Tremelimumab

Prevention approach aims to keep patients on immune checkpoint inhibitor (ICI) therapy and avoid immunosuppressive irEC treatments, representing an additional broad therapeutic opportunity for SER-155 Seres expects to submit plans for the next irEC study design to the FDA in Q1 2027 Study builds on encouraging investigator-sponsored trial (IST) results, in which 12 of 15 participants (80%) with moderate-to-severe irEC achieved an immunosuppressive-free clinical response of diarrhea following treatment with SER-155 CAMBRIDGE, Mass., Nov. 04, 2026 (GLOBE NEWSWIRE) -- Seres Therapeutics, Inc. (Nasdaq: MCRB), (Seres or the Company), a leading live biotherapeutics company, today reported third quarter 2026 financial results and announced it is progressing plans for a next study evaluating SER-155 for the prevention of immune checkpoint inhibitor-related enterocolitis (irEC) in patients initiating immune checkpoint inhibitor (ICI) cancer therapy, which is expected to include a dose optimization component. The Company anticipates submitting the study design to the FDA in the first quarter of 2027. The planned study builds on previously announced positive topline results from an investigator-sponsored trial (IST) conducted at Memorial Sloan Kettering Cancer Center (MSK) in patients with moderate-to-severe irEC, in which 80% of participants achieved an immunosuppressive-free clinical response at Day 15, following treatment with SER-155. SER-155 was well tolerated, with no drug-related serious adverse events observed. irEC is a frequent and debilitating adverse reaction associated with widely used ICI cancer therapy that often requires patients to halt life-saving ICI treatment and begin systemic immunosuppressive corticosteroids. irEC is listed as an adverse reaction in the labels of all approved ICIs, including PD-1 inhibitors (Keytruda ® , Opdivo ® , Zynyz ® ), PD-L1 inhibitors (Imfinzi ® , Bavencio ® ), CTLA-4 inhibitors (Yervoy ® , Imjudo ® ), and LAG-3 inhibitor (Opdualag) - all of which were therapies received by patients in the IST. "The irEC IST provided promising evidence that orally administered SER-155 improved epithelial barrier integrity and reduced gastrointestinal inflammation without systemic immunosuppression and was well-tolerated in patients with ICI-induced enterocolitis, " said Richard Kender, Executive Chairman and Interim Chief Executive Officer of Seres. "Based on those results, and in consultation with key opinion leaders in the field, we determined that developing SER-155 to prevent irEC could address a significant unmet clinical need in patients being treated with ICIs for their cancer. We believe SER-155 may enable ICI patients, of whom there are currently estimated to be approximately 300,000 in the U.S. alone, to remain on their therapy by reducing the occurrence of irEC, which often requires the halting of life-saving cancer treatment. We also think this development approach offers a time and capital efficient path to clinical data and positions SER-155 to potentially address a broad ICI-treated population and look forward to submitting our planned study design to the FDA in the first quarter of 2027. We are pleased to have two oncology-focused programs for SER-155, one with the goal of preventing irEC, and the other, in allogeneic hematopoietic stem cell transplant (allo-HCT), aimed at reducing the risk of bloodstream infections, a leading cause of mortality in these patients. We continue to seek capital through partnerships and other sources to advance our programs in irEC and in allo-HCT, which is Phase 2 ready, pending funding." Recent Highlights SER-155 for the prevention of irEC Seres intends to advance SER-155 into a next study evaluating prophylactic oral administration