Seres Therapeutics, Inc.

Previous wording

In our placebo-controlled Phase 1b study of SER-155 in allo-HSCT, Cohort 2 results demonstrated that SER-155 was associated with a 77% relative risk reduction in bacterial BSIs and a significant reduction in systemic antibiotic exposure as well as a lower incidence of febrile neutropenia, as compared to placebo through day 100 post HSCT. SER-155 was generally well tolerated, with no observed treatment-related serious adverse events. In December 2024, the FDA granted Breakthrough Therapy designation to SER-155 for the reduction of BSIs in patients 18 years and older undergoing allo-HSCT. In January 2025, we reported exploratory translational biomarker data from the SER-155 Phase 1b study which provided evidence supporting the intended therapeutic mechanisms, including promotion of intestinal epithelial barrier integrity to reduce the potential of bacterial translocation into the bloodstream, and reduction of systemic inflammatory responses. In the first quarter of 2025, we received feedback from the FDA regarding the development strategy for SER-155 in patients undergoing allo-HSCT. The FDA provided input on certain elements of the next study, including a recommendation for a Phase 2 study, feedback on the primary endpoint, and confirmation of their expectations for the manufacture and control of SER-155. Based on FDA feedback and strategic considerations, we are designing the next SER-155 allo-HSCT study as a standalone Phase 2 study that provides a time and capital-efficient path to obtaining clinical results and, if successful, supports a subsequent Phase 3 study for product registration. The Phase 2 study is expected to target 248 participants and incorporate an adaptive design and an interim data analysis when approximately half of the enrolled participants have reached the primary endpoint timepoint. We expect to obtain interim clinical results within twelve months following study initiation, which we believe will facilitate timely engagement with the FDA on the design of a Phase 3 study and inform development in adjacent medically vulnerable patient populations. We plan to submit the Phase 2 protocol to the FDA in the coming weeks. We are actively seeking a partner to provide financial resources and other capabilities to support our goal to maximize the SER-155 opportunity.

Current wording

In our placebo-controlled Phase 1b study of SER-155 in allo-HSCT, Cohort 2 results demonstrated that SER-155 was associated with a 77% relative risk reduction in bacterial BSIs and a significant reduction in systemic antibiotic exposure as well as a lower incidence of febrile neutropenia, as compared to placebo through day 100 post HSCT. SER-155 was generally well tolerated, with no observed treatment-related serious adverse events. In December 2024, the FDA granted Breakthrough Therapy designation to SER-155 for the reduction of BSIs in patients 18 years and older undergoing allo-HSCT. In January 2025, we reported exploratory translational biomarker data from the SER-155 Phase 1b study which provided evidence supporting the intended therapeutic mechanisms, including promotion of intestinal epithelial barrier integrity to reduce the potential of bacterial translocation into the bloodstream, and reduction of systemic inflammatory responses.

Previous wording

In the first quarter of 2025, we received feedback from the FDA regarding the development strategy for SER-155 in patients undergoing allo-HSCT. The FDA provided input on certain elements of the next study, including a recommendation for a Phase 2 study, feedback on the primary endpoint, and confirmation of their expectations for the manufacture and control of SER-155. Based on FDA feedback and strategic considerations, we are designing the next SER-155 allo-HSCT study as a standalone Phase 2 study that provides a time and capital-efficient path to obtaining clinical results and, if successful, supports a subsequent Phase 3 study for product registration. The Phase 2 study is expected to target 248 participants and incorporate an adaptive design and an interim data analysis when approximately half of the enrolled participants have reached the primary endpoint timepoint. We expect to obtain interim clinical results within twelve months following study initiation, which we believe will facilitate timely engagement with the FDA on the design of a Phase 3 study and inform development in adjacent medically vulnerable patient populations. We plan to submit the Phase 2 protocol to the FDA in the coming weeks. We are actively seeking a partner to provide financial resources and other capabilities to support our goal to maximize the SER-155 opportunity.

Current wording

Based on prior FDA feedback, we have continued preparations for a SER-155 Phase 2 study in allo-HSCT that could provide a time and capital-efficient path to obtaining clinical results. We require additional capital to begin this study. In May 2025, we filed the SER-155 Phase 2 protocol with the FDA and are awaiting feedback, which is expected to support finalizing the protocol. The SER-155 Phase 2 study is expected to enroll approximately 248 participants and incorporate an adaptive design and an interim data analysis when approximately half of the enrolled participants have reached the primary endpoint. We expect to obtain the interim clinical results within twelve months following study initiation, which we believe will facilitate timely engagement with the FDA on the design of a Phase 3 study and inform development in adjacent medically vulnerable patient populations. We believe that positive results, if achieved, from the Phase 2 study could enable advancement into a single Phase 3 trial to support registration.

Previous wording

Our partnership discussions are focused on supporting SER-155 clinical advancement to reduce the risk of BSIs, including life-threatening and antimicrobial resistant infections, in medically vulnerable patient populations. We believe that SER-155 and other cultivated live biotherapeutic candidates could be developed in additional patient populations beyond allo-HSCT, including autologous-HSCT patients, cancer patients with neutropenia, chimeric antigen receptors therapy recipients, or CAR-T, individuals with chronic liver disease, or CLD, solid organ transplant recipients, as well as patients in the intensive care unit and long-term acute care facilities.

Current wording

Our business development discussions are focused on supporting SER-155 clinical advancement to reduce the risk of BSIs, including life-threatening and antimicrobial resistant infections, in medically vulnerable patient populations. We believe that SER-155 and other cultivated live biotherapeutic candidates could be developed in additional patient populations beyond allo-HSCT, including autologous-HSCT patients, cancer patients with neutropenia, chimeric antigen receptors therapy recipients, or CAR-T, individuals with chronic liver disease, or CLD, solid organ transplant recipients, as well as patients in the intensive care unit and long-term acute care facilities.

