8-K: Seres Therapeutics Reports Positive SER-155 Data and Extends Cash Runway into Q1 2026

Seres Therapeutics announces positive clinical data for SER-155, provides business updates, and reports financial results for Q4 and full year 2024, extending its cash runway into Q1 2026.

Summary

• Seres Therapeutics reported its Q4 and full year 2024 financial results and provided business updates on March 13, 2025.
• The company is focused on advancing SER-155, a novel live biotherapeutic candidate designed to prevent life-threatening bloodstream infections in allo-HSCT recipients.
• Phase 1b clinical results showed a 77% relative risk reduction in bloodstream infections (BSIs) with SER-155.
• The FDA granted Breakthrough Therapy designation to SER-155 for reduction of bloodstream infections in adults undergoing allo-HSCT.
• Seres plans to submit a draft study protocol to the FDA in Q2 2025 for the next SER-155 study, which could be a standalone Phase 2 or a Phase 2/3 seamless design.
• Exploratory translational biomarker data from the SER-155 Phase 1b study support the intended therapeutic mechanisms.
• Market research indicates strong potential for SER-155 in allo-HSCT, with approximately 9,300 allo-HSCT procedures conducted annually in the US.
• Seres sold its VOWST business to Nestl in September 2024 for gross proceeds of approximately $175 million.
• Seres expects to receive a second installment payment of $25 million from Nestl in July 2025.
• The company reported a net loss from continuing operations of $125.8 million for the full year 2024.
• As of December 31, 2024, Seres had $30.8 million in cash and cash equivalents.
• Seres expects to fund operations into Q1 2026 based on current cash, expected payments from Nestl, and current operating plans.

Sentiment

Score: 8

Explanation: The document presents a positive outlook due to the promising clinical data for SER-155, FDA Breakthrough Therapy designation, and the extended cash runway. The sale of the VOWST business provides financial stability, although the company still faces risks and uncertainties.

Positives

• SER-155 shows significant promise in reducing bloodstream infections in allo-HSCT recipients.
• FDA Breakthrough Therapy designation for SER-155 provides access to senior management at FDA and more communication and guidance from FDA to expedite the development of medicines.
• Sale of VOWST business to Nestl provides Seres with significant capital and allows for a more focused organization.
• Exploratory biomarker data supports the intended therapeutic mechanisms of SER-155.
• Market research indicates a high unmet need and strong potential for SER-155 in allo-HSCT.

Negatives

• Seres reported a net loss from continuing operations of $125.8 million for the full year 2024.
• The company had $30.8 million in cash and cash equivalents as of December 31, 2024, requiring reliance on future payments and potential partnerships to extend the cash runway.
• The company is reliant on a second installment payment of $25 million from Nestl in July 2025.
• The company is reliant on potential future sales-based milestone payments of $275M from Nestl.

Risks

• The company's ability to secure a partnership for SER-155 development is uncertain.
• Clinical trials may not be successful, and regulatory approvals may not be obtained.
• The company faces competition in the development of live biotherapeutics.
• The company's intellectual property may not be adequately protected.
• The company may not be able to retain key personnel or manage its growth effectively.

Future Outlook

Seres expects to fund operations into Q1 2026 based on current cash, expected payments from Nestl, and current operating plans. The company plans to submit a draft protocol for the next SER-155 study to the FDA in Q2 2025 and is pursuing a strategic partnership to accelerate SER-155 development.

Management Comments

• We have made significant progress advancing SER-155 as a novel live biotherapeutic candidate designed to prevent life-threatening bloodstream infections in allo-HSCT recipients, said Eric Shaff, President and Chief Executive Officer of Seres.
• Recently released exploratory translational biomarker results from our SER-155 Phase 1b study provide supportive mechanistic data, consistent with the observed clinical results that showed a reduction in the risk of BSIs, Mr. Shaff continued.
• We believe the data also offer further evidence of the potential of Seres biotherapeutic approach to benefit patients living with inflammatory and immune diseases such as ulcerative colitis and Crohns disease.

Industry Context

Seres is operating in the emerging field of microbiome therapeutics, aiming to address unmet needs in preventing infections and treating immune-related diseases. The company's focus on SER-155 aligns with the growing concern over antimicrobial resistance and the need for novel approaches to prevent bloodstream infections in vulnerable patient populations.

Comparison to Industry Standards

• The 77% relative risk reduction in BSIs observed with SER-155 in the Phase 1b study is a significant result compared to existing prophylactic measures.
• Current standards of care, such as fluoroquinolones, are facing increasing resistance, highlighting the need for new therapies like SER-155.
• Prevymis, used for viral infection prophylaxis in allo-HSCT and solid organ transplant populations, provides a precedent for the use of prophylactic therapies in medically vulnerable patients.
• The estimated cost of allo-HSCT in the US is approximately $400,000 per patient in the first year, with infections adding an incremental cost of around $180,000, underscoring the potential economic benefit of SER-155.

Management Changes

Related Party Transactions

• The sale of the VOWST business to Socit des Produits Nestl S.A (SPN) is a related party transaction.
• The appointment of Hans-Juergen Woerle, M.D., as a director and member of the Science and Clinical Development Committee is related to the Nestl transaction.

Stakeholder Impact

• Shareholders: The positive clinical data and extended cash runway are likely to be viewed favorably by shareholders.
• Patients: SER-155 has the potential to improve outcomes for patients undergoing allo-HSCT by reducing the risk of bloodstream infections.
• Employees: The sale of the VOWST business may have resulted in some job losses, but the company is now more focused on its core pipeline programs.
• Nestl: The acquisition of the VOWST business allows Nestl to expand its portfolio of microbiome therapeutics.

Next Steps

• Submit to FDA a draft protocol for the next study of SER-155 in allo-HSCT in Q2 2025.
• Present SER-155 Phase 1b clinical and exploratory translational biomarker data at the European Bone Marrow Transplant meeting in March 2025.
• Receive a $25 million installment payment from Nestl in July 2025.
• Continue pursuing a strategic partnership for SER-155 development.

Key Dates