Seres Therapeutics, Inc. is a commercial-stage microbiome therapeutics company. It is focused on the development and commercialization of a novel class of biological drugs, which are designed to treat disease by modulating the microbiome to restore health by repairing the function of a disrupted microbiome to a non-disease state. Its lead program, VOWST, is to prevent recurrence of Clostridioides difficile infection (CDI) in patients 18 or older following antibacterial treatment for recurrent CDI. Building upon VOWST, it is developing novel microbiome therapeutics, such as SER-155, to specifically target infections and antimicrobial resistance. SER-155, an oral microbiome therapeutic candidate consisting of a consortium of cultivated bacteria, is designed to prevent enteric-derived infections and resulting blood stream infections and induce immune tolerance responses to reduce the incidence of GvHD in patients undergoing allogeneic hematopoietic stem cell transplantation (allo-HSCT).