Seres Therapeutics, Inc., a microbiome therapeutics platform company, engages in developing bacterial consortia that are designed to functionally interact with host cells and tissues to treat disease. The company's lead product candidate is the SER-109, an oral microbiome therapeutic candidate that has completed Phase III clinical trial for the treatment of clostridium difficile infection (CDI). It is also developing SER-287 that is in Phase IIb clinical trial to treat ulcerative colitis; SER-401, which is in Phase Ib clinical trial for use with checkpoint inhibitors in patients with metastatic melanoma; and SER-301 that is in the Phase 1b clinical trial for the treatment of inflammatory bowel disease. In addition, the company engages in the development of SER-262 to treat an initial recurrence of CDI; and SER-155, a cultivated bacteria microbiome drug designed to prevent mortality due to gastrointestinal infections, bacteremia, and graft versus host diseases in immunocompromised patients receiving allogeneic hematopoietic stem cell transplantation and solid organ transplants. It has license and collaboration agreements with Nestec Ltd. and Memorial Sloan Kettering Cancer Center. The company was formerly known as Seres Health, Inc. and changed its name to Seres Therapeutics, Inc. in May 2015. Seres Therapeutics, Inc. was incorporated in 2010 and is headquartered in Cambridge, Massachusetts.