At Jun 30, 2026. Does not include the $12.5M received from Nestlé on Jul 1, 2026.
10-Q, acc. 0001193125-26-334174
Clinical-stage · live biotherapeutics
Live biotherapeutics for medically vulnerable patients.
Seres develops treatments “to prevent bacterial bloodstream and antimicrobial resistant (‘AMR’) infections as well as to treat GI-related immune diseases,” in its own words. It sold VOWST, the first orally administered microbiome therapeutic it brought to FDA approval, to Nestlé Health Science in 2024. Its latest filings disclose substantial doubt about its ability to continue as a going concern.
- Cash, Jun 30, 2026$15.6M
- Runway, per the companyThrough Q1 2027
- Going concernDoubt disclosed
Snapshot
The record, in filed numbers
Every figure here is taken from a Seres SEC filing and cites its accession number. Periods are labelled by the date they end.
Six months ended Jun 30, 2026, against ($52.1M) a year earlier. Net result was a loss of ($15.3M) after a $25.0M gain on the VOWST sale.
10-Q, acc. 0001193125-26-334174The company expects to fund operations through then, including the two $12.5M Nestlé payments. It says this excludes any future partnership or other capital.
8-K, acc. 0001193125-26-333820As of Aug 3, 2026. A 1-for-20 reverse split took effect on Apr 21, 2025.
10-Q, acc. 0001193125-26-334174Company
What Seres is building
Seres describes itself as a clinical-stage biotechnology company developing live biotherapeutic products (LBPs) for unmet needs in oncology that can interrupt patients’ cancer care or lead to mortality, and for inflammatory and immune diseases.
It says its candidates work by modulating host function at the mucosal epithelial barrier–immune interface in the gastrointestinal tract. The company led the development and FDA approval of VOWST, then sold that business to Nestlé Health Science. Its corporate site identifies Seres as a Flagship Pioneering company.
Source: company press release, Aug 5, 2026 (8-K) and Form 10-K for the year ended Dec 31, 2025 (filing index).
Protect the barrier
Protect and improve the integrity of the mucosal epithelial barrier.
Induce tolerance
Induce immune homeostasis and tolerance.
Prevent overgrowth
Prevent colonization and overgrowth of pathogens in the GI tract.
The three steps use the company’s own verbs from its Aug 5, 2026 release. Mechanism descriptions are the company’s, not findings of this page.
Pipeline
Where each program stands
Status is as stated in the company’s filings. Early-phase and investigator-sponsored results may not predict later-stage outcomes.
SER-155Bloodstream infections in allogeneic stem cell transplant
PreclinicalIND-enablingPhase 1bPhase 2
- Fast Track designation (Dec 2023) and Breakthrough Therapy designation (Dec 2024).
- In a placebo-controlled Phase 1b, SER-155 was associated with a 77% relative risk reduction in bacterial bloodstream infections through day 100, per the company.
- Phase 2-ready, pending funding. The 10-K says the company paused additional investment in this program after filing the final protocol with the FDA in Jan 2026.
SER-155Immune checkpoint inhibitor-related enterocolitis (irEC)
PreclinicalIND-enablingIST top-linePhase 2
- Top-line results from an investigator-sponsored study (IST) of 15 participants, reported Jul 8, 2026. See the data below.
- The company is evaluating the design of a Phase 2 study. The 10-Q says additional funding is needed to conduct one.
SER-603Inflammatory bowel disease
PreclinicalIND-enablingClinicalPhase 2
- The company says it is advancing IND-enabling studies.
SER-147Preclinical program
PreclinicalIND-enablingClinicalPhase 2
- Per the 10-K, ready to progress to IND-enabling activities, including manufacturing.
Sources: 10-K for the year ended Dec 31, 2025 and the Aug 5, 2026 results release. “IST” means investigator-sponsored study. A filled segment is the furthest stage the filings describe, with earlier stages implied rather than separately reported; an outlined segment has not started.
Clinical data · Jul 8, 2026
SER-155 in irEC: top-line results from 15 participants
An investigator-sponsored study at Memorial Sloan Kettering (NCT06801067) gave SER-155 to 15 people with moderate-to-severe (Grade 2–3) irEC. The primary endpoint was a clinical response at Day 15 without immunosuppressive therapy.
