Seres Therapeutics (MCRB) 2024 Cantor Fitzgerald Global Healthcare Conference summary

Recent strategic developments

• Announced sale of rights to VOWST to Nestlé Health Science, improving financial position and enabling debt retirement.

• Streamlined operations and reduced cash burn to focus on advancing the pipeline, especially SER-155 and SER-147.

• FDA approval of VOWST in April 2023 validated the live biotherapeutic approach for preventing C. diff recurrence.

• End-to-end capabilities in discovery, development, and manufacturing of live biotherapeutics established.

• Plans to seek breakthrough therapy designation for SER-155 and engage with the FDA for next steps.

SER-155 clinical progress and data

• Phase 1b Cohort 2 study in allo-HSCT patients showed SER-155 was well tolerated and significantly reduced bloodstream infections.

• SER-155 group had lower incidence of febrile neutropenia and reduced systemic antibiotic use compared to placebo.

• Engraftment of SER-155 strains in the GI tract was rapid, robust, and durable through 100 days post-transplant.

• Lower pathogen domination observed in SER-155 arm versus historical controls.

• Study supports continued development of SER-155 for allo-HSCT and potential expansion to other high-risk populations.

Scientific and clinical rationale

• Disruption of the gut microbiome in immunocompromised patients is linked to higher infection and mortality rates.

• SER-155 designed to restore microbiome diversity, target specific pathogens, and support mucosal barrier integrity.

• Metagenomic sequencing used to quantify pathogen domination and guide therapeutic design.

• Clinical and preclinical data show correlation between pathogen abundance in the gut and bloodstream infections.

• Optimization of consortia based on functional properties and competitive inhibition of multiple pathogens.