MCRB Stock: Insider Activity, Filings & Research
Seres Therapeutics, Inc. (MCRB) — Drillr’s hub for MCRB insider activity, SEC filings, earnings signals and AI research. Over the trailing 3 months, MCRB insiders filed 0 open-market buys and 4 sales (SEC Form 4).
MCRB insider trading activity (SEC Form 4)
| Date | Insider | Type | Shares | Price |
|---|---|---|---|---|
| May 19, 2026 | DesRosier Thomasofficer: See Remarks | Option | 133 | — |
| May 19, 2026 | DesRosier Thomasofficer: See Remarks | Option | 244 | — |
| May 19, 2026 | Brady Kellyofficer: See Remarks | Option | 91 | — |
| May 19, 2026 | Shaff Eric D.director | Option | 722 | — |
| May 19, 2026 | DesRosier Thomasofficer: See Remarks | Sell | 79 | $7.53 |
| May 19, 2026 | Shaff Eric D.director | Option | 391 | — |
| May 19, 2026 | Brady Kellyofficer: See Remarks | Option | 89 | — |
| May 19, 2026 | Henn Matthew Rofficer: See Remarks | Sell | 77 | $7.53 |
| May 19, 2026 | Henn Matthew Rofficer: See Remarks | Option | 97 | — |
| May 19, 2026 | Henn Matthew Rofficer: See Remarks | Option | 141 | — |
| May 19, 2026 | Brady Kellyofficer: See Remarks | Sell | 59 | $7.53 |
| May 19, 2026 | Brady Kellyofficer: See Remarks | Option | 180 | — |
| May 19, 2026 | Shaff Eric D.director | Option | 331 | — |
| May 19, 2026 | Henn Matthew Rofficer: See Remarks | Option | 238 | — |
| May 19, 2026 | Shaff Eric D.director | Sell | 259 | $7.53 |
Source: MCRB SEC Form 4 filings, latest May 19, 2026. For informational purposes only — not investment advice.
Seres Therapeutics, Inc. company profile
Overview
Seres Therapeutics, Inc. (NASDAQ:MCRB) is a microbiome therapeutics platform company founded in 2010 and headquartered in Cambridge, Massachusetts. The company was originally incorporated as Seres Health, Inc. before changing its name in May 2015, the same year it went public. Seres focuses on developing bacterial consortia designed to functionally interact with host cells and tissues to treat various diseases. The company has undergone significant strategic transformation in recent years, including the sale of its first approved product VOWST to Nestlé Health Science in 2024 for $155 million, allowing it to focus on its pipeline of live biotherapeutic products for preventing infections in medically vulnerable patient populations.
Business
Seres Therapeutics operates in the emerging field of microbiome therapeutics, a specialized area within biotechnology that harnesses the power of beneficial bacteria to treat diseases. The human microbiome consists of trillions of microorganisms that live in and on our bodies, particularly in the gut, and play crucial roles in digestion, immune function, and overall health. When this delicate bacterial ecosystem becomes disrupted—often due to antibiotic use, illness, or medical treatments—harmful pathogens can take over and cause serious infections. The company's core technology involves developing live biotherapeutic products (LBPs), which are essentially carefully selected and cultivated bacterial consortia (groups of beneficial bacteria) that can be administered orally to restore healthy microbiome function. Unlike probiotics available over-the-counter, these are prescription medicines that undergo rigorous clinical testing and FDA approval processes. Seres' primary focus areas include: 1. SER-155 - The company's lead pipeline candidate, designed to prevent bloodstream infections in patients undergoing allogeneic hematopoietic stem cell transplantation (allo-HSCT). These are cancer patients receiving bone marrow transplants who are extremely vulnerable to life-threatening infections due to their compromised immune systems. SER-155 has shown a 77% relative risk reduction in bacterial bloodstream infections in clinical trials and has received FDA Breakthrough Therapy Designation. 2. SER-147 - An early-stage program targeting patients with chronic liver disease, who are also at high risk for serious infections due to their compromised immune systems and altered gut microbiomes. 3. Historical VOWST program - Previously the company's flagship product for treating recurrent Clostridioides difficile infections, which was sold to Nestlé Health Science in 2024. This represented approximately 100% of the company's historical revenue generation. The company also has several other early-stage programs exploring applications in inflammatory bowel disease, cancer immunotherapy, and other conditions affecting immunocompromised patients.
