Seres Therapeutics Implements Strategic Restructuring Amid Financial Challenges

Seres Therapeutics, a prominent microbiome biopharma company, has announced a significant workforce reduction as part of its efforts to conserve resources and advance its pipeline. The Cambridge, Massachusetts-based firm is taking decisive action to extend its cash runway and focus on key development programs.

Layoffs and Financial Restructuring

Seres has revealed plans to lay off 25% of its workforce, a move aimed at preserving capital for its phase 2 study of SER-155, a biotherapeutic designed to prevent bloodstream infections in adults undergoing allogeneic hematopoietic stem cell transplant. This restructuring is expected to incur severance costs between $1 million and $1.4 million.

The company's co-CEOs, Thomas DesRosier and Marella Thorell, emphasized that employees critical to the phase 2 study preparations will be retained. They stated, "While we advance SER-155 phase 2 study start-up activities, we continue to engage in active discussions with multiple parties seeking capital to initiate the study, and to support our broader portfolio of product candidates with applications for inflammatory diseases."

Focus on SER-155 and Clinical Development

Seres is placing a strong emphasis on its SER-155 program, with recent "constructive" conversations with the FDA regarding the study protocol. The company anticipates interim results within 12 months of initiating the 248-person trial.

This strategic pivot comes in the wake of Seres' success with Vowst, which became the first FDA-approved oral microbiome therapeutic for Clostridioides difficile infection. The rights to Vowst were sold to commercialization partner Nestlé Health Science a year ago, marking a significant milestone for the company.

Financial Outlook and Future Plans

The restructuring measures, including the layoffs and additional operational streamlining, are projected to extend Seres' cash runway "well into" the second quarter of 2026. This extension is crucial, as the company's current cash reserves were previously expected to be depleted by March 2026.

Seres continues to explore various avenues for securing additional capital to support its development pipeline, particularly for inflammatory disease applications. The company's leadership views these cost reduction actions as necessary steps to provide opportunities for advancing their strategic priorities in a challenging financial landscape.