MCRB News & Events

Seres Therapeutics announced three presentations at the 2026 European Society of Clinical Microbiology and Infectious Diseases, ESCMID, global congress, taking place April 17-21 in Munich, Germany. A poster presentation by Seres highlighted biomarker and clinical pharmacology data from the Company's Phase 1b study of SER-155, evaluating changes in gastrointestinal microbiome composition following administration in patients undergoing allogeneic hematopoietic cell transplantation. Data showed that administration of SER-155 induced a significant and durable shift in GI microbiome composition relative to placebo, characterized by high SER-155 species relative abundance. This shift is associated with improved GI epithelial barrier integrity that could reduce the likelihood of bacterial translocation from the GI to the bloodstream. In contrast, placebo-treated participants showed low abundance of SER-155 species and related Firmicutes, high abundance of Bacteroidetes, and a compromised GI epithelial barrier. These findings are consistent with the intended mechanisms of action of SER-155, including protection of the GI epithelial barrier, and align with previously reported clinical observation of reduced incidence of bloodstream infections in SER-155-treated patients following allo-HCT.

Reports FY25 revenue $789k. "As highlighted in our recent announcements, we are prioritizing our promising inflammatory and immunology biotherapeutics portfolio, including SER-603 for inflammatory bowel disease," said Richard Kender, Executive Chair and interim CEO of Seres. "We are on track to report clinical data from the fully enrolled investigator-sponsored study at Memorial Sloan Kettering Cancer Center evaluating SER-155 to treat immune checkpoint inhibitor-related enterocolitis in the second quarter of this year. This serious condition affects up to 50% of immune checkpoint-treated cancer patients, with rates varying based on cancer drug and treatment regimen, and represents a sizable therapeutic and commercial opportunity. Additionally, our SER-155 program for the prevention of serious bloodstream infections in patients undergoing allo-HSCT for blood cancer is Phase 2 ready, and we continue to seek funding to support further development."

Seres Therapeutics announced the appointment of Richard Kender as executive chair and interim CEO. Kender has served on the Seres board of directors since September 2014. Tom DesRosier and Marella Thorell, previously co-CEOs of Seres, will continue to serve as chief legal officer and CFO, respectively. Stephen Berenson, outgoing Seres board chairman, stated, "On behalf of the entire board, I wish to thank Tom and Marella for their continued strong leadership. They provided essential continuity of leadership; drove the organization to advance SER-155 to Phase 2 readiness; and shaped the strategy for the next phase of Seres' development, including the Company's engagement with potential strategic partners. We are pleased to continue to work with both of them in their roles as Chief Legal Officer and Chief Financial Officer."