Trial Shows Therapy Controls Gut Disorder with Healthy Microbes

Clostridium difficile bacteria (James Archer, CDC)

23 May 2022. Results from a clinical trial show a microbiome treatment produces healthy gut microbes that reduce recurrences of C. difficile infections. Findings from the trial were presented this weekend by researchers from Seres Therapeutics Inc. in spoken and poster presentations at the 2022 Digestive Disease Week annual meeting in San Diego.

Clostridium difficile or C. difficile infections often result from bacteria contracted in in health care facilities. The disease, according to Centers for Disease Control and Prevention, causes diarrhea that can become life-threatening, and also result as a side-effect of antibiotics. People age 65 or older taking antibiotics, particularly those in nursing homes or long-term care facilities, as well those with previous C. difficile infections or weakened immune systems are considered most vulnerable.  CDC says in 2017, C. difficile was responsible for some 223,900 cases, leading to 12,800 deaths in the U.S.

Seres Therapeutics is a biotechnology company in Cambridge, Massachusetts developing therapies for the microbiome, communities of bacteria and other microbes in the gut, associated with health conditions in the digestive tract and elsewhere in the body. The company focuses particularly on disruptions in the microbiome that increase susceptibility to infections, inflammatory disorders, or cancer. The Seres technology is based on a library of microbial strains from healthy donors, subjected to computational analyses to identify microbial collections associated with healthy and diseased states. The company then assesses these combinations to find collections of microbes for correcting disruptions and return the microbiome to a healthy state.

Seres’s lead product, code-named SER-109, is an an oral drug for C. difficile. The company derives SER-109 from refined Firmicute spores, bacteria in the gut associated with obesity and microbiome disruptions known as dysbiosis. SER-109 is designed to rebuild healthy microbes and rebalanced the microbiome after taking antibiotics for C. difficile, taken as a capsule by patients each day for four days. In July 2021, Science & Enterprise reported on the company licensing SER-109 to Nestlé Health Science that could bring Seres as much as $525 million if all terms of the deal are fulfilled.

Recurrences within two weeks of taking antibiotics

The late-stage clinical trial enrolled 182 individuals with three or more C. difficile infections, and also taking antibiotics. Participants were randomly assigned to receive SER-109 or a placebo capsule, then tracked for 24 weeks. The study team looked primarily for recurring C. difficile infections in the eight weeks after participants took SER-109 or a placebo, as well as further C. difficile infections and any adverse effects for up to 24 weeks.

Results from the trial show 88 percent of patients taking SER-109 do not experience recurring C. difficile infections, compared to 60 percent for placebo recipients in the eight weeks after taking the drug or placebo. The study team also found C. difficile recurrences are most likely to occur in the two weeks after taking antibiotics, when the microbiome is most vulnerable. Adverse effects during the trial, says Seres, were similar for SER-109 and placebo recipients.

In a separate analysis of stool samples from participants in the trial, the study team found SER-109 recipients with higher concentrations of fatty acids including butyrate, valerate and hexanoate, associated with inhibiting C. difficile bacteria. During the first two weeks after the treatment, SER-109 recipients show rapid increases in these fatty acids, which stay higher than placebo recipients for eight weeks.

“These findings suggest,” says Seres’s chief medical officer Lisa von Moltke in a company statement, “that the first two weeks following antibiotic treatment is the time when microbiome therapeutics have the greatest potential benefit, by restoring bacterial diversity and disrupting the cycle of recurrent C. difficile.”

More from Science & Enterprise:

• Hydrogel Shown to Boost Beneficial Gut Microbes
• Trial Begins Testing Crispr Gut Microbiome Therapy
• Antimicrobial Resistance Fund Invests in Two Biotechs
• Microbiome Health Company Raises $40M in Early Funds
• Microbiome Therapy Shown to Cut Covid-19 Health Needs

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