Seres Therapeutics, Inc.
For the period ended Sep 30, 2026. Filed Nov 4, 2026.
View on SEC.govAbout this filing
A company's report for each of its first three quarters. The financial statements are not audited. It shows how the business has moved since the last annual report, and what management says changed.
Sep 30, 2026 · Filed Nov 4, 2026
What changed in Risk Factors?
Read the current filingPrevious report: 10-Q
Period ended 2026-06-30; filed 2026-08-05.
0001193125-26-334174
Item 1A. Risk FactorsCurrent report: 10-Q
Period ended 2026-09-30; filed 2026-11-04.
0001193125-26-446427
Item 1A. Risk FactorsThe baseline is this issuer’s latest earlier reporting period of the same form that was filed before the current report. A previous 10-Q is a different quarter, not a year-over-year comparison. Amendments are excluded.
Compared 358 previous paragraphs and 358 current paragraphs.
345 unchanged; 13 reworded; 0 added; 0 removed; 0 previous and 0 current paragraphs rearranged.
Tables are not compared: 0 previous and 0 current tables excluded. Dates, whitespace, punctuation and numbering changes are ignored; changes to financial figures remain significant.
A changed paragraph is not evidence that risk increased or decreased. An unchanged paragraph does not establish that risk stayed the same.
Reworded paragraphs (13)
Previous wording
Based on our currently available cash resources, the $12.5 million Milestone Termination Payment received from SPN in July 2026, and the expected receipt of the additional $12.5 million Milestone Termination Payment due from SPN in October 2026, and considering our future operating plans, we anticipate that we will require additional funding following the first quarter of 2027. The ability to obtain additional equity or other financing, including through partnerships, with terms favorable or acceptable to us cannot be considered probable according to the applicable accounting standards because they are outside our control. Therefore, there is substantial doubt about our ability to continue as a going concern for at least 12 months from the date that our condensed consolidated financial statements for the six months ended June 30, 2026 were issued. Substantial doubt about our ability to continue as a going concern may materially and adversely affect the price per share of our common stock, and it may be more difficult for us to obtain financing or enter into a partnership. If potential collaborators or partners decline to do business with us or potential investors decline to participate in any future financings due to such concerns, our ability to increase our cash position may be limited. The perception that we may not be able to continue as a going concern may cause others to choose not to deal with us due to concerns about our ability to meet our contractual obligations. We have prepared our consolidated financial statements on a going concern basis, which contemplates the realization of assets and the satisfaction of liabilities and commitments in the normal course of business. Our unaudited consolidated financial statements included in this Quarterly Report on Form 10-Q do not include any adjustments to reflect the possible inability of the Company to continue as a going concern within 12 months after the issuance of such financial statements.
Current wording
Based on our currently available cash resources and the $12.5 million Milestone Termination Payment received from SPN in October 2026, and considering our future operating plans, we anticipate that we will require additional funding following the first quarter of 2027. The ability to obtain additional equity or other financing, including through partnerships, with terms favorable or acceptable to us cannot be considered probable according to the applicable accounting standards because they are outside our control. Therefore, there is substantial doubt about our ability to continue as a going concern for at least 12 months from the date that our condensed consolidated financial statements for the nine months ended September 30, 2026 were issued. Substantial doubt about our ability to continue as a going concern may materially and adversely affect the price per share of our common stock, and it may be more difficult for us to obtain financing or enter into a partnership. If potential collaborators or partners decline to do business with us or potential investors decline to participate in any future financings due to such concerns, our ability to increase our cash position may be limited. The perception that we may not be able to continue as a going concern may cause others to choose not to deal with us due to concerns about our ability to meet our contractual obligations. We have prepared our consolidated financial statements on a going concern basis, which contemplates the realization of assets and the satisfaction of liabilities and commitments in the normal course of business. Our unaudited consolidated financial statements included in this Quarterly Report on Form 10-Q do not include any adjustments to reflect the possible inability of the Company to continue as a going concern within 12 months after the issuance of such financial statements.
