A Study to Assess Efficacy and Safety of SER-287 in Adults With Active Mild-to-Moderate Ulcerative Colitis (ECO-RESET)
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ClinicalTrials.gov Identifier: NCT03759041 |
Recruitment Status :
Terminated
(Due to the lack of a clinical efficacy signal in the induction treatment phase, Seres closed the dosing phases of open label and maintenance portions of the study. Patients who had received prior doses were followed for safety data.)
First Posted : November 29, 2018
Results First Posted : June 21, 2022
Last Update Posted : August 12, 2022
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Condition or disease | Intervention/treatment | Phase |
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Ulcerative Colitis | Drug: Vancomycin Pre-Treatment Drug: Placebo for Vancomycin Pre-Treatment Drug: SER-287 Drug: Placebo for SER-287 | Phase 2 |
Study Type : | Interventional (Clinical Trial) |
Actual Enrollment : | 203 participants |
Allocation: | Randomized |
Intervention Model: | Parallel Assignment |
Masking: | Triple (Participant, Investigator, Outcomes Assessor) |
Primary Purpose: | Treatment |
Official Title: | ECO-RESET: A Phase 2B, Randomized, Double-Blind, Placebo-Controlled, Multiple Dose, Multicenter Study to Assess Efficacy and Safety of SER-287 in Adults With Active Mild-to-Moderate Ulcerative Colitis |
Actual Study Start Date : | December 19, 2018 |
Actual Primary Completion Date : | May 28, 2021 |
Actual Study Completion Date : | October 13, 2021 |

Arm | Intervention/treatment |
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Placebo Comparator: Placebo (after placebo pre-treatment)
Once-daily dosing of Placebo (after placebo pre-treatment)
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Drug: Placebo for Vancomycin Pre-Treatment
Four times per day dosing of placebo pre-treatment Drug: Placebo for SER-287 Once-daily dosing of Placebo for SER-287 |
Experimental: SER-287 Induction Dosing (after vancomycin pre-treatment)
Once-daily dosing of SER-287 (Induction Dose, after vancomycin pre-treatment)
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Drug: Vancomycin Pre-Treatment
Four times per day dosing of vancomycin pre-treatment Drug: SER-287 Once-daily dosing of SER-287
Other Name: Eubacterial Spores, Purified Suspension, Encapsulated |
Experimental: SER-287 Step-Down Induction Dosing (after vancomycin pre-treatment)
Once-daily dosing of SER-287 (Step-Down Induction Dose, after vancomycin pre-treatment)
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Drug: Vancomycin Pre-Treatment
Four times per day dosing of vancomycin pre-treatment Drug: SER-287 Once-daily dosing of SER-287
Other Name: Eubacterial Spores, Purified Suspension, Encapsulated |
- Clinical Remission (Count of Participants) [ Time Frame: After 10 weeks of induction dosing ]
Clinical remission for the induction treatment period:
- Stool Frequency subscore = 0 or 1, with at least 1-point decrease from baseline
- Rectal Bleeding subscore = 0
- Endoscopic subscore = 0 or 1 on modified Mayo Score, with at least 1-point decrease from baseline
- No occurrence of UC Flare during the treatment period
Clinical remission was measured using 3 components of the modified Mayo Score (stool frequency, rectal bleeding and endoscopic subscore), a measure of UC disease activity. These 3 components are each graded from 0 to 3, and are summed together for a composite score, with a higher overall score indicating more severe disease (0 = no disease; 9 = worst disease). The modified Mayo endoscopic subscore excludes friability from an endoscopic subscore of 1.
- Endoscopic Improvement (Count of Participants) [ Time Frame: After 10 weeks of induction dosing ]
Endoscopic subscore decrease from baseline of at least 1 point, as assessed by flexible sigmoidoscopy or colonoscopy.
Endoscopic improvement was measured using the modified Mayo Score endoscopic subscore, graded from 0 to 3, with higher scores indicating more severe disease. The modified Mayo endoscopic subscore excludes friability from an endoscopic subscore of 1.

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Ages Eligible for Study: | 18 Years to 80 Years (Adult, Older Adult) |
Sexes Eligible for Study: | All |
Accepts Healthy Volunteers: | No |
Inclusion Criteria:
- Documented diagnosis of UC at least three months prior to screening, and with a minimum disease extent of 15 cm from the anal verge
- Active mild-to-moderate UC
- Inadequate response to, loss of response to, or intolerance of, at least one of the following conventional therapies: 5-ASA compounds, corticosteroids, 6-mercaptopurine (6-MP) or azathioprine (AZA), anti-TNFα, anti-integrin or tofacitinib
Exclusion Criteria:
- Known history of Crohn's disease
- No previous history of treatment for UC (treatment-naïve)
- Subjects on steroid medication who are unable to have steroids tapered and be completely off steroids at least two weeks prior to screening
- Unable to stop steroid enemas or suppositories, or 5-ASA enemas or suppositories, at least two weeks prior to screening
- Subjects who have received any investigational or approved biologic therapy within eight weeks or five half-lives prior to screening (whichever is longer)
- Subjects who have received any investigational or approved non-biologic therapy, except for those specifically listed in the Permitted Concomitant Medications, for the treatment of underlying disease, within 30 days or five half-lives prior to screening (whichever is longer)
- Major gastrointestinal surgery (not including appendectomy or cholecystectomy) within two months before screening, or any history of total colectomy

To learn more about this study, you or your doctor may contact the study research staff using the contact information provided by the sponsor.
Please refer to this study by its ClinicalTrials.gov identifier (NCT number): NCT03759041

Study Director: | Lisa von Moltke, MD | Seres Therapeutics, Inc. |
Documents provided by Seres Therapeutics, Inc.:
Responsible Party: | Seres Therapeutics, Inc. |
ClinicalTrials.gov Identifier: | NCT03759041 |
Other Study ID Numbers: |
SERES-201 |
First Posted: | November 29, 2018 Key Record Dates |
Results First Posted: | June 21, 2022 |
Last Update Posted: | August 12, 2022 |
Last Verified: | July 2022 |
Studies a U.S. FDA-regulated Drug Product: | Yes |
Studies a U.S. FDA-regulated Device Product: | No |
microbiome |
Colitis Colitis, Ulcerative Ulcer Gastroenteritis Gastrointestinal Diseases Digestive System Diseases Colonic Diseases |
Intestinal Diseases Pathologic Processes Inflammatory Bowel Diseases Vancomycin Anti-Bacterial Agents Anti-Infective Agents |