Investigational Microbiome Drug Safe, Effective in Patients With Recurrent C. Diff Infection


SER-109, an investigational, biologically derived microbiome therapeutic of purified Firmicute spores, showed efficacy in treating recurrent Clostridioides difficile (C. diff) infection (rCDI), according to a study published in Antimicrobial Stewardship & Healthcare Epidemiology. The treatment was also well-tolerated, with a similar safety profile to placebo, according to the investigators.1

“By enriching for Firmicute spores, SER-109 achieves high efficacy while mitigating risk of transmitting infectious agents, beyond donor screening alone,” the study authors wrote. “SER-109 represents a major paradigm shift in the clinical management of patients with rCDI.”1

C. diff is the most common health care-associated infection occurring in US hospitals. Approximately 450,000 cases of C. diff infection (CDI) occur each year in the United States, with incidence rates increasing over the past 20 years. CDI is recurrent in approximately 25% of patients treated for an initial episode, and the rate of recurrence is between 40% and 65% for patients who had a prior recurrence.2

The study analyzed 182 patients with rCDI, defined as more than 3 episodes in 12 months, screened at 75 sites in the United States and Canada. After completing a treatment cycle of 10–21 days of vancomycin or fidaxomicin, adults with symptom resolution were randomized 1:1 to receive either SER-109 at a rate of 4 capsules a day for 3 days, or a placebo at the same rate. Of the patients evaluated, 59.9% were female and the mean age was 65.5 years.1

According to the investigators, a significantly lower proportion of the patients receiving SER-109 had rCDI after dosing at week 8 compared to patients receiving placebo. The cohort receiving SER-109 had an 11.1% rate of rCDI, compared to 41.3% of the placebo arm.

Further, SER-109 was well-tolerated, with the most common treatment-emergent adverse events (TEAEs) being mild to moderate gastrointestinal symptoms. No serious TEAEs, infections, deaths, or drug discontinuations were associated with the use of SER-109.1


  1. McGovern, B., Sims, M., Kraft, C., Wang, E., Brady, K., Ford, C., . . . Von Moltke, L. (2021). Efficacy and Safety of Investigational Microbiome Drug SER-109 for Treatment of Recurrent Clostridioides difficile Infection. Antimicrobial Stewardship & Healthcare Epidemiology, 1(S1), S5-S5. doi:10.1017/ash.2021.10
  2. Feuerstadt P, Stong L, Dahdal DN et al. Healthcare resource utilization and direct medical costs associated with index and recurrent Clostridioides difficile infection: a real-world data analysis. J Med Econ 2021 ,23:603-609. doi:10.1080/13696998.2020.1
Related Videos
palliative and hospice care/ Image Credits: © David Pereiras -
multiple myeloma clinical trial daratumumab/ Image Credits: © Dragana Gordic -
multiple myeloma clinical trial/Image Credits: © Studio Romantic -
Medicine tablets on counting tray with counting spatula at pharmacy | Image Credit: sutlafk -
pharmacy oncology, Image Credit: © Konstantin Yuganov -
Mayo Clinic oncology pharmacy
Testicular cancer and prostate cancer concept. | Image Credit: kenchiro168 -
Medicine tablets on counting tray with counting spatula at pharmacy | Image Credit: sutlafk -
Capsules medicine and white medicine bottles on table | Image Credit: Satawat -
© 2024 MJH Life Sciences

All rights reserved.