活体生物药SER-155使移植患者血流感染相对风险降低77%：1b期结果登上《自然·医学》
总部位于马萨诸塞州 Cambridge 的生物科技公司 Seres Therapeutics（纳斯达克代码：MCRB）11月3日宣布，其在研口服活体生物药 SER-155 用于接受异基因造血细胞移植（allo-HCT）成人患者的 1b 期临床研究结果，已刊登于11月3日出版的医学期刊《自然·医学》（Nature Medicine）。该药旨在降低免疫功能脆弱患者的血流感染风险。
这项研究（编号 NCT04995653）分为两个队列：队列1为开放标签，评估安全性与药物药理；队列2为随机、双盲、安慰剂对照，评估移植后100天内的血流感染、全身抗生素暴露与发热性中性粒细胞减少等临床结局。
队列2数据显示，用药组血流感染发生率为 10%，安慰剂组为 42.9%，相对风险降低 77%（p=0.0423）；用药组全身抗生素暴露显著更低，平均 9.2 天对安慰剂组 21.1 天（p=0.0494）；发热性中性粒细胞减少发生率也较低，为 65% 对 78.6%。SER-155 菌株在受试者胃肠道内成功定植，药物总体耐受良好，未观察到与治疗相关的严重不良事件。
公司称，转化生物标志物分析支持该药的作用机制：许多移植患者的血流感染源于肠道，病原体在受损的肠黏膜屏障处扩增并进入血液；SER-155 一方面抑制病原体在胃肠道定植扩增，另一方面保护并改善黏膜上皮屏障完整性。用药组粪便白蛋白（上皮屏障完整性标志物）显著下降，全身炎症标志物水平也更低。
Seres 总裁兼首席科学官 Matthew Henn 表示，在《自然·医学》发表是 SER-155 项目的重要里程碑；该活体生物药疗法还有潜力应对免疫功能低下患者中持续出现的抗微生物药物耐药感染。公司执行董事长兼临时首席执行官 Richard Kender 表示，这组经同行评审的结果强化了公司对该药预防血流感染潜力的信心。
SER-155 已获美国食品药品监管局（FDA）突破性疗法认定与快速通道认定，用于降低异基因造血细胞移植患者的血流感染风险；公司已与 FDA 就拟议的 2 期研究方案达成一致，该药在这一适应症上已准备进入 2 期，待资金到位。公司同时还在开发 SER-155 用于免疫检查点抑制剂相关肠炎，今年7月公布的一组研究者发起试验中，15 名患者有 12 名在第15天达到无免疫抑制治疗的临床应答。
（来源：Seres Therapeutics）
Live Biotherapeutic SER-155 Cut Bloodstream Infection Risk by 77% in Transplant Patients: Phase 1b Results Published in Nature Medicine
Seres Therapeutics, Inc. (Nasdaq: MCRB), a live biotherapeutics company based in Cambridge, Massachusetts, announced on November 3 that results from its Phase 1b clinical study of SER-155 in adults undergoing allogeneic hematopoietic cell transplantation (allo-HCT) have been published in the November 3, 2026 issue of Nature Medicine. SER-155 is an investigational, oral, cultivated multi-strain live biotherapeutic product designed to reduce the risk of bloodstream infections (BSIs) in medically vulnerable patients.
The Phase 1b study (NCT04995653) had two cohorts: an open-label cohort assessing safety and drug pharmacology, and a randomized, double-blind, placebo-controlled cohort evaluating safety, drug pharmacology and clinical outcomes, including BSIs, systemic antibiotic exposure and febrile neutropenia, through day 100 after transplant.
In Cohort 2, BSIs occurred in 10% of patients receiving SER-155 compared with 42.9% of patients receiving placebo, a 77% relative risk reduction (p=0.0423). Patients receiving SER-155 also had significantly lower systemic antibiotic exposure, a mean of 9.2 days compared with 21.1 days for placebo (p=0.0494), and a numerically lower incidence of febrile neutropenia, 65% compared with 78.6%. SER-155 strains engrafted in the gastrointestinal tract, and the product was generally well tolerated, with no treatment-related serious adverse events observed.
Translational biomarker analyses support the drug's mechanisms, the company said: many bloodstream infections in transplant patients originate in the gut, when pathogens expand and cross a damaged intestinal barrier. Compared with placebo, SER-155 led to a statistically significant decrease in fecal albumin, an established biomarker of epithelial barrier integrity, and lower plasma levels of biomarkers of systemic inflammation.
"Publication in Nature Medicine is an important milestone for the SER-155 program and recognition of the innovative science being advanced by Seres," said Matthew Henn, Ph.D., president and chief scientific officer of Seres Therapeutics. Executive chairman and interim chief executive officer Richard Kender said the peer-reviewed results reinforce the company's belief in SER-155's potential to prevent bloodstream infections in immunocompromised patients such as allo-HCT recipients.
SER-155 has received Breakthrough Therapy designation from the U.S. Food and Drug Administration (FDA) for the reduction of BSIs in adults undergoing allo-HCT, as well as Fast Track designation, and the company has aligned with the FDA on its proposed Phase 2 study protocol; the program is Phase 2-ready in allo-HCT, pending receipt of funding. Seres is also developing SER-155 for immune checkpoint inhibitor-related enterocolitis, where a July 2026 investigator-sponsored trial at Memorial Sloan Kettering Cancer Center reported that 12 of 15 patients achieved an immunosuppressive-free clinical response at day 15.
(Source: Seres Therapeutics)
来源：Seres Therapeutics
发布：GSM·美国（发布链接）
图片来源：图：实验室人员检查血液样本（资料图）。National Eye Institute / Rhoda Baer Photography，CC BY 2.0，经 Wikimedia Commons。 / Photo: A laboratory worker examines a blood sample (file photo). National Eye Institute / Rhoda Baer Photography, CC BY 2.0, via Wikimedia Commons.
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