in patients initiating ICI therapy, with a dose optimization component, dependent on funding. The study is being designed in consultation with leading oncologists and irEC experts. As part of the development program, Seres plans to engage with the FDA to discuss study design and potential endpoints, which could include incidence of irEC (all grades), ICI administration, and safety. In addition, Seres looks forward to receiving FDA feedback on plans to optimize prophylactic dosing for the study, which could include a healthy volunteer study component or a dosing lead-in element, the results of which are expected to inform the prophylactic dosing course, before initiating dosing in the broader ICI population. As in the completed IST, the Company anticipates enrolling patients across a wide range of ICI types. The prevention approach is designed to reduce incidence of irEC, keep patients on ICI therapy and avoid immunosuppressive irEC treatments. irEC is among the most frequent and severe immune-related adverse reactions in patients receiving ICIs, and affects up to 50% of ICI recipients, with rates varying by ICI type and regimen. Current standard of care for moderate or worse irEC (Grade 2 or above) requires halting life-saving ICI therapy and initiating a systemic immunosuppressive corticosteroid, a biologic, or both, which carry their own toxicities and may compromise the anti-cancer effect of ICI therapy. The planned next study builds on encouraging topline results from the open-label IST (NCT06801067) conducted at MSK evaluating SER-155 as a potential treatment in irEC, which Seres reported in July. The study enrolled 15 participants with moderate-to-severe (Grade 2-3) irEC (which represents approximately 25% of all ICI recipients) who were naïve to immunosuppressive therapy; 12 of 15 (80%) of participants treated with SER-155 achieved an immunosuppressive-free clinical response at Day 15, the primary efficacy endpoint, defined as at least a one-grade improvement in diarrhea symptoms without immunosuppressive therapy. Five of 15 participants (33%) achieved immunosuppressive-free complete clinical remission at Day 15. SER-155 was generally well tolerated through Day 43, with no serious adverse events assessed as related to SER-155. In the IST, translational biomarkers of gastrointestinal inflammation and mucosal epithelial barrier integrity both improved following SER-155 treatment, with statistically significant reductions by Day 43. ICIs represent one of the largest and fastest-growing segments of the oncology market, with the worldwide market valued at well over $50 billion in 2025. In the U.S. alone, it is estimated that 300,000 patients are currently on ICIs, representing a large potential target patient population for SER-155 as a preventative treatment for irEC, and a potential multi-billion-dollar commercial opportunity, as the Company believes that both patients and clinicians will be motivated to adopt a prophylactic approach that could permit patients to remain on their ICI therapy. Seres expects to submit the proposed next study design to the FDA in the first quarter of 2027 and engage with the agency thereafter. Seres and MSK will present a poster entitled “High Immunosuppressive-Free Response Rate of irEC with SER-155, an Investigational Oral Live Biotherapeutic, as First-Line Therapy, in a Phase 1b Study” at the Society for Immunotherapy of Cancer (SITC) 2026 Annual Meeting in Phoenix, AZ on November 7, 2026. This poster will highlight the promising results of the IST. Broader pipeline and portfolio SER-155 remains Phase 2 ready for the prevention of bloodstream infections in adults undergoing allo-HCT for the treatment of blood cancer, pending funding. SER-155 has received Breakthrough