Previous wording

Our product candidates are in early-stage clinical or preclinical development. Our ability to achieve profitability will depend heavily on the successful development and eventual commercialization of one or more of our product candidates. Since our inception, we have incurred significant operating losses. Our loss from operations was $27.2 million for the three months ended March 31, 2025. As of March 31, 2025, we had an accumulated deficit of $945.4 million.

Current wording

Our product candidates are in early-stage clinical or preclinical development. Our ability to achieve profitability will depend heavily on the successful development and eventual commercialization of one or more of our product candidates. Since our inception, we have incurred significant operating losses. Our loss from operations was $52.1 million for the six months ended June 30, 2025. As of June 30, 2025, we had an accumulated deficit of $965.3 million.

Previous wording

As of March 31, 2025, we had cash and cash equivalents totaling $58.8 million. Based on our currently available cash resources, including the capital obtained from the Transaction, and the expected receipt of the Second Installment Payment, which is subject to material compliance with the TSA, and considering our future operating plans and our ongoing obligations related to the Transaction, we anticipate that we will require additional funding in the first quarter of 2026. In accordance with applicable accounting standards, we evaluated whether there are conditions and events, considered in the aggregate, that raise substantial doubt about our ability to continue as a going concern within 12 months after the date of the issuance of the condensed consolidated financial statements included elsewhere in this Quarterly Report on Form 10-Q. In performing this analysis, we excluded certain elements of our operating plan that cannot be considered probable of occurring. Under the applicable accounting standards, the receipt of contingent payments from the Transaction and any future equity issuances cannot be considered probable, as these events are outside our control. Accordingly, management has concluded that substantial doubt exists about our ability to continue as a going concern for 12 months from the date the condensed consolidated financial statements included elsewhere in this Quarterly Report on Form 10-Q, are issued. See “Risk Factors— Risks Related to Our Financial Position and Need for Additional Capital —We have identified conditions and events that raise substantial doubt regarding our ability to continue as a going concern.”

Current wording

As of June 30, 2025, we had cash and cash equivalents totaling $45.4 million. Based on our currently available cash resources, including the capital obtained from the Transaction, and considering our future operating plans and our ongoing obligations related to the Transaction, we anticipate that we will require additional funding in the first quarter of 2026. In accordance with applicable accounting standards, we evaluated whether there are conditions and events, considered in the aggregate, that raise substantial doubt about our ability to continue as a going concern within 12 months after the date of the issuance of the condensed consolidated financial statements included elsewhere in this Quarterly Report on Form 10-Q. In performing this analysis, we excluded certain elements of our operating plan that cannot be considered probable of occurring. Under the applicable accounting standards, any future transactions or equity issuances cannot be considered probable, as these events are outside our control. Accordingly, management has concluded that substantial doubt exists about our ability to continue as a going concern for 12 months from the date the condensed consolidated financial statements included elsewhere in this Quarterly Report on Form 10-Q, are issued. See “Risk Factors— Risks

Previous wording

cash installment payments of $50 million, which was received on January 15, 2025, and $25 million due on July 1, 2025, or the Second Installment Payment (to be reduced by approximately $1.5 million related to certain employment obligations assumed by SPN, as described below), conditioned on our material compliance with obligations under the TSA (as defined below), which was entered into at Closing between us and Nestlé Enterprises S.A., an affiliate of SPN, or NESA;

Current wording

cash installment payments of $50 million, which was received on January 15, 2025, and $25 million, which was received on July 1, 2025 (offset by $1.4 million paid by us to Nestlé on July 1, 2025 related to certain employment obligations assumed by SPN, as described below), conditioned on our material compliance with obligations under the TSA (as defined below), which was entered into at Closing between us and Nestlé Enterprises S.A., an affiliate of SPN, or NESA;

Previous wording

See Risk Factors— Risks Related to Our Financial Position and Need for Additional Capital— The total amount of the Second Installment Payment and Milestone Payments we may receive from the Transaction, and the amounts payable or due under the Profit Sharing Payments, are subject to various risks and uncertainties.

Current wording

See Risk Factors— Risks Related to Our Financial Position and Need for Additional Capital— The total amount of the Milestone Payments we may receive from the Transaction, and the amounts payable or due under the Profit Sharing Payments, are subject to various risks and uncertainties.

Previous wording

As they are earned, the Milestone Payments will be satisfied as follows: (1) first, by set-off against all accrued interest on the Prepaid Milestone until the amount of such accrued interest has been paid in full, (2) second, by set-off against the outstanding balance of the Prepaid Milestone until the Prepaid Milestone has been repaid in full and (3) thereafter, in cash. If any amount of the Prepaid Milestone (and any accrued interest thereon) remains outstanding as of following the last day of the Milestone Period (defined below), the balance thereof (together with any interest accrued thereon) will be forgiven and the right of set-off of SPN with respect thereto will be deemed forfeited. The Second Installment Payment due on July 1, 2025 will be reduced by approximately $1.5 million related to certain employment obligations assumed by SPN with respect to the period ending as of the Closing Date.

Current wording

As they are earned, the Milestone Payments will be satisfied as follows: (1) first, by set-off against all accrued interest on the Prepaid Milestone until the amount of such accrued interest has been paid in full, (2) second, by set-off against the outstanding balance of the Prepaid Milestone until the Prepaid Milestone has been repaid in full and (3) thereafter, in cash. If any amount of the Prepaid Milestone (and any accrued interest thereon) remains outstanding as of following the last day of the Milestone Period (defined below), the balance thereof (together with any interest accrued thereon) will be forgiven and the right of set-off of SPN with respect thereto will be deemed forfeited. The installment payment received on July 1, 2025 was offset by $1.4 million we paid to Nestlé on the same date related to certain employment obligations assumed by SPN with respect to the period ending as of the Closing Date.