Previous wording
the cost of conducting clinical trials for SER-155 in allo-HCT and other targeted indications, and other product candidates in our pipeline;
Current wording
the cost of conducting clinical trials for SER-155 in allo-HCT, irEC, and other targeted indications, and other product candidates in our pipeline;
Previous wording
Since inception, we have incurred significant operating losses. As of June 30, 2026, we had cash and cash equivalents totaling $15.6 million and an accumulated deficit of $987.7 million. For the six months ended June 30, 2026, we incurred a net loss from operations of $42.2 million. As noted elsewhere in this Quarterly Report on Form 10-Q, we have identified conditions and events that raise substantial doubt about our ability to continue as a going concern. To date, we have financed our operations through the public offerings of our common stock, private placements of our common stock and preferred stock, payments under our prior collaboration agreements and loan facility, and payments from government entities for research grants. We have devoted substantially all of our financial resources and efforts to developing our live biotherapeutics platform, identifying potential product candidates and conducting preclinical studies and clinical trials. We have only developed one FDA-approved product, VOWST, which was sold to SPN in September 2024. We have not completed development of any of our other product candidates, which we call live biotherapeutic candidates, or other drugs or biologics. We expect to continue to incur significant expenses and operating losses for the foreseeable future. Our expenses may increase substantially in connection with our ongoing and future activities, particularly if and as we:
Current wording
Since inception, we have incurred significant operating losses. As of September 30, 2026, we had cash and cash equivalents totaling $17.5 million and an accumulated deficit of $1,004.0 million. For the nine months ended September 30, 2026, we incurred a net loss from operations of $58.3 million. As noted elsewhere in this Quarterly Report on Form 10-Q, we have identified conditions and events that raise substantial doubt about our ability to continue as a going concern. To date, we have financed our operations through the public offerings of our common stock, private placements of our common stock and preferred stock, payments under our prior collaboration agreements and loan facility, and payments from government entities for research grants. We have devoted substantially all of our financial resources and efforts to developing our live biotherapeutics platform, identifying potential product candidates and conducting preclinical studies and clinical trials. We have only developed one FDA-approved product, VOWST, which was sold to SPN in September 2024. We have not completed development of any of our other product candidates, which we call live biotherapeutic candidates, or other drugs or biologics. We expect to continue to incur significant expenses and operating losses for the foreseeable future. Our expenses may increase substantially in connection with our ongoing and future activities, particularly if and as we:
Previous wording
conduct clinical trials for SER-155 in allo-HCT and for other medically vulnerable populations;
Current wording
conduct clinical trials for SER-155 in allo-HCT, irEC, and for other medically vulnerable populations;
Previous wording
We will need to secure additional funding to maintain operations beyond our current cash runway. Based on our currently available cash resources, the $12.5 million Milestone Termination Payment received from SPN in July 2026, and the expected receipt of the additional $12.5 million Milestone Termination Payment due from SPN in October 2026, and considering our future operating plans, we anticipate that we will require additional funding following the first quarter of 2027. However, due to our smaller business size and the early stage of development of our remaining assets, there can be no assurance that we will be able to raise the required capital on favorable terms, or at all. This potential inability to obtain necessary funding could have a material adverse effect on our growth prospects, financial condition, and results of operations.
Current wording
We will need to secure additional funding to maintain operations beyond our current cash runway. Based on our currently available cash resources, the $12.5 million Milestone Termination Payment received from SPN in October 2026, and considering our future operating plans, we anticipate that we will require additional funding following the first quarter of 2027. However, due to our smaller business size and the early stage of development of our remaining assets, there can be no assurance that we will be able to raise the required capital on favorable terms, or at all. This potential inability to obtain necessary funding could have a material adverse effect on our growth prospects, financial condition, and results of operations.