Revenue model
Seres Therapeutics operates a research and development-focused business model typical of clinical-stage biotechnology companies. The company does not currently generate product revenue, as it sold its only approved product VOWST to Nestlé Health Science in 2024. Going forward, the company's revenue model will depend on successfully developing and commercializing its pipeline candidates or entering into partnership agreements. The company's potential revenue streams include: 1. Product sales - Once SER-155 or other pipeline candidates receive FDA approval, the company would generate revenue through direct sales to hospitals and healthcare providers. The target patient population for SER-155 includes approximately 9,300 allo-HSCT procedures annually in the US and 20,000 in Europe, representing a significant commercial opportunity given the high unmet medical need. 2. Partnership agreements - Seres is actively seeking development partners who can provide financial support, global clinical trial expertise, and commercialization capabilities. Such partnerships typically involve upfront payments, milestone payments, and royalty sharing arrangements. 3. Licensing revenue - The company has existing licensing agreements, including one with Nestlé Health Science that provides ongoing milestone payments (such as the anticipated $23.5 million installment in July 2025). Factors that could increase profitability include successful clinical trial outcomes, FDA approvals, favorable reimbursement decisions by insurance companies, and expansion into additional patient populations. The company's margins could be negatively impacted by clinical trial failures, regulatory delays, manufacturing scale-up challenges, competition from alternative treatments, and the high costs associated with serving specialized hospital-based patient populations. The company's current cash burn rate and lack of revenue make it heavily dependent on raising additional capital or securing partnerships to fund operations.
Competitive moat
Seres Therapeutics operates in a nascent field with limited competitive moat protection. The company's primary competitive advantages stem from its first-mover position in microbiome therapeutics and its clinical development expertise, but these advantages are relatively weak and face several challenges. The company's potential moat elements include its proprietary bacterial consortia, clinical trial data demonstrating efficacy, and regulatory relationships with the FDA. SER-155's Breakthrough Therapy Designation provides some regulatory advantage and expedited review pathways. The company also benefits from the high barriers to entry in developing live biotherapeutic products, which require specialized manufacturing capabilities, complex clinical trial designs, and significant regulatory expertise. However, the moat is limited by several factors. The microbiome therapeutics field is rapidly evolving with numerous competitors entering the space, including large pharmaceutical companies with greater resources. The company's bacterial strains, while proprietary, may not be strongly defensible against alternative approaches or competing bacterial consortia. Additionally, the relatively small target patient populations make the commercial opportunity attractive to larger competitors who could potentially develop superior products or acquire competing assets. The company's lack of an approved product following the VOWST sale further weakens its competitive position. While SER-155 shows promise, clinical-stage assets remain unproven until they successfully complete Phase 3 trials and receive regulatory approval. The company's dependence on partnerships for future development also limits its control over competitive positioning and commercial strategy. Overall, Seres operates in an innovative but highly competitive space with limited sustainable competitive advantages.
Risks & safety
Seres Therapeutics presents a mixed margin of safety profile typical of clinical-stage biotechnology companies, with both positive and concerning financial metrics. **Liquidity and Solvency:** - Cash position: $58.8 million as of Q1 2025, providing runway into Q1 2026 - Current ratio: 2.11 (Q1 2025), indicating adequate short-term liquidity - Debt-to-equity ratio: 1.77, manageable but elevated - Positive free cash flow of $26.9 million in Q1 2025, though this appears to be driven by one-time factors rather than operational improvements **Valuation Metrics:** - Market cap: approximately $72 million - Price-to-book ratio: 43.11, indicating significant premium to book value - Enterprise value appears reasonable relative to clinical-stage biotech peers - Graham net-net value is negative, suggesting limited asset protection **Other Considerations:** - Expected $23.5 million milestone payment from Nestlé in July 2025 provides near-term cash flow visibility - High cash burn historically, though recent restructuring has reduced operating expenses - Single-asset risk concentrated in SER-155 program - Partnership dependency for future development funding creates execution risk
Recent development
Over the past few years, Seres Therapeutics has undergone a significant strategic transformation. The company's most notable development was the sale of VOWST, its first and only FDA-approved microbiome therapeutic for recurrent C. difficile infections, to Nestlé Health Science for $155 million in 2024. This transaction allowed the company to retire debt, reduce headcount by approximately 41%, and refocus entirely on its pipeline development. The company has pivoted to concentrate on SER-155 as its primary development priority. This live biotherapeutic product targets the prevention of bloodstream infections in patients undergoing allogeneic hematopoietic stem cell transplantation. Key milestones include completing a successful Phase 1b study demonstrating a 77% relative risk reduction in bacterial bloodstream infections, receiving FDA Breakthrough Therapy Designation, and preparing to initiate a Phase 2 study with 248 participants. Seres has also expanded its pipeline focus to include SER-147 for patients with chronic liver disease and is exploring applications in additional vulnerable patient populations including CAR-T therapy recipients, cancer patients with neutropenia, and those with inflammatory bowel diseases. The company has implemented a more disciplined, data-driven approach to pipeline prioritization, focusing on areas with strong scientific rationale, significant unmet medical needs, and clear commercial potential. Operationally, the company has streamlined its organization to approximately 100 employees and is actively pursuing partnership opportunities to provide financial support and global clinical development expertise for its pipeline programs. This strategic shift from a commercial-stage company back to a focused pipeline development organization represents a significant repositioning aimed at maximizing the value of its live biotherapeutic platform technology.
MCRB company profile · for informational purposes only — not investment advice.
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