Previous wording

We estimated the costs associated with these future payments and recorded them within accrued liabilities due to SPN - related party on our condensed consolidated balance sheets as of the Closing. The contingent liabilities are remeasured at each reporting period based on (i) cash payments made by the Company to reduce the accrued liabilities due to SPN - related party and (ii) revised estimates of the total remaining liabilities due to SPN - related party. As of March 31, 2025, the contingent liabilities included $8.0 million associated with the Profit Sharing Payments, $2.8 million associated with the MSK Agreement, $1.1 million associated with our obligation to pay 80.1% of the costs associated with the lease of the Waltham facility through December 31, 2025, $1.5 million associated with certain employment-related costs for conveying employees, and $0.5 million associated with our ongoing post-marketing safety study of VOWST. We recorded a gain of $2.2 million for the three months ended March 31, 2025 primarily as a result of SPN's actual first quarter of 2025 Profit Sharing as compared to the previous estimate.

Current wording

We estimated the costs associated with these future payments and recorded them within accrued liabilities due to SPN - related party on our condensed consolidated balance sheets as of the Closing. The contingent liabilities are remeasured at each reporting period based on (i) cash payments made by the Company to reduce the accrued liabilities due to SPN - related party and (ii) revised estimates of the total remaining liabilities due to SPN - related party. As of June 30, 2025, the contingent liabilities included $8.0 million associated with the Profit Sharing Payments, $2.8 million associated with the MSK Agreement, $0.9 million associated with our obligation to pay 80.1% of the costs associated with the lease of the Waltham facility through December 31, 2025, $1.4 million associated with certain employment-related costs for conveying employees, and $0.4 million associated with our ongoing post-marketing safety study of VOWST. We recorded a gain of $0.2 million for the three months ended June 30, 2025 primarily as a result of actual post-marketing safety study costs that were lower than the previous estimate.

Previous wording

In connection with the Closing, we and SPN entered into a securities purchase agreement, or the Securities Purchase Agreement, pursuant to which SPN purchased 714,285 shares of our common stock, or the Shares, at Closing, at a purchase price per share of $21.00, for an aggregate purchase price of $15 million. Under the terms of the Securities Purchase Agreement, SPN agreed not to sell or transfer the Shares for a period of six months after Closing, subject to certain customary exceptions. We agreed to register the resale of the Shares by SPN within 90 days of Closing. On October 1, 2024, we filed a registration statement to register the Shares, which became effective on October 11, 2024. In addition, under the terms of the Securities Purchase Agreement, for as long as SPN, together with its affiliates, beneficially owns at least 10% of our outstanding shares of common stock, we agreed to take such action within our control to include one individual designated by SPN in the slate of nominees recommended by our board of directors (or the applicable committee of the board of directors) to our stockholders for election to the board of directors at the applicable stockholder meeting. SPN designated Hans-Juergen Woerle, M.D., Ph.D., and on February 4, 2025, our board of directors appointed Dr. Woerle to the board as a Class III director, with a term expiring at our 2027 annual meeting of stockholders. The Securities Purchase Agreement contains customary representations and warranties and closing conditions.

Current wording

In connection with the Closing, we and SPN entered into a securities purchase agreement, or the Securities Purchase Agreement, pursuant to which SPN purchased 714,285 shares of our common stock, or the Shares, at Closing, at a purchase price per share of $21.00, for an aggregate purchase price of $15 million. Under the terms of the Securities Purchase Agreement, SPN agreed not to sell or transfer the Shares for a period of six months after Closing, subject to certain customary exceptions. We agreed to register the resale of the Shares by SPN within 90 days of Closing. On October 1, 2024, we filed a registration statement to register the Shares, which became effective on October 11, 2024. In addition, under the terms of the Securities Purchase Agreement, for as long as SPN, together with its affiliates, beneficially owns at least 10% of our outstanding shares of common stock, we agreed to take such action within our control to include one individual designated by SPN in the slate of nominees recommended by our Board (or the applicable committee of the board of directors) to our stockholders for election to the Board at the applicable stockholder meeting. SPN designated Hans-Juergen Woerle, M.D., Ph.D., and on February 4, 2025, our Board appointed Dr. Woerle to the Board as a Class III director, with a term expiring at our 2027 annual meeting of stockholders. The Securities Purchase Agreement contains customary representations and warranties and closing conditions.

Previous wording

In connection with the Closing, we entered into a Transition Services Agreement, or the TSA, with NESA, which provides for services to be performed by us in order to facilitate a transition of the business associated with the VOWST Business to NESA and its affiliates. The scope of the transition services includes the provision of certain manufacturing services and certain administrative functions related to the VOWST Business and operations, including the maintenance of certain manufacturing services and the related facility in which such services are currently conducted. We will provide the manufacturing services until December 31, 2025, which period may be extended by up to six months (solely to ensure the manufacturing facility is in a state of compliance with the biologics license application for VOWST and readiness for potential regulatory inspection), and other services, for the duration specified in the schedule to the TSA for each service. NESA has agreed to pay us for certain fixed costs, including a monthly fixed fee and a variable per batch fee for preserved raw material suspension manufacturing, or PRMS, and will reimburse us for certain costs of the transition services performed by us under the TSA. The know-how and other intellectual property generated in connection with the performance of the TSA will be owned by NESA with us having a non-exclusive license to such know-how and other intellectual property under the Cross-License Agreement. During the term of the TSA, upon NESA's request, we will transfer the specifications for materials and documentation necessary to enable PRMS manufacturing services to a third party service provider designated by NESA. In the event of a material failure by us to deliver PRMS under the TSA, NESA will have step-in rights to negotiate to enter into a direct lease with the landlord of the manufacturing facility with respect to the portion of such facility used in connection with the VOWST Business or to cause such services to be performed, with any reasonable out-of-pocket costs and expenses incurred in connection therewith reimbursed by us.

