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Product Pipeline

Seres Therapeutics’ proprietary discovery and design platform enables us to identify key alterations in the microbiome that are associated with or lead to specific diseases, and to rationally design tailored therapies that disrupt the disease state and establish a healthy microbiome.

Our lead development candidate, SER-109, is an investigational oral microbiome therapeutic for the prevention of Clostridium difficile infection (CDI) in adults who have had three or more episodes of CDI within the previous nine months. The FDA has designated SER-109 as a Breakthrough Therapy.

We are currently evaluating SER-262, the first synthetically-derived and designed microbiome therapeutic ever to reach clinical-stage development, in a Phase 1b study in patients with primary Clostridium difficile infection. In addition, Seres’ program SER-109 continues to be evaluated in a Phase 2 study in multiply recurrent CDI. Interim 8-week results announced on July 29, 2016 from the SER-109 Phase 2 study indicate that the study’s primary efficacy endpoint was not achieved. The company continues to gather and analyze study data.

According to the Centers for Disease Control, CDI is one of the top three most urgent antibiotic-resistant bacterial threats in the U.S. Between 640,000 and 820,000 patients in the U.S. experience a first occurrence of CDI each year; and recurrent CDI, which is caused by antibiotic disruption of the microbiome, affects 85,000 to 110,000 patients each year.

In addition to our CDI product candidates, we are developing Ecobiotic® drugs to treat inflammatory bowel disease, including ulcerative colitis (UC), and various enteric pathogens, such as antibiotic-resistant bacteria. Our clinical candidate SER-287 is currently being evaluated in a Phase 1b study in patients with UC. We are also researching the use of Ecobiotic® drugs for the treatment of metabolic diseases, such as non-insulin dependent type 2 diabetes, other inflammatory diseases, such as Crohn’s disease, and infections related to antibiotic use, cancer chemotherapy, and immune suppression.

Microbiome Overview

Learn more about the microbiome


Clinical Trials

Review our ongoing clinical trials



Dysbiosis and Clostridium difficile infection.

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