Therapy and Fast Track designations for this indication. Efforts continue to secure funding to advance clinical development for this program. On November 3, Seres announced that results from its Phase 1b clinical study of SER-155 in adults undergoing allo-HCT were published in Nature Medicine, marking an important milestone for the program and providing recognition of the innovative science being advanced by the Company. The publication reported that SER-155 was generally well tolerated and was associated with a 77% relative risk reduction in BSIs compared with placebo. Seres continues to progress development of SER-428, an investigational oral liquid formulation based on a subset of SER-155 strains supported by a grant from CARB-X (Combating Antibiotic-Resistant Bacteria Biopharmaceutical Accelerator), for dosing in patients who cannot take oral capsules, including critically ill patients who receive nutrition and medications via feeding tube. Seres is designing a Phase 1b open-label trial, in collaboration with Daniel E. Freedberg, M.D., M.S., of Columbia University, and in consultation with CARB-X, to evaluate SER-428 in patients with sepsis who are receiving antibiotics in the Medical Intensive Care Unit (MICU) and are at high risk of additional infection. Further clinical development of SER-428 will be progressed pending funding from grants or other sources. The Company continues to advance IND-enabling activities for SER-603, in development for inflammatory bowel disease (IBD), and is engaging potential collaborators to support the clinical advancement of this program as a mono and/or combination therapy. Corporate Updates In October, Seres received the second of the two $12.5 million payments related to the buy-out of potential future VOWST net sales-based milestones from Nestlé Health Science (Nestlé). On July 31, Seres entered into an agreement to terminate the lease for its facility at 200 Sidney Street in Cambridge, MA. The early termination materially eliminates the Company's obligations under the lease as of December 31, 2026, and results in reduced ongoing facility-related cash costs beginning in 2027. Third Quarter 2026 Financial Results Net loss was $16.3 million for the third quarter of 2026, compared to net income of $8.2 million for the same period in 2025. The difference is primarily due to a $25 million installment payment received in the third quarter of 2025 related to the sale of the VOWST business to Nestlé, recognized as a Gain on Sale. Research and development expenses were $5.6 million for the third quarter of 2026, compared with $12.6 million for the same period in 2025, reflecting lower facilities costs, transition services agreement (TSA) costs, personnel-related expenses and SER-155 costs driven by lower activities in these areas and cost reduction efforts. General and administrative expenses were $5.4 million for the third quarter of 2026, compared with $9.5 million for the same period in 2025, due to lower personnel-related expenses, facilities costs, and IT costs, including those related to IT services provided under the TSA. In the third quarter of 2026, the Company recorded a $5.7 million non-cash impairment of assets charge related to the early termination of its lease at 200 Sidney Street. Cash and Cash Runway As of September 30, 2026, Seres had $17.5 million in cash and cash equivalents. Based on Seres' currently available cash resources, including the $12.5 million payment received from Nestlé in October, and considering future operating plans, the Company expects to fund operations through the first quarter of 2027. This projection excludes proceeds from any potential future partnerships or other sources of capital. About Seres Therapeutics Seres Therapeutics, Inc. (Nasdaq: