Seres Pauses SER-155 Phase 2 Study Amid Cost-Cutting Measures
Written by Emily J. Thompson, Senior Investment Analyst
Updated: Feb 12 2026
0mins
Should l Buy MCRB?
Source: stocktwits
- Study Pause Reason: Seres announced the pause of the SER-155 Phase 2 study following the completion of site evaluation and qualification with its contract research organization, despite the drug substance already being manufactured, which could hinder future R&D progress.
- Strategic Shift: The company will refocus its operations on high-value early-stage pipeline programs, particularly those targeting inflammatory bowel disease (IBD), aiming to seek greater market opportunities amid limited resources.
- Cash Runway Extension: Through cost-cutting measures, including a 30% workforce reduction, Seres expects to extend its cash runway into Q3 2026, which will support the continued development of immune-related disease programs while seeking additional funding for the SER-155 Phase 2 study.
- Market Reaction: While retail sentiment on Stocktwits remains in the 'bullish' territory, MCRB stock has fallen 51% year-to-date and 75% over the past 12 months, indicating investor concerns about the company's future prospects.
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Analyst Views on MCRB
Wall Street analysts forecast MCRB stock price to rise
2 Analyst Rating
2 Buy
0 Hold
0 Sell
Moderate Buy
Current: 8.740
Low
22.00
Averages
22.00
High
22.00
Current: 8.740
Low
22.00
Averages
22.00
High
22.00
About MCRB
Seres Therapeutics, Inc. is a clinical-stage company focused on improving patient outcomes in medically vulnerable populations through novel live biotherapeutics. It is developing SER-155, which has shown a significant reduction in bloodstream infections and related complications (as compared to placebo) in a Phase 1b clinical study in patients undergoing allo-HSCT and Fast Track designation to reduce the risk of infection and graft-versus-host disease in adults undergoing allo-HSCT. SER-155 and the Company’s other pipeline programs are designed to target multiple disease-relevant pathways. In addition to allo-HSCT, it intends to evaluate SER-155 and other cultivated live biotherapeutic candidates in other medically patient populations, including autologous-HSCT patients, cancer patients with neutropenia, CAR-T recipients, individuals with chronic liver disease, solid organ transplant recipients, as well as patients in the intensive care unit and long-term acute care facilities.
About the author
Emily J. Thompson
Emily J. Thompson, a Chartered Financial Analyst (CFA) with 12 years in investment research, graduated with honors from the Wharton School. Specializing in industrial and technology stocks, she provides in-depth analysis for Intellectia’s earnings and market brief reports.
Seres Therapeutics Appoints New Executive Chair and Interim CEO
- Executive Changes: Seres Therapeutics announced the appointment of Richard Kenderas as Executive Chair and interim CEO, who has been on the board since September 2014, suggesting his extensive experience will guide the company's strategic direction.
- Management Stability: Former co-CEOs Thomas DesRosier and Marella Thorell will continue as Chief Legal Officer and Chief Financial Officer, respectively, ensuring continuity and stability in management, which is crucial for maintaining investor confidence.
- Investment Pause Impact: Following the pause in investments for its lead program, Seres faces market concerns regarding its future growth potential, leading to a decline in stock price, reflecting investor caution towards the company's strategic adjustments.
- Market Reaction: Despite strong SER-155 data, the increased dilution risk has prompted analysts to adjust Seres' rating to 'Hold', which may affect the company's future financing capabilities and market performance.
See More
Seres Therapeutics Pauses SER-155 Investment Amid Funding Challenges
- Investment Pause: Seres Therapeutics announced a pause on additional investments for its mid-stage trial, resulting in a ~25% drop in premarket trading, indicating significant funding challenges for its lead asset SER-155.
- Focus on Early Programs: The company will shift its focus to earlier-stage programs, including a fully enrolled study for SER-155 in immune checkpoint-related enterocolitis, expected to generate data by early Q2 2026, highlighting potential market demand for cancer therapies.
