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A successful SER-109 Phase 1b study has been completed, and the results were published in the Journal of Infectious Diseases.

Based on the successful SER-109 Phase 1b results, Seres completed and reported a placebo controlled Phase 2 study (ECOSPOR). Following the Phase 2 results, Seres performed a detailed and comprehensive review of the SER-109 program. The summary of these findings can be found here.

Seres is currently evaluating SER-109 in a Phase 3 clinical study (ECOSPOR III) in patients with multiply recurrent C. difficile infection.


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About Clostridium difficile

Clostridium difficile (C. difficile) is a bacterium that causes an infection of the gut. Most doctors and patients call this infection “C. diff” for short. C. difficile infection (CDI) can cause many loose watery bowel movements (diarrhea) and painful stomach cramps. The main cause of CDI is antibiotics, which wipe out the good bacteria of the gut, which may permit some bad bacteria, like C. difficile, to take over and cause infection.

Many patients can be successfully treated for CDI with antibiotics that target these bad bacteria. However, some patients keep getting the infection again and again. Recurrent C. diff is a major problem because there are no good methods to prevent the infection from recurring. Part of the problem is that the good bacteria are still missing from the gut. Without those good bacteria, the patient has limited defense against getting CDI again—even if antibiotics temporarily diminish the diarrhea.

For someone with recurrent CDI, diarrhea is a daily problem that can be frequent and start without warning. Patients with frequent diarrhea and stomach discomfort have trouble doing many of their usual daily activities. Some even have trouble leaving the house. However, the good news is that research is going on right now to find a medicine to prevent CDI from recurring.

Take charge of your C. difficile with SER-109 for recurrent infections

Learn more about our clinical trial


Clostridium difficile infection

Learn more about C. difficile and how it affects patients across the country


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