MCRB) is a clinical-stage biotechnology company developing novel live biotherapeutics products in oncology that address causes of mortality and discontinuation of life-saving cancer treatment, and in inflammatory and immune (I&I) diseases, by modulating host function to protect and improve mucosal epithelial barrier integrity, induce immune homeostasis and tolerance, and prevent the colonization and overgrowth of pathogens in the gastrointestinal (GI) tract. The Company previously led the development and FDA approval of VOWST™, the first orally administered microbiome therapeutic, which was subsequently divested to Nestlé Health Science. SER-155, an investigational cultivated multi-strain biotherapeutic, which has received Breakthrough Therapy and Fast Track designations, is being advanced for the prevention of bloodstream infections in patients undergoing allogeneic hematopoietic stem cell transplant (allo-HCT), and is Phase 2 ready, pending receipt of funding. SER-155 is also being developed to prevent immune checkpoint inhibitor-related enterocolitis (irEC), with the aim of enabling patients to continue their ICI cancer therapy and avoid the need for immunosuppressive steroid treatment. Following promising results from an investigator-sponsored trial, Seres plans to submit the design of a study for the prevention of irEC in patients initiating ICI therapy to the FDA. The Company is advancing IND-enabling studies for SER-603, which is in development for inflammatory bowel disease. Mechanistically, Seres' biotherapeutics target the mucosal epithelial barrier-immune interface and are optimized to modulate host function to increase mucosal epithelium integrity, induce immune homeostasis, and prevent the colonization and overgrowth of harmful bacteria in the GI tract. For more information, please visit Forward-Looking Statements This press release contains forward-looking statements within the meaning of the Private Securities Litigation Reform Act of 1995. All statements contained in this press release that do not relate to matters of historical fact should be considered forward-looking statements, including, without limitation, statements about: SER-155 and its intended uses and benefits in irEC; our clinical development plans for SER-155, SER-603 and SER-428, including the design and timing of the next planned study of SER-155 for the prevention of irEC; potential accessibility for patients; planned submissions to and/or engagement with regulatory authorities, including the anticipated timing of FDA feedback; the timing and results of clinical studies and data readouts; the anticipated content and timing of upcoming presentations and conferences; current or future product candidates and their potential impacts and outcomes; the size of potential patient populations and markets and the potential commercial opportunity for SER-155; engagement with potential partners and financing sources; our ability to access capital to advance our programs; IND-enabling activities; our cash runway; the anticipated effects of our lease termination, including expected reductions in facility-related costs; our planned strategic focus; the anticipated timing of any of the foregoing; and other statements that are not historical fact. These forward-looking statements are based on management's current expectations. These statements are neither promises nor guarantees, but involve known and unknown risks, uncertainties and other important factors that may cause our actual results, performance or achievements to be materially different from any future results, performance or achievements expressed or implied by the forward-looking statements, including, but not limited to, the following: (1) our need for additional funding; (2) our