Current wording

In connection with the Closing, we entered into a Transition Services Agreement, or the TSA, with NESA, which provides for services to be performed by us in order to facilitate a transition of the business associated with the VOWST Business to NESA and its affiliates. The scope of the transition services includes the provision of certain manufacturing services and certain administrative functions related to the VOWST Business and operations, including the maintenance of certain manufacturing services and the related facility in which such services are currently conducted. NESA has agreed to pay us for certain fixed costs, including a monthly fixed fee and a variable per batch fee for preserved raw material suspension manufacturing, or PRMS, and will reimburse us for certain costs of the transition services performed by us under the TSA, including labor. We will provide the manufacturing services until December 31, 2025 and other services for the duration specified in the schedule to the TSA for each service. Following the completion of PRMS manufacturing in the second quarter of 2025, manufacturing services primarily consist of costs incurred to ensure compliance of the facility and management of in-process inventories and samples. The know-how and other intellectual property generated in connection with the performance of the TSA will be owned by NESA with us having a non-exclusive license to such know-how and other intellectual property under the Cross-License Agreement. During the term of the TSA, upon NESA's request, we will transfer the specifications for materials and documentation necessary to enable PRMS manufacturing services to a third party service provider designated by NESA. In the event of a material failure by us to deliver PRMS under the TSA, NESA will have step-in rights to negotiate to enter into a direct lease with the landlord of the manufacturing facility with respect to the portion of such facility used in connection with the VOWST Business or to cause such services to be performed, with any reasonable out-of-pocket costs and expenses incurred in connection therewith reimbursed by us.

Previous wording

In connection with the Closing, we entered into a cross-license agreement with SPN under which, we granted to SPN a perpetual, worldwide, non-exclusive, fully paid-up license under certain Seres patents that have been issued or will issue in the future and current know-how controlled by us that is not transferred to SPN pursuant to the Purchase Agreement. In the field of the treatment of Clostridioides difficile infections, or CDI, and rCDI and associated complications, or collectively, the CDI Field, the license to SPN under such Seres patents and know-how is exclusive to SPN for five years after the Closing and co-exclusive between SPN and Seres following that five year period. The license from Seres to SPN is to issued Seres patents that currently or in the future cover the Product or improvements thereof and know-how that is used or reasonably useful in connection with the exploitation of the VOWST Business. See “Intellectual Property” below.

Current wording

In connection with the Closing, we entered into a cross-license agreement with SPN under which, we granted to SPN a perpetual, worldwide, non-exclusive, fully paid-up license under certain Seres patents that have been issued or will issue in the future and current know-how controlled by us that is not transferred to SPN pursuant to the Purchase Agreement. In the field of the treatment of Clostridioides difficile infections, or CDI, and rCDI and associated complications, or collectively, the CDI Field, the license to SPN under such Seres patents and know-how is exclusive to SPN for five years after the Closing and co-exclusive between SPN and Seres following that five year period. The license from Seres to SPN is to issued Seres patents that currently or in the future cover the

Previous wording

The incidence of BSIs was significantly lower in the SER-155 arm compared with the placebo arm (2/20 (10%) vs. 6/14 (42.9%), respectively; [Odds Ratio: 0.15; 95% CI: 0.01, 1.13, p=0.0423]), which represents a relative risk reduction of approximately 77% and an absolute risk reduction of approximately 33%. In addition, while antibiotic starts were similar in each arm, patients administered SER-155 were treated with antibiotics for a significantly shorter duration compared to patients in the placebo arm (9.2 days vs. 21.1 days, respectively, with a mean difference of -11.9 days [95% CI: -23.85, -0.04; p=0.0494]). The incidence of febrile neutropenia was lower in patients administered SER-155 compared to placebo (65% vs. 78.6%, respectively; [Odds Ratio: 0.51; 95% CI: 0.07, 2.99; p=0.4674]). Six cases of gastrointestinal infections (C. difficile infections) were observed in the study, with four cases (20%) in the SER-155 arm and two cases (14.3%) in the placebo arm.

Current wording

The incidence of BSIs was significantly lower in the SER-155 arm compared with the placebo arm (2/20 (10%) vs. 6/14 (42.9%), respectively; [Odds Ratio: 0.15; 95% CI: 0.01, 1.13, p=0.0423]), which represents a relative risk reduction of approximately 77% and an absolute risk reduction of approximately 33%, resulting in a number needed to treat (NNT) of 3 for SER-155 to prevent a BSI event. In addition, while antibiotic starts were similar in each arm, patients administered SER-155 were treated with antibiotics for a significantly shorter duration compared to patients in the placebo arm (9.2 days vs. 21.1 days, respectively, with a mean difference of -11.9 days [95% CI: -23.85, -0.04; p=0.0494]). The incidence of febrile neutropenia was lower in patients administered SER-155 compared to placebo (65% vs. 78.6%, respectively; [Odds Ratio: 0.51; 95% CI: 0.07, 2.99; p=0.4674]). Six cases of gastrointestinal infections (C. difficile infections) were observed in the study, with four cases (20%) in the SER-155 arm and two cases (14.3%) in the placebo arm.

