Seres Provides Program and Corporate Updates and Prioritizes Emerging Programs in Inflammatory & Immune Diseases

Core Insights - Seres Therapeutics has finalized the protocol for the Phase 2 study of SER-155 in patients undergoing allogeneic hematopoietic stem cell transplant (allo-HSCT) and is pausing further investment while seeking funding for the study [1][3] - The company has reduced its workforce by approximately 30% to extend its cash runway through Q3 2026, allowing for continued development of its live biotherapeutic programs [1][3] - Seres is focusing on advancing early-stage live biotherapeutic programs targeting inflammatory and immune diseases, including SER-603 for ulcerative colitis and Crohn's disease [2][5] Financial and Operational Strategy - The workforce reduction and other cost-saving measures are expected to extend the company's cash runway, providing opportunities to advance its therapeutic programs and pursue collaborations [1][3] - The company anticipates reporting initial clinical results from the fully enrolled SER-155 study in immune checkpoint related enterocolitis (irEC) in early Q2 2026, which could highlight the potential of live biotherapeutics [3][4] Clinical Development - SER-155 has shown a significant reduction in bloodstream infections in a Phase 1b clinical study and has received Breakthrough Therapy and Fast Track designations [6] - The ongoing investigator-sponsored trial at Memorial Sloan Kettering Cancer Center is evaluating SER-155 in 15 participants with irEC, a severe adverse event in patients receiving immune checkpoint inhibitors [4][5] - Data from the SER-155 study could support the use of live biotherapeutics as a non-immunosuppressive treatment option for inflammatory and immune diseases linked to colitis [5][6]