Bezlotoxumab compared with Fecal Microbiota Transplantation for prevention of recurrent Clostridioides difficile infection Katherine Lee, PharmD1, Carolyn Alonso, MD, FIDSA2 Monica Mahoney, PharmD, BCPS AQ-ID, BCIDP1 1Department of Pharmacy, Beth Israel Deaconess Medical Center, Boston, MA 2Division of Infectious Diseases, Beth Israel Deaconess Medical Center, Boston, MA

Background Study Design Results (cont.)* Discussion . Retrospective, single-center, cohort analysis . Bezlotoxumab was approved in 2016 as an Risk factors for recurrence . Overall, patients treated with bezlotoxumab at a tertiary academic medical center 60% p=0.4 4 were less likely to have severe CDI, but more adjunct to standard of care antibacterial p=0.34 Inclusion criteria: 50% likely to be immunocompromised treatment for Clostridioides difficile infection 6 Adult patients who received bezlotoxumab or FMT (CDI) to prevent recurrence 40% 5 . Bezlotoxumab showed a low rate of between 2017 and 2019 . The MODIFY I & II trials established efficacy 30% p=1 recurrence within 3 months (14.3%), similar to p=1 clinical trials of bezlotoxumab for preventing recurrent CDI Patients who received bezlotoxumab matched 2:1 20% 1 2 1 1 . Based on this small retrospective review, which was sustained for up to 12 weeks after to patients who received FMT 10% 1 Percent Patients of Percent bezlotoxumab had a higher rate of clinical bezlotoxumab administration FMT Bezlotoxumab 0% 0 1 2 3 or more cure than FMT . FMT is another treatment option which may n=14 n=7 be reserved for patients with recurrent CDI FMT (n=14) Bezlotoxumab (n=7) . Bezlotoxumab should be considered early in . The risk of recurrence may increase with Results therapy to reduce future hospitalizations and Number of occurrences at time of treatment improve patient quality of life each additional risk factor 12 Patient characteristics 90% p=0.57 . Bezlotoxumab and FMT have not been FMT Bezlotoxumab 80% 5 Therapy Received (n=14) (n=7) 70% References compared head-to-head 60% Age (years) (mean [SD]) 62.5  15.1 61  14.7 50% 1. McDonald LC, Gerding DN, Johnson S, et al. Clinical Age ≥ 65 (years) (no. 7 (50) 3 (42.9) 40% p=0.25 Practice Guidelines for Clostridium difficile Infection in Risk factors for recurrence [%]) 2 30% Adults and Children: 2017 Update by the Infectious Sex (no. [%]) 12 (85.7) female 3 (42.8) female . Age greater than 65 years 20% p=1 Diseases Society of America (IDSA) and Society for

Weight (kg) (mean [SD]) 82.2  28.3 72.8  28.0 Patients of Percent 10% 1 1 . Immunocompromised 0 Healthcare Epidemiology of America (SHEA). Clin Infect Immunocompromised 0% 5 (35.7) 3 (42.8) Dis 2018; 66:e1 . Previous severe CDI (no. [%]) Initial episode 1st recurrence 2nd or more recurrence 2. Wilcox MH, Gerding DN, Poxton IR, et al. Bezlotoxumab . Chronic proton pump inhibitor (PPI) use FMT (n=14) Bezlotoxumab (n=7) Recent hospital for prevention of recurrent Clostridium difficile infection. . Hospital admission 48 hours in prior 90 admission 48 hours in 7 (50) 4 (57.1) NEJM. 2017;376(4):305-17. prior 90 days (no. [%]) Outcomes days Chronic PPI use (no. 90% 6 3. Song JH, Kim YS. Recurrent Clostridium difficile infection: 6 (42.8) 4 (57.1) . Antibiotic exposure within prior 30 days [%]) 80% p=0.17 risk factors, treatment, and prevention. Gut Liver. 2019 Antibiotic treatment 70% Jan;13(1):16-24 . Concomitant antibiotics 60% within 30 days prior to 4 (28.5) 4 (57.1) 7 4. Gerding DN, Kelly CP, Rahav G, et al. Bezlotoxumab for . Previous recurrence diagnoses (no. [%]) 50% 40% p=0.62 prevention of recurrent Clostridium difficile infection in . C. difficile ribotype NAP1/BI/027 (not Concomitant antibiotic 4 2 (14.3) 2 (28.6) 30% p=0.53 patients at increased risk for recurrence. Clin Infect Dis. collected in this study) (no. [%]) 20% 1 2 2018;67(5):649-56 Severity of disease (IDSA criteria) (no. [%]) 10%

Percent Patients of Percent 0 0% Objective Non-severe 3 (21.4) 2 (28.6) Clinical cure† Recurrence within 3 Mortality‡ Disclosures Severe 8 (57.1) 3 (42.6) months Katherine Lee: nothing to disclose To identify characteristics and treatment history Fulminant 2 (14.3) 1 (14.3) FMT (n=14) Bezlotoxumab (n=7) Carolyn Alonso: research support from Merck Unable to quantify 1 (7.1) 1 (14.3) *p=values determined using Fisher’s exact Monica Mahoney: research support from Merck; advisory board from of patients who received bezlotoxumab or FMT † Clinical cure defined as no further follow up appointments for CDI or treatment with CDI Tetraphase, Qpex, and Spero; speakers bureau from Cepheid and antibiotics recorded in the BIDMC medical records at BIDMC ‡from any cause Tetraphase