Previous wording
The UK regulatory framework in relation to clinical trials is derived from the now-repealed EU Clinical Trials Directive (as implemented into UK law, through the Medicines for Human Use (Clinical Trials) Regulations 2004, as amended). In April 2025, the UK government adopted the Medicines for Human Use (Clinical Trials) Amendment Regulations. The amendment, which will take full effect in April 2026, aims to provide a more flexible regime to make it easier to conduct clinical trials in the UK, increase the transparency of clinical trials conducted in the UK and make clinical trials more patient centered.
Current wording
The UK regulatory framework in relation to clinical trials is derived from the now-repealed EU Clinical Trials Directive (as implemented into UK law, through the Medicines for Human Use (Clinical Trials) Regulations 2004, as amended). In April 2025, the UK government adopted the Medicines for Human Use (Clinical Trials) Amendment Regulations. The amendment, which took full effect in April 2026, aims to provide a more flexible regime to make it easier to conduct clinical trials in the UK, increase the transparency of clinical trials conducted in the UK and make clinical trials more patient centered.
Previous wording
The ability of the FDA and other regulatory authorities to review and approve new products can be affected by a variety of factors, including government budget and funding levels, statutory, regulatory, and policy changes, the FDA’s and other regulatory authorities' ability to hire and retain key personnel and accept the payment of user fees, and other events that may otherwise affect the FDA’s and other regulatory authorities' ability to perform routine functions. Average review times at the FDA have fluctuated in recent years as a result. In addition, government funding of other government agencies that fund research and development activities is subject to the political process, which is inherently fluid and unpredictable. Disruptions at the FDA and other regulatory authorities, such as the EMA, may also slow the time necessary for new drugs and biologics to be reviewed and/or approved by necessary regulatory authorities, which would adversely affect our business. For example, in recent years, the U.S. government has shut down several times and certain regulatory authorities, such as the FDA, have had to furlough critical FDA employees and stop critical activities. In addition, the current U.S. Presidential administration has issued certain policies and Executive Orders directed towards reducing the employee headcount and costs associated with U.S. administrative agencies, including the FDA, and it remains unclear the degree to which these efforts may limit or otherwise adversely affect the FDA's ability to conduct routine activities.
Current wording
The ability of the FDA and other regulatory authorities to review and approve new products can be affected by a variety of factors, including government budget and funding levels, statutory, regulatory, and policy changes, the FDA’s and other regulatory authorities' ability to hire and retain key personnel and accept the payment of user fees, and other events that may otherwise affect the FDA’s and other regulatory authorities' ability to perform routine functions. Average review times at the FDA have fluctuated in recent years as a result. In addition, government funding of other government agencies that fund research and development activities is subject to the political process, which is inherently fluid and unpredictable. Disruptions at the FDA and other regulatory authorities, such as the EMA, may also slow the time necessary for new drugs and biologics to be reviewed and/or approved by necessary regulatory authorities, which would adversely affect our business. For example, in recent years, the U.S. government has shut down several times and certain regulatory authorities, such as the FDA, have had to furlough critical FDA employees and stop critical activities. In addition, the current U.S. Presidential administration has issued certain policies and Executive Orders directed towards reducing the employee headcount and costs associated with U.S. administrative agencies, including the FDA, which have led to substantial changes in senior personnel, and it remains unclear the degree to which these efforts and the resulting personnel changes may limit or otherwise adversely affect the FDA's ability to conduct routine activities.
Previous wording
We believe that any of our product candidates approved as a biological product under a BLA should also qualify for the 12-year period of reference product exclusivity. However, there is a risk that this exclusivity could be shortened due to congressional action or otherwise, or that the FDA will not consider our product candidates to be reference products for competing products, potentially creating the opportunity for generic competition sooner than anticipated.
Current wording
We believe that any of our product candidates approved as a biological product under a BLA should also qualify for the 12-year period of reference product exclusivity. However, there is a risk that this exclusivity could be shortened due to congressional action or otherwise, or that the FDA will not consider our product candidates to be reference products for competing products, potentially creating the opportunity for generic competition sooner than anticipated. Moreover, the extent to which a biosimilar, once approved, could be substituted for any one of our reference products in a way that is similar to traditional generic substitution for non-biological products will depend on a number of specific marketplace and regulatory factors that are still developing. For example, in recent years, the FDA has sought to reduce the data required for biosimilar product sponsors to demonstrate biosimilarity to, or interchangeability with, a biologic reference product, which could increase the potential for biosimilar competition.
