8-K: Seres Therapeutics Reports Q2 Loss, Seeks SER-155 Funding

Seres Therapeutics announced second quarter 2025 financial results, a reduced net loss, and active pursuit of capital to advance its lead drug candidate, SER-155, into Phase 2 clinical trials.

Summary

• Reported a net loss from continuing operations of $19.9 million for Q2 2025, an improvement from $26.2 million for the same period in 2024.
• Research and development (R&D) expenses decreased to $12.9 million in Q2 2025 from $15.8 million in Q2 2024, primarily due to the completion of the SER-155 Phase 1b study and lower personnel costs.
• General and administrative (G&A) expenses decreased to $10.3 million in Q2 2025 from $13.1 million in Q2 2024, mainly due to lower personnel and IT-related expenses.
• Cash and cash equivalents stood at $45.4 million as of June 30, 2025.
• The company expects its current cash position, including a $25 million payment received from Nestlé Health Science in July 2025, to fund operations into the first quarter of 2026.
• A Phase 2 study protocol for SER-155, designed to prevent bloodstream infections, was submitted to the FDA in May 2025, with anticipated FDA feedback to finalize the protocol.
• The SER-155 Phase 2 study is expected to enroll approximately 248 participants and include an interim data analysis within 12 months of study initiation, with commencement being funding dependent.
• Seres is actively engaging with multiple parties to secure capital and resources through partnerships, out-licensing deals, or mergers to advance SER-155 and other product candidates.
• Thomas DesRosier and Marella Thorell were appointed co-Chief Executive Officers, effective August 1, 2025, following the departure of former CEO Eric Shaff, who remains a Director.
• Robert Rosiello joined the board of directors on August 5, 2025, filling a vacancy.

Sentiment

Score: 7

Explanation: The company shows strong clinical progress with SER-155, positive Phase 1b data, and reduced operating losses. However, the short cash runway and explicit dependency of the lead program's next phase on new funding introduce significant financial uncertainty and risk, despite active efforts to secure capital.

Positives

• Net loss from continuing operations decreased to $19.9 million in Q2 2025 from $26.2 million in Q2 2024, indicating improved financial efficiency.
• R&D expenses decreased by $2.9 million and G&A expenses decreased by $2.8 million year-over-year, reflecting successful cost reduction efforts.
• Received the expected $25 million installment payment from Nestlé Health Science in July 2025, strengthening the cash position.
• Submitted the SER-155 Phase 2 study protocol to the FDA, indicating progress in clinical development for a key pipeline asset.
• SER-155 has received Breakthrough Therapy and Fast Track designations, highlighting its potential and facilitating expedited development.
• Phase 1b data for SER-155 demonstrated a significant 77% relative risk reduction in bacterial bloodstream infections and reduced systemic antibiotic exposure.
• Exploratory biomarker data from the SER-155 Phase 1b study support its mechanism of action and potential for broader applications in inflammatory and immune diseases.
• Active discussions are underway with multiple parties for potential business development and partnerships to secure capital for SER-155 and other live biotherapeutic product candidates.
• The VOWST asset sale to Nestlé Health Science has provided capital and streamlined the organization, allowing for a focused pipeline development.

Negatives

• The company continues to operate at a net loss from continuing operations, despite a reduction from the prior year.
• The cash runway is projected only into the first quarter of 2026, indicating a near-term need for significant additional funding.
• The commencement of the critical SER-155 Phase 2 study is explicitly stated as being funding dependent, posing a risk to its timeline.
• The company has incurred significant losses historically and states it may never become profitable, as per forward-looking statements.
• There is a risk of receiving notice of failure to satisfy a continued listing rule from The Nasdaq Stock Market LLC.

Risks

• Need for additional funding to support operations and clinical development.
• Ability to continue as a going concern is uncertain without further capital.
• Significant accumulated losses and no current profitability, with no guarantee of future profitability.
• Limited operating history as a company.
• Expected payments from the VOWST sale are subject to risks and uncertainties.
• May not realize the anticipated benefits of the VOWST sale and could face new challenges as a smaller, less diversified company.
• Potential failure to satisfy Nasdaq continued listing rules.
• Reliance on a novel approach to therapeutic intervention (live biotherapeutics) which may face unforeseen challenges.
• Dependence on third parties to conduct clinical trials and manufacture product candidates.
• Ability to achieve market acceptance necessary for commercial success of product candidates.
• Competition from other pharmaceutical and biotechnology companies.
• Ability to protect intellectual property rights.
• Challenges in managing the recent CEO transition, retaining key personnel, and managing company growth.