ability to continue as a going concern; (3) we have incurred significant losses, are not currently profitable and may never become profitable; (4) our cost reduction actions may not achieve their intended benefits, including an extended cash runway; (5) our limited operating history; (6) we may not be able to realize the anticipated benefits of the VOWST sale, and may face new challenges as a smaller, less diversified company; (7) we have in the past and may in the future receive notice of the failure to satisfy a continued listing rule from The Nasdaq Stock Market LLC; (8) our novel approach to therapeutic intervention; (9) our reliance on third parties to conduct our clinical trials and manufacture our product candidates; (10) our ability to achieve market acceptance necessary for commercial success; (11) the competition we will face; (12) our ability to protect our intellectual property; (13) impact of our recent management transitions and appointments and our ability to retain key personnel; and (14) disruptions at the FDA or other government agencies. These and other important factors discussed under the caption "Risk Factors" in our Quarterly Report on Form 10-Q for the quarterly period ended September 30, 2026, to be filed with the Securities and Exchange Commission (SEC), as well as our other reports filed with the SEC, could cause actual results to differ materially from those indicated by the forward-looking statements made in this press release. Any such forward-looking statements represent management's estimates as of the date of this press release. While we may elect to update such forward-looking statements at some point in the future, except as required by law, we disclaim any obligation to do so, even if subsequent events cause our views to change. These forward-looking statements should not be relied upon as representing our views as of any date subsequent to the date of this press release. SERES THERAPEUTICS, INC. CONDENSED CONSOLIDATED BALANCE SHEETS (unaudited, in thousands, except share and per share data) September 30, December 31, 2026 2025 Assets Current assets: Cash and cash equivalents $ 17,528 $ 45,766 Accounts receivable due from SPN - related party 12,500 360 Accounts receivable 183 157 Prepaid expenses and other current assets 4,212 3,093 Total current assets 34,423 49,376 Property and equipment, net 2,999 7,635 Operating lease assets 27,662 72,483 Restricted cash 773 8,668 Other non-current assets 31 31 Total assets $ 65,888 $ 138,193 Liabilities and Stockholders’ Equity Current liabilities: Accounts payable $ 1,461 $ 1,682 Accrued expenses and other current liabilities 3,504 3,972 Accrued liabilities due to SPN - related party 3,278 3,278 Operating lease liabilities 12,650 10,390 Total current liabilities 20,893 19,322 Operating lease liabilities, net of current portion 23,122 72,576 Other long-term liabilities 514 2,077 Total liabilities 44,529 93,975 Commitments and contingencies (Note 9) Stockholders’ equity: Preferred stock, $0.001 par value; 10,000,000 shares authorized at September 30, 2026 and December 31, 2025; no shares issued and outstanding at September 30, 2026 and December 31, 2025 — — Common stock, $0.001 par value; 360,000,000 shares authorized at September 30, 2026 and December 31, 2025; 10,049,501 and 9,556,466 shares issued and outstanding at September 30, 2026 and December 31, 2025, respectively 10 10 Additional paid-in capital 1,025,370 1,016,611 Accumulated deficit (1,004,021 ) (972,403 ) Total stockholders’ equity 21,359 44,218 Total liabilities and stockholders’ equity $ 65,888 $ 138,193 SERES THERAPEUTICS, INC. CONDENSED CONSOLIDATED STATEMENTS OF OPERATIONS AND COMPREHENSIVE (LOSS) INCOME (unaudited, in thousands, except share and per share data) Three