Seres Therapeutics: Unpacking Strategic Contradictions in Partnerships and FDA Engagements

SER-155 Clinical Progress:
- Seres Therapeutics reported highly promising results for SER-155, demonstrating a 77% relative risk reduction in bloodstream infections in allo-HSCT patients compared to placebo.
- The positive clinical outcomes are attributed to SER-155's potential to promote immune reconstitution and its placebo-like safety profile, which supports its development for vulnerable patient groups.

Funding and Strategic Partnerships:
- Seres is actively seeking partnerships, out-licensing deals, mergers, and other structures to secure capital and resources for SER-155's development.
- The company is considering various structures that provide financial support and leverage Seres' expertise in the microbiome field, with the goal of advancing its clinical candidates more effectively.

Financial Performance and Cash Runway:
- Seres reported a net loss of $19.9 million in Q2 2025, down from $26.2 million in the same quarter last year.
- The improvement was due to lower research and development expenses, particularly related to completed studies, and reduced general and administrative expenses, including personnel and IT costs.

Expansion into EU and Global Studies:
- Seres plans to include EU countries in the Phase II study for SER-155, supported by encouraging feedback from European physicians.
- The study design is robust and well-powered, which is expected to be well-received by both U.S. and EU regulatory authorities, facilitating global study execution.