Seres Therapeutics Reports SER-155 Phase 1b Cohort 1 Results Showing Successful Drug Bacteria Engraftment and Substantial Reduction in Pathogen Domination in the Gastrointestinal Microbiome

Author's Avatar
May 09, 2023

Seres+Therapeutics%2C+Inc. (Nasdaq: MCRB), a leading microbiome therapeutics company, today reported initial clinical data about SER-155. SER-155 is an oral, cultivated bacterial consortia investigational therapeutic designed to prevent enteric-derived infections and resulting blood stream infections, as well as induce immune tolerance responses to reduce the incidence of graft-versus-host disease (GvHD) in patients undergoing allogeneic hematopoietic stem cell transplantation (allo-HSCT). Gastrointestinal (GI) microbiome data from the first 100 days post HSCT in Cohort 1 of the SER-155 Phase 1b open-label study showed the successful engraftment of SER-155 bacterial strains and a substantial reduction in the cumulative incidence of pathogen domination, a biomarker associated with the risk of serious enteric infections and bloodstream infections, as well as GvHD. The tolerability profile observed was favorable, with no serious adverse events attributed to SER-155 administration. Enrollment in the placebo-controlled Cohort 2 portion of the study is ongoing and topline results are anticipated in mid-2024.