Months Ended September 30, Nine Months Ended September 30, 2026 2025 2026 2025 Revenue: Grant revenue 593 351 1,687 351 Total revenue 593 351 1,687 351 Operating expenses: Research and development expenses 5,592 12,616 27,928 37,376 General and administrative expenses 5,448 9,476 20,579 31,617 Impairment of long-lived assets 5,705 — 11,512 — Manufacturing services — 736 — 5,952 Total operating expenses 16,745 22,828 60,019 74,945 Loss from operations (16,152 ) (22,477 ) (58,332 ) (74,594 ) Other income (expense): Gain on sale of VOWST Business — 27,222 25,000 79,588 Interest income 146 618 652 1,782 Other income (expense) (1) (280 ) 2,841 1,062 14,255 Total other income (expense), net (134 ) 30,681 26,714 95,625 Net (loss) income and comprehensive (loss) income $ (16,286 ) $ 8,204 $ (31,618 ) $ 21,031 Net (loss) income per share attributable to common stockholders - basic $ (1.63 ) $ 0.94 $ (3.24 ) $ 2.41 Net (loss) income per share attributable to common stockholders - diluted $ (1.63 ) $ 0.94 $ (3.24 ) $ 2.40 Weighted average common shares outstanding - basic 9,982,031 8,758,692 9,764,763 8,735,418 Weighted average common shares outstanding - diluted 9,982,031 8,771,519 9,764,763 8,744,797 [1] Includes $0, $0, $2,028, and $11,827 for the three and nine months ended September 30, 2026 and 2025 related to reimbursement received from SPN (related party) for transition services provided by the Company. Investor and Media Contact: IR@serestherapeutics.com Carlo Tanzi, Ph.D. Kendall Investor Relations ctanzi@kendallir.com

编者按：EV-303和EV-304研究拓展了肌层浸润性膀胱癌（MIBC）的治疗模式，将围手术期维恩妥尤单抗联合帕博利珠单抗纳入治疗方案。在2026年欧洲肿瘤内科学会（ESMO）年会上，Ⅲ期VOLGA研究公布了阳性结果：结果显示，针对顺铂不耐受的MIBC患者，与单纯根治性膀胱切除术（RC）相比，新辅助维恩妥尤单抗联合围手术期度伐利尤单抗（联合或不联合曲美木单抗）方案在主要终点无事件生存期（EFS）方面带来显著改善：中位EFS尚未达到 vs 12.1个月（HR 0.51；95%CI 0.38–0.67；P<0.0001）。 VOLGA研究速递 研究背景 对于肌层浸润性膀胱癌（MIBC）患者，临床治疗标准在不断演变。研究者评估了以下治疗方案是否有效：在新辅助阶段给予度伐利尤单抗±曲美木单抗联合维恩妥尤单抗（D±T+EV），随后进行根治性膀胱切除术（RC），并在术后给予度伐利尤单抗±曲美木单抗（D±T）辅助治疗。 研究方法 VOLGA是一项3期、随机、开放标签临床研究，纳入了MIBC患者（分期为cT2-T4aN0/1M0或cT1N1M0），这些患者不适合接受或拒绝接受顺铂治疗，且计划进行RC。患者按1:1:1的比例随机分配至D+EV组、D+T+EV组或对照组。D+EV组和D+T+EV组接受围手术期D±T治疗（新辅助阶段：3个周期的D，2个周期的T；辅助阶段：9个周期的D，1个周期的T）以及3个周期的新辅助EV治疗；在新辅助治疗后进行RC。对照组接受RC，随后进行观察或接受当地获批的辅助治疗。双重主要终点为2组的无事件生存期（EFS，D+EV组vs 对照组，D+T+EV组 vs 对照组）。OS为关键次要终点。同时评估了安全性。此处报告预先设定的期中分析结果（数据截止日期：2026年3月2日）。 △ VOLGA研究设计 研究结果 共有233例、233例和229例患者分别被随机分配至D+EV组、D+T+EV组和对照组。分别有85%（D+EV组）、79%（D+T+EV组）和78%（对照组）的患者完成了RC；此外，55%（D+EV组）和42%（D+T+EV组）的患者完成了辅助治疗。 EFS的中位随访时间为22.9个月。与对照组相比，D+EV方案在无事件生存期（EFS，HR 0.51，95% CI 0.38~0.67，P<0.0001；24个月生存率：64% vs 45%）和总生存期（OS，HR 0.58，95% CI 0.40~0.83，P=0.0027；24个月生存率：78% vs 69%）方面均显示出显著改善。D+T+EV方案在EFS方面也较对照组有显著改善（HR 0.61，95% CI 0.47~0.80，P=0.0004；24个月生存率：60% vs 45%），OS未达到统计学显著性；目前随访仍在进行。 △ VOLGA研究EFS分析 △ VOLGA研究OS分析 根据当地病理学评估，D+EV组中有45%（95% CI：38.6~51.7）的患者达到病理完全缓解，而对照组中该比例为10%（95% CI：6.1~14.2）。 △ VOLGA研究pCR分析 在D+EV组和D+T+EV组中，分别有30%和42%的患者出现了3/4级的治疗相关不良事件。 △ VOLGA研究不良事件分析 此外，研究还对ctDNA进行探索性分析。结果显示，60%基线ctDNA阳性的患者实现了ctDNA清除。 △ VOLGA研究ctDNA分析 △ VOLGA研究患者生活质量分析 研究结论 EFS的双重主要终点均已达到。围手术期使用D联合3个周期的新辅助EV治疗，与对照组相比，在OS方面也显示出显著改善。安全性特征与各药物单药治疗时的已知安全性特征一致。 研究解读 荷兰阿姆斯特丹荷兰癌症研究所Michiel van der Heijden教授在讨论中指出，VOLGA研究的结果显然是积极的，这与针对顺铂不耐受的患者群体开展的EV-303研究（评估EV联合帕博利珠单抗的疗效）结果一致。针对顺铂耐受患者群体开展的EV-304研究已经促使美国食品药品监督管理局（FDA）扩大了该联合疗法的适应症范围，将其纳入肌层浸润性膀胱癌（MIBC）的围手术期治疗。在VOLGA研究中，度伐利尤单抗联合维恩妥尤单抗的安全性特征与各药物单药治疗时的安全性特征一致。 Michiel van der Heijden教授强调，目前关于抗体偶联药物（ADC）联合免疫检查点抑制剂治疗膀胱癌的数据已相当有效且一致；相比之下，免疫检查点抑制剂联合化疗在膀胱癌治疗中的表现则缺乏一致性——本次大会上公布的一些阴性结果便印证了这一点。对于尿路上皮癌，多种具有不同靶点和载荷的ADC药物正在研发。来自中国的一项研究显示，靶向HER2的药物维迪西妥单抗展现出了令人振奋的数据；结合EV的相关数据来看，这表明维迪西妥单抗所携带的vedotin载荷在尿路上皮癌中具有特别显著的活性。Michiel van der Heijden教授提到，在尿路上皮癌中，通过抑制拓扑异构酶的ADC治疗策略，目前也有几项临床试验正在进行。 （来源：《肿瘤瞭望》编辑部） 声 明 凡署名原创的文章版权属《肿瘤瞭望》所有，欢迎分享、转载。本文仅供医疗卫生专业人士了解最新医药资讯参考使用，不代表本平台观点。该等信息不能以任何方式取代专业的医疗指导，也不应被视为诊疗建议，如果该信息被用于资讯以外的目的，本站及作者不承担相关责任。