Previous wording

(ASTCT) and Center for International Blood and Marrow Transplant Research (CIBMTR). SER-155 Phase 1b clinical study data were also featured in an oral presentation in the Best Abstracts in Infectious Diseases track at the Tandem meeting.

Current wording

In February 2025, clinical and biomarker results from our biotherapeutic programs were presented as a poster at the 2025 Tandem Transplantation & Cellular Therapy Meetings of the American Society for Transplantation and Cellular Therapy (ASTCT) and Center for International Blood and Marrow Transplant Research (CIBMTR). SER-155 Phase 1b clinical study data were also featured in an oral presentation in the Best Abstracts in Infectious Diseases track at the Tandem meeting.

Previous wording

In April 2025, we presented SER-155 Phase 1b clinical and exploratory biomarker results at the 5th annual meeting of the European Society for Blood and Marrow Transplantation, or EBMT. Our presented poster was recognized by the EBMT scientific organizing committee and obtained the “Best Clinical Poster Award.”

Current wording

In April 2025, we presented SER-155 Phase 1b clinical and exploratory biomarker results at the 51st annual meeting of the European Society for Blood and Marrow Transplantation, or EBMT. Our presented poster was recognized by the EBMT scientific organizing committee and obtained the “Best Clinical Poster Award.”

Previous wording

In May 2025, we presented data at the Digestive Disease Week, or DDW conference highlighting preclinical and clinical data that enable identification of patients with a disease etiology linked to the gastrointestinal microbiome, and the identification of microbiome-based biomarkers that are predictive of response and suitable for patient selection and stratification in clinical trials. Our poster, entitled “Candidate Biomarkers of Microbiome Disruption for Patient Selection or Stratification in Clinical Trials of Microbiome Therapies in Ulcerative Colitis” received a Poster of Distinction award in the Microbiome and Microbial Therapies subgroup. We believe that the data generated suggest that live biotherapeutics could provide a novel modality that could benefit patients living with gut-related inflammatory and immune diseases that are not effectively addressed today. Furthermore, research indicates that specific patient subpopulations optimally suited for biotherapeutic-based treatments may be identifiable. We are exploring options, including potential partnerships, to advance the development of our biotherapeutics in inflammatory and immune diseases, including ulcerative colitis and Crohn’s disease.

Current wording

In May 2025, we presented data at the Digestive Disease Week, or DDW conference highlighting preclinical and clinical data that enable identification of patients with a disease etiology linked to the gastrointestinal microbiome, and the identification of microbiome-based biomarkers that are predictive of response and suitable for patient selection and stratification in clinical trials. Our poster, entitled “Candidate Biomarkers of Microbiome Disruption for Patient Selection or Stratification in Clinical Trials of Microbiome Therapies in Ulcerative Colitis” received a Poster of Distinction award in the Microbiome and Microbial Therapies subgroup. We believe that the data generated suggest that live biotherapeutics could provide a novel treatment modality that could benefit patients living with gut-related inflammatory and immune diseases that are not effectively addressed today. Furthermore, research indicates that specific patient subpopulations optimally suited for biotherapeutic-based treatments may be identifiable. We are exploring options, including potential partnerships, to advance the development of our biotherapeutics in inflammatory and immune diseases, including ulcerative colitis and Crohn’s disease.

Previous wording

We have an extensive patent portfolio directed to rationally designed ecologies of spores and microbes. The portfolio includes both company-owned patents and applications, and those that we have rights to as licensee. The patents and applications included in our portfolio cover both composition of matter and methods (e.g., method of treating). Our intellectual property rights related to SER-155 and SER-147 extend through 2043 (not including any potential term extension). We plan on continuing to broaden our patent portfolio. Currently, we have 21 active patent families, which includes 19 nationalized applications, one at the PCT stage, and one at the provisional stage. To date, we have obtained issuance of 32 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.

Current wording

We have an extensive patent portfolio directed to rationally designed ecologies of spores and microbes. The portfolio includes both company-owned patents and applications, and those that we have rights to as licensee. The patents and applications included in our portfolio cover both composition of matter and methods (e.g., method of treating). Our intellectual property rights related to SER-155 and SER-147 extend through at least 2043 (not including any potential term extension). We plan on continuing to broaden our patent portfolio. Currently, we have 23 active patent families, which includes 20 nationalized applications and three at the provisional stage. To date, we have obtained issuance of 32 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.

Previous wording

We will provide the manufacturing services until December 31, 2025, which period may be extended by up to six months. We expect manufacturing services expenses to increase in 2025 as compared to 2024, given the TSA obligations exist for the full year in 2025 as compared to one quarter in 2024.

Current wording

We will provide the manufacturing services until December 31, 2025. We expect manufacturing services expenses to increase in 2025 as compared to 2024, given the TSA obligations exist for the full year in 2025 as compared to one quarter in 2024.

Previous wording

the amount Nestlé agrees to pay for costs associated with preserved raw material suspension ("PRMS") manufacturing; and reimbursement for certain labor and other passthrough costs of the transition services performed by the Company under the TSA; and

Current wording

the amount Nestlé agrees to pay for costs associated with PRMS manufacturing; and reimbursement for certain labor and other passthrough costs of the transition services performed by the Company under the TSA; and

Previous wording

Since our inception in 2010, we have not recorded any U.S. federal or state income tax benefits for the net losses we have incurred in each year or our earned research and development tax credits, due to our uncertainty of realizing a benefit from those items. We did not provide for any income taxes in the three months ended March 31, 2025 or 2024.

Current wording

Since our inception in 2010, we have not recorded any U.S. federal or state income tax benefits for the net losses we have incurred in each year or our earned research and development tax credits, due to our uncertainty of realizing a benefit from those items. We did not provide for any income taxes in the three and six months ended June 30, 2025 or 2024.