Future Outlook

The company's future outlook is centered on advancing SER-155, with plans to finalize the Phase 2 protocol with FDA feedback and initiate the study, contingent on securing additional funding. Interim clinical results from the Phase 2 study are anticipated within 12 months of initiation, which could inform the design of a Phase 3 study and enable development in adjacent patient populations. The company also intends to evaluate SER-155 and other cultivated live biotherapeutic candidates in other medically vulnerable patient populations, including autologous-HSCT patients, cancer patients with neutropenia, CAR-T recipients, individuals with chronic liver disease, solid organ transplant recipients, and patients in intensive care and long-term acute care facilities. Additionally, Seres is exploring potential R&D partnerships to advance its investigational live biotherapeutics in inflammatory and immune diseases, such as ulcerative colitis and Crohn's disease. The company is actively evaluating cost reduction actions to extend its cash runway and is engaging in discussions for strategic partnerships, out-licensing deals, or mergers to secure necessary capital and resources.

Management Comments

• We are in active discussions with multiple parties seeking capital and other resources to support further development of SER-155 for the prevention of BSIs and our broader portfolio of live biotherapeutic product candidates with applications for inflammatory diseases. The types of transactions we are evaluating include partnerships, out-licensing deals, mergers, and other structures to access capital, and aim to leverage Seres expertise and track record of successfully bringing a live biotherapeutic product to the market.
• Our clinical data underscore the potential of SER-155 to transform care for allo-HSCT recipients and other high-risk patients vulnerable to bloodstream infections, an area of significant unmet need and commercial opportunity.
• Informed by constructive FDA feedback, we have submitted a protocol to the agency for a well-powered, placebo-controlled SER-155 Phase 2 study, which includes a planned interim analysis designed to enable an expedited readout. The FDA has continued to engage with the Company and has indicated they will provide feedback, which we expect will support finalizing the protocol.

Industry Context

Seres Therapeutics operates at the forefront of the live biotherapeutics industry, having pioneered VOWST, the first FDA-approved oral microbiome therapeutic. This positions the company uniquely in addressing unmet medical needs through microbiome-based interventions. The focus on SER-155 for preventing bloodstream infections in allogeneic hematopoietic stem cell transplant (allo-HSCT) recipients addresses a critical challenge in oncology and transplant medicine, where current prophylactic treatments are losing efficacy due to antimicrobial resistance. The high incidence of infections and associated mortality in this vulnerable patient population highlights a significant market opportunity. The company's strategy aligns with broader industry trends emphasizing precision medicine and novel therapeutic modalities, particularly in areas with high unmet needs where traditional antibiotics are failing. The comparison to Merck's Prevymis, a successful viral prophylaxis drug in transplant settings, underscores the potential for a blockbuster market in infection prevention for this patient group.

Comparison to Industry Standards

• VOWST, Seres's previously owned asset, achieved FDA approval as the first-ever oral microbiome therapeutic, demonstrating an approximately 88% sustained clinical response rate in preventing C. difficile infection recurrence, setting a high benchmark for the efficacy of live biotherapeutics.
• SER-155's Phase 1b study showed a 77% relative risk reduction in bacterial bloodstream infections (BSIs) and reduced systemic antibiotic exposure in allo-HSCT patients, which is a strong efficacy signal compared to the high BSI rates (e.g., ~40% in the placebo arm of the SER-155 study) and decreasing efficacy of standard antibacterial prophylaxis like fluoroquinolones.
• The company explicitly positions SER-155 as having 'blockbuster commercial potential' comparable to Prevymis (letermovir), Merck's viral prophylaxis drug, which generated $785 million in worldwide sales in 2024, indicating a substantial market for infection prevention in transplant patients.
• Healthcare providers (HCPs) surveyed by Seres indicated that a 50% reduction in BSIs would be 'transformative' and support broad inclusion in standard protocols for allo-HSCT patients, suggesting SER-155's 77% reduction significantly exceeds this threshold.
• The current standard of care for BSI prevention in allo-HSCT patients, such as fluoroquinolones, is noted to be decreasing in efficacy due to rising resistance, with BSI rates remaining high despite prophylaxis, making SER-155's novel approach a potential game-changer in an area of significant unmet need.

