Recruiting
Phase 1

SER-155

Sponsor:

Memorial Sloan Kettering Cancer Center

Code:

NCT06801067

Conditions

Diarrhea

Enterocolitis

Eligibility Criteria

Sex: All

Age: 18+

Healthy Volunteers: Not accepted

Interventions

SER-155

Study Details

Brief summary:

The purpose of this study is to find out whether SER-155 may be a safe first treatment that causes few or mild side effects for people due to irEC.

Conditions

Diarrhea

Enterocolitis

Study ID

NCT06801067

Start date

Jan 24, 2025

Status verified date

Jul, 2026

Completion date

Jan 24, 2027

Anticipated

Primary completion date

Jan 24, 2027

Anticipated

Eligibility Criteria

Eligibility Criteria

Sex: All

Age: 18+

Healthy Volunteers: Not accepted

Inclusion Criteria:

  • Age > 18 years
  • Receipt of ICI (single-agent or combination) within the 180 days preceding screening.

Concurrent treatment with cytotoxic chemotherapy or other tumor-directed agents is permitted.

  • Grade 2 - 3 diarrhea (i.e., increase of at least 4 bowel movements a day above baseline during the screening window), deemed by the treating provider as likely related to ICI therapy, with or without concomitant symptoms of grade 1 - 2 colitis (e.g.

abdominal pain, bloody or mucoid stools)

  • Able to swallow oral medication
  • Individuals of childbearing potential willing to use a highly effective method of contraception (failure rate of <1% per year when used consistently and correctly) for 30 days after the last dose of SER-155.
  • Willing to provide written informed consent, comply with the protocol, and understand the potential risks and benefits of study enrollment and treatment.

Exclusion Criteria:

  • Active GI infection, including untreated viral, bacterial or fungal cause(s) of diarrhea.
  • Received immunosuppressive therapies for suspected or confirmed irEC, including systemic corticosteroids (either oral or intravenous) and/or infliximab, vedolizumab or ustekinumab
  • Grade 3 colitis symptoms, i.e. severe abdominal pain or peritoneal signs
  • Admitted to the hospital for irEC
  • Prednisone (or steroid equivalent) dose > 10 mg a day for a non-GI irAE at time of screening
  • Pre-existing inflammatory bowel disease (e.g. Crohn's disease or ulcerative colitis) or microscopic colitis
  • Pregnant or lactating women
  • Any condition that requires ongoing prophylactic or therapeutic antibacterial antibiotics
  • Severe neutropenia, as defined by an absolute neutrophil count (ANC) < 500 cells/mm\^3, at time of screening
  • Treatment with investigational medications used for diarrhea/colitis treatment and microbiome therapeutics within 30 days prior to enrollment
  • Known allergy or intolerance to oral vancomycin
  • Unable to comply with the protocol requirements
  • Any condition that in the opinion of the investigator may increase the risk of study participation and/or may interfere with the interpretation of study results

Study Design

Enrollment

15 participants

Anticipated

Intervention Model

Single group

Primary purpose

Treatment

Interventions and Outcome Measures

Arms

experimental: Participants with Immune checkpoint inhibitor-related enterocolitis (irEC)

Participants with grade 2-3 diarrhea from irEC who have not yet received immunosuppressive therapy for irEC

Interventions

SER-155

SER-155 (Cultivated Multi-Strain Live Bacterial Therapeutic, Encapsulated) is an experimental designed ecology of 16 unique, human-commensal bacterial strains encapsulated for oral administration and will be provided by Seres as an investigational drug

Primary outcome measure

  • Proportion of participants with treatment-related adverse events of special interest [ Time Frame: 1 year ]
  • Proportion of patients with treatment-related adverse events [ Time Frame: 1 year ]

Central Contacts and Locations

Central contacts

David Faleck, MD

212-639-8286faleckd@mskcc.org

Michael Postow, MD

646-888-4315PostowM@mskcc.org

Locations

Memoral Sloan Kettering at Basking Ridge (Limited Protocol Activities)

Recruiting

Basking Ridge, New Jersey, United States, 07920

Contacts

David Faleck, MD

212-639-8286

Memorial Sloan Kettering Monmouth (All Protocol Activities)

Recruiting

Middletown, New Jersey, United States, 07748

Contacts

David Faleck, MD

212-639-8286

Memorial Sloan Kettering Bergen (All Protocol Activities)

Recruiting

Montvale, New Jersey, United States, 07645

Contacts

David Faleck, MD

212-639-8286

Memorial Sloan Kettering Suffolk-Commack (Limited protocol activity)

Recruiting

Commack, New York, United States, 11725

Contacts

David Faleck, MD

212-639-8286

Memorial Sloan Kettering Westchester (Limited Protocol Activities)

Recruiting

Harrison, New York, United States, 10604

Contacts

David Faleck, MD

212-639-8286

Memorial Sloan Kettering Cancer Center (All Protocol Activities)

Recruiting

New York, New York, United States, 10065

Contacts

David Faleck, MD

212-639-8286

Memorial Sloan Kettering Nassau (Limited protocol activities)

Recruiting

Rockville Centre, New York, United States, 11553

Contacts

David Faleck, MD

212-639-8286

More Information

Sponsor

Memorial Sloan Kettering Cancer Center

Last update posted

Jul 28, 2026

Last verified

Jul, 2026

Keywords

  • Diarrhea
  • SER-155
  • Enterocolitis
  • Memorial Sloan Kettering Cancer Center
  • 24-231

Trial information was received from ClinicalTrials.gov and was last updated on 2026-09-10. This information was provided to ClinicalTrials.gov by Memorial Sloan Kettering Cancer Center on 2026-07-28.