Previous wording

Our condensed consolidated financial statements are prepared in accordance with accounting principles generally accepted in the United States. The preparation of these condensed consolidated financial statements requires the application of appropriate technical accounting rules and guidance, as well as the use of estimates. The application of these policies necessarily involves judgments regarding future events. These estimates and judgments, in and of themselves, could materially impact the condensed consolidated financial statements and disclosures based on varying assumptions. The accounting policies discussed in our Annual Report on Form 10-K for the fiscal year ended December 31, 2024, filed with the SEC on March 13, 2025, or the Annual Report, are considered by management to be the most important to an understanding of the consolidated financial statements because of their significance to the portrayal of our financial condition and results of operations. There have been no material changes to that information disclosed in our Annual Report during the three months ended March 31, 2025.

Current wording

Our condensed consolidated financial statements are prepared in accordance with accounting principles generally accepted in the United States. The preparation of these condensed consolidated financial statements requires the application of appropriate technical accounting rules and guidance, as well as the use of estimates. The application of these policies necessarily involves judgments regarding future events. These estimates and judgments, in and of themselves, could materially impact the condensed consolidated financial statements and disclosures based on varying assumptions. The accounting policies discussed in our Annual Report on Form 10-K for the fiscal year ended December 31, 2024, filed with the SEC on March 13, 2025, or the Annual Report, are considered by management to be the most important to an understanding of the consolidated financial statements because of their significance to the portrayal of our financial condition and results of operations. There have been no material changes to that information disclosed in our Annual Report during the three and six months ended June 30, 2025.

Previous wording

a decrease in personnel-related costs of $1.7 million primarily due to a decrease in salaries, bonus, employee benefits expenses, and stock-based compensation expense due to lower headcount;

Current wording

a decrease in personnel-related costs of $0.8 million primarily due to a decrease in salaries, bonus, employee benefits expenses, and stock-based compensation expense due to lower headcount;

Previous wording

a decrease of $1.8 million in expenses related to our SER-155 program due to lower clinical trial costs as the Phase 1b study has largely been completed.

Current wording

a decrease of $1.2 million in expenses related to our SER-155 program due to lower clinical trial costs as the Phase 1b study has largely been completed.

Previous wording

General and administrative expenses were $11.9 million for three months ended March 31, 2025 compared to $14.9 million for the three months ended March 31, 2024. The decrease of $3.1 million was primarily due to the following:

Current wording

General and administrative expenses were $10.3 million for the three months ended June 30, 2025 compared to $13.1 million for the three months ended June 30, 2024. The decrease of $2.8 million was primarily due to the following:

Previous wording

a decrease in personnel-related costs of $2.5 million primarily due to a decrease in salaries, bonus, employee benefits expenses, and stock-based compensation expenses due to the decrease in headcount period over period; and

Current wording

a decrease in personnel-related costs of $2.0 million primarily due to a decrease in salaries, bonus, employee benefits expenses, and stock-based compensation expenses due to the decrease in headcount period over period; and

Previous wording

Beginning with the effectiveness of the TSA with Nestlé in the fourth quarter of 2024, manufacturing services resulted in $3.5 million of expenses for the three months ended March 31, 2025. The expenses are associated with the PRMS manufacturing performed on behalf of Nestlé, including labor, materials, allocated facility-related, lab supplies and other manufacturing costs that would have been capitalized into inventory prior to the sale of VOWST Business.

Current wording

Manufacturing services costs began with the effectiveness of the TSA with Nestlé in the fourth quarter of 2024 and resulted in $1.7 million of expenses for the three months ended June 30, 2025. The expenses are associated with the PRMS manufacturing performed on behalf of Nestlé, including labor, materials, allocated facility-related, lab supplies and other manufacturing costs that would have been capitalized into inventory prior to the sale of VOWST Business.

Previous wording

a decrease of $4.0 million in expenses related to our live biotherapeutics platform and research and development operations due to a decrease of $3.4 million of facilities and depreciation expense primarily related to the impairment charge that we recorded in the first quarter of 2024, as well as decreases of $0.3 million of lab assays and $0.3 million of clinical storage costs, and

Current wording

a decrease of $4.9 million in expenses related to our live biotherapeutics platform and research and development operations due to a decrease of $3.9 million of facilities and depreciation expense primarily related to the impairment charge that we recorded in the first quarter of 2024, as well as decreases of $0.5 million of employee-related costs, $0.3 million of clinical storage costs, and $0.2 million of lab assays, and

Previous wording

a decrease in facility-related and other costs of $1.1 million primarily related to headcount-based information technology costs that were reduced following the decrease in headcount, as well as impairment charges recorded in the first quarter of 2024 related to our idled donor collection facility in Cambridge, Massachusetts.

Current wording

a decrease in facility-related and other costs of $2.0 million primarily related to headcount-based information technology costs that were reduced following the decrease in headcount, as well as impairment charges recorded in the first quarter of 2024 related to our idled donor collection facility in Cambridge, Massachusetts.

Previous wording

The decrease of $3.6 million was partially offset by an increase in professional fees of $0.6 million due to an increase in consulting fees, which were primarily related to information technology consultants engaged to assist with the TSA, which costs are reimbursable by Nestlé.

Current wording

These decreases were partially offset by an increase in professional fees of $0.6 million due to an increase in consulting fees, which were primarily related to information technology consultants engaged to assist with the TSA, which costs are reimbursable by Nestlé.

Previous wording

Other income, net was $59.9 million and $1.5 million for the three months ended March 31, 2025 and 2024. The increase in other income, net was primarily due to the $50.0 million installment payment received from Nestlé in January 2025 that was conditioned on the Company’s material compliance with obligations under the TSA, as well as $6.3 million of reimbursement income associated with the performance of TSA services. The increases were partially offset by a decrease in interest income of $1.0 million due to our lower cash balance.

