Seres Reveals SER-155 Phase 1b GI Microbiome Shifts Linked to Reduced Bloodstream Infections
Seres Therapeutics presented Phase 1b SER-155 data showing a durable shift in GI microbiome composition and improved epithelial barrier integrity, potentially lowering bloodstream infections in allo-HCT patients. The company also showcased its MiGut in vitro colonic model collaboration with the University of Leeds to enhance live biotherapeutic development for IBD.
1. Phase 1b Trial Demonstrates Durable GI Microbiome Shift
Seres conducted a randomized, placebo-controlled Phase 1b study (NCT04995653) in allo-HCT patients, where SER-155 achieved significant and durable increases in target species abundance and enhanced GI epithelial barrier integrity compared with placebo, correlating with reduced bloodstream infection incidence.
2. MiGut Model Advances IBD Development
An oral presentation showcased the University of Leeds MiGut in vitro colonic model co-developed with Seres, which replicates patient-specific microbiome composition and inflammatory responses to evaluate live biotherapeutic strain engraftment and metabolic-immune effects in IBD contexts.
3. Symposium Highlights Microbiome’s Role in Transplant Outcomes
Dr. Jonathan Peled will discuss strategies targeting the gut microbiome to prevent bacterial translocation in immunocompromised allo-HCT patients, underscoring SER-155’s mechanism in protecting epithelial barrier and reducing infection risk.
4. SER-155 Regulatory and Development Status
SER-155, granted Breakthrough Therapy and Fast Track designations for bloodstream infection reduction, is Phase 2 ready pending funding, while Seres advances other pipeline candidates such as SER-603 for IBD and an irEC trial of SER-155.