Each mark is one participant. Filled marks are the count reported.
Immunosuppressive-free clinical response, Day 15Primary endpoint. At least a 1-grade improvement in diarrhea. 8 of the 12 reached a 2-grade improvement or more.
Complete clinical remission, Day 15Diarrhea resolved to Grade 0 without immunosuppressive therapy.
Immunosuppressive-free response kept, Day 43The other 7 Day-15 responders were treated with non-systemic, GI-targeted immunosuppressives after Day 15.
Complete remission kept, Day 43Immunosuppressive-free.
Rows count participants against the same 15 and are not tracked person by person: the filing does not say which participants appear in more than one row.
Safety
Generally well tolerated through Day 43 with no safety concerns identified. No serious adverse events were assessed as related to SER-155, and no bloodstream infections were reported through Day 43.
Why it matters to the company
Moderate-to-severe irEC affects approximately 25% of people in the US who receive immune checkpoint inhibitor therapy, and the company says clinical guidelines call for halting that therapy and starting systemic corticosteroids. It says these results support continued development.
What it is not
A 15-participant, investigator-sponsored, top-line readout. It is not a Phase 2 result, and the 10-Q says additional funding is needed to run one.
Source: Form 8-K dated Jul 8, 2026, acc. 0001193125-26-298005.
VOWST divestiture
Two future milestones exchanged for $25.0 million now
Seres sold its VOWST business to Nestlé Health Science in September 2024. On Jun 2, 2026 the two companies amended the purchase agreement.
What was given up
Nestlé’s obligation to pay two one-time contingent milestones was terminated:
- $125.0M if annual worldwide VOWST net sales first reached $400.0M
- $150.0M if annual worldwide VOWST net sales first reached $750.0M
The milestone interest payments that Seres would have owed Nestlé were also eliminated.
What Seres receives
A one-time $25.0M Milestone Termination Payment, in two parts. Seres recognized a $25.0M gain on the sale of the VOWST business in the second quarter of 2026.
- Jul 1, 2026$12.5MReceived
- Oct 1, 2026$12.5MExpected
Sources: Form 8-K dated Jun 5, 2026, acc. 0001193125-26-258366; results release of Aug 5, 2026, acc. 0001193125-26-333820.
Financials
Cash, runway and results, as reported
The 2025 net income is not an operating profit. It comes from $99.7M of other income, including an $80.7M gain on the VOWST sale, against a $94.0M loss from operations.
Bars start at zero and are drawn to scale. Sources: 10-K for FY2024 (Dec 2023 balance), 10-K for FY2025 (Dec 2024 and 2025), 10-Q (Jun 2026).
$15.6MCash, Jun 30, 2026
$12.5MReceived Jul 1, 2026
$12.5MExpected Oct 1, 2026
Company guidance The company expects to fund operations through the first quarter of 2027, considering its operating plans and cash resources including both payments. It says this excludes proceeds from any potential future partnerships or other sources of capital. The 10-Q adds that the company anticipates needing additional funding following the first quarter of 2027.
Lengths are to scale. The stacked bar is this page’s arithmetic, not a total the company reports. Source: results release, Aug 5, 2026 (8-K).
