% of the overall abundance. The maximum likelihood estimate of π is shown with the 95% confidence interval for each group. The “Pooled” group consists of the least abundant taxa which jointly represent <5% of the overall abundance. Figure 4. Kullback-Leibler (KL) Divergence Comparison for Arm A (2 doses of RBX2660)

Sa1774 Does the Donor Matter? Donor vs. Patient Effects in the Outcome of Next-Generation Fecal Transplant for Recurrent Clostridium difficile Infection

1. Gough E, Shaikh H, Manges AR. Systematic review of intestinal microbiota transplantation (fecal bacteriotherapy) for recurrent Clostridium difficile infection. Clinical Infectious Diseases 2011;53(10):994–1002. 2. Kassam Z, Lee CH, Yuan Y, et al. Fecal microbiota transplantation for Clostridium difficile infection: systematic review and meta-analysis. Am J Gastroenterol. 2013;108:500–508. 3. Keller JJ, Kuijper EJ. Treatment of recurrent and severe Clostridium difficile infection. Annu Rev Med. 2015;66:373-86. 4. van Nood E, Vrieze A, Nieuwdorp M, et al. Duodenal infusion of donor feces for recurrent Clostridium difficile. N Engl JMed. 2013;368:407–415. 5. Lee CH, Belanger JE, Kassam Z et al. The outcome and long-term follow-up of 94 patients with recurrent and refractory Clostridium difficile infection using single to multiple fecal microbiota transplantation via retention enema. Eur J Clin Microbiol Infect Dis. 2014;33(8):1425-8. Does the Donor Matter? Donor vs. Patient Effects in the Outcome of Next-Generation Fecal Transplant for Recurrent Clostridium difficile Infection Courtney Jones, BSa, Robert Hardi, MDb, Bill Shannon, PhDc aRebiotix Inc., Roseville, MN; bCapital Digestive Care, cBioRankings LLC, St. Louis, MO