Previous wording
Our patent portfolio currently includes 20 active patent application families (which includes an exclusive license to certain IP from Memorial Sloan Kettering Cancer Center). Of these, 16 applications have been nationalized, three are at the PCT stage, and one is at the provisional stage. To date, we have obtained issuance of 33 U.S. patents (which includes three as licensee). Of the issued U.S. patents, 13 U.S. patents (including one as licensee) have been assigned to Nestlé Health Science as part of its purchase of VOWST. We cannot provide any assurances that any of our pending patent applications will mature into issued patents and, if they do, that such patents or our current patents will include claims with a scope sufficient to protect our product candidates or otherwise provide any competitive advantage. For example, we are pursuing claims to therapeutic, binary compositions of certain bacterial populations. Any claims that may issue may provide coverage for such binary compositions and/or their use. However, there can be no assurance that an alternative composition that may fall outside the scope of such claims will not be equally effective. Further, while our product candidates are made up of specific cultivated bacteria, third-party compositions may have greater complexity and variability (e.g., lot to lot variations), and it is possible that a patent claim may provide coverage for some but not all third-party compositions. These and other factors may provide opportunities for our competitors to design around our patents, should they issue.
Current wording
Our patent portfolio currently includes 21 active patent application families (which includes an exclusive license to certain IP from Memorial Sloan Kettering Cancer Center). Of these, 16 applications have been nationalized, three are at the PCT stage, and one is at the provisional stage. To date, we have obtained issuance of 33 U.S. patents (which includes three as licensee). Of the issued U.S. patents, 13 U.S. patents (including one as licensee) have been assigned to Nestlé Health Science as part of its purchase of VOWST. We cannot provide any assurances that any of our pending patent applications will mature into issued patents and, if they do, that such patents or our current patents will include claims with a scope sufficient to protect our product candidates or otherwise provide any competitive advantage. For example, we are pursuing claims to therapeutic, binary compositions of certain bacterial populations. Any claims that may issue may provide coverage for such binary compositions and/or their use. However, there can be no assurance that an alternative composition that may fall outside the scope of such claims will not be equally effective. Further, while our product candidates are made up of specific cultivated bacteria, third-party compositions may have greater complexity and variability (e.g., lot to lot variations), and it is possible that a patent claim may provide coverage for some but not all third-party compositions. These and other factors may provide opportunities for our competitors to design around our patents, should they issue.
Previous wording
On February 27, 2026, the board of directors appointed Richard N. Kender, a current member of the board of directors, to serve as Executive Chair of the Board and as Interim Chief Executive Officer of the Company, Matthew Henn, Ph.D., the Company’s Chief Scientific Officer, to the additional role of President, and Kelly Brady, M.S., the Company’s Senior Vice President, Clinical Development, to the role of Executive Vice President, Chief Operating Officer, each effective March 2, 2026 (the “Effective Date”). As a result of the appointment of Mr. Kender as Interim Chief Executive Officer, Thomas J. DesRosier and Marella Thorell ceased serving as Co-Presidents and Co-Chief Executive Officers of the Company as of the Effective Date. Mr. DesRosier continues to serve as the Company’s Executive Vice President, Chief Legal Officer, and Ms. Thorell continues to serve as the Company’s Executive Vice President, Chief Financial Officer.
Current wording
On February 27, 2026, the board of directors appointed Richard N. Kender, a current member of the board of directors, to serve as Executive Chair of the Board and as Interim Chief Executive Officer of the Company, Matthew Henn, Ph.D., the Company’s Chief Scientific Officer, to the additional role of President, and Kelly Brady, M.S., the Company’s Senior Vice President, Clinical Development, to the role of Executive Vice President, Chief Operating Officer, each effective March 2, 2026. As a result of the appointment of Mr. Kender as Interim Chief Executive Officer, Thomas J. DesRosier and Marella Thorell ceased serving as Co-Presidents and Co-Chief Executive Officers of the Company as of March 2, 2026. Mr. DesRosier continues to serve as the Company’s Executive Vice President and Chief Legal Officer. On October 22, 2026, Ms. Thorell resigned as Executive Vice President and Chief Financial Officer, effective November 15, 2026, and Mr. Kender will serve as our principal financial officer and principal accounting officer on an interim basis.
