Our Programs

Seres’ live biotherapeutics represent an entirely new class of potential medicines with promise across a wide range of diseases.

Preclinical
Phase 1b
Phase 2
Phase 3
FDA Approval
INFECTION & ANTIMICROBIAL RESISTANCE
The gut microbiome plays a key role in preventing pathogen colonization and maintaining intestinal barrier integrity, reducing the risk of Gl-derived and systemic infections, including antimicrobial resistant infections. Seres is developing live biotherapeutics to prevent infection-related complications in high-risk patients, including allo-HSCT patients, cancer patients with neutropenia, CAR-T recipients, individuals with chronic liver disease, solid organ transplant recipients, as well as patients in the intensive care unit and long-term acute care facilities.

Product overview

SER-155 is an investigational, oral, live biotherapeutic designed to decolonize gastrointestinal (GI) pathogens, improve epithelial barrier integrity, and induce immune tolerance to prevent bacterial bloodstream and antimicrobial resistant (AMR) infections as well as other pathogen-associated negative clinical outcomes in allo-HSCT patients.

Mechanism of action

SER-155 is a multifunctional consortium of commensal bacteria designed based on human clinical insights. SER-155 is designed to augment the following microbiome functions, which are associated with better survival and lower rates of infection and GvHD in patients undergoing stem cell transplantation.

Unmet need in allo-HSCT

Clinical evidence from our collaborators at Memorial Sloan Kettering Cancer Center have shown that allo-HSCT patients with decreased diversity of commensal microbes and pathogen domination in the gastrointestinal tract were significantly more likely to die due to infection and/or lethal GvHD.

Status of clinical development

SER-155 has been evaluated in a Phase 1b placebo-controlled study (ClincalTrials.gov: NCT04995653) in patients undergoing allo-HSCT, which demonstrated significant reduction in both bacterial bloodstream infections and systemic antibiotic exposure, as well as lower incidence of febrile neutropenia (as compared to placebo) through day 100 post allo-HSCT. Seres is currently preparing for a Phase 2 study.

INFLAMMATORY AND IMMUNE DISEASES
The gut microbiome functions as a regulator of inflammatory responses and immune homeostasis. Seres is developing live biotherapeutics that target the mucosal barrier-immune interface to promote protective responses in vulnerable patients, including those with chronic inflammatory diseases like inflammatory bowel disease. In parallel, Seres is pursuing the development of microbiome-based functional biomarkers that are predictive of immune response to advanced therapies to enable precision medicine approaches to heterogeneous diseases.
 
COMMERCIAL PRODUCT
VOWST™ is Seres' first commercialized product, having received FDA approval in April 2023 to prevent the recurrence of C. difficile infection in adults. In clinical studies, it showed an 88% response rate in preventing infection recurrence at up to eight weeks, as well as a well-tolerated safety profile.
  1. Expanded Access/Compassionate Use: To learn more about the Expanded Access program, click here.
  2. SER-155 has received FDA Breakthrough Therapy designation for reduction of bloodstream infections in adults undergoing allo-HSCT, as well as Fast Track designation for reducing the risk of infection and GvHD in patients undergoing allo-HSCT.
  3. VOWST rights sold to Nestlé Health Science on September 30, 2024 – Seres due to receive future financial considerations.

Scientific Presentations

SEE Scientific Presentations

Publications

SEE Publications

Collaborators

Seres has established collaborations with field-leading research institutions and partnered with non-profit organizations to support the development of our novel live biotherapeutics.

  • Strategic research collaboration aimed at defining microbiome signatures of disease in high-risk patient populations and enabling streamlined access to patients and emerging/novel approaches to studying the microbiome to advance development of live biotherapeutics

  • Partnered on IBD. CCF is a non-profit, volunteer-fueled organization dedicated to finding cures for Crohn’s disease and ulcerative colitis and improving the quality of life of children and adults affected by these diseases.

  • Partnered on SER-155 program. CARB-X is a global non-profit partnership accelerating antibacterial products to address drug-resistant bacteria, a leading cause of death around the world.