- Layoff Plans: Seres plans to lay off nearly 30% of its workforce to extend its cash runway through Q3 2026, a move aimed at streamlining operations and reducing costs to support the development of its early-stage pipeline.
- Regulatory Preparedness: CEO Marella Thorell stated that the company has taken extensive steps to prepare for a robust SER-155 Phase 2 study, including submitting a final protocol to the FDA, demonstrating commitment and confidence in future research.
See More
Seres Pauses SER-155 Phase 2 Study Amid Cost-Cutting Measures
- Study Pause Reason: Seres announced the pause of the SER-155 Phase 2 study following the completion of site evaluation and qualification with its contract research organization, despite the drug substance already being manufactured, which could hinder future R&D progress.
- Strategic Shift: The company will refocus its operations on high-value early-stage pipeline programs, particularly those targeting inflammatory bowel disease (IBD), aiming to seek greater market opportunities amid limited resources.
- Cash Runway Extension: Through cost-cutting measures, including a 30% workforce reduction, Seres expects to extend its cash runway into Q3 2026, which will support the continued development of immune-related disease programs while seeking additional funding for the SER-155 Phase 2 study.
- Market Reaction: While retail sentiment on Stocktwits remains in the 'bullish' territory, MCRB stock has fallen 51% year-to-date and 75% over the past 12 months, indicating investor concerns about the company's future prospects.
See More
Seres Therapeutics Stock Declines Amid Strategic Shift
- Strategic Shift: Seres Therapeutics announced a pivot towards emerging programs in inflammatory and immune diseases, resulting in a 16.25% drop in stock price during Thursday's premarket session, raising investor concerns about its current pipeline and funding strategies.
- Clinical Trial Update: The company has finalized the protocol for its Phase 2 study of SER-155 and is pausing further investment in this program, with results from the investigator-sponsored study expected in early Q2 2026, indicating a focus on early-stage programs.
- Workforce Reduction: Seres announced a 30% workforce reduction aimed at extending its cash runway through Q3 2026, allowing it to concentrate on advancing early-stage live biotherapeutic programs and pursue potential collaborations, highlighting financial constraints.
- Technical Trend Analysis: Currently trading at $11.80, Seres stock is 24.4% below its 20-day simple moving average, indicating a bearish trend and ongoing operational challenges, as the stock has decreased by 13.86% over the past 12 months.
See More
Seres (MCRB) Third Quarter 2025 Earnings Call Summary
- Author's Perspective: The views and opinions presented are solely those of the author.
- No Official Endorsement: The content does not necessarily reflect the views of Nasdaq, Inc.
See More
Seres Receives Positive Input from FDA on Phase 2 Study Protocol for SER-155; Plans Workforce Reduction
FDA Feedback on SER-155: Seres Therapeutics received constructive feedback from the FDA regarding the Phase 2 study protocol for SER-155, aimed at preventing bloodstream infections in adults undergoing stem cell transplants, which will aid in finalizing the protocol.
Workforce Reduction and Financial Outlook: The company is reducing its workforce by approximately 25%, which is expected to incur cash payments of $1.0 - $1.4 million in Q4 2025, while extending its cash runway into the second quarter of 2026.
See More
Seres Therapeutics Appoints New Executive Chair and Interim CEO
- Executive Changes: Seres Therapeutics announced the appointment of Richard Kenderas as Executive Chair and interim CEO, who has been on the board since September 2014, suggesting his extensive experience will guide the company's strategic direction.
- Management Stability: Former co-CEOs Thomas DesRosier and Marella Thorell will continue as Chief Legal Officer and Chief Financial Officer, respectively, ensuring continuity and stability in management, which is crucial for maintaining investor confidence.
- Investment Pause Impact: Following the pause in investments for its lead program, Seres faces market concerns regarding its future growth potential, leading to a decline in stock price, reflecting investor caution towards the company's strategic adjustments.