| Line | FY2025 | FY2024 |
|---|---|---|
| Grant revenue (CARB-X reimbursable costs) | 0.8 | nil |
| Research and development | 49.1 | 64.6 |
| General and administrative | 39.2 | 53.2 |
| Manufacturing services | 6.5 | 3.5 |
| Total operating expenses | 94.8 | 121.3 |
| Loss from operations | (94.0) | (121.3) |
| Gain on sale of VOWST business | 80.7 | 5.7 |
| Interest income | 2.2 | 4.0 |
| Other income (expense), net | 16.8 | (14.1) |
| Total other income (expense), net | 99.7 | (4.5) |
| Net income (loss) from continuing operations | 5.7 | (125.8) |
| Line | 2026 | 2025 |
|---|---|---|
| Grant revenue | 1.1 | nil |
| Research and development | 22.3 | 24.8 |
| General and administrative | 15.1 | 22.1 |
| Impairment of long-lived assets | 5.8 | nil |
| Manufacturing services | nil | 5.2 |
| Total operating expenses | 43.3 | 52.1 |
| Loss from operations | (42.2) | (52.1) |
| Gain on sale of VOWST business | 25.0 | 52.4 |
| Interest income | 0.5 | 1.2 |
| Other income (expense), net | 1.3 | 11.4 |
| Total other income (expense), net | 26.8 | 64.9 |
| Net income (loss) | (15.3) | 12.8 |
Sources: 10-K acc. 0001193125-26-103276; 10-Q acc. 0001193125-26-334174. Figures are rounded to $0.1M, so columns may not sum exactly. FY2024 net income including discontinued operations was $0.1M. Only FY2025 and FY2024 revenue is shown: the 10-K reports the sold VOWST business as discontinued operations, so earlier years are recast, and SEC revenue tags change basis across them.
Material disclosure
Going concern, funding and listing status
These are the company’s own filed words. They are stated here at the same weight as the clinical data.
“These conditions raise substantial doubt about the Company’s ability to continue as a going concern.”
Notes to the condensed financial statements, Form 10-Q for the quarter ended Jun 30, 2026
“If we are unable to raise capital or secure a partnership or other business development transaction, we could be required to implement further cost-reduction measures, reduce or delay our product development programs … or pursue other alternatives, which could include seeking relief under the U.S. Bankruptcy Code or winding down our operations.”
Risk factors, Form 10-K for the year ended Dec 31, 2025
What the company says it will do
Management plans to provide for capital needs through financing or other strategic transactions, including potential business development transactions, and by selling shares under its at-the-market equity offering. The filing adds that there is no assurance it can access additional capital.
Nasdaq listing
Nasdaq notified Seres in Nov 2024 that its bid price had closed below the $1.00 minimum. The company effected a 1-for-20 reverse stock split on Apr 21, 2025 and regained compliance. The 10-Q warns that a new period below $1.00 for 30 consecutive business days would bring another non-compliance notice and delisting risk.
Costs already cut
Announced Sep 23, 2025: a workforce reduction of approximately 25%, including reductions effective in Aug 2025. Announced Feb 12, 2026: a further reduction of approximately 30%. Q2 2026: early termination of part of the leased space at 101 Cambridgepark Drive, with a $5.8M impairment charge. Jul 31, 2026: an agreement on 200 Sidney Street under which 21,295 of 68,636 rentable square feet were surrendered effective Aug 1, 2026 and the lease on the remaining space now ends Dec 31, 2026 instead of Jan 13, 2031.
Leadership
Effective Mar 2, 2026, director Richard N. Kender became Executive Chair and Interim Chief Executive Officer. The two Co-Presidents and Co-CEOs stepped out of those roles; one continues as Chief Legal Officer and the other as Chief Financial Officer.
Sources: 10-Q acc. 0001193125-26-334174; 10-K acc. 0001193125-26-103276; 8-Ks acc. 0001193125-25-230118, 0001193125-26-085368, 0001193125-26-258366, 0001193125-26-332742.
Filings
Recent filings, newest first
Each entry links to its SEC EDGAR filing index. Labels describe the filing’s items; they are not company headlines.
2026
- Quarterly report, three and six months ended Jun 30, 202610-Q
- Second-quarter results and cash runway8-K
- Early termination of part of the 200 Sidney Street lease8-K
- SER-155 irEC top-line results and corporate presentation8-K
- Reconvened annual meeting results and incentive plan amendment8-K
- Amendment to the Nestlé asset purchase agreement8-K
- First-quarter results8-K
- Annual report for the year ended Dec 31, 202510-K
- Executive Chair, Interim CEO and officer appointments8-K
2025
Investor relations
Official sources and contact
This page is a concept and does not collect email or run alerts. Company news, the official alert service and IR contacts are on Seres’s own investor site.
Headquarters
101 Cambridgepark DriveCambridge, MA 02140
(617) 945-9626