Seres Therapeutics Presents Expanded SER-155 Exploratory Biomarker Data at 2025 ASCO Annual Meeting

Core Insights - Seres Therapeutics is presenting new exploratory biomarker data from its SER-155 Phase 1b study at the 2025 ASCO Annual Meeting, highlighting its potential role in promoting peripheral T-cell recovery and immune reconstitution post allo-HSCT [1][2] Group 1: SER-155 Study Findings - The SER-155 Phase 1b study showed improved intestinal epithelial barrier integrity and modulation of systemic inflammatory responses, with a 77% relative risk reduction in bloodstream infections (BSIs) [2][5] - New biomarker data indicates significantly higher levels of the homeostatic cytokine IL-7 and increased frequency of CD4+ T cells in the SER-155 treatment group compared to placebo, suggesting enhanced immune recovery [2][3] Group 2: Clinical Development Plans - The company plans to submit a Phase 2 trial protocol for SER-155 to the FDA soon and is seeking partners for continued clinical development [3] - SER-155 has received Breakthrough Therapy designation for reducing bloodstream infections and Fast Track designation for reducing infection risk and graft-versus-host disease in allo-HSCT patients [5][6] Group 3: About SER-155 - SER-155 is an investigational oral live biotherapeutic designed to decolonize gastrointestinal pathogens, improve epithelial barrier integrity, and induce immune homeostasis to prevent bacterial bloodstream infections in allo-HSCT patients [4][6] - The product has demonstrated a significant reduction in bloodstream infections and related complications in a Phase 1b clinical study [6]