Previous wording
Our executive officers, directors and stockholders who owned more than 5% of our outstanding common stock and their respective affiliates, in the aggregate, hold shares representing approximately 29% of our outstanding voting stock as of December 31, 2025. As a result, if these stockholders were to choose to act together, they would be able to significantly influence all matters submitted to our stockholders for approval, as well as our management and affairs. For example, these persons, if they choose to act together, would significantly influence the election of directors and approval of any merger, consolidation or sale of all or substantially all of our assets. This concentration of ownership control may:
Current wording
Our executive officers, directors and stockholders who owned more than 5% of our outstanding common stock and their respective affiliates, in the aggregate, hold shares representing approximately 29% of our outstanding voting stock as of December 31, 2025. As a result, if these stockholders were to choose to act together, they would be able to significantly influence all matters submitted to our stockholders for approval, as well as our management and affairs. For example, these persons, if they choose to act together, would significantly influence the approval of any merger, consolidation or sale of all or substantially all of our assets. This concentration of ownership control may:
Previous wording
We are a “smaller reporting company” as defined under the rules promulgated under the Exchange Act. We will remain a smaller reporting company until the fiscal year following the determination that both (i) the value of our voting and non-voting common shares held by non-affiliates is more than $250.0 million measured on the last business day of our second fiscal quarter and (ii) our annual revenues are more than $100.0 million during the most recently completed fiscal year and the value of our voting and non voting common shares held by non-affiliates is $700.0 million or more as measured on the last business day of our second fiscal quarter. Smaller reporting companies are able to provide simplified executive compensation disclosure and have certain other reduced disclosure obligations, including, among other things, being required to provide only two years of audited financial statements and not being required to provide selected financial data, or supplemental financial information.
Current wording
We are a “smaller reporting company” as defined under the rules promulgated under the Exchange Act. We will remain a smaller reporting company until the fiscal year following the determination that both (i) the value of our voting and non-voting common shares held by non-affiliates is more than $250.0 million measured on the last business day of our second fiscal quarter and (ii) our annual revenues are more than $100.0 million during the most recently completed fiscal year and the value of our voting and nonvoting common shares held by non-affiliates is $700.0 million or more as measured on the last business day of our second fiscal quarter. Smaller reporting companies are able to provide simplified executive compensation disclosure and have certain other reduced disclosure obligations, including, among other things, being required to provide only two years of audited financial statements and not being required to provide selected financial data, or supplemental financial information.
Previous wording
Our restated certificate of incorporation specifies that, unless we consent in writing to the selection of an alternative forum, the Court of Chancery of the State of Delaware will be the sole and exclusive forum for most legal actions involving actions brought against us by stockholders. In addition, our bylaws provide that the federal district courts of the United States are the exclusive forum for any complaint raising a cause of action arising under the Securities Act. Any person or entity purchasing or otherwise acquiring any interest in shares of our capital stock shall be deemed to have notice of and to have consented to the provisions of our restated certificate of incorporation and bylaws described above.
Current wording
Our restated certificate of incorporation specifies that, unless we consent in writing to the selection of an alternative forum, the Court of Chancery of the State of Delaware will be the sole and exclusive forum for most legal actions involving actions brought against us by stockholders. In addition, our bylaws provide that the federal district courts of the United States are the exclusive forum for any complaint raising a cause of action arising under the Securities Act. Any person or entity purchasing or otherwise acquiring any interest in shares of our capital stock shall be deemed to have notice of and consented to the provisions of our restated certificate of incorporation and bylaws described above.