Current wording

Other income, net was $64.9 million and $4.2 million for the six months ended June 30, 2025 and 2024, respectively. The $60.7 million increase in other income, net was primarily due to the $50.0 million installment payment received from Nestlé in January 2025 that was conditioned on the Company’s material compliance with obligations under the TSA, $9.8 million of reimbursement income from Nestlé associated with the performance of TSA services, as well as a $2.4 million gain as a result of a change in estimate of the accrued liabilities due to SPN - related party. The increases were partially offset by a decrease in interest income of $1.7 million due to our lower cash balance.

Previous wording

cash installment payments of $50 million, which was received on January 15, 2025, and $25 million due on July 1, 2025, or the Second Installment Payment (to be reduced by approximately $1.5 million related to certain employment obligations assumed by SPN, as described below), conditioned on our material compliance with obligations under the TSA entered into at Closing between us and NESA;

Current wording

cash installment payments of $50 million, which was received on January 15, 2025, and $25 million, which was received on July 1, 2025 (offset by $1.4 million paid by us to Nestlé on July 1, 2025 related to certain employment obligations assumed by SPN, as described below), conditioned on our material compliance with obligations under the TSA entered into at Closing between us and NESA;

Previous wording

As they are earned, the Milestone Payments will be satisfied as follows: (i) first, by set-off against all accrued interest on the Prepaid Milestone until the amount of such accrued interest has been paid in full, (ii) second, by set-off against the outstanding balance of the Prepaid Milestone until the Prepaid Milestone has been repaid in full and (iii) thereafter, in cash. If any amount of the Prepaid Milestone (and any accrued interest thereon) remains outstanding as of following the last day of the Milestone Period (defined below), the balance thereof (together with any interest accrued thereon) will be forgiven and the right of set-off of SPN with respect thereto will be deemed forfeited. The Second Installment Payment due on July 1, 2025 will be reduced by approximately $1.5 million related to certain employment obligations assumed by SPN through the period prior to the Closing Date.

Current wording

As they are earned, the Milestone Payments will be satisfied as follows: (i) first, by set-off against all accrued interest on the Prepaid Milestone until the amount of such accrued interest has been paid in full, (ii) second, by set-off against the outstanding balance of the Prepaid Milestone until the Prepaid Milestone has been repaid in full and (iii) thereafter, in cash. If any amount of the Prepaid Milestone (and any accrued interest thereon) remains outstanding as of following the last day of the Milestone Period (defined below), the balance thereof (together with any interest accrued thereon) will be forgiven and the right of set-off of SPN with respect thereto will be deemed forfeited. The installment payment received on July 1, 2025 was offset by $1.4 million that we paid to Nestlé on the same date related to certain employment obligations assumed by SPN through the period prior to the Closing Date.

Previous wording

As of March 31, 2025, we had cash and cash equivalents totaling $58.8 million and an accumulated deficit of $945.4 million. For the three months ended March 31, 2025, we incurred a loss from continuing operations of $27.2 million. We expect that our operating losses and negative cash flows will continue for the foreseeable future.

Current wording

As of June 30, 2025, we had cash and cash equivalents totaling $45.4 million and an accumulated deficit of $965.3 million. For the six months ended June 30, 2025, we incurred a loss from continuing operations of $52.1 million. We expect that our operating losses and negative cash flows will continue for the foreseeable future.

Previous wording

Under applicable accounting standards, we have the responsibility to evaluate whether conditions or events raise substantial doubt about our ability to meet our future financial obligations as they become due within 12 months after the date the consolidated financial statements are issued. The ability to obtain the Second Installment Payment and sufficient additional equity, collaborations or other financing with terms favorable or acceptable to us cannot be considered probable, as these events are outside of our control. Based on our currently available cash resources, including the capital obtained from the Transaction, and the expected receipt of the Second Installment Payment, which is subject to material compliance with the TSA, and considering our future operating plans and our ongoing obligations related to the Transaction, we anticipate that we will require additional funding in the first quarter of 2026. Accordingly, management has concluded that these circumstances raise substantial doubt about our ability to continue as a going concern. 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. If potential collaborators 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. We will need to generate significant revenues to achieve profitability, and we may never do so. Because of the numerous risks and uncertainties associated with the development of our current and any future product candidates, the development of our platform and technology and because the extent to which we may enter into collaborations with third parties for development of any of our product candidates is unknown, we are unable to estimate the amounts of increased capital outlays and operating expenses required for completing the research and development of our product candidates.

Current wording

Under applicable accounting standards, we have the responsibility to evaluate whether conditions or events raise substantial doubt about our ability to meet our future financial obligations as they become due within 12 months after the date the consolidated financial statements are issued. The ability to obtain sufficient proceeds from additional equity offerings, collaborations or other financing with terms favorable or acceptable to us cannot be considered probable, as these events are outside of our control. Based on our currently available cash resources, including the capital obtained from the Transaction, and considering our future operating plans and our ongoing obligations related to the Transaction, we anticipate that we will require additional funding in the first quarter of 2026. Accordingly, management has concluded that these circumstances raise substantial doubt about our ability to continue as a going concern. 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. If potential collaborators 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. We will need to generate significant revenues to achieve profitability, and we may never do so. Because of the numerous risks and uncertainties associated with the development of our current and any future product candidates, the development of our platform and technology and because the extent to which we may enter into collaborations with third parties for development of any of our product candidates is unknown, we are unable to estimate the amounts of increased capital outlays and operating expenses required for completing the research and development of our product candidates.

