Seres Therapeutics, Inc. announced preliminary key VOWST (fecal microbiota spores, live-brpk) launch metrics and receipt of US FDA Fast Track Designation for SER-155 ahead of its presentation at the 42nd Annual J.P. Morgan Healthcare Conference on January 10th. VOWST, the first FDA approved orally administered microbiome therapeutic, received FDA approval in April of 2023 and is indicated to prevent the recurrence of Clostridioides difficile infection (CDI) in adults following antibacterial treatment for recurrent CDI (rCDI). VOWST is being commercialized by Nestlé Health Science in collaboration with Seres.

SER-155 builds upon the clinical success of VOWST and is an investigational oral, cultivated microbiome therapeutic designed to prevent GI-associated bacterial infections, including blood stream infections, and to reduce the incidence of severe acute graft-versus-host disease (GvHD) in immunocompromised patients undergoing allogeneic hematopoietic stem cell transplantation (allo-HSCT). Seres 2023 Highlights: VOWST received FDA approval in April as the first and only FDA approved orally administered microbiome therapeutic to prevent recurrence of CDI in patients with rCDI, after treatment with standard of care antibacterials. Strong adoption of VOWST since commercial launch in June 2023 with broad utilization, continued quarter over quarter growth, and significant progress achieving patient access.

Production of VOWST commercial supply enabled a strong commercial launch within weeks of approval; progress in expansion of VOWST manufacturing capacity. SER-155 Phase 1b Cohort 1 clinical data showed favorable tolerability, successful drug bacteria engraftment, and a substantial reduction in pathogen domination in the gastrointestinal microbiome supporting progression to the placebo-controlled Cohort 2. SER-155 received US FDA Fast Track Designation. Completed strategic restructuring of Company to focus resources and investment on continued VOWST growth, completion of SER-155 Phase 1b study and supporting longer-term business sustainability.

Named to ?TIME 100 Most Influential Companies? list of 100 companies making an extraordinary impact around the world. Anticipated 2024 Milestones: Expect continued progress in 2024 towards commercial priorities including: Expansion of the number of HCPs prescribing VOWST as a result of new efforts scaled in Fourth Quarter 2023 such as strengthened promotional campaigns and expanded reach of HCP and patient digital promotion.

Growth of VOWST utilization earlier in the treatment paradigm including in patients experiencing their first recurrence. Maintenance of strong patient access and expansion of payer coverage for VOWST across Commercial and Medicare Part D plans. Increasing penetration of the hospital outflow patient segment.

SER-155 Phase 1b placebo-controlled Cohort 2 data readout anticipated in third quarter of 2024. Seres ended 2023 with preliminary cash, cash equivalents and investments of approximately $128 million (unaudited). Seres anticipates that this year-end cash balance, in conjunction with the anticipated savings from the restructuring announced in November 2023 and the expected receipt of the $45 million Tranche B under its existing senior secured debt facility (the Term Loan Facility) with Oaktree Capital Management, L.P. (Oaktree), will support its operations into the fourth quarter of 2024.

VOWST is indicated to prevent the recurrence of Clostridioides difficile infection (CDI) in individuals 18 years of age and older following antibacterial treatment for recurrent CDI. Limitation of Use: VOWST is not indicated for treatment of CDI.