Management Changes

Related Party Transactions

• Received a $25 million installment payment from Nestlé Health Science in July 2025, as expected, and concurrently paid Nestlé $1.4 million in employment-related obligations.
• Manufacturing services expenses of $1.7 million for Q2 2025 relate to the provision of services under the Transition Service Agreement (TSA) with Nestlé, with reimbursement recognized in other income.
• Accounts receivable due from SPN (Société des Produits Nestlé S.A.) related party, amounted to $882 thousand as of June 30, 2025.
• Accrued liabilities due to SPN related party, amounted to $13.453 million as of June 30, 2025.
• Other income includes $3.490 million for the three months ended June 30, 2025, and $9.799 million for the six months ended June 30, 2025, related to reimbursement received from SPN for transition services provided by the company.

Stakeholder Impact

• **Shareholders:** Face potential dilution if future capital raises involve equity. The short cash runway and funding dependency for SER-155's next clinical phase introduce significant financial risk and uncertainty, though positive clinical data for SER-155 could drive long-term value if funding is secured. Management changes aim to provide stable leadership.
• **Employees:** The company has implemented and continues to evaluate cost reduction actions, which may imply potential workforce adjustments. New co-CEOs are in place, providing leadership continuity.
• **Customers (future patients):** Potential for a novel therapeutic (SER-155) to prevent life-threatening bacterial infections in highly vulnerable patient populations, addressing a significant unmet medical need.
• **Partners (Nestlé Health Science):** Ongoing relationship for manufacturing services under the TSA and potential future sales-based milestone payments from the VOWST asset sale.
• **Regulatory Authorities (FDA):** Continued engagement and collaboration on the development pathway for SER-155, including protocol submission and anticipated feedback.

Next Steps

• Anticipate and incorporate FDA feedback to finalize the SER-155 Phase 2 protocol.
• Initiate the SER-155 Phase 2 study, contingent on securing necessary funding.
• Obtain interim clinical results from the SER-155 Phase 2 study within 12 months following study initiation.
• Engage with the FDA on the design of a Phase 3 study based on interim Phase 2 results.
• Evaluate SER-155 and other cultivated live biotherapeutic candidates in additional medically vulnerable patient populations (e.g., autologous-HSCT, cancer patients with neutropenia, CAR-T recipients, chronic liver disease, solid organ transplant recipients, ICU, and long-term acute care facilities).
• Explore potential R&D partnerships to advance development of investigational live biotherapeutics in inflammatory and immune diseases, including ulcerative colitis and Crohn's disease.
• Continue to evaluate and implement cost reduction actions aimed at extending the cash runway.
• Continue active discussions with multiple parties regarding various deal structures to secure capital and other resources.
• Complete the remaining Transition Service Agreement (TSA) activities related to the VOWST asset sale, including manufacturing services through the end of 2025.

Key Dates

Recommendation

Seres Therapeutics presents a mixed but potentially promising outlook. The company has demonstrated strong clinical efficacy for SER-155 in Phase 1b, addressing a critical unmet medical need with Breakthrough Therapy designation, and has successfully reduced its operating losses. However, the very limited cash runway into Q1 2026 and the explicit statement that the crucial SER-155 Phase 2 study is 'funding dependent' introduce significant financial uncertainty. While management is actively seeking strategic partnerships and capital, the success and terms of these efforts are not guaranteed. A 'hold' recommendation is appropriate for a seasoned investor, as the stock's near-term performance will heavily depend on the outcome of these funding initiatives. Positive news on securing capital could lead to significant upside, while failure to do so would pose substantial downside risk. Monitoring the progress of capital discussions and the initiation of the Phase 2 trial is key.

Keywords

Live Biotherapeutics, SER-155, Bloodstream Infections, Hematopoietic Stem Cell Transplant, Allo-HSCT, Microbiome, Clinical Trials, Biotechnology, Pharmaceutical, Infection Prevention, FDA Breakthrough Therapy, Financial Results, Capital Raise, Corporate Governance