- Market Reaction: Despite strong SER-155 data, the increased dilution risk has prompted analysts to adjust Seres' rating to 'Hold', which may affect the company's future financing capabilities and market performance.
See More
Seres Therapeutics Pauses SER-155 Investment Amid Funding Challenges
- Investment Pause: Seres Therapeutics announced a pause on additional investments for its mid-stage trial, resulting in a ~25% drop in premarket trading, indicating significant funding challenges for its lead asset SER-155.
- Focus on Early Programs: The company will shift its focus to earlier-stage programs, including a fully enrolled study for SER-155 in immune checkpoint-related enterocolitis, expected to generate data by early Q2 2026, highlighting potential market demand for cancer therapies.
- Layoff Plans: Seres plans to lay off nearly 30% of its workforce to extend its cash runway through Q3 2026, a move aimed at streamlining operations and reducing costs to support the development of its early-stage pipeline.
- Regulatory Preparedness: CEO Marella Thorell stated that the company has taken extensive steps to prepare for a robust SER-155 Phase 2 study, including submitting a final protocol to the FDA, demonstrating commitment and confidence in future research.
See More
Seres Pauses SER-155 Phase 2 Study Amid Cost-Cutting Measures
- Study Pause Reason: Seres announced the pause of the SER-155 Phase 2 study following the completion of site evaluation and qualification with its contract research organization, despite the drug substance already being manufactured, which could hinder future R&D progress.
- Strategic Shift: The company will refocus its operations on high-value early-stage pipeline programs, particularly those targeting inflammatory bowel disease (IBD), aiming to seek greater market opportunities amid limited resources.
- Cash Runway Extension: Through cost-cutting measures, including a 30% workforce reduction, Seres expects to extend its cash runway into Q3 2026, which will support the continued development of immune-related disease programs while seeking additional funding for the SER-155 Phase 2 study.
- Market Reaction: While retail sentiment on Stocktwits remains in the 'bullish' territory, MCRB stock has fallen 51% year-to-date and 75% over the past 12 months, indicating investor concerns about the company's future prospects.
See More
Seres Therapeutics Stock Declines Amid Strategic Shift
- Strategic Shift: Seres Therapeutics announced a pivot towards emerging programs in inflammatory and immune diseases, resulting in a 16.25% drop in stock price during Thursday's premarket session, raising investor concerns about its current pipeline and funding strategies.
- Clinical Trial Update: The company has finalized the protocol for its Phase 2 study of SER-155 and is pausing further investment in this program, with results from the investigator-sponsored study expected in early Q2 2026, indicating a focus on early-stage programs.
- Workforce Reduction: Seres announced a 30% workforce reduction aimed at extending its cash runway through Q3 2026, allowing it to concentrate on advancing early-stage live biotherapeutic programs and pursue potential collaborations, highlighting financial constraints.
- Technical Trend Analysis: Currently trading at $11.80, Seres stock is 24.4% below its 20-day simple moving average, indicating a bearish trend and ongoing operational challenges, as the stock has decreased by 13.86% over the past 12 months.
See More
Seres (MCRB) Third Quarter 2025 Earnings Call Summary
- Author's Perspective: The views and opinions presented are solely those of the author.
- No Official Endorsement: The content does not necessarily reflect the views of Nasdaq, Inc.
See More
Seres Receives Positive Input from FDA on Phase 2 Study Protocol for SER-155; Plans Workforce Reduction
FDA Feedback on SER-155: Seres Therapeutics received constructive feedback from the FDA regarding the Phase 2 study protocol for SER-155, aimed at preventing bloodstream infections in adults undergoing stem cell transplants, which will aid in finalizing the protocol.
Workforce Reduction and Financial Outlook: The company is reducing its workforce by approximately 25%, which is expected to incur cash payments of $1.0 - $1.4 million in Q4 2025, while extending its cash runway into the second quarter of 2026.
See More