Previous wording

During the three months ended March 31, 2025, cash provided by operating activities was $26.9 million due to net income of $32.7 million and non-cash charges of $5.9 million, partially offset by changes in our operating assets and liabilities of $11.0 million. Non-cash charges consisted of stock-based compensation expense of $2.8 million, $2.0 million related to the amortization of right-of-use assets, and $1.1 million of depreciation and amortization. Changes in our operating assets and liabilities during the three months ended March 31, 2025 consisted of an increase in accounts receivable due from SPN of $0.7 million, a decrease in accrued liabilities due to SPN of $3.9 million, a decrease in operating lease liabilities of $2.1 million, a decrease in accrued expenses and other current and long-term liabilities of $4.4 million, and a decrease increase in accounts payable of $2.0 million, partially offset by a decrease in prepaid expenses and other current and other non-current assets of $1.3 million.

Current wording

During the six months ended June 30, 2025, cash provided by operating activities was $13.6 million due to net income of $12.8 million and non-cash charges of $11.4 million, partially offset by changes in our operating assets and liabilities of $10.6 million. Non-cash charges consisted of stock-based compensation expense of $5.2 million, $4.1 million related to the amortization of right-of-use assets, and $2.1 million of depreciation and amortization. Changes in our operating assets and liabilities during the six months ended June 30, 2025 consisted of a decrease in accrued liabilities due to SPN of $4.3 million, a decrease in operating lease liabilities of $4.2 million, a decrease in accrued expenses and other current and long-term liabilities of $4.8 million, and a decrease in accounts payable of $1.9 million, partially offset by a decrease in prepaid expenses and other current and other non-current assets of $3.4 million and a decrease in accounts receivable due from SPN of $1.2 million.

Previous wording

During the three months ended March 31, 2024, operating activities used $35.2 million of cash, primarily due to a net loss of $40.1 million and changes in our operating assets and liabilities of $9.2 million, partially offset by non-cash charges of $14.1 million. Non-cash charges consisted of stock-based compensation expense of $6.5 million, $2.4 million related to the amortization of right-of-use assets, $1.6 million of depreciation and amortization, $0.5 million of amortization of debt issuance costs, $0.3 million loss on disposal of fixed assets, and $3.3 million of impairment charges related to our long-lived assets. These were partially offset by a $0.4 million increase in the fair value of warrants. Changes in our operating assets and liabilities during the three months ended March 31, 2024 consisted of a decrease in accrued expenses and other current and long-term liabilities of $4.2 million, a decrease in operating lease liabilities of $0.2 million, and an increase in inventories of $12.3 million related to the capitalization of VOWST manufacturing costs during the period, partially offset by a decrease in prepaid expenses and other current and other non-current assets of $4.4 million, a decrease in collaboration receivable - related party of $1.3 million, an increase in deferred income - related party of $0.4 million, and an increase in accounts payable of $1.6 million.

Current wording

During the six months ended June 30, 2024, operating activities used $75.0 million of cash, primarily due to a net loss of $73.0 million and changes in our operating assets and liabilities of $25.8 million, partially offset by non-cash charges of $23.7 million. Non-cash charges consisted of stock-based compensation expense of $12.0 million, $4.8 million related to the amortization of right-of-use assets, $3.0 million of depreciation and amortization, $1.0 million of amortization of debt issuance costs, $0.3 million loss on disposal of fixed assets, and $3.3 million of impairment charges related to our long-lived assets. These were partially offset by a $0.5 million decrease in the fair value of warrants. Changes in our operating assets and liabilities during the six months ended June 30, 2024 consisted of a decrease in operating lease liabilities of $2.3 million, an increase in inventories of $23.4 million related to the capitalization of VOWST manufacturing costs during the period, and an increase in collaboration receivable - related party of $9.9 million, partially offset by an increase in accrued expenses and other current and long-term liabilities of $5.8 million, a decrease in prepaid expenses and other current and other noncurrent assets of $2.5 million, an increase in deferred income - related party of $0.2 million, and an increase in accounts payable of $1.2 million.

Previous wording

During the three months ended March 31, 2025, net cash used in investing activities was $0.1 million, consisting entirely of purchases of property and equipment.

Current wording

During the six months ended June 30, 2025, net cash used in investing activities was $0.2 million, consisting entirely of purchases of property and equipment.

Previous wording

During the three months ended March 31, 2025, net cash provided by financing activities was $1.2 million, consisting of $1.0 million from the issuance of common stock under our at the market equity program, net of issuance costs and $0.2 million from the issuance of common stock under our 2015 Employee Stock Purchase Plan, or ESPP.

Current wording

During the six months ended June 30, 2025, net cash provided by financing activities was $1.2 million, consisting of $1.0 million from the issuance of common stock under our at the market equity program, net of issuance costs and $0.2 million from the issuance of common stock under our 2015 Employee Stock Purchase Plan, or ESPP.

Previous wording

During the three months ended March 31, 2024, net cash provided by financing activities was $18.8 million, consisting of $18.4 million from the issuance of common stock under our at the market equity program, net of issuance costs and $0.4 million in connection with the issuance of common stock under our 2015 Employee Stock Purchase Plan, or ESPP.

Current wording

During the six months ended June 30, 2024, net cash provided by financing activities was $18.8 million, consisting of $18.4 million from the issuance of common stock under our at the market equity program, net of issuance costs and $0.4 million in connection with the issuance of common stock under our ESPP.

Previous wording

the total amount of the Second Installment Payment and Milestone Payments we may receive from the Transaction, and the amounts payable or due under the Profit Sharing Payments;

Current wording

the total amount of the Milestone Payments we may receive from the Transaction, and the amounts